From: Mel Gorman <[email protected]> commit 9ee493ce0a60bf42c0f8fd0b0fe91df5704a1cbf upstream.
When under significant memory pressure, a process enters direct reclaim and immediately afterwards tries to allocate a page. If it fails and no further progress is made, it's possible the system will go OOM. However, on systems with large amounts of memory, it's possible that a significant number of pages are on per-cpu lists and inaccessible to the calling process. This leads to a process entering direct reclaim more often than it should increasing the pressure on the system and compounding the problem. This patch notes that if direct reclaim is making progress but allocations are still failing that the system is already under heavy pressure. In this case, it drains the per-cpu lists and tries the allocation a second time before continuing. Signed-off-by: Mel Gorman <[email protected]> Reviewed-by: Minchan Kim <[email protected]> Reviewed-by: KAMEZAWA Hiroyuki <[email protected]> Reviewed-by: KOSAKI Motohiro <[email protected]> Reviewed-by: Christoph Lameter <[email protected]> Cc: Dave Chinner <[email protected]> Cc: Wu Fengguang <[email protected]> Cc: David Rientjes <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Paul Gortmaker <[email protected]> --- mm/page_alloc.c | 20 ++++++++++++++++---- 1 files changed, 16 insertions(+), 4 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 35268ac..a2af9bc 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1703,6 +1703,7 @@ __alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order, struct page *page = NULL; struct reclaim_state reclaim_state; struct task_struct *p = current; + bool drained = false; cond_resched(); @@ -1721,14 +1722,25 @@ __alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order, cond_resched(); - if (order != 0) - drain_all_pages(); + if (unlikely(!(*did_some_progress))) + return NULL; - if (likely(*did_some_progress)) - page = get_page_from_freelist(gfp_mask, nodemask, order, +retry: + page = get_page_from_freelist(gfp_mask, nodemask, order, zonelist, high_zoneidx, alloc_flags, preferred_zone, migratetype); + + /* + * If an allocation failed after direct reclaim, it could be because + * pages