[lkml]   [2010]   [Feb]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[patch 6/7 -mm] oom: avoid oom killer for lowmem allocations
If memory has been depleted in lowmem zones even with the protection
afforded to it by /proc/sys/vm/lowmem_reserve_ratio, it is unlikely that
killing current users will help. The memory is either reclaimable (or
migratable) already, in which case we should not invoke the oom killer at
all, or it is pinned by an application for I/O. Killing such an
application may leave the hardware in an unspecified state and there is
no guarantee that it will be able to make a timely exit.

Lowmem allocations are now failed in oom conditions so that the task can
perhaps recover or try again later. Killing current is an unnecessary
result for simply making a GFP_DMA or GFP_DMA32 page allocation and no
lowmem allocations use the now-deprecated __GFP_NOFAIL bit so retrying is

Previously, the heuristic provided some protection for those tasks with
CAP_SYS_RAWIO, but this is no longer necessary since we will not be
killing tasks for the purposes of ISA allocations.

Signed-off-by: David Rientjes <>
mm/page_alloc.c | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1914,6 +1914,9 @@ rebalance:
* running out of options and have to consider going OOM
if (!did_some_progress) {
+ /* The oom killer won't necessarily free lowmem */
+ if (high_zoneidx < ZONE_NORMAL)
+ goto nopage;
if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY)) {
if (oom_killer_disabled)
goto nopage;

 \ /
  Last update: 2010-02-10 17:35    [W:0.123 / U:1.776 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site