configure
aclocal.m4
autom4te.cache/
-config.h
+/config.h
+/include/ust/config.h
/config.h.in
config/
config.log
* Dual LGPL v2.1/GPL v2 license.
*/
+#define BUILD_BUG_ON(condition) \
+ ((void) sizeof(char[-!!(condition)]))
+
/**
* BUILD_RUNTIME_BUG_ON - check condition at build (if constant) or runtime
* @condition: the condition which should be false.
#include <sys/types.h>
#include <ust/config.h>
+#include <urcu/arch.h>
#define likely(x) __builtin_expect(!!(x), 1)
#define unlikely(x) __builtin_expect(!!(x), 0)
ust_safe_snprintf(____buf, sizeof(____buf), fmt, ## args); \
\
/* Add end of string in case of buffer overflow. */ \
- ____buf[sizeof(____buf)-1] = 0; \
+ ____buf[sizeof(____buf) - 1] = 0; \
\
patient_write(STDERR_FILENO, ____buf, strlen(____buf)); \
/* Can't print errors because we are in the error printing code path. */ \
lib_LTLIBRARIES = libringbuffer.la
+noinst_HEADERS = \
+ smp.h
+
libringbuffer_la_SOURCES = \
+ smp.c \
ring_buffer_backend.c \
- ring_buffer_frontend.c \
- ring_buffer_abi.c
+ ring_buffer_frontend.c
libringbuffer_la_LDFLAGS = -no-undefined -version-info 0:0:0
extern int lib_ring_buffer_read_cstr(struct lib_ring_buffer_backend *bufb,
size_t offset, void *dest, size_t len);
-extern struct page **
-lib_ring_buffer_read_get_page(struct lib_ring_buffer_backend *bufb, size_t offset,
- void ***virt);
-
/*
* Return the address where a given offset is located.
* Should be used to get the current subbuffer header pointer. Given we know
{
struct lib_ring_buffer_backend *bufb = &ctx->buf->backend;
struct channel_backend *chanb = &ctx->chan->backend;
- size_t sbidx, index;
+ size_t sbidx;
size_t offset = ctx->buf_offset;
- ssize_t pagecpy;
struct lib_ring_buffer_backend_pages *rpages;
unsigned long sb_bindex, id;
offset &= chanb->buf_size - 1;
sbidx = offset >> chanb->subbuf_size_order;
- index = (offset & (chanb->subbuf_size - 1)) >> get_count_order(PAGE_SIZE);
- pagecpy = min_t(size_t, len, (-offset) & ~PAGE_MASK);
- id = bufb->buf_wsb[sbidx].id;
+ id = shmp(bufb->buf_wsb)[sbidx].id;
sb_bindex = subbuffer_id_get_index(config, id);
- rpages = bufb->array[sb_bindex];
+ rpages = shmp(bufb->array)[sb_bindex];
CHAN_WARN_ON(ctx->chan,
config->mode == RING_BUFFER_OVERWRITE
&& subbuffer_id_is_noref(config, id));
- if (likely(pagecpy == len))
- lib_ring_buffer_do_copy(config,
- rpages->p[index].virt
- + (offset & ~PAGE_MASK),
- src, len);
- else
- _lib_ring_buffer_write(bufb, offset, src, len, 0);
+ /*
+ * Underlying layer should never ask for writes across
+ * subbuffers.
+ */
+ CHAN_WARN_ON(chanb, offset >= chanb->buf_size);
+ lib_ring_buffer_do_copy(config,
+ shmp(rpages->p) + (offset & ~(chanb->subbuf_size - 1)),
+ src, len);
ctx->buf_offset += len;
}
unsigned long records_unread = 0, sb_bindex, id;
unsigned int i;
- for (i = 0; i < bufb->chan->backend.num_subbuf; i++) {
- id = bufb->buf_wsb[i].id;
+ for (i = 0; i < shmp(bufb->chan)->backend.num_subbuf; i++) {
+ id = shmp(bufb->buf_wsb)[i].id;
sb_bindex = subbuffer_id_get_index(config, id);
- pages = bufb->array[sb_bindex];
+ pages = shmp(bufb->array)[sb_bindex];
records_unread += v_read(config, &pages->records_unread);
}
if (config->mode == RING_BUFFER_OVERWRITE) {
id = bufb->buf_rsb.id;
sb_bindex = subbuffer_id_get_index(config, id);
- pages = bufb->array[sb_bindex];
+ pages = shmp(bufb->array)[sb_bindex];
records_unread += v_read(config, &pages->records_unread);
}
return records_unread;
#include "config.h"
#include "backend_types.h"
#include "frontend_types.h"
+#include "shm.h"
/* Ring buffer backend API presented to the frontend */
/* Ring buffer and channel backend create/free */
int lib_ring_buffer_backend_create(struct lib_ring_buffer_backend *bufb,
- struct channel_backend *chan, int cpu);
+ struct channel_backend *chan, int cpu,
+ struct shm_header *shm_header);
void channel_backend_unregister_notifiers(struct channel_backend *chanb);
void lib_ring_buffer_backend_free(struct lib_ring_buffer_backend *bufb);
int channel_backend_init(struct channel_backend *chanb,
const char *name,
const struct lib_ring_buffer_config *config,
void *priv, size_t subbuf_size,
- size_t num_subbuf);
+ size_t num_subbuf, struct shm_header *shm_header);
void channel_backend_free(struct channel_backend *chanb);
void lib_ring_buffer_backend_reset(struct lib_ring_buffer_backend *bufb);
{
unsigned long sb_bindex;
- sb_bindex = subbuffer_id_get_index(config, bufb->buf_wsb[idx].id);
- v_inc(config, &bufb->array[sb_bindex]->records_commit);
+ sb_bindex = subbuffer_id_get_index(config, shmp(bufb->buf_wsb)[idx].id);
+ v_inc(config, &shmp(bufb->array)[sb_bindex]->records_commit);
}
/*
sb_bindex = subbuffer_id_get_index(config, bufb->buf_rsb.id);
CHAN_WARN_ON(bufb->chan,
- !v_read(config, &bufb->array[sb_bindex]->records_unread));
+ !v_read(config, &shmp(bufb->array)[sb_bindex]->records_unread));
/* Non-atomic decrement protected by exclusive subbuffer access */
- _v_dec(config, &bufb->array[sb_bindex]->records_unread);
+ _v_dec(config, &shmp(bufb->array)[sb_bindex]->records_unread);
v_inc(config, &bufb->records_read);
}
{
unsigned long sb_bindex;
- sb_bindex = subbuffer_id_get_index(config, bufb->buf_wsb[idx].id);
- return v_read(config, &bufb->array[sb_bindex]->records_commit);
+ sb_bindex = subbuffer_id_get_index(config, shmp(bufb->buf_wsb)[idx].id);
+ return v_read(config, &shmp(bufb->array)[sb_bindex]->records_commit);
}
/*
struct lib_ring_buffer_backend_pages *pages;
unsigned long overruns, sb_bindex;
- sb_bindex = subbuffer_id_get_index(config, bufb->buf_wsb[idx].id);
- pages = bufb->array[sb_bindex];
+ sb_bindex = subbuffer_id_get_index(config, shmp(bufb->buf_wsb)[idx].id);
+ pages = shmp(bufb->array)[sb_bindex];
overruns = v_read(config, &pages->records_unread);
v_set(config, &pages->records_unread,
v_read(config, &pages->records_commit));
struct lib_ring_buffer_backend_pages *pages;
unsigned long sb_bindex;
- sb_bindex = subbuffer_id_get_index(config, bufb->buf_wsb[idx].id);
- pages = bufb->array[sb_bindex];
+ sb_bindex = subbuffer_id_get_index(config, shmp(bufb->buf_wsb)[idx].id);
+ pages = shmp(bufb->array)[sb_bindex];
pages->data_size = data_size;
}
unsigned long sb_bindex;
sb_bindex = subbuffer_id_get_index(config, bufb->buf_rsb.id);
- pages = bufb->array[sb_bindex];
+ pages = shmp(bufb->array)[sb_bindex];
return pages->data_size;
}
struct lib_ring_buffer_backend_pages *pages;
unsigned long sb_bindex;
- sb_bindex = subbuffer_id_get_index(config, bufb->buf_wsb[idx].id);
- pages = bufb->array[sb_bindex];
+ sb_bindex = subbuffer_id_get_index(config, shmp(bufb->buf_wsb)[idx].id);
+ pages = shmp(bufb->array)[sb_bindex];
return pages->data_size;
}
* Performing a volatile access to read the sb_pages, because we want to
* read a coherent version of the pointer and the associated noref flag.
*/
- id = CMM_ACCESS_ONCE(bufb->buf_wsb[idx].id);
+ id = CMM_ACCESS_ONCE(shmp(bufb->buf_wsb)[idx].id);
for (;;) {
/* This check is called on the fast path for each record. */
if (likely(!subbuffer_id_is_noref(config, id))) {
}
new_id = id;
subbuffer_id_clear_noref(config, &new_id);
- new_id = uatomic_cmpxchg(&bufb->buf_wsb[idx].id, id, new_id);
+ new_id = uatomic_cmpxchg(&shmp(bufb->buf_wsb)[idx].id, id, new_id);
if (likely(new_id == id))
break;
id = new_id;
* readers of the noref flag.
*/
CHAN_WARN_ON(bufb->chan,
- subbuffer_id_is_noref(config, bufb->buf_wsb[idx].id));
+ subbuffer_id_is_noref(config, shmp(bufb->buf_wsb)[idx].id));
/*
* Memory barrier that ensures counter stores are ordered before set
* noref and offset.
*/
cmm_smp_mb();
- subbuffer_id_set_noref_offset(config, &bufb->buf_wsb[idx].id, offset);
+ subbuffer_id_set_noref_offset(config, &shmp(bufb->buf_wsb)[idx].id, offset);
}
/**
* old_wpage, because the value read will be confirmed by the
* following cmpxchg().
*/
- old_id = bufb->buf_wsb[consumed_idx].id;
+ old_id = shmp(bufb->buf_wsb)[consumed_idx].id;
if (unlikely(!subbuffer_id_is_noref(config, old_id)))
return -EAGAIN;
/*
!subbuffer_id_is_noref(config, bufb->buf_rsb.id));
subbuffer_id_set_noref_offset(config, &bufb->buf_rsb.id,
consumed_count);
- new_id = uatomic_cmpxchg(&bufb->buf_wsb[consumed_idx].id, old_id,
+ new_id = uatomic_cmpxchg(&shmp(bufb->buf_wsb)[consumed_idx].id, old_id,
bufb->buf_rsb.id);
if (unlikely(old_id != new_id))
return -EAGAIN;
bufb->buf_rsb.id = new_id;
} else {
/* No page exchange, use the writer page directly */
- bufb->buf_rsb.id = bufb->buf_wsb[consumed_idx].id;
+ bufb->buf_rsb.id = shmp(bufb->buf_wsb)[consumed_idx].id;
}
return 0;
}
* Dual LGPL v2.1/GPL v2 license.
*/
-struct lib_ring_buffer_backend_page {
- void *virt; /* page virtual address (cached) */
- struct page *page; /* pointer to page structure */
-};
+#include "shm.h"
struct lib_ring_buffer_backend_pages {
unsigned long mmap_offset; /* offset of the subbuffer in mmap */
union v_atomic records_commit; /* current records committed count */
union v_atomic records_unread; /* records to read */
unsigned long data_size; /* Amount of data to read from subbuf */
- struct lib_ring_buffer_backend_page p[];
+ DECLARE_SHMP(char, p); /* Backing memory map */
};
struct lib_ring_buffer_backend_subbuffer {
struct lib_ring_buffer_backend {
/* Array of ring_buffer_backend_subbuffer for writer */
- struct lib_ring_buffer_backend_subbuffer *buf_wsb;
+ DECLARE_SHMP(struct lib_ring_buffer_backend_subbuffer, buf_wsb);
/* ring_buffer_backend_subbuffer for reader */
struct lib_ring_buffer_backend_subbuffer buf_rsb;
/*
* Pointer array of backend pages, for whole buffer.
* Indexed by ring_buffer_backend_subbuffer identifier (id) index.
*/
- struct lib_ring_buffer_backend_pages **array;
- unsigned int num_pages_per_subbuf;
+ DECLARE_SHMP(struct lib_ring_buffer_backend_pages *, array);
+ DECLARE_SHMP(char, memory_map); /* memory mapping */
- struct channel *chan; /* Associated channel */
+ DECLARE_SHMP(struct channel, chan); /* Associated channel */
int cpu; /* This buffer's cpu. -1 if global. */
union v_atomic records_read; /* Number of records read */
unsigned int allocated:1; /* Bool: is buffer allocated ? */
*/
unsigned int buf_size_order; /* Order of buffer size */
int extra_reader_sb:1; /* Bool: has extra reader subbuffer */
- struct lib_ring_buffer *buf; /* Channel per-cpu buffers */
-
+ DECLARE_SHMP(struct lib_ring_buffer, buf); /* Channel per-cpu buffers */
unsigned long num_subbuf; /* Number of sub-buffers for writer */
u64 start_tsc; /* Channel creation TSC value */
void *priv; /* Client-specific information */
--- /dev/null
+#ifndef _LINUX_RING_BUFFER_CONFIG_H
+#define _LINUX_RING_BUFFER_CONFIG_H
+
+/*
+ * linux/ringbuffer/config.h
+ *
+ * Copyright (C) 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * Ring buffer configuration header. Note: after declaring the standard inline
+ * functions, clients should also include linux/ringbuffer/api.h.
+ *
+ * Dual LGPL v2.1/GPL v2 license.
+ */
+
+#include <errno.h>
+#include "ust/kcompat/kcompat.h"
+#include "ust/align.h"
+
+struct lib_ring_buffer;
+struct channel;
+struct lib_ring_buffer_config;
+struct lib_ring_buffer_ctx;
+
+/*
+ * Ring buffer client callbacks. Only used by slow path, never on fast path.
+ * For the fast path, record_header_size(), ring_buffer_clock_read() should be
+ * provided as inline functions too. These may simply return 0 if not used by
+ * the client.
