From: Martin Leisener Date: Wed, 10 Jun 2015 13:17:37 +0000 (+0200) Subject: Fix: Building the event list fails on fragmented memory X-Git-Tag: v2.7.0-rc1~1 X-Git-Url: http://git.lttng.org./?a=commitdiff_plain;h=a606b6e893b99bc31cacee98415942dbc577c90c;hp=a606b6e893b99bc31cacee98415942dbc577c90c;p=lttng-modules.git Fix: Building the event list fails on fragmented memory On a small arm imx6 solo with 256MB RAM it often happens that memory becomes fragmented rather quickly, so that kmalloc will not be able to get enough consecutive pages (enocuntered for example if you enable all kernel events: lttng enable-event -k syscall --all). This patch switches the allocation to vmalloc. Tested for x86 on Ubuntu 12.04 Lts and on imx6 solo 256MB RAM If this patch is not applied, you can identify low and/or fragmented memory failures by looking at the kernel ring buffer (please ignore DMA, it is due to some memory setup misconfiguration, should read Normal): ... [ 321.993820] lttng-sessiond: page allocation failure: order:4, mode:0x1040d0 ... [ 321.994711] lowmem_reserve[]: 0 0 0 [ 321.994727] DMA: 801*4kB (UEMC) 424*8kB (EMC) 355*16kB (UEMC) 344*32kB (MC) 340*64kB (C) 8*128kB (C) 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB 0*8192kB 0*16384kB 0*32768kB = 46068kB [ Edit by Mathieu: use vzalloc() rather than vmalloc() + memset 0. ] Signed-off-by: Martin Leisener Signed-off-by: Mathieu Desnoyers ---