| 1 | /* |
| 2 | * lttng-context-need-reschedule.c |
| 3 | * |
| 4 | * LTTng need_reschedule context. |
| 5 | * |
| 6 | * Copyright (C) 2009-2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 7 | * |
| 8 | * This library is free software; you can redistribute it and/or |
| 9 | * modify it under the terms of the GNU Lesser General Public |
| 10 | * License as published by the Free Software Foundation; only |
| 11 | * version 2.1 of the License. |
| 12 | * |
| 13 | * This library is distributed in the hope that it will be useful, |
| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 16 | * Lesser General Public License for more details. |
| 17 | * |
| 18 | * You should have received a copy of the GNU Lesser General Public |
| 19 | * License along with this library; if not, write to the Free Software |
| 20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 21 | */ |
| 22 | |
| 23 | #include <linux/module.h> |
| 24 | #include <linux/slab.h> |
| 25 | #include <linux/sched.h> |
| 26 | #include <linux/irqflags.h> |
| 27 | #include "lttng-events.h" |
| 28 | #include "wrapper/ringbuffer/frontend_types.h" |
| 29 | #include "wrapper/vmalloc.h" |
| 30 | #include "lttng-tracer.h" |
| 31 | |
| 32 | static |
| 33 | size_t need_reschedule_get_size(size_t offset) |
| 34 | { |
| 35 | size_t size = 0; |
| 36 | |
| 37 | size += lib_ring_buffer_align(offset, lttng_alignof(uint8_t)); |
| 38 | size += sizeof(uint8_t); |
| 39 | return size; |
| 40 | } |
| 41 | |
| 42 | static |
| 43 | void need_reschedule_record(struct lttng_ctx_field *field, |
| 44 | struct lib_ring_buffer_ctx *ctx, |
| 45 | struct lttng_channel *chan) |
| 46 | { |
| 47 | uint8_t need_reschedule = test_tsk_need_resched(current); |
| 48 | |
| 49 | lib_ring_buffer_align_ctx(ctx, lttng_alignof(need_reschedule)); |
| 50 | chan->ops->event_write(ctx, &need_reschedule, sizeof(need_reschedule)); |
| 51 | } |
| 52 | |
| 53 | static |
| 54 | void need_reschedule_get_value(struct lttng_ctx_field *field, |
| 55 | struct lttng_probe_ctx *lttng_probe_ctx, |
| 56 | union lttng_ctx_value *value) |
| 57 | { |
| 58 | value->s64 = test_tsk_need_resched(current);; |
| 59 | } |
| 60 | |
| 61 | int lttng_add_need_reschedule_to_ctx(struct lttng_ctx **ctx) |
| 62 | { |
| 63 | struct lttng_ctx_field *field; |
| 64 | |
| 65 | field = lttng_append_context(ctx); |
| 66 | if (!field) |
| 67 | return -ENOMEM; |
| 68 | if (lttng_find_context(*ctx, "need_reschedule")) { |
| 69 | lttng_remove_context_field(ctx, field); |
| 70 | return -EEXIST; |
| 71 | } |
| 72 | field->event_field.name = "need_reschedule"; |
| 73 | field->event_field.type.atype = atype_integer; |
| 74 | field->event_field.type.u.basic.integer.size = sizeof(uint8_t) * CHAR_BIT; |
| 75 | field->event_field.type.u.basic.integer.alignment = lttng_alignof(uint8_t) * CHAR_BIT; |
| 76 | field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(uint8_t); |
| 77 | field->event_field.type.u.basic.integer.reverse_byte_order = 0; |
| 78 | field->event_field.type.u.basic.integer.base = 10; |
| 79 | field->event_field.type.u.basic.integer.encoding = lttng_encode_none; |
| 80 | field->get_size = need_reschedule_get_size; |
| 81 | field->record = need_reschedule_record; |
| 82 | field->get_value = need_reschedule_get_value; |
| 83 | lttng_context_update(*ctx); |
| 84 | wrapper_vmalloc_sync_all(); |
| 85 | return 0; |
| 86 | } |
| 87 | EXPORT_SYMBOL_GPL(lttng_add_need_reschedule_to_ctx); |