+ */
+struct lib_ring_buffer_client_cb {
+ /* Mandatory callbacks */
+
+ /* A static inline version is also required for fast path */
+ u64 (*ring_buffer_clock_read) (struct channel *chan);
+ size_t (*record_header_size) (const struct lib_ring_buffer_config *config,
+ struct channel *chan, size_t offset,
+ size_t *pre_header_padding,
+ struct lib_ring_buffer_ctx *ctx);
+
+ /* Slow path only, at subbuffer switch */
+ size_t (*subbuffer_header_size) (void);
+ void (*buffer_begin) (struct lib_ring_buffer *buf, u64 tsc,
+ unsigned int subbuf_idx);
+ void (*buffer_end) (struct lib_ring_buffer *buf, u64 tsc,
+ unsigned int subbuf_idx, unsigned long data_size);
+
+ /* Optional callbacks (can be set to NULL) */
+
+ /* Called at buffer creation/finalize */
+ int (*buffer_create) (struct lib_ring_buffer *buf, void *priv,
+ int cpu, const char *name);
+ /*
+ * Clients should guarantee that no new reader handle can be opened
+ * after finalize.
+ */
+ void (*buffer_finalize) (struct lib_ring_buffer *buf, void *priv, int cpu);
+
+ /*
+ * Extract header length, payload length and timestamp from event
+ * record. Used by buffer iterators. Timestamp is only used by channel
+ * iterator.
+ */
+ void (*record_get) (const struct lib_ring_buffer_config *config,
+ struct channel *chan, struct lib_ring_buffer *buf,
+ size_t offset, size_t *header_len,
+ size_t *payload_len, u64 *timestamp);
+};
+
+/*
+ * Ring buffer instance configuration.
+ *
+ * Declare as "static const" within the client object to ensure the inline fast
+ * paths can be optimized.
+ *
+ * alloc/sync pairs:
+ *
+ * RING_BUFFER_ALLOC_PER_CPU and RING_BUFFER_SYNC_PER_CPU :
+ * Per-cpu buffers with per-cpu synchronization. Tracing must be performed
+ * with preemption disabled (lib_ring_buffer_get_cpu() and
+ * lib_ring_buffer_put_cpu()).
+ *
+ * RING_BUFFER_ALLOC_PER_CPU and RING_BUFFER_SYNC_GLOBAL :
+ * Per-cpu buffer with global synchronization. Tracing can be performed with
+ * preemption enabled, statistically stays on the local buffers.
+ *
+ * RING_BUFFER_ALLOC_GLOBAL and RING_BUFFER_SYNC_PER_CPU :
+ * Should only be used for buffers belonging to a single thread or protected
+ * by mutual exclusion by the client. Note that periodical sub-buffer switch
+ * should be disabled in this kind of configuration.
+ *
+ * RING_BUFFER_ALLOC_GLOBAL and RING_BUFFER_SYNC_GLOBAL :
+ * Global shared buffer with global synchronization.
+ *
+ * wakeup:
+ *
+ * RING_BUFFER_WAKEUP_BY_TIMER uses per-cpu deferrable timers to poll the
+ * buffers and wake up readers if data is ready. Mainly useful for tracers which
+ * don't want to call into the wakeup code on the tracing path. Use in
+ * combination with "read_timer_interval" channel_create() argument.
+ *
+ * RING_BUFFER_WAKEUP_BY_WRITER directly wakes up readers when a subbuffer is
+ * ready to read. Lower latencies before the reader is woken up. Mainly suitable
+ * for drivers.
+ *
+ * RING_BUFFER_WAKEUP_NONE does not perform any wakeup whatsoever. The client
+ * has the responsibility to perform wakeups.
+ */
+struct lib_ring_buffer_config {
+ enum {
+ RING_BUFFER_ALLOC_PER_CPU,
+ RING_BUFFER_ALLOC_GLOBAL,
+ } alloc;
+ enum {
+ RING_BUFFER_SYNC_PER_CPU, /* Wait-free */
+ RING_BUFFER_SYNC_GLOBAL, /* Lock-free */
+ } sync;
+ enum {
+ RING_BUFFER_OVERWRITE, /* Overwrite when buffer full */
+ RING_BUFFER_DISCARD, /* Discard when buffer full */
+ } mode;
+ enum {
+ RING_BUFFER_SPLICE,
+ RING_BUFFER_MMAP,
+ RING_BUFFER_READ, /* TODO */
+ RING_BUFFER_ITERATOR,
+ RING_BUFFER_NONE,
+ } output;
+ enum {
+ RING_BUFFER_PAGE,
+ RING_BUFFER_VMAP, /* TODO */
+ RING_BUFFER_STATIC, /* TODO */
+ } backend;
+ enum {
+ RING_BUFFER_NO_OOPS_CONSISTENCY,
+ RING_BUFFER_OOPS_CONSISTENCY,
+ } oops;
+ enum {
+ RING_BUFFER_IPI_BARRIER,
+ RING_BUFFER_NO_IPI_BARRIER,
+ } ipi;
+ enum {
+ RING_BUFFER_WAKEUP_BY_TIMER, /* wake up performed by timer */
+ RING_BUFFER_WAKEUP_BY_WRITER, /*
+ * writer wakes up reader,
+ * not lock-free
+ * (takes spinlock).
+ */
+ } wakeup;
+ /*
+ * tsc_bits: timestamp bits saved at each record.
+ * 0 and 64 disable the timestamp compression scheme.
+ */
+ unsigned int tsc_bits;
+ struct lib_ring_buffer_client_cb cb;
+};
+
+/*
+ * ring buffer context
+ *
+ * Context passed to lib_ring_buffer_reserve(), lib_ring_buffer_commit(),
+ * lib_ring_buffer_try_discard_reserve(), lib_ring_buffer_align_ctx() and
+ * lib_ring_buffer_write().
+ */
+struct lib_ring_buffer_ctx {
+ /* input received by lib_ring_buffer_reserve(), saved here. */
+ struct channel *chan; /* channel */
+ void *priv; /* client private data */
+ size_t data_size; /* size of payload */
+ int largest_align; /*
+ * alignment of the largest element
+ * in the payload
+ */
+ int cpu; /* processor id */
+
+ /* output from lib_ring_buffer_reserve() */
+ struct lib_ring_buffer *buf; /*
+ * buffer corresponding to processor id
+ * for this channel
+ */
+ size_t slot_size; /* size of the reserved slot */
+ unsigned long buf_offset; /* offset following the record header */
+ unsigned long pre_offset; /*
+ * Initial offset position _before_
+ * the record is written. Positioned
+ * prior to record header alignment
+ * padding.
+ */
+ u64 tsc; /* time-stamp counter value */
+ unsigned int rflags; /* reservation flags */
+};
+
+/**
+ * lib_ring_buffer_ctx_init - initialize ring buffer context
+ * @ctx: ring buffer context to initialize
+ * @chan: channel
+ * @priv: client private data
+ * @data_size: size of record data payload
+ * @largest_align: largest alignment within data payload types
+ * @cpu: processor id
+ */
+static inline
+void lib_ring_buffer_ctx_init(struct lib_ring_buffer_ctx *ctx,
+ struct channel *chan, void *priv,
+ size_t data_size, int largest_align,
+ int cpu)
+{
+ ctx->chan = chan;
+ ctx->priv = priv;
+ ctx->data_size = data_size;
+ ctx->largest_align = largest_align;
+ ctx->cpu = cpu;
+ ctx->rflags = 0;
+}
+
+/*
+ * Reservation flags.
+ *
+ * RING_BUFFER_RFLAG_FULL_TSC
+ *
+ * This flag is passed to record_header_size() and to the primitive used to
+ * write the record header. It indicates that the full 64-bit time value is
+ * needed in the record header. If this flag is not set, the record header needs
+ * only to contain "tsc_bits" bit of time value.
+ *
+ * Reservation flags can be added by the client, starting from
+ * "(RING_BUFFER_FLAGS_END << 0)". It can be used to pass information from
+ * record_header_size() to lib_ring_buffer_write_record_header().
+ */
+#define RING_BUFFER_RFLAG_FULL_TSC (1U << 0)
+#define RING_BUFFER_RFLAG_END (1U << 1)
+
+/*
+ * We need to define RING_BUFFER_ALIGN_ATTR so it is known early at
+ * compile-time. We have to duplicate the "config->align" information and the
+ * definition here because config->align is used both in the slow and fast
+ * paths, but RING_BUFFER_ALIGN_ATTR is only available for the client code.
+ */
+#ifdef RING_BUFFER_ALIGN
+
+# define RING_BUFFER_ALIGN_ATTR /* Default arch alignment */
+
+/*
+ * Calculate the offset needed to align the type.
+ * size_of_type must be non-zero.
+ */
+static inline
+unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type)
+{
+ return offset_align(align_drift, size_of_type);
+}
+
+#else
+
+# define RING_BUFFER_ALIGN_ATTR __attribute__((packed))
+
+/*
+ * Calculate the offset needed to align the type.
+ * size_of_type must be non-zero.
+ */
+static inline
+unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type)
+{
+ return 0;
+}
+
+#endif
+
+/**
+ * lib_ring_buffer_align_ctx - Align context offset on "alignment"
+ * @ctx: ring buffer context.
+ */
+static inline
+void lib_ring_buffer_align_ctx(struct lib_ring_buffer_ctx *ctx,
+ size_t alignment)
+{
+ ctx->buf_offset += lib_ring_buffer_align(ctx->buf_offset,
+ alignment);
+}
+
+/*
+ * lib_ring_buffer_check_config() returns 0 on success.
+ * Used internally to check for valid configurations at channel creation.
+ */
+static inline
+int lib_ring_buffer_check_config(const struct lib_ring_buffer_config *config,
+ unsigned int switch_timer_interval,
+ unsigned int read_timer_interval)
+{
+ if (config->alloc == RING_BUFFER_ALLOC_GLOBAL
+ && config->sync == RING_BUFFER_SYNC_PER_CPU
+ && switch_timer_interval)
+ return -EINVAL;
+ return 0;
+}
+
+#include "vatomic.h"
+
+#endif /* _LINUX_RING_BUFFER_CONFIG_H */
#include <urcu/compiler.h>
#include <urcu/uatomic.h>
+#include "smp.h"
/* Internal helpers */
#include "frontend_internal.h"
void *buf_addr,
size_t subbuf_size, size_t num_subbuf,
unsigned int switch_timer_interval,
- unsigned int read_timer_interval);
+ unsigned int read_timer_interval,
+ int *shmid);
/*
* channel_destroy returns the private data pointer. It finalizes all channel's
* only performed at channel destruction.
*/
#define for_each_channel_cpu(cpu, chan) \
- for ((cpu) = -1; \
- ({ (cpu) = cpumask_next(cpu, (chan)->backend.cpumask); \
- cmm_smp_read_barrier_depends(); (cpu) < nr_cpu_ids; });)
+ for_each_possible_cpu(cpu)
extern struct lib_ring_buffer *channel_get_ring_buffer(
const struct lib_ring_buffer_config *config,
{
lib_ring_buffer_put_subbuf(buf);
lib_ring_buffer_move_consumer(buf, subbuf_align(buf->cons_snapshot,
- buf->backend.chan));
+ shmp(buf->backend.chan)));
}
extern void channel_reset(struct channel *chan);
#include "config.h"
#include "backend_types.h"
#include "frontend_types.h"
+#include "shm.h"
/* Buffer offset macros */
unsigned long idx)
{
if (config->oops == RING_BUFFER_OOPS_CONSISTENCY)
- v_set(config, &buf->commit_hot[idx].seq, commit_count);
+ v_set(config, &shmp(buf->commit_hot)[idx].seq, commit_count);
}
static inline
consumed_old = uatomic_read(&buf->consumed);
consumed_idx = subbuf_index(consumed_old, chan);
- commit_count = v_read(config, &buf->commit_cold[consumed_idx].cc_sb);
+ commit_count = v_read(config, &shmp(buf->commit_cold)[consumed_idx].cc_sb);
/*
* No memory barrier here, since we are only interested
* in a statistically correct polling result. The next poll will
do {
offset = v_read(config, &buf->offset);
idx = subbuf_index(offset, chan);
- commit_count = v_read(config, &buf->commit_hot[idx].cc);
+ commit_count = v_read(config, &shmp(buf->commit_hot)[idx].cc);
} while (offset != v_read(config, &buf->offset));
return ((buf_trunc(offset, chan) >> chan->backend.num_subbuf_order)
* The subbuffer size is least 2 bytes (minimum size: 1 page).
* This guarantees that old_commit_count + 1 != commit_count.
*/
- if (likely(v_cmpxchg(config, &buf->commit_cold[idx].cc_sb,
+ if (likely(v_cmpxchg(config, &shmp(buf->commit_cold)[idx].cc_sb,
old_commit_count, old_commit_count + 1)
== old_commit_count)) {
/*
*/
cmm_smp_mb();
/* End of exclusive subbuffer access */
- v_set(config, &buf->commit_cold[idx].cc_sb,
+ v_set(config, &shmp(buf->commit_cold)[idx].cc_sb,
commit_count);
lib_ring_buffer_vmcore_check_deliver(config, buf,
commit_count, idx);
if (unlikely(subbuf_offset(offset - commit_count, chan)))
return;
- commit_seq_old = v_read(config, &buf->commit_hot[idx].seq);
+ commit_seq_old = v_read(config, &shmp(buf->commit_hot)[idx].seq);
while ((long) (commit_seq_old - commit_count) < 0)
- commit_seq_old = v_cmpxchg(config, &buf->commit_hot[idx].seq,
+ commit_seq_old = v_cmpxchg(config, &shmp(buf->commit_hot)[idx].seq,
commit_seq_old, commit_count);
}
extern int lib_ring_buffer_create(struct lib_ring_buffer *buf,
- struct channel_backend *chanb, int cpu);
+ struct channel_backend *chanb, int cpu,
+ struct shm_header *shm_header);
extern void lib_ring_buffer_free(struct lib_ring_buffer *buf);
/* Keep track of trap nesting inside ring buffer code */
* Dual LGPL v2.1/GPL v2 license.
*/
+#include <string.h>
+
#include <urcu/list.h>
#include <urcu/uatomic.h>
#include <urcu/ref.h>
#include "usterr_signal_safe.h"
#include "config.h"
#include "backend_types.h"
+#include "shm.h"
/*
* A switch is done during tracing or as a final flush after tracing (so it
//wait_queue_head_t read_wait; /* reader wait queue */
int finalized; /* Has channel been finalized */
struct urcu_ref ref; /* Reference count */
-};
+ DECLARE_SHMP(struct shm_header, shm_header);
+} ____cacheline_aligned;
/* Per-subbuffer commit counters used on the hot path */
struct commit_counters_hot {
union v_atomic cc; /* Commit counter */
union v_atomic seq; /* Consecutive commits */
-};
+} ____cacheline_aligned;
/* Per-subbuffer commit counters used only on cold paths */
struct commit_counters_cold {
union v_atomic cc_sb; /* Incremented _once_ at sb switch */
-};
+} ____cacheline_aligned;
/* ring buffer state */
struct lib_ring_buffer {
/* First 32 bytes cache-hot cacheline */
union v_atomic offset; /* Current offset in the buffer */
- struct commit_counters_hot *commit_hot;
+ DECLARE_SHMP(struct commit_counters_hot, commit_hot);
/* Commit count per sub-buffer */
long consumed; /*
* Current offset in the buffer
struct lib_ring_buffer_backend backend; /* Associated backend */
- struct commit_counters_cold *commit_cold;
+ DECLARE_SHMP(struct commit_counters_cold, commit_cold);
/* Commit count per sub-buffer */
long active_readers; /*
* Active readers count
int get_subbuf:1; /* Sub-buffer being held by reader */
int switch_timer_enabled:1; /* Protected by ring_buffer_nohz_lock */
int read_timer_enabled:1; /* Protected by ring_buffer_nohz_lock */
-};
+} ____cacheline_aligned;
static inline
void *channel_get_private(struct channel *chan)
+++ /dev/null
-#ifndef _LINUX_RING_BUFFER_ITERATOR_H
-#define _LINUX_RING_BUFFER_ITERATOR_H
-
-/*
- * linux/ringbuffer/iterator.h
- *
- * (C) Copyright 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * Ring buffer and channel iterators.
- *
- * Author:
- * Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * Dual LGPL v2.1/GPL v2 license.
- */
-
-#include "backend.h"
-#include "frontend.h"
-
-/*
- * lib_ring_buffer_get_next_record advances the buffer read position to the next
- * record. It returns either the size of the next record, -EAGAIN if there is
- * currently no data available, or -ENODATA if no data is available and buffer
- * is finalized.
- */
-extern ssize_t lib_ring_buffer_get_next_record(struct channel *chan,
- struct lib_ring_buffer *buf);
-
-/*
- * channel_get_next_record advances the buffer read position to the next record.
- * It returns either the size of the next record, -EAGAIN if there is currently
- * no data available, or -ENODATA if no data is available and buffer is
- * finalized.
- * Returns the current buffer in ret_buf.
- */
-extern ssize_t channel_get_next_record(struct channel *chan,
- struct lib_ring_buffer **ret_buf);
-
-/**
- * read_current_record - copy the buffer current record into dest.
- * @buf: ring buffer
- * @dest: destination where the record should be copied
- *
- * dest should be large enough to contain the record. Returns the number of
- * bytes copied.
- */
-static inline size_t read_current_record(struct lib_ring_buffer *buf, void *dest)
-{
- return lib_ring_buffer_read(&buf->backend, buf->iter.read_offset,
- dest, buf->iter.payload_len);
-}
-
-extern int lib_ring_buffer_iterator_open(struct lib_ring_buffer *buf);
-extern void lib_ring_buffer_iterator_release(struct lib_ring_buffer *buf);
-extern int channel_iterator_open(struct channel *chan);
-extern void channel_iterator_release(struct channel *chan);
-
-extern const struct file_operations channel_payload_file_operations;
-extern const struct file_operations lib_ring_buffer_payload_file_operations;
-
-/*
- * Used internally.
- */
-int channel_iterator_init(struct channel *chan);
-void channel_iterator_unregister_notifiers(struct channel *chan);
-void channel_iterator_free(struct channel *chan);
-void channel_iterator_reset(struct channel *chan);
-void lib_ring_buffer_iterator_reset(struct lib_ring_buffer *buf);
-
-#endif /* _LINUX_RING_BUFFER_ITERATOR_H */
.compat_ioctl = lib_ring_buffer_compat_ioctl,
#endif
};
-EXPORT_SYMBOL_GPL(lib_ring_buffer_file_operations);
-
-MODULE_LICENSE("GPL and additional rights");
-MODULE_AUTHOR("Mathieu Desnoyers");
-MODULE_DESCRIPTION("Ring Buffer Library VFS");
#include "config.h"
#include "backend.h"
#include "frontend.h"
+#include "smp.h"
/**
* lib_ring_buffer_backend_allocate - allocate a channel buffer
int lib_ring_buffer_backend_allocate(const struct lib_ring_buffer_config *config,
struct lib_ring_buffer_backend *bufb,
size_t size, size_t num_subbuf,
- int extra_reader_sb)
+ int extra_reader_sb,
+ struct shm_header *shm_header)
{
- struct channel_backend *chanb = &bufb->chan->backend;
- unsigned long j, num_pages, num_pages_per_subbuf, page_idx = 0;
+ struct channel_backend *chanb = &shmp(bufb->chan)->backend;
unsigned long subbuf_size, mmap_offset = 0;
unsigned long num_subbuf_alloc;
- struct page **pages;
- void **virt;
unsigned long i;
- num_pages = size >> get_count_order(PAGE_SIZE);
- num_pages_per_subbuf = num_pages >> get_count_order(num_subbuf);
subbuf_size = chanb->subbuf_size;
num_subbuf_alloc = num_subbuf;
- if (extra_reader_sb) {
- num_pages += num_pages_per_subbuf; /* Add pages for reader */
+ if (extra_reader_sb)
num_subbuf_alloc++;
- }
-
- pages = malloc_align(sizeof(*pages) * num_pages);
- if (unlikely(!pages))
- goto pages_error;
- virt = malloc_align(sizeof(*virt) * num_pages);
- if (unlikely(!virt))
- goto virt_error;
-
- bufb->array = malloc_align(sizeof(*bufb->array) * num_subbuf_alloc);
- if (unlikely(!bufb->array))
+ set_shmp(bufb->array, zalloc_shm(shm_header,
+ sizeof(*bufb->array) * num_subbuf_alloc));
+ if (unlikely(!shmp(bufb->array)))
goto array_error;
- for (i = 0; i < num_pages; i++) {
- pages[i] = alloc_pages_node(cpu_to_node(max(bufb->cpu, 0)),
- GFP_KERNEL | __GFP_ZERO, 0);
- if (unlikely(!pages[i]))
- goto depopulate;
- virt[i] = page_address(pages[i]);
- }
- bufb->num_pages_per_subbuf = num_pages_per_subbuf;
+ set_shmp(bufb->memory_map, zalloc_shm(shm_header,
+ subbuf_size * num_subbuf_alloc));
+ if (unlikely(!shmp(bufb->memory_map)))
+ goto memory_map_error;
/* Allocate backend pages array elements */
for (i = 0; i < num_subbuf_alloc; i++) {
- bufb->array[i] =
- zmalloc_align(
+ set_shmp(bufb->array[i],
+ zalloc_shm(shm_header,
sizeof(struct lib_ring_buffer_backend_pages) +
- sizeof(struct lib_ring_buffer_backend_page)
- * num_pages_per_subbuf);
- if (!bufb->array[i])
+ subbuf_size));
+ if (!shmp(bufb->array[i]))
goto free_array;
}
/* Allocate write-side subbuffer table */
- bufb->buf_wsb = zmalloc_align(
+ bufb->buf_wsb = zalloc_shm(shm_header,
sizeof(struct lib_ring_buffer_backend_subbuffer)
* num_subbuf);
- if (unlikely(!bufb->buf_wsb))
+ if (unlikely(!shmp(bufb->buf_wsb)))
goto free_array;
for (i = 0; i < num_subbuf; i++)
- bufb->buf_wsb[i].id = subbuffer_id(config, 0, 1, i);
+ shmp(bufb->buf_wsb)[i].id = subbuffer_id(config, 0, 1, i);
/* Assign read-side subbuffer table */
if (extra_reader_sb)
/* Assign pages to page index */
for (i = 0; i < num_subbuf_alloc; i++) {
- for (j = 0; j < num_pages_per_subbuf; j++) {
- CHAN_WARN_ON(chanb, page_idx > num_pages);
- bufb->array[i]->p[j].virt = virt[page_idx];
- bufb->array[i]->p[j].page = pages[page_idx];
- page_idx++;
- }
+ set_shmp(shmp(bufb->array)[i]->p,
+ &shmp(bufb->memory_map)[i * subbuf_size]);
if (config->output == RING_BUFFER_MMAP) {
- bufb->array[i]->mmap_offset = mmap_offset;
+ shmp(bufb->array)[i]->mmap_offset = mmap_offset;
mmap_offset += subbuf_size;
}
}
- kfree(virt);
- kfree(pages);
return 0;
free_array:
- for (i = 0; (i < num_subbuf_alloc && bufb->array[i]); i++)
- kfree(bufb->array[i]);
-depopulate:
- /* Free all allocated pages */
- for (i = 0; (i < num_pages && pages[i]); i++)
- __free_page(pages[i]);
- kfree(bufb->array);
+ /* bufb->array[i] will be freed by shm teardown */
+memory_map_error:
+ /* bufb->array will be freed by shm teardown */
array_error:
- kfree(virt);
-virt_error:
- kfree(pages);
-pages_error:
return -ENOMEM;
}
int lib_ring_buffer_backend_create(struct lib_ring_buffer_backend *bufb,
- struct channel_backend *chanb, int cpu)
+ struct channel_backend *chanb, int cpu,
+ struct shm_header *shm_header)
{
const struct lib_ring_buffer_config *config = chanb->config;
- bufb->chan = caa_container_of(chanb, struct channel, backend);
+ set_shmp(&bufb->chan, caa_container_of(chanb, struct channel, backend));
bufb->cpu = cpu;
return lib_ring_buffer_backend_allocate(config, bufb, chanb->buf_size,
chanb->num_subbuf,
- chanb->extra_reader_sb);
+ chanb->extra_reader_sb,
+ shm_header);
}
void lib_ring_buffer_backend_free(struct lib_ring_buffer_backend *bufb)
{
- struct channel_backend *chanb = &bufb->chan->backend;
- unsigned long i, j, num_subbuf_alloc;
-
- num_subbuf_alloc = chanb->num_subbuf;
- if (chanb->extra_reader_sb)
- num_subbuf_alloc++;
-
- kfree(bufb->buf_wsb);
- for (i = 0; i < num_subbuf_alloc; i++) {
- for (j = 0; j < bufb->num_pages_per_subbuf; j++)
- __free_page(bufb->array[i]->p[j].page);
- kfree(bufb->array[i]);
- }
- kfree(bufb->array);
+ /* bufb->buf_wsb will be freed by shm teardown */
+ /* bufb->array[i] will be freed by shm teardown */
+ /* bufb->array will be freed by shm teardown */
bufb->allocated = 0;
}
void lib_ring_buffer_backend_reset(struct lib_ring_buffer_backend *bufb)
{
- struct channel_backend *chanb = &bufb->chan->backend;
+ struct channel_backend *chanb = &shmp(bufb->chan)->backend;
const struct lib_ring_buffer_config *config = chanb->config;
unsigned long num_subbuf_alloc;
unsigned int i;
num_subbuf_alloc++;
for (i = 0; i < chanb->num_subbuf; i++)
- bufb->buf_wsb[i].id = subbuffer_id(config, 0, 1, i);
+ shmp(bufb->buf_wsb)[i].id = subbuffer_id(config, 0, 1, i);
if (chanb->extra_reader_sb)
bufb->buf_rsb.id = subbuffer_id(config, 0, 1,
num_subbuf_alloc - 1);
for (i = 0; i < num_subbuf_alloc; i++) {
/* Don't reset mmap_offset */
- v_set(config, &bufb->array[i]->records_commit, 0);
- v_set(config, &bufb->array[i]->records_unread, 0);
- bufb->array[i]->data_size = 0;
+ v_set(config, &shmp(bufb->array)[i]->records_commit, 0);
+ v_set(config, &shmp(bufb->array)[i]->records_unread, 0);
+ shmp(bufb->array)[i]->data_size = 0;
/* Don't reset backend page and virt addresses */
}
/* Don't reset num_pages_per_subbuf, cpu, allocated */
chanb->start_tsc = config->cb.ring_buffer_clock_read(chan);
}
-#ifdef CONFIG_HOTPLUG_CPU
-/**
- * lib_ring_buffer_cpu_hp_callback - CPU hotplug callback
- * @nb: notifier block
- * @action: hotplug action to take
- * @hcpu: CPU number
- *
- * Returns the success/failure of the operation. (%NOTIFY_OK, %NOTIFY_BAD)
- */
-static
-int __cpuinit lib_ring_buffer_cpu_hp_callback(struct notifier_block *nb,
- unsigned long action,
- void *hcpu)
-{
- unsigned int cpu = (unsigned long)hcpu;
- struct channel_backend *chanb = caa_container_of(nb, struct channel_backend,
- cpu_hp_notifier);
- const struct lib_ring_buffer_config *config = chanb->config;
- struct lib_ring_buffer *buf;
- int ret;
-
- CHAN_WARN_ON(chanb, config->alloc == RING_BUFFER_ALLOC_GLOBAL);
-
- switch (action) {
- case CPU_UP_PREPARE:
- case CPU_UP_PREPARE_FROZEN:
- buf = per_cpu_ptr(chanb->buf, cpu);
- ret = lib_ring_buffer_create(buf, chanb, cpu);
- if (ret) {
- printk(KERN_ERR
- "ring_buffer_cpu_hp_callback: cpu %d "
- "buffer creation failed\n", cpu);
- return NOTIFY_BAD;
- }
- break;
- case CPU_DEAD:
- case CPU_DEAD_FROZEN:
- /* No need to do a buffer switch here, because it will happen
- * when tracing is stopped, or will be done by switch timer CPU
- * DEAD callback. */
- break;
- }
- return NOTIFY_OK;
-}
-#endif
-
/**
* channel_backend_init - initialize a channel backend
* @chanb: channel backend
* @parent: dentry of parent directory, %NULL for root directory
* @subbuf_size: size of sub-buffers (> PAGE_SIZE, power of 2)
* @num_subbuf: number of sub-buffers (power of 2)
+ * @shm_header: shared memory header
*
* Returns channel pointer if successful, %NULL otherwise.
*
int channel_backend_init(struct channel_backend *chanb,
const char *name,
const struct lib_ring_buffer_config *config,
- void *priv, size_t subbuf_size, size_t num_subbuf)
+ void *priv, size_t subbuf_size, size_t num_subbuf,
+ struct shm_header *shm_header)
{
struct channel *chan = caa_container_of(chanb, struct channel, backend);
unsigned int i;
chanb->extra_reader_sb =
(config->mode == RING_BUFFER_OVERWRITE) ? 1 : 0;
chanb->num_subbuf = num_subbuf;
- strlcpy(chanb->name, name, NAME_MAX);
+ strncpy(chanb->name, name, NAME_MAX);
+ chanb->name[NAME_MAX - 1] = '\0';
chanb->config = config;
if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) {
- if (!zalloc_cpumask_var(&chanb->cpumask, GFP_KERNEL))
- return -ENOMEM;
- }
+ struct lib_ring_buffer *buf;
+ size_t alloc_size;
- if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) {
/* Allocating the buffer per-cpu structures */
- chanb->buf = alloc_percpu(struct lib_ring_buffer);
- if (!chanb->buf)
- goto free_cpumask;
+ alloc_size = sizeof(struct lib_ring_buffer);
+ buf = zalloc_shm(shm_header, alloc_size * num_possible_cpus());
+ if (!buf)
+ goto end;
+ set_shmp(chanb->buf, buf);
/*
- * In case of non-hotplug cpu, if the ring-buffer is allocated
- * in early initcall, it will not be notified of secondary cpus.
- * In that off case, we need to allocate for all possible cpus.
- */
-#ifdef CONFIG_HOTPLUG_CPU
- /*
- * buf->backend.allocated test takes care of concurrent CPU
- * hotplug.
- * Priority higher than frontend, so we create the ring buffer
- * before we start the timer.
+ * We need to allocate for all possible cpus.
*/
- chanb->cpu_hp_notifier.notifier_call =
- lib_ring_buffer_cpu_hp_callback;
- chanb->cpu_hp_notifier.priority = 5;
- register_hotcpu_notifier(&chanb->cpu_hp_notifier);
-
- get_online_cpus();
- for_each_online_cpu(i) {
- ret = lib_ring_buffer_create(per_cpu_ptr(chanb->buf, i),
- chanb, i);
- if (ret)
- goto free_bufs; /* cpu hotplug locked */
- }
- put_online_cpus();
-#else
for_each_possible_cpu(i) {
- ret = lib_ring_buffer_create(per_cpu_ptr(chanb->buf, i),
- chanb, i);
+ ret = lib_ring_buffer_create(&shmp(chanb->buf)[i],
+ chanb, i, shm_header);
if (ret)
goto free_bufs; /* cpu hotplug locked */
}
-#endif
} else {
- chanb->buf = kzalloc(sizeof(struct lib_ring_buffer), GFP_KERNEL);
- if (!chanb->buf)
- goto free_cpumask;
- ret = lib_ring_buffer_create(chanb->buf, chanb, -1);
+ struct lib_ring_buffer *buf;
+ size_t alloc_size;
+
+ alloc_size = sizeof(struct lib_ring_buffer);
+ chanb->buf = zmalloc(sizeof(struct lib_ring_buffer));
+ buf = zalloc_shm(shm_header, alloc_size);
+ if (!buf)
+ goto end;
+ set_shmp(chanb->buf, buf);
+ ret = lib_ring_buffer_create(shmp(chanb->buf), chanb, -1,
+ shm_header);
if (ret)
goto free_bufs;
}
free_bufs:
if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) {
for_each_possible_cpu(i) {
- struct lib_ring_buffer *buf = per_cpu_ptr(chanb->buf, i);
+ struct lib_ring_buffer *buf = &shmp(chanb->buf)[i];
if (!buf->backend.allocated)
continue;
lib_ring_buffer_free(buf);
}
-#ifdef CONFIG_HOTPLUG_CPU
- put_online_cpus();
-#endif
- free_percpu(chanb->buf);
- } else
- kfree(chanb->buf);
-free_cpumask:
- if (config->alloc == RING_BUFFER_ALLOC_PER_CPU)
- free_cpumask_var(chanb->cpumask);
+ }
+ /* We only free the buffer data upon shm teardown */
+end:
return -ENOMEM;
}
-/**
- * channel_backend_unregister_notifiers - unregister notifiers
- * @chan: the channel
- *
- * Holds CPU hotplug.
- */
-void channel_backend_unregister_notifiers(struct channel_backend *chanb)
-{
- const struct lib_ring_buffer_config *config = chanb->config;
-
- if (config->alloc == RING_BUFFER_ALLOC_PER_CPU)
- unregister_hotcpu_notifier(&chanb->cpu_hp_notifier);
-}
-
/**
* channel_backend_free - destroy the channel
* @chan: the channel
if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) {
for_each_possible_cpu(i) {
- struct lib_ring_buffer *buf = per_cpu_ptr(chanb->buf, i);
+ struct lib_ring_buffer *buf = &shmp(chanb->buf)[i];
if (!buf->backend.allocated)
continue;
lib_ring_buffer_free(buf);
}
- free_cpumask_var(chanb->cpumask);
- free_percpu(chanb->buf);
} else {
- struct lib_ring_buffer *buf = chanb->buf;
+ struct lib_ring_buffer *buf = shmp(chanb->buf);
CHAN_WARN_ON(chanb, !buf->backend.allocated);
lib_ring_buffer_free(buf);
- kfree(buf);
}
+ /* We only free the buffer data upon shm teardown */
}
-/**
- * lib_ring_buffer_write - write data to a ring_buffer buffer.
- * @bufb : buffer backend
- * @offset : offset within the buffer
- * @src : source address
- * @len : length to write
- * @pagecpy : page size copied so far
- */
-void _lib_ring_buffer_write(struct lib_ring_buffer_backend *bufb, size_t offset,
- const void *src, size_t len, ssize_t pagecpy)
-{
- struct channel_backend *chanb = &bufb->chan->backend;
- const struct lib_ring_buffer_config *config = chanb->config;
- size_t sbidx, index;
- struct lib_ring_buffer_backend_pages *rpages;
- unsigned long sb_bindex, id;
-
- do {
- len -= pagecpy;
- src += pagecpy;
- offset += pagecpy;
- sbidx = offset >> chanb->subbuf_size_order;
- index = (offset & (chanb->subbuf_size - 1)) >> get_count_order(PAGE_SIZE);
-
- /*
- * Underlying layer should never ask for writes across
- * subbuffers.
- */
- CHAN_WARN_ON(chanb, offset >= chanb->buf_size);
-
- pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK));
- id = bufb->buf_wsb[sbidx].id;
- sb_bindex = subbuffer_id_get_index(config, id);
- rpages = bufb->array[sb_bindex];
- CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE
- && subbuffer_id_is_noref(config, id));
- lib_ring_buffer_do_copy(config,
- rpages->p[index].virt
- + (offset & ~PAGE_MASK),
- src, pagecpy);
- } while (unlikely(len != pagecpy));
-}
-EXPORT_SYMBOL_GPL(_lib_ring_buffer_write);
-
/**
* lib_ring_buffer_read - read data from ring_buffer_buffer.
* @bufb : buffer backend
size_t lib_ring_buffer_read(struct lib_ring_buffer_backend *bufb, size_t offset,
void *dest, size_t len)
{
- struct channel_backend *chanb = &bufb->chan->backend;
+ struct channel_backend *chanb = &shmp(bufb->chan)->backend;
const struct lib_ring_buffer_config *config = chanb->config;
- size_t index;
- ssize_t pagecpy, orig_len;
+ ssize_t orig_len;
struct lib_ring_buffer_backend_pages *rpages;
unsigned long sb_bindex, id;
orig_len = len;
offset &= chanb->buf_size - 1;
- index = (offset & (chanb->subbuf_size - 1)) >> get_count_order(PAGE_SIZE);
+
if (unlikely(!len))
return 0;
- for (;;) {
- pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK));
- id = bufb->buf_rsb.id;
- sb_bindex = subbuffer_id_get_index(config, id);
- rpages = bufb->array[sb_bindex];
- CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE
- && subbuffer_id_is_noref(config, id));
- memcpy(dest, rpages->p[index].virt + (offset & ~PAGE_MASK),
- pagecpy);
- len -= pagecpy;
- if (likely(!len))
- break;
- dest += pagecpy;
- offset += pagecpy;
- index = (offset & (chanb->subbuf_size - 1)) >> get_count_order(PAGE_SIZE);
- /*
- * Underlying layer should never ask for reads across
- * subbuffers.
- */
- CHAN_WARN_ON(chanb, offset >= chanb->buf_size);
- }
+ id = bufb->buf_rsb.id;
+ sb_bindex = subbuffer_id_get_index(config, id);
+ rpages = shmp(bufb->array)[sb_bindex];
+ /*
+ * Underlying layer should never ask for reads across
+ * subbuffers.
+ */
+ CHAN_WARN_ON(chanb, offset >= chanb->buf_size);
+ CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE
+ && subbuffer_id_is_noref(config, id));
+ memcpy(dest, shmp(rpages->p) + (offset & ~(chanb->subbuf_size - 1)), len);
return orig_len;
}
-EXPORT_SYMBOL_GPL(lib_ring_buffer_read);
/**
* lib_ring_buffer_read_cstr - read a C-style string from ring_buffer.
int lib_ring_buffer_read_cstr(struct lib_ring_buffer_backend *bufb, size_t offset,
void *dest, size_t len)
{
- struct channel_backend *chanb = &bufb->chan->backend;
+ struct channel_backend *chanb = &shmp(bufb->chan)->backend;
const struct lib_ring_buffer_config *config = chanb->config;
- size_t index;
- ssize_t pagecpy, pagelen, strpagelen, orig_offset;
+ ssize_t string_len, orig_offset;
char *str;
struct lib_ring_buffer_backend_pages *rpages;
unsigned long sb_bindex, id;
offset &= chanb->buf_size - 1;
- index = (offset & (chanb->subbuf_size - 1)) >> get_count_order(PAGE_SIZE);
orig_offset = offset;
- for (;;) {
- id = bufb->buf_rsb.id;
- sb_bindex = subbuffer_id_get_index(config, id);
- rpages = bufb->array[sb_bindex];
- CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE
- && subbuffer_id_is_noref(config, id));
- str = (char *)rpages->p[index].virt + (offset & ~PAGE_MASK);
- pagelen = PAGE_SIZE - (offset & ~PAGE_MASK);
- strpagelen = strnlen(str, pagelen);
- if (len) {
- pagecpy = min_t(size_t, len, strpagelen);
- if (dest) {
- memcpy(dest, str, pagecpy);
- dest += pagecpy;
- }
- len -= pagecpy;
- }
- offset += strpagelen;
- index = (offset & (chanb->subbuf_size - 1)) >> get_count_order(PAGE_SIZE);
- if (strpagelen < pagelen)
- break;
- /*
- * Underlying layer should never ask for reads across
- * subbuffers.
- */
- CHAN_WARN_ON(chanb, offset >= chanb->buf_size);
- }
- if (dest && len)
- ((char *)dest)[0] = 0;
- return offset - orig_offset;
-}
-EXPORT_SYMBOL_GPL(lib_ring_buffer_read_cstr);
-
-/**
- * lib_ring_buffer_read_get_page - Get a whole page to read from
- * @bufb : buffer backend
- * @offset : offset within the buffer
- * @virt : pointer to page address (output)
- *
- * Should be protected by get_subbuf/put_subbuf.
- * Returns the pointer to the page struct pointer.
- */
-struct page **lib_ring_buffer_read_get_page(struct lib_ring_buffer_backend *bufb,
- size_t offset, void ***virt)
-{
- size_t index;
- struct lib_ring_buffer_backend_pages *rpages;
- struct channel_backend *chanb = &bufb->chan->backend;
- const struct lib_ring_buffer_config *config = chanb->config;
- unsigned long sb_bindex, id;
-
- offset &= chanb->buf_size - 1;
- index = (offset & (chanb->subbuf_size - 1)) >> get_count_order(PAGE_SIZE);
id = bufb->buf_rsb.id;
sb_bindex = subbuffer_id_get_index(config, id);
- rpages = bufb->array[sb_bindex];
+ rpages = shmp(bufb->array)[sb_bindex];
+ /*
+ * Underlying layer should never ask for reads across
+ * subbuffers.
+ */
+ CHAN_WARN_ON(chanb, offset >= chanb->buf_size);
CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE
&& subbuffer_id_is_noref(config, id));
- *virt = &rpages->p[index].virt;
- return &rpages->p[index].page;
+ str = (char *)shmp(rpages->p) + (offset & ~(chanb->subbuf_size - 1));
+ string_len = strnlen(str, len);
+ if (dest && len) {
+ memcpy(dest, str, string_len);
+ ((char *)dest)[0] = 0;
+ }
+ return offset - orig_offset;
}
-EXPORT_SYMBOL_GPL(lib_ring_buffer_read_get_page);
/**
* lib_ring_buffer_read_offset_address - get address of a buffer location
void *lib_ring_buffer_read_offset_address(struct lib_ring_buffer_backend *bufb,
size_t offset)
{
- size_t index;
struct lib_ring_buffer_backend_pages *rpages;
- struct channel_backend *chanb = &bufb->chan->backend;
+ struct channel_backend *chanb = &shmp(bufb->chan)->backend;
const struct lib_ring_buffer_config *config = chanb->config;
unsigned long sb_bindex, id;
offset &= chanb->buf_size - 1;
- index = (offset & (chanb->subbuf_size - 1)) >> get_count_order(PAGE_SIZE);
id = bufb->buf_rsb.id;
sb_bindex = subbuffer_id_get_index(config, id);
- rpages = bufb->array[sb_bindex];
+ rpages = shmp(bufb->array)[sb_bindex];
CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE
&& subbuffer_id_is_noref(config, id));
- return rpages->p[index].virt + (offset & ~PAGE_MASK);
+ return shmp(rpages->p) + (offset & ~(chanb->subbuf_size - 1));
}
-EXPORT_SYMBOL_GPL(lib_ring_buffer_read_offset_address);
/**
* lib_ring_buffer_offset_address - get address of a location within the buffer
void *lib_ring_buffer_offset_address(struct lib_ring_buffer_backend *bufb,
size_t offset)
{
- size_t sbidx, index;
+ size_t sbidx;
struct lib_ring_buffer_backend_pages *rpages;
- struct channel_backend *chanb = &bufb->chan->backend;
+ struct channel_backend *chanb = &shmp(bufb->chan)->backend;
const struct lib_ring_buffer_config *config = chanb->config;
unsigned long sb_bindex, id;
offset &= chanb->buf_size - 1;
sbidx = offset >> chanb->subbuf_size_order;
- index = (offset & (chanb->subbuf_size - 1)) >> get_count_order(PAGE_SIZE);
- id = bufb->buf_wsb[sbidx].id;
+ id = shmp(bufb->buf_wsb)[sbidx].id;
sb_bindex = subbuffer_id_get_index(config, id);
- rpages = bufb->array[sb_bindex];
+ rpages = shmp(bufb->array)[sb_bindex];
CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE
&& subbuffer_id_is_noref(config, id));
- return rpages->p[index].virt + (offset & ~PAGE_MASK);
+ return shmp(rpages->p) + (offset & ~(chanb->subbuf_size - 1));
}
-EXPORT_SYMBOL_GPL(lib_ring_buffer_offset_address);
* Dual LGPL v2.1/GPL v2 license.
*/
+#include <sys/types.h>
+#include <sys/shm.h>
#include <urcu/compiler.h>
+#include <urcu/ref.h>
+#include "smp.h"
#include "config.h"
#include "backend.h"
#include "frontend.h"
-#include "iterator.h"
-#include "nohz.h"
+#include "shm.h"
/*
* Internal structure representing offsets to use at a sub-buffer switch.
switch_old_end:1;
};
-#ifdef CONFIG_NO_HZ
-enum tick_nohz_val {
- TICK_NOHZ_STOP,
- TICK_NOHZ_FLUSH,
- TICK_NOHZ_RESTART,
-};
-
-static ATOMIC_NOTIFIER_HEAD(tick_nohz_notifier);
-#endif /* CONFIG_NO_HZ */
-
-static DEFINE_PER_CPU(spinlock_t, ring_buffer_nohz_lock);
-
-DEFINE_PER_CPU(unsigned int, lib_ring_buffer_nesting);
-EXPORT_PER_CPU_SYMBOL(lib_ring_buffer_nesting);
+__thread unsigned int lib_ring_buffer_nesting;
static
void lib_ring_buffer_print_errors(struct channel *chan,
*/
void lib_ring_buffer_free(struct lib_ring_buffer *buf)
{
- struct channel *chan = buf->backend.chan;
+ struct channel *chan = shmp(buf->backend.chan);
lib_ring_buffer_print_errors(chan, buf, buf->backend.cpu);
- kfree(buf->commit_hot);
- kfree(buf->commit_cold);
+ free(shmp(buf->commit_hot));
+ free(shmp(buf->commit_cold));
lib_ring_buffer_backend_free(&buf->backend);
}
*/
void lib_ring_buffer_reset(struct lib_ring_buffer *buf)
{
- struct channel *chan = buf->backend.chan;
+ struct channel *chan = shmp(buf->backend.chan);
const struct lib_ring_buffer_config *config = chan->backend.config;
unsigned int i;
* Reset iterator first. It will put the subbuffer if it currently holds
* it.
*/
- lib_ring_buffer_iterator_reset(buf);
v_set(config, &buf->offset, 0);
for (i = 0; i < chan->backend.num_subbuf; i++) {
- v_set(config, &buf->commit_hot[i].cc, 0);
- v_set(config, &buf->commit_hot[i].seq, 0);
- v_set(config, &buf->commit_cold[i].cc_sb, 0);
+ v_set(config, &shmp(buf->commit_hot)[i].cc, 0);
+ v_set(config, &shmp(buf->commit_hot)[i].seq, 0);
+ v_set(config, &shmp(buf->commit_cold)[i].cc_sb, 0);
}
- atomic_long_set(&buf->consumed, 0);
- atomic_set(&buf->record_disabled, 0);
+ uatomic_set(&buf->consumed, 0);
+ uatomic_set(&buf->record_disabled, 0);
v_set(config, &buf->last_tsc, 0);
lib_ring_buffer_backend_reset(&buf->backend);
/* Don't reset number of active readers */
v_set(config, &buf->records_overrun, 0);
buf->finalized = 0;
}
-EXPORT_SYMBOL_GPL(lib_ring_buffer_reset);
/**
* channel_reset - Reset channel to initial values.
/*
* Reset iterators first. Will put the subbuffer if held for reading.
*/
- channel_iterator_reset(chan);
- atomic_set(&chan->record_disabled, 0);
+ uatomic_set(&chan->record_disabled, 0);
/* Don't reset commit_count_mask, still valid */
channel_backend_reset(&chan->backend);
/* Don't reset switch/read timer interval */
/* Don't reset notifiers and notifier enable bits */
/* Don't reset reader reference count */
}
-EXPORT_SYMBOL_GPL(channel_reset);
/*
* Must be called under cpu hotplug protection.
*/
int lib_ring_buffer_create(struct lib_ring_buffer *buf,
- struct channel_backend *chanb, int cpu)
+ struct channel_backend *chanb, int cpu,
+ struct shm_header *shm_header)
{
const struct lib_ring_buffer_config *config = chanb->config;
struct channel *chan = caa_container_of(chanb, struct channel, backend);
if (buf->backend.allocated)
return 0;
- /*
- * Paranoia: per cpu dynamic allocation is not officially documented as
- * zeroing the memory, so let's do it here too, just in case.
- */
- memset(buf, 0, sizeof(*buf));
-
- ret = lib_ring_buffer_backend_create(&buf->backend, &chan->backend, cpu);
+ ret = lib_ring_buffer_backend_create(&buf->backend, &chan->backend,
+ cpu, shm_header);
if (ret)
return ret;
- buf->commit_hot =
- kzalloc_node(ALIGN(sizeof(*buf->commit_hot)
- * chan->backend.num_subbuf,
- 1 << INTERNODE_CACHE_SHIFT),
- GFP_KERNEL, cpu_to_node(max(cpu, 0)));
- if (!buf->commit_hot) {
+ set_shmp(&buf->commit_hot,
+ zalloc_shm(shm_header,
+ sizeof(*buf->commit_hot) * chan->backend.num_subbuf));
+ if (!shmp(buf->commit_hot)) {
ret = -ENOMEM;
goto free_chanbuf;
}
- buf->commit_cold =
- kzalloc_node(ALIGN(sizeof(*buf->commit_cold)
- * chan->backend.num_subbuf,
- 1 << INTERNODE_CACHE_SHIFT),
- GFP_KERNEL, cpu_to_node(max(cpu, 0)));
- if (!buf->commit_cold) {
+ set_shmp(&buf->commit_cold,
+ zalloc_shm(shm_header,
+ sizeof(*buf->commit_cold) * chan->backend.num_subbuf));
+ if (!shmp(buf->commit_cold)) {
ret = -ENOMEM;
goto free_commit;
}
num_subbuf = chan->backend.num_subbuf;
- init_waitqueue_head(&buf->read_wait);
- raw_spin_lock_init(&buf->raw_tick_nohz_spinlock);
+ //init_waitqueue_head(&buf->read_wait);
/*
* Write the subbuffer header for first subbuffer so we know the total
*/
subbuf_header_size = config->cb.subbuffer_header_size();
v_set(config, &buf->offset, subbuf_header_size);
- subbuffer_id_clear_noref(config, &buf->backend.buf_wsb[0].id);
- tsc = config->cb.ring_buffer_clock_read(buf->backend.chan);
+ subbuffer_id_clear_noref(config, &shmp(buf->backend.buf_wsb)[0].id);
+ tsc = config->cb.ring_buffer_clock_read(shmp(buf->backend.chan));
config->cb.buffer_begin(buf, tsc, 0);
- v_add(config, subbuf_header_size, &buf->commit_hot[0].cc);
+ v_add(config, subbuf_header_size, &shmp(buf->commit_hot)[0].cc);
if (config->cb.buffer_create) {
ret = config->cb.buffer_create(buf, priv, cpu, chanb->name);
if (ret)
goto free_init;
}
-
- /*
- * Ensure the buffer is ready before setting it to allocated and setting
- * the cpumask.
- * Used for cpu hotplug vs cpumask iteration.
- */
- smp_wmb();
buf->backend.allocated = 1;
-
- if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) {
- CHAN_WARN_ON(chan, cpumask_test_cpu(cpu,
- chan->backend.cpumask));
- cpumask_set_cpu(cpu, chan->backend.cpumask);
- }
-
return 0;
/* Error handling */
free_init:
- kfree(buf->commit_cold);
+ /* commit_cold will be freed by shm teardown */
free_commit:
- kfree(buf->commit_hot);
+ /* commit_hot will be freed by shm teardown */
free_chanbuf:
lib_ring_buffer_backend_free(&buf->backend);
return ret;
static void switch_buffer_timer(unsigned long data)
{
struct lib_ring_buffer *buf = (struct lib_ring_buffer *)data;
- struct channel *chan = buf->backend.chan;
+ struct channel *chan = shmp(buf->backend.chan);
const struct lib_ring_buffer_config *config = chan->backend.config;
/*
* Only flush buffers periodically if readers are active.
*/
- if (atomic_long_read(&buf->active_readers))
+ if (uatomic_read(&buf->active_readers))
lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
- if (config->alloc == RING_BUFFER_ALLOC_PER_CPU)
- mod_timer_pinned(&buf->switch_timer,
- jiffies + chan->switch_timer_interval);
- else
- mod_timer(&buf->switch_timer,
- jiffies + chan->switch_timer_interval);
+ //TODO timers
+ //if (config->alloc == RING_BUFFER_ALLOC_PER_CPU)
+ // mod_timer_pinned(&buf->switch_timer,
+ // jiffies + chan->switch_timer_interval);
+ //else
+ // mod_timer(&buf->switch_timer,
+ // jiffies + chan->switch_timer_interval);
}
-/*
- * Called with ring_buffer_nohz_lock held for per-cpu buffers.
- */
static void lib_ring_buffer_start_switch_timer(struct lib_ring_buffer *buf)
{
- struct channel *chan = buf->backend.chan;
+ struct channel *chan = shmp(buf->backend.chan);
const struct lib_ring_buffer_config *config = chan->backend.config;
if (!chan->switch_timer_interval || buf->switch_timer_enabled)
return;
- init_timer(&buf->switch_timer);
- buf->switch_timer.function = switch_buffer_timer;
- buf->switch_timer.expires = jiffies + chan->switch_timer_interval;
- buf->switch_timer.data = (unsigned long)buf;
- if (config->alloc == RING_BUFFER_ALLOC_PER_CPU)
- add_timer_on(&buf->switch_timer, buf->backend.cpu);
- else
- add_timer(&buf->switch_timer);
+ //TODO
+ //init_timer(&buf->switch_timer);
+ //buf->switch_timer.function = switch_buffer_timer;
+ //buf->switch_timer.expires = jiffies + chan->switch_timer_interval;
+ //buf->switch_timer.data = (unsigned long)buf;
+ //if (config->alloc == RING_BUFFER_ALLOC_PER_CPU)
+ // add_timer_on(&buf->switch_timer, buf->backend.cpu);
+ //else
+ // add_timer(&buf->switch_timer);
buf->switch_timer_enabled = 1;
}
-/*
- * Called with ring_buffer_nohz_lock held for per-cpu buffers.
- */
static void lib_ring_buffer_stop_switch_timer(struct lib_ring_buffer *buf)
{
- struct channel *chan = buf->backend.chan;
+ struct channel *chan = shmp(buf->backend.chan);
if (!chan->switch_timer_interval || !buf->switch_timer_enabled)
return;
- del_timer_sync(&buf->switch_timer);
+ //TODO
+ //del_timer_sync(&buf->switch_timer);
buf->switch_timer_enabled = 0;
}
static void read_buffer_timer(unsigned long data)
{
struct lib_ring_buffer *buf = (struct lib_ring_buffer *)data;
- struct channel *chan = buf->backend.chan;
+ struct channel *chan = shmp(buf->backend.chan);
const struct lib_ring_buffer_config *config = chan->backend.config;
CHAN_WARN_ON(chan, !buf->backend.allocated);
- if (atomic_long_read(&buf->active_readers)
+ if (uatomic_read(&buf->active_readers)
&& lib_ring_buffer_poll_deliver(config, buf, chan)) {
- wake_up_interruptible(&buf->read_wait);
- wake_up_interruptible(&chan->read_wait);
+ //TODO
+ //wake_up_interruptible(&buf->read_wait);
+ //wake_up_interruptible(&chan->read_wait);
}
- if (config->alloc == RING_BUFFER_ALLOC_PER_CPU)
- mod_timer_pinned(&buf->read_timer,
- jiffies + chan->read_timer_interval);
- else
- mod_timer(&buf->read_timer,
- jiffies + chan->read_timer_interval);
+ //TODO
+ //if (config->alloc == RING_BUFFER_ALLOC_PER_CPU)
+ // mod_timer_pinned(&buf->read_timer,
+ // jiffies + chan->read_timer_interval);
+ //else
+ // mod_timer(&buf->read_timer,
+ // jiffies + chan->read_timer_interval);
}
-/*
- * Called with ring_buffer_nohz_lock held for per-cpu buffers.
- */
static void lib_ring_buffer_start_read_timer(struct lib_ring_buffer *buf)
{
- struct channel *chan = buf->backend.chan;
+ struct channel *chan = shmp(buf->backend.chan);
const struct lib_ring_buffer_config *config = chan->backend.config;
if (config->wakeup != RING_BUFFER_WAKEUP_BY_TIMER
|| buf->read_timer_enabled)
return;
- init_timer(&buf->read_timer);
- buf->read_timer.function = read_buffer_timer;
- buf->read_timer.expires = jiffies + chan->read_timer_interval;
- buf->read_timer.data = (unsigned long)buf;
+ //TODO
+ //init_timer(&buf->read_timer);
+ //buf->read_timer.function = read_buffer_timer;
+ //buf->read_timer.expires = jiffies + chan->read_timer_interval;
+ //buf->read_timer.data = (unsigned long)buf;
- if (config->alloc == RING_BUFFER_ALLOC_PER_CPU)
- add_timer_on(&buf->read_timer, buf->backend.cpu);
- else
- add_timer(&buf->read_timer);
+ //if (config->alloc == RING_BUFFER_ALLOC_PER_CPU)
+ // add_timer_on(&buf->read_timer, buf->backend.cpu);
+ //else
+ // add_timer(&buf->read_timer);
buf->read_timer_enabled = 1;
}
-/*
- * Called with ring_buffer_nohz_lock held for per-cpu buffers.
- */
static void lib_ring_buffer_stop_read_timer(struct lib_ring_buffer *buf)
{
- struct channel *chan = buf->backend.chan;
+ struct channel *chan = shmp(buf->backend.chan);
const struct lib_ring_buffer_config *config = chan->backend.config;
if (config->wakeup != RING_BUFFER_WAKEUP_BY_TIMER
|| !buf->read_timer_enabled)
return;
- del_timer_sync(&buf->read_timer);
+ //TODO
+ //del_timer_sync(&buf->read_timer);
/*
* do one more check to catch data that has been written in the last
* timer period.
*/
if (lib_ring_buffer_poll_deliver(config, buf, chan)) {
- wake_up_interruptible(&buf->read_wait);
- wake_up_interruptible(&chan->read_wait);
+ //TODO
+ //wake_up_interruptible(&buf->read_wait);
+ //wake_up_interruptible(&chan->read_wait);
}
buf->read_timer_enabled = 0;
}
-#ifdef CONFIG_HOTPLUG_CPU
-/**
- * lib_ring_buffer_cpu_hp_callback - CPU hotplug callback
- * @nb: notifier block
- * @action: hotplug action to take
- * @hcpu: CPU number
- *
- * Returns the success/failure of the operation. (%NOTIFY_OK, %NOTIFY_BAD)
- */
-static
-int __cpuinit lib_ring_buffer_cpu_hp_callback(struct notifier_block *nb,
- unsigned long action,
- void *hcpu)
-{
- unsigned int cpu = (unsigned long)hcpu;
- struct channel *chan = caa_container_of(nb, struct channel,
- cpu_hp_notifier);
- struct lib_ring_buffer *buf = per_cpu_ptr(chan->backend.buf, cpu);
- const struct lib_ring_buffer_config *config = chan->backend.config;
-
- if (!chan->cpu_hp_enable)
- return NOTIFY_DONE;
-
- CHAN_WARN_ON(chan, config->alloc == RING_BUFFER_ALLOC_GLOBAL);
-
- switch (action) {
- case CPU_DOWN_FAILED:
- case CPU_DOWN_FAILED_FROZEN:
- case CPU_ONLINE:
- case CPU_ONLINE_FROZEN:
- wake_up_interruptible(&chan->hp_wait);
- lib_ring_buffer_start_switch_timer(buf);
- lib_ring_buffer_start_read_timer(buf);
- return NOTIFY_OK;
-
- case CPU_DOWN_PREPARE:
- case CPU_DOWN_PREPARE_FROZEN:
- lib_ring_buffer_stop_switch_timer(buf);
- lib_ring_buffer_stop_read_timer(buf);
- return NOTIFY_OK;
-
- case CPU_DEAD:
- case CPU_DEAD_FROZEN:
- /*
- * Performing a buffer switch on a remote CPU. Performed by
- * the CPU responsible for doing the hotunplug after the target
- * CPU stopped running completely. Ensures that all data
- * from that remote CPU is flushed.
- */
- lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
- return NOTIFY_OK;
-
- default:
- return NOTIFY_DONE;
- }
-}
-#endif
-
-#if defined(CONFIG_NO_HZ) && defined(CONFIG_LIB_RING_BUFFER)
-/*
- * For per-cpu buffers, call the reader wakeups before switching the buffer, so
- * that wake-up-tracing generated events are flushed before going idle (in
- * tick_nohz). We test if the spinlock is locked to deal with the race where
- * readers try to sample the ring buffer before we perform the switch. We let
- * the readers retry in that case. If there is data in the buffer, the wake up
- * is going to forbid the CPU running the reader thread from going idle.
- */
-static int notrace ring_buffer_tick_nohz_callback(struct notifier_block *nb,
- unsigned long val,
- void *data)
-{
- struct channel *chan = caa_container_of(nb, struct channel,
- tick_nohz_notifier);
- const struct lib_ring_buffer_config *config = chan->backend.config;
- struct lib_ring_buffer *buf;
- int cpu = smp_processor_id();
-
- if (config->alloc != RING_BUFFER_ALLOC_PER_CPU) {
- /*
- * We don't support keeping the system idle with global buffers
- * and streaming active. In order to do so, we would need to
- * sample a non-nohz-cpumask racelessly with the nohz updates
- * without adding synchronization overhead to nohz. Leave this
- * use-case out for now.
- */
- return 0;
- }
-
- buf = channel_get_ring_buffer(config, chan, cpu);
- switch (val) {
- case TICK_NOHZ_FLUSH:
- raw_spin_lock(&buf->raw_tick_nohz_spinlock);
- if (config->wakeup == RING_BUFFER_WAKEUP_BY_TIMER
- && chan->read_timer_interval
- && atomic_long_read(&buf->active_readers)
- && (lib_ring_buffer_poll_deliver(config, buf, chan)
- || lib_ring_buffer_pending_data(config, buf, chan))) {
- wake_up_interruptible(&buf->read_wait);
- wake_up_interruptible(&chan->read_wait);
- }
- if (chan->switch_timer_interval)
- lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
- raw_spin_unlock(&buf->raw_tick_nohz_spinlock);
- break;
- case TICK_NOHZ_STOP:
- spin_lock(&__get_cpu_var(ring_buffer_nohz_lock));
- lib_ring_buffer_stop_switch_timer(buf);
- lib_ring_buffer_stop_read_timer(buf);
- spin_unlock(&__get_cpu_var(ring_buffer_nohz_lock));
- break;
- case TICK_NOHZ_RESTART:
- spin_lock(&__get_cpu_var(ring_buffer_nohz_lock));
- lib_ring_buffer_start_read_timer(buf);
- lib_ring_buffer_start_switch_timer(buf);
- spin_unlock(&__get_cpu_var(ring_buffer_nohz_lock));
- break;
- }
-
- return 0;
-}
-
-void notrace lib_ring_buffer_tick_nohz_flush(void)
-{
- atomic_notifier_call_chain(&tick_nohz_notifier, TICK_NOHZ_FLUSH,
- NULL);
-}
-
-void notrace lib_ring_buffer_tick_nohz_stop(void)
-{
- atomic_notifier_call_chain(&tick_nohz_notifier, TICK_NOHZ_STOP,
- NULL);
-}
-
-void notrace lib_ring_buffer_tick_nohz_restart(void)
-{
- atomic_notifier_call_chain(&tick_nohz_notifier, TICK_NOHZ_RESTART,
- NULL);
-}
-#endif /* defined(CONFIG_NO_HZ) && defined(CONFIG_LIB_RING_BUFFER) */
-
-/*
- * Holds CPU hotplug.
- */
static void channel_unregister_notifiers(struct channel *chan)
{
const struct lib_ring_buffer_config *config = chan->backend.config;
int cpu;
- channel_iterator_unregister_notifiers(chan);
if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) {
-#ifdef CONFIG_NO_HZ
- /*
- * Remove the nohz notifier first, so we are certain we stop
- * the timers.
- */
- atomic_notifier_chain_unregister(&tick_nohz_notifier,
- &chan->tick_nohz_notifier);
- /*
- * ring_buffer_nohz_lock will not be needed below, because
- * we just removed the notifiers, which were the only source of
- * concurrency.
- */
-#endif /* CONFIG_NO_HZ */
-#ifdef CONFIG_HOTPLUG_CPU
- get_online_cpus();
- chan->cpu_hp_enable = 0;
- for_each_online_cpu(cpu) {
- struct lib_ring_buffer *buf = per_cpu_ptr(chan->backend.buf,
- cpu);
- lib_ring_buffer_stop_switch_timer(buf);
- lib_ring_buffer_stop_read_timer(buf);
- }
- put_online_cpus();
- unregister_cpu_notifier(&chan->cpu_hp_notifier);
-#else
for_each_possible_cpu(cpu) {
- struct lib_ring_buffer *buf = per_cpu_ptr(chan->backend.buf,
- cpu);
+ struct lib_ring_buffer *buf = &shmp(chan->backend.buf)[cpu];
+
lib_ring_buffer_stop_switch_timer(buf);
lib_ring_buffer_stop_read_timer(buf);
}
-#endif
} else {
- struct lib_ring_buffer *buf = chan->backend.buf;
+ struct lib_ring_buffer *buf = shmp(chan->backend.buf);
lib_ring_buffer_stop_switch_timer(buf);
lib_ring_buffer_stop_read_timer(buf);
static void channel_free(struct channel *chan)
{
- channel_iterator_free(chan);
channel_backend_free(&chan->backend);
- kfree(chan);
+ free(chan);
}
/**
* padding to let readers get those sub-buffers.
* Used for live streaming.
* @read_timer_interval: Time interval (in us) to wake up pending readers.
+ * @shmid: shared memory ID (output)
*
* Holds cpu hotplug.
* Returns NULL on failure.
const char *name, void *priv, void *buf_addr,
size_t subbuf_size,
size_t num_subbuf, unsigned int switch_timer_interval,
- unsigned int read_timer_interval)
+ unsigned int read_timer_interval,
+ int *shmid)
{
int ret, cpu;
struct channel *chan;
+ size_t shmsize, bufshmsize;
+ struct shm_header *shm_header;
+ unsigned long num_subbuf_alloc;
if (lib_ring_buffer_check_config(config, switch_timer_interval,
read_timer_interval))
return NULL;
- chan = kzalloc(sizeof(struct channel), GFP_KERNEL);
- if (!chan)
+ /* Calculate the shm allocation layout */
+ shmsize = sizeof(struct shm_header);
+ shmsize += sizeof(struct channel);
+
+ /* Per-cpu buffer size: control (prior to backend) */
+ bufshmsize = sizeof(struct lib_ring_buffer);
+ shmsize += bufshmsize * num_possible_cpus();
+
+ /* Per-cpu buffer size: backend */
+ /* num_subbuf + 1 is the worse case */
+ num_subbuf_alloc = num_subbuf + 1;
+ bufshmsize = sizeof(struct lib_ring_buffer_backend_pages *) * num_subbuf_alloc;
+ bufshmsize += subbuf_size * (num_subbuf_alloc);
+ bufshmsize += (sizeof(struct lib_ring_buffer_backend_pages) + subbuf_size) * num_subbuf_alloc;
+ bufshmsize += sizeof(struct lib_ring_buffer_backend_subbuffer) * num_subbuf;
+ shmsize += bufshmsize * num_possible_cpus();
+
+ /* Per-cpu buffer size: control (after backend) */
+ bufshmsize += sizeof(struct commit_counters_hot) * num_subbuf;
+ bufshmsize += sizeof(struct commit_counters_cold) * num_subbuf;
+
+ /* Allocate shm */
+ *shmid = shmget(getpid(), shmsize, IPC_CREAT | IPC_EXCL | 0700);
+ if (*shmid < 0) {
+ if (errno == EINVAL)
+ ERR("shmget() returned EINVAL; maybe /proc/sys/kernel/shmmax should be increased.");
+ else
+ PERROR("shmget");
return NULL;
+ }
- ret = channel_backend_init(&chan->backend, name, config, priv,
- subbuf_size, num_subbuf);
- if (ret)
- goto error;
+ shm_header = shmat(*shmid, NULL, 0);
+ if (shm_header == (void *) -1) {
+ perror("shmat");
+ goto destroy_shmem;
+ }
- ret = channel_iterator_init(chan);
+ /* Already mark the shared memory for destruction. This will occur only
+ * when all users have detached.
+ */
+ ret = shmctl(*shmid, IPC_RMID, NULL);
+ if (ret == -1) {
+ perror("shmctl");
+ goto destroy_shmem;
+ }
+
+ shm_header->magic = SHM_MAGIC;
+ shm_header->major = SHM_MAJOR;
+ shm_header->major = SHM_MINOR;
+ shm_header->bits_per_long = CAA_BITS_PER_LONG;
+ shm_header->shm_size = shmsize;
+ shm_header->shm_allocated = sizeof(struct shm_header);
+
+ chan = zalloc_shm(shm_header, sizeof(struct channel));
+ if (!chan)
+ goto destroy_shmem;
+ set_shmp(shm_header->chan, chan);
+
+ ret = channel_backend_init(&chan->backend, name, config, priv,
+ subbuf_size, num_subbuf, shm_header);
if (ret)
- goto error_free_backend;
+ goto destroy_shmem;
chan->commit_count_mask = (~0UL >> chan->backend.num_subbuf_order);
- chan->switch_timer_interval = usecs_to_jiffies(switch_timer_interval);
- chan->read_timer_interval = usecs_to_jiffies(read_timer_interval);
- kref_init(&chan->ref);
- init_waitqueue_head(&chan->read_wait);
- init_waitqueue_head(&chan->hp_wait);
+ //TODO
+ //chan->switch_timer_interval = usecs_to_jiffies(switch_timer_interval);
+ //chan->read_timer_interval = usecs_to_jiffies(read_timer_interval);
+ urcu_ref_init(&chan->ref);
+ //TODO
+ //init_waitqueue_head(&chan->read_wait);
+ //init_waitqueue_head(&chan->hp_wait);
if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) {
-#if defined(CONFIG_NO_HZ) && defined(CONFIG_LIB_RING_BUFFER)
- /* Only benefit from NO_HZ idle with per-cpu buffers for now. */
- chan->tick_nohz_notifier.notifier_call =
- ring_buffer_tick_nohz_callback;
- chan->tick_nohz_notifier.priority = ~0U;
- atomic_notifier_chain_register(&tick_nohz_notifier,
- &chan->tick_nohz_notifier);
-#endif /* defined(CONFIG_NO_HZ) && defined(CONFIG_LIB_RING_BUFFER) */
-
/*
* In case of non-hotplug cpu, if the ring-buffer is allocated
* in early initcall, it will not be notified of secondary cpus.
* In that off case, we need to allocate for all possible cpus.
*/
-#ifdef CONFIG_HOTPLUG_CPU
- chan->cpu_hp_notifier.notifier_call =
- lib_ring_buffer_cpu_hp_callback;
- chan->cpu_hp_notifier.priority = 6;
- register_cpu_notifier(&chan->cpu_hp_notifier);
-
- get_online_cpus();
- for_each_online_cpu(cpu) {
- struct lib_ring_buffer *buf = per_cpu_ptr(chan->backend.buf,
- cpu);
- spin_lock(&per_cpu(ring_buffer_nohz_lock, cpu));
- lib_ring_buffer_start_switch_timer(buf);
- lib_ring_buffer_start_read_timer(buf);
- spin_unlock(&per_cpu(ring_buffer_nohz_lock, cpu));
- }
- chan->cpu_hp_enable = 1;
- put_online_cpus();
-#else
for_each_possible_cpu(cpu) {
- struct lib_ring_buffer *buf = per_cpu_ptr(chan->backend.buf,
- cpu);
- spin_lock(&per_cpu(ring_buffer_nohz_lock, cpu));
+ struct lib_ring_buffer *buf = &shmp(chan->backend.buf)[cpu];
lib_ring_buffer_start_switch_timer(buf);
lib_ring_buffer_start_read_timer(buf);
- spin_unlock(&per_cpu(ring_buffer_nohz_lock, cpu));
}
-#endif
} else {
- struct lib_ring_buffer *buf = chan->backend.buf;
+ struct lib_ring_buffer *buf = shmp(chan->backend.buf);
lib_ring_buffer_start_switch_timer(buf);
lib_ring_buffer_start_read_timer(buf);
return chan;
-error_free_backend:
- channel_backend_free(&chan->backend);
-error:
- kfree(chan);
+destroy_shmem:
+ ret = shmctl(*shmid, IPC_RMID, NULL);
+ if (ret == -1) {
+ perror("shmctl");
+ }
return NULL;
}
-EXPORT_SYMBOL_GPL(channel_create);
static
-void channel_release(struct kref *kref)
+void channel_release(struct urcu_ref *ref)
{
- struct channel *chan = caa_container_of(kref, struct channel, ref);
+ struct channel *chan = caa_container_of(ref, struct channel, ref);
channel_free(chan);
}
channel_unregister_notifiers(chan);
if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) {
- /*
- * No need to hold cpu hotplug, because all notifiers have been
- * unregistered.
- */
for_each_channel_cpu(cpu, chan) {
- struct lib_ring_buffer *buf = per_cpu_ptr(chan->backend.buf,
- cpu);
+ struct lib_ring_buffer *buf = &shmp(chan->backend.buf)[cpu];
if (config->cb.buffer_finalize)
config->cb.buffer_finalize(buf,
/*
* Perform flush before writing to finalized.
*/
- smp_wmb();
+ cmm_smp_wmb();
CMM_ACCESS_ONCE(buf->finalized) = 1;
- wake_up_interruptible(&buf->read_wait);
+ //wake_up_interruptible(&buf->read_wait);
}
} else {
- struct lib_ring_buffer *buf = chan->backend.buf;
+ struct lib_ring_buffer *buf = shmp(chan->backend.buf);
if (config->cb.buffer_finalize)
config->cb.buffer_finalize(buf, chan->backend.priv, -1);
/*
* Perform flush before writing to finalized.
*/
- smp_wmb();
+ cmm_smp_wmb();
CMM_ACCESS_ONCE(buf->finalized) = 1;
- wake_up_interruptible(&buf->read_wait);
+ //wake_up_interruptible(&buf->read_wait);
}
CMM_ACCESS_ONCE(chan->finalized) = 1;
- wake_up_interruptible(&chan->hp_wait);
- wake_up_interruptible(&chan->read_wait);
- kref_put(&chan->ref, channel_release);
+ //wake_up_interruptible(&chan->hp_wait);
+ //wake_up_interruptible(&chan->read_wait);
+ urcu_ref_put(&chan->ref, channel_release);
priv = chan->backend.priv;
return priv;
}
-EXPORT_SYMBOL_GPL(channel_destroy);
struct lib_ring_buffer *channel_get_ring_buffer(
const struct lib_ring_buffer_config *config,
struct channel *chan, int cpu)
{
if (config->alloc == RING_BUFFER_ALLOC_GLOBAL)
- return chan->backend.buf;
+ return shmp(chan->backend.buf);
else
- return per_cpu_ptr(chan->backend.buf, cpu);
+ return &shmp(chan->backend.buf)[cpu];
}
-EXPORT_SYMBOL_GPL(channel_get_ring_buffer);
int lib_ring_buffer_open_read(struct lib_ring_buffer *buf)
{
- struct channel *chan = buf->backend.chan;
+ struct channel *chan = shmp(buf->backend.chan);
- if (!atomic_long_add_unless(&buf->active_readers, 1, 1))
+ if (uatomic_cmpxchg(&buf->active_readers, 0, 1) != 0)
return -EBUSY;
- kref_get(&chan->ref);
- smp_mb__after_atomic_inc();
+ urcu_ref_get(&chan->ref);
+ cmm_smp_mb();
return 0;
}
-EXPORT_SYMBOL_GPL(lib_ring_buffer_open_read);
void lib_ring_buffer_release_read(struct lib_ring_buffer *buf)
{
- struct channel *chan = buf->backend.chan;
-
- CHAN_WARN_ON(chan, atomic_long_read(&buf->active_readers) != 1);
- smp_mb__before_atomic_dec();
- atomic_long_dec(&buf->active_readers);
- kref_put(&chan->ref, channel_release);
-}
-EXPORT_SYMBOL_GPL(lib_ring_buffer_release_read);
+ struct channel *chan = shmp(buf->backend.chan);
-/*
- * Promote compiler barrier to a smp_mb().
- * For the specific ring buffer case, this IPI call should be removed if the
- * architecture does not reorder writes. This should eventually be provided by
- * a separate architecture-specific infrastructure.
- */
-static void remote_mb(void *info)
-{
- smp_mb();
+ CHAN_WARN_ON(chan, uatomic_read(&buf->active_readers) != 1);
+ cmm_smp_mb();
+ uatomic_dec(&buf->active_readers);
+ urcu_ref_put(&chan->ref, channel_release);
}
/**
*
* Returns -ENODATA if buffer is finalized, -EAGAIN if there is currently no
* data to read at consumed position, or 0 if the get operation succeeds.
- * Busy-loop trying to get data if the tick_nohz sequence lock is held.
*/
int lib_ring_buffer_snapshot(struct lib_ring_buffer *buf,
unsigned long *consumed, unsigned long *produced)
{
- struct channel *chan = buf->backend.chan;
+ struct channel *chan = shmp(buf->backend.chan);
const struct lib_ring_buffer_config *config = chan->backend.config;
unsigned long consumed_cur, write_offset;
int finalized;
-retry:
finalized = CMM_ACCESS_ONCE(buf->finalized);
/*
* Read finalized before counters.
*/
- smp_rmb();
- consumed_cur = atomic_long_read(&buf->consumed);
+ cmm_smp_rmb();
+ consumed_cur = uatomic_read(&buf->consumed);
/*
* No need to issue a memory barrier between consumed count read and
* write offset read, because consumed count can only change
*/
if (finalized)
return -ENODATA;
- else if (raw_spin_is_locked(&buf->raw_tick_nohz_spinlock))
- goto retry;
else
return -EAGAIN;
}
-EXPORT_SYMBOL_GPL(lib_ring_buffer_snapshot);
/**
* lib_ring_buffer_put_snapshot - move consumed counter forward
unsigned long consumed_new)
{
struct lib_ring_buffer_backend *bufb = &buf->backend;
- struct channel *chan = bufb->chan;
+ struct channel *chan = shmp(bufb->chan);
unsigned long consumed;
- CHAN_WARN_ON(chan, atomic_long_read(&buf->active_readers) != 1);
+ CHAN_WARN_ON(chan, uatomic_read(&buf->active_readers) != 1);
/*
* Only push the consumed value forward.
* If the consumed cmpxchg fails, this is because we have been pushed by
* the writer in flight recorder mode.
*/
- consumed = atomic_long_read(&buf->consumed);
+ consumed = uatomic_read(&buf->consumed);
while ((long) consumed - (long) consumed_new < 0)
- consumed = atomic_long_cmpxchg(&buf->consumed, consumed,
- consumed_new);
+ consumed = uatomic_cmpxchg(&buf->consumed, consumed,
+ consumed_new);
}
-EXPORT_SYMBOL_GPL(lib_ring_buffer_move_consumer);
/**
* lib_ring_buffer_get_subbuf - get exclusive access to subbuffer for reading
*
* Returns -ENODATA if buffer is finalized, -EAGAIN if there is currently no
* data to read at consumed position, or 0 if the get operation succeeds.
- * Busy-loop trying to get data if the tick_nohz sequence lock is held.
*/
int lib_ring_buffer_get_subbuf(struct lib_ring_buffer *buf,
unsigned long consumed)
{
- struct channel *chan = buf->backend.chan;
+ struct channel *chan = shmp(buf->backend.chan);
const struct lib_ring_buffer_config *config = chan->backend.config;
unsigned long consumed_cur, consumed_idx, commit_count, write_offset;
int ret;
/*
* Read finalized before counters.
*/
- smp_rmb();
- consumed_cur = atomic_long_read(&buf->consumed);
+ cmm_smp_rmb();
+ consumed_cur = uatomic_read(&buf->consumed);
consumed_idx = subbuf_index(consumed, chan);
- commit_count = v_read(config, &buf->commit_cold[consumed_idx].cc_sb);
+ commit_count = v_read(config, &shmp(buf->commit_cold)[consumed_idx].cc_sb);
/*
* Make sure we read the commit count before reading the buffer
* data and the write offset. Correct consumed offset ordering
* wrt commit count is insured by the use of cmpxchg to update
* the consumed offset.
- * smp_call_function_single can fail if the remote CPU is offline,
- * this is OK because then there is no wmb to execute there.
- * If our thread is executing on the same CPU as the on the buffers
- * belongs to, we don't have to synchronize it at all. If we are
- * migrated, the scheduler will take care of the memory barriers.
- * Normally, smp_call_function_single() should ensure program order when
- * executing the remote function, which implies that it surrounds the
- * function execution with :
- * smp_mb()
- * send IPI
- * csd_lock_wait
- * recv IPI
- * smp_mb()
- * exec. function
- * smp_mb()
- * csd unlock
- * smp_mb()
- *
- * However, smp_call_function_single() does not seem to clearly execute
- * such barriers. It depends on spinlock semantic to provide the barrier
- * before executing the IPI and, when busy-looping, csd_lock_wait only
- * executes smp_mb() when it has to wait for the other CPU.
- *
- * I don't trust this code. Therefore, let's add the smp_mb() sequence
- * required ourself, even if duplicated. It has no performance impact
- * anyway.
- *
- * smp_mb() is needed because smp_rmb() and smp_wmb() only order read vs
- * read and write vs write. They do not ensure core synchronization. We
- * really have to ensure total order between the 3 barriers running on
- * the 2 CPUs.
*/
- if (config->ipi == RING_BUFFER_IPI_BARRIER) {
- if (config->sync == RING_BUFFER_SYNC_PER_CPU
- && config->alloc == RING_BUFFER_ALLOC_PER_CPU) {
- if (raw_smp_processor_id() != buf->backend.cpu) {
- /* Total order with IPI handler smp_mb() */
- smp_mb();
- smp_call_function_single(buf->backend.cpu,
- remote_mb, NULL, 1);
- /* Total order with IPI handler smp_mb() */
- smp_mb();
- }
- } else {
- /* Total order with IPI handler smp_mb() */
- smp_mb();
- smp_call_function(remote_mb, NULL, 1);
- /* Total order with IPI handler smp_mb() */
- smp_mb();
- }
- } else {
- /*
- * Local rmb to match the remote wmb to read the commit count
- * before the buffer data and the write offset.
- */
- smp_rmb();
- }
+ /*
+ * Local rmb to match the remote wmb to read the commit count
+ * before the buffer data and the write offset.
+ */
+ cmm_smp_rmb();
write_offset = v_read(config, &buf->offset);
*/
if (finalized)
return -ENODATA;
- else if (raw_spin_is_locked(&buf->raw_tick_nohz_spinlock))
- goto retry;
else
return -EAGAIN;
}
-EXPORT_SYMBOL_GPL(lib_ring_buffer_get_subbuf);
/**
* lib_ring_buffer_put_subbuf - release exclusive subbuffer access
void lib_ring_buffer_put_subbuf(struct lib_ring_buffer *buf)
{
struct lib_ring_buffer_backend *bufb = &buf->backend;
- struct channel *chan = bufb->chan;
+ struct channel *chan = shmp(bufb->chan);
const struct lib_ring_buffer_config *config = chan->backend.config;
unsigned long read_sb_bindex, consumed_idx, consumed;
- CHAN_WARN_ON(chan, atomic_long_read(&buf->active_readers) != 1);
+ CHAN_WARN_ON(chan, uatomic_read(&buf->active_readers) != 1);
if (!buf->get_subbuf) {
/*
*/
read_sb_bindex = subbuffer_id_get_index(config, bufb->buf_rsb.id);
v_add(config, v_read(config,
- &bufb->array[read_sb_bindex]->records_unread),
+ &shmp(bufb->array)[read_sb_bindex]->records_unread),
&bufb->records_read);
- v_set(config, &bufb->array[read_sb_bindex]->records_unread, 0);
+ v_set(config, &shmp(bufb->array)[read_sb_bindex]->records_unread, 0);
CHAN_WARN_ON(chan, config->mode == RING_BUFFER_OVERWRITE
&& subbuffer_id_is_noref(config, bufb->buf_rsb.id));
subbuffer_id_set_noref(config, &bufb->buf_rsb.id);
* if the writer concurrently updated it.
*/
}
-EXPORT_SYMBOL_GPL(lib_ring_buffer_put_subbuf);
/*
* cons_offset is an iterator on all subbuffer offsets between the reader
unsigned long cons_idx, commit_count, commit_count_sb;
cons_idx = subbuf_index(cons_offset, chan);
- commit_count = v_read(config, &buf->commit_hot[cons_idx].cc);
- commit_count_sb = v_read(config, &buf->commit_cold[cons_idx].cc_sb);
+ commit_count = v_read(config, &shmp(buf->commit_hot)[cons_idx].cc);
+ commit_count_sb = v_read(config, &shmp(buf->commit_cold)[cons_idx].cc_sb);
if (subbuf_offset(commit_count, chan) != 0)
- printk(KERN_WARNING
- "ring buffer %s, cpu %d: "
+ ERRMSG("ring buffer %s, cpu %d: "
"commit count in subbuffer %lu,\n"
"expecting multiples of %lu bytes\n"
" [ %lu bytes committed, %lu bytes reader-visible ]\n",
chan->backend.subbuf_size,
commit_count, commit_count_sb);
- printk(KERN_DEBUG "ring buffer: %s, cpu %d: %lu bytes committed\n",
+ ERRMSG("ring buffer: %s, cpu %d: %lu bytes committed\n",
chan->backend.name, cpu, commit_count);
}
* references are left.
*/
write_offset = v_read(config, &buf->offset);
- cons_offset = atomic_long_read(&buf->consumed);
+ cons_offset = uatomic_read(&buf->consumed);
if (write_offset != cons_offset)
- printk(KERN_WARNING
- "ring buffer %s, cpu %d: "
+ ERRMSG("ring buffer %s, cpu %d: "
"non-consumed data\n"
" [ %lu bytes written, %lu bytes read ]\n",
chan->backend.name, cpu, write_offset, cons_offset);
- for (cons_offset = atomic_long_read(&buf->consumed);
+ for (cons_offset = uatomic_read(&buf->consumed);
(long) (subbuf_trunc((unsigned long) v_read(config, &buf->offset),
chan)
- cons_offset) > 0;
const struct lib_ring_buffer_config *config = chan->backend.config;
void *priv = chan->backend.priv;
- printk(KERN_DEBUG "ring buffer %s, cpu %d: %lu records written, "
+ ERRMSG("ring buffer %s, cpu %d: %lu records written, "
"%lu records overrun\n",
chan->backend.name, cpu,
v_read(config, &buf->records_count),
if (v_read(config, &buf->records_lost_full)
|| v_read(config, &buf->records_lost_wrap)
|| v_read(config, &buf->records_lost_big))
- printk(KERN_WARNING
- "ring buffer %s, cpu %d: records were lost. Caused by:\n"
+ ERRMSG("ring buffer %s, cpu %d: records were lost. Caused by:\n"
" [ %lu buffer full, %lu nest buffer wrap-around, "
"%lu event too big ]\n",
chan->backend.name, cpu,
* Order all writes to buffer before the commit count update that will
* determine that the subbuffer is full.
*/
- if (config->ipi == RING_BUFFER_IPI_BARRIER) {
- /*
- * Must write slot data before incrementing commit count. This
- * compiler barrier is upgraded into a smp_mb() by the IPI sent
- * by get_subbuf().
- */
- barrier();
- } else
- smp_wmb();
+ cmm_smp_wmb();
v_add(config, config->cb.subbuffer_header_size(),
- &buf->commit_hot[oldidx].cc);
- commit_count = v_read(config, &buf->commit_hot[oldidx].cc);
+ &shmp(buf->commit_hot)[oldidx].cc);
+ commit_count = v_read(config, &shmp(buf->commit_hot)[oldidx].cc);
/* Check if the written buffer has to be delivered */
lib_ring_buffer_check_deliver(config, buf, chan, offsets->old,
commit_count, oldidx);
* Order all writes to buffer before the commit count update that will
* determine that the subbuffer is full.
*/
- if (config->ipi == RING_BUFFER_IPI_BARRIER) {
- /*
- * Must write slot data before incrementing commit count. This
- * compiler barrier is upgraded into a smp_mb() by the IPI sent
- * by get_subbuf().
- */
- barrier();
- } else
- smp_wmb();
- v_add(config, padding_size, &buf->commit_hot[oldidx].cc);
- commit_count = v_read(config, &buf->commit_hot[oldidx].cc);
+ cmm_smp_wmb();
+ v_add(config, padding_size, &shmp(buf->commit_hot)[oldidx].cc);
+ commit_count = v_read(config, &shmp(buf->commit_hot)[oldidx].cc);
lib_ring_buffer_check_deliver(config, buf, chan, offsets->old - 1,
commit_count, oldidx);
lib_ring_buffer_write_commit_counter(config, buf, chan, oldidx,
* Order all writes to buffer before the commit count update that will
* determine that the subbuffer is full.
*/
- if (config->ipi == RING_BUFFER_IPI_BARRIER) {
- /*
- * Must write slot data before incrementing commit count. This
- * compiler barrier is upgraded into a smp_mb() by the IPI sent
- * by get_subbuf().
- */
- barrier();
- } else
- smp_wmb();
+ cmm_smp_wmb();
v_add(config, config->cb.subbuffer_header_size(),
- &buf->commit_hot[beginidx].cc);
- commit_count = v_read(config, &buf->commit_hot[beginidx].cc);
+ &shmp(buf->commit_hot)[beginidx].cc);
+ commit_count = v_read(config, &shmp(buf->commit_hot)[beginidx].cc);
/* Check if the written buffer has to be delivered */
lib_ring_buffer_check_deliver(config, buf, chan, offsets->begin,
commit_count, beginidx);
* Order all writes to buffer before the commit count update that will
* determine that the subbuffer is full.
*/
- if (config->ipi == RING_BUFFER_IPI_BARRIER) {
- /*
- * Must write slot data before incrementing commit count. This
- * compiler barrier is upgraded into a smp_mb() by the IPI sent
- * by get_subbuf().
- */
- barrier();
- } else
- smp_wmb();
- v_add(config, padding_size, &buf->commit_hot[endidx].cc);
- commit_count = v_read(config, &buf->commit_hot[endidx].cc);
+ cmm_smp_wmb();
+ v_add(config, padding_size, &shmp(buf->commit_hot)[endidx].cc);
+ commit_count = v_read(config, &shmp(buf->commit_hot)[endidx].cc);
lib_ring_buffer_check_deliver(config, buf, chan, offsets->end - 1,
commit_count, endidx);
lib_ring_buffer_write_commit_counter(config, buf, chan, endidx,
* The next record that reserves space will be responsible for
* populating the following subbuffer header. We choose not to populate
* the next subbuffer header here because we want to be able to use
- * SWITCH_ACTIVE for periodical buffer flush and CPU tick_nohz stop
- * buffer flush, which must guarantee that all the buffer content
- * (records and header timestamps) are visible to the reader. This is
- * required for quiescence guarantees for the fusion merge.
+ * SWITCH_ACTIVE for periodical buffer flush, which must
+ * guarantee that all the buffer content (records and header
+ * timestamps) are visible to the reader. This is required for
+ * quiescence guarantees for the fusion merge.
*/
if (mode == SWITCH_FLUSH || off > 0) {
if (unlikely(off == 0)) {
*/
void lib_ring_buffer_switch_slow(struct lib_ring_buffer *buf, enum switch_mode mode)
{
- struct channel *chan = buf->backend.chan;
+ struct channel *chan = shmp(buf->backend.chan);
const struct lib_ring_buffer_config *config = chan->backend.config;
struct switch_offsets offsets;
unsigned long oldidx;
*/
lib_ring_buffer_switch_old_end(buf, chan, &offsets, tsc);
}
-EXPORT_SYMBOL_GPL(lib_ring_buffer_switch_slow);
/*
* Returns :
(buf_trunc(offsets->begin, chan)
>> chan->backend.num_subbuf_order)
- ((unsigned long) v_read(config,
- &buf->commit_cold[sb_index].cc_sb)
+ &shmp(buf->commit_cold)[sb_index].cc_sb)
& chan->commit_count_mask);
if (likely(reserve_commit_diff == 0)) {
/* Next subbuffer not being written to. */
if (unlikely(config->mode != RING_BUFFER_OVERWRITE &&
subbuf_trunc(offsets->begin, chan)
- subbuf_trunc((unsigned long)
- atomic_long_read(&buf->consumed), chan)
+ uatomic_read(&buf->consumed), chan)
>= chan->backend.buf_size)) {
/*
* We do not overwrite non consumed buffers
int ret;
if (config->alloc == RING_BUFFER_ALLOC_PER_CPU)
- buf = per_cpu_ptr(chan->backend.buf, ctx->cpu);
+ buf = &shmp(chan->backend.buf)[ctx->cpu];
else
- buf = chan->backend.buf;
+ buf = shmp(chan->backend.buf);
ctx->buf = buf;
offsets.size = 0;
ctx->buf_offset = offsets.begin + offsets.pre_header_padding;
return 0;
}
-EXPORT_SYMBOL_GPL(lib_ring_buffer_reserve_slow);
--- /dev/null
+#ifndef _LIBRINGBUFFER_SHM_H
+#define _LIBRINGBUFFER_SHM_H
+
+/*
+ * libringbuffer/shm.h
+ *
+ * Copyright 2011 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * Dual LGPL v2.1/GPL v2 license.
+ */
+
+#include <stdint.h>
+#include "ust/core.h"
+
+#define SHM_MAGIC 0x54335433
+#define SHM_MAJOR 0
+#define SHM_MINOR 1
+
+/*
+ * Defining a max shm offset, for debugging purposes.
+ */
+#if (CAA_BITS_PER_LONG == 32)
+/* Define the maximum shared memory size to 128MB on 32-bit machines */
+#define MAX_SHM_SIZE 134217728
+#else
+/* Define the maximum shared memory size to 8GB on 64-bit machines */
+#define MAX_SHM_SIZE 8589934592
+#endif
+
+#define DECLARE_SHMP(type, name) type *****name
+
+struct shm_header {
+ uint32_t magic;
+ uint8_t major;
+ uint8_t minor;
+ uint8_t bits_per_long;
+ size_t shm_size, shm_allocated;
+
+ DECLARE_SHMP(struct channel, chan);
+};
+
+#define shmp(shm_offset) \
+ ((__typeof__(****(shm_offset))) (((char *) &(shm_offset)) + (ptrdiff_t) (shm_offset)))
+
+#define _shmp_abs(a) ((a < 0) ? -(a) : (a))
+
+static inline
+void _set_shmp(ptrdiff_t *shm_offset, void *ptr)
+{
+ *shm_offset = (((char *) ptr) - ((char *) shm_offset));
+ assert(_shmp_abs(*shm_offset) < MAX_SHM_SIZE);
+}
+
+#define set_shmp(shm_offset, ptr) \
+ _set_shmp((ptrdiff_t *) ****(shm_offset), ptr)
+
+/* Shared memory is already zeroed by shmget */
+/* *NOT* multithread-safe (should be protected by mutex) */
+static inline
+void *zalloc_shm(struct shm_header *shm_header, size_t len)
+{
+ void *ret;
+
+ if (shm_header->shm_size - shm_header->shm_allocated < len)
+ return NULL;
+ ret = (char *) shm_header + shm_header->shm_allocated;
+ shm_header->shm_allocated += len;
+ return ret;
+}
+
+#endif /* _LIBRINGBUFFER_SHM_H */
--- /dev/null
+/*
+ * libust/smp.c
+ *
+ * Copyright 2011 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * Dual LGPL v2.1/GPL v2 license.
+ */
+
+#include <unistd.h>
+#include "ust/core.h"
+#include "usterr.h"
+#include <pthread.h>
+#include "smp.h"
+
+int __num_possible_cpus;
+
+void _get_num_possible_cpus(void)
+{
+ int result;
+
+ /* On Linux, when some processors are offline
+ * _SC_NPROCESSORS_CONF counts the offline
+ * processors, whereas _SC_NPROCESSORS_ONLN
+ * does not. If we used _SC_NPROCESSORS_ONLN,
+ * getcpu() could return a value greater than
+ * this sysconf, in which case the arrays
+ * indexed by processor would overflow.
+ */
+ result = sysconf(_SC_NPROCESSORS_CONF);
+ if (result == -1)
+ return;
+ __num_possible_cpus = result;
+}
--- /dev/null
+#ifndef _LIBRINGBUFFER_SMP_H
+#define _LIBRINGBUFFER_SMP_H
+
+/*
+ * libringbuffer/smp.h
+ *
+ * Copyright 2011 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * Dual LGPL v2.1/GPL v2 license.
+ */
+
+#include <ust/core.h>
+
+/*
+ * 4kB of per-cpu data available. Enough to hold the control structures,
+ * but not ring buffers.
+ */
+#define PER_CPU_MEM_SIZE 4096
+
+extern int __num_possible_cpus;
+extern void _get_num_possible_cpus(void);
+
+static inline
+int num_possible_cpus(void)
+{
+ if (!__num_possible_cpus)
+ _get_num_possible_cpus();
+ return __num_possible_cpus;
+}
+
+/*
+ * get_cpu() returns the current CPU number. It may change due to
+ * migration, so it is only statistically accurate.
+ */
+#ifndef UST_VALGRIND
+static inline
+int get_cpu(void)
+{
+ int cpu;
+
+ cpu = sched_getcpu();
+ if (likely(cpu >= 0))
+ return cpu;
+ /*
+ * If getcpu(2) is not implemented in the Kernel use CPU 0 as fallback.
+ */
+ return 0;
+}
+
+#else /* #else #ifndef UST_VALGRIND */
+static inline
+int get_cpu(void)
+{
+ /*
+ * Valgrind does not support the sched_getcpu() vsyscall.
+ * It causes it to detect a segfault in the program and stop it.
+ * So if we want to check libust with valgrind, we have to refrain
+ * from using this call. TODO: it would probably be better to return
+ * other values too, to better test it.
+ */
+ return 0;
+}
+#endif /* #else #ifndef UST_VALGRIND */
+
+static inline
+void put_cpu(void)
+{
+}
+
+#define for_each_possible_cpu(cpu) \
+ for ((cpu) = 0; (cpu) < num_possible_cpus(); (cpu)++)
+
+#endif /* _LIBRINGBUFFER_SMP_H */
static void ltt_force_switch(struct ust_buffer *buf,
enum force_switch_mode mode);
-static int get_n_cpus(void)
-{
- int result;
- static int n_cpus = 0;
-
- if(!n_cpus) {
- /* On Linux, when some processors are offline
- * _SC_NPROCESSORS_CONF counts the offline
- * processors, whereas _SC_NPROCESSORS_ONLN
- * does not. If we used _SC_NPROCESSORS_ONLN,
- * getcpu() could return a value greater than
- * this sysconf, in which case the arrays
- * indexed by processor would overflow.
- */
- result = sysconf(_SC_NPROCESSORS_CONF);
- if(result == -1) {
- return -1;
- }
-
- n_cpus = result;
- }
-
- return n_cpus;
-}
-
/**
* _ust_buffers_strncpy_fixup - Fix an incomplete string in a ltt_relay buffer.
* @buf : buffer
header->freq_scale = trace->freq_scale;
}
-#ifndef UST_VALGRIND
-
-static __inline__ int ust_get_cpu(void)
-{
- int cpu;
-
- cpu = sched_getcpu();
- if (likely(cpu >= 0))
- return cpu;
- /*
- * If getcpu(2) is not implemented in the Kernel use CPU 0 as fallback.
- */
- return 0;
-}
-
-#else /* #else #ifndef UST_VALGRIND */
-
-static __inline__ int ust_get_cpu(void)
-{
- /*
- * Valgrind does not support the sched_getcpu() vsyscall.
- * It causes it to detect a segfault in the program and stop it.
- * So if we want to check libust with valgrind, we have to refrain
- * from using this call. TODO: it would probably be better to return
- * other values too, to better test it.
- */
- return 0;
-}
-
-#endif /* #else #ifndef UST_VALGRIND */
-
/*
* Size reserved for high priority events (interrupts, NMI, BH) at the end of a
* nearly full buffer. User space won't use this last amount of space when in
projects / lttng-ust.git / commitdiff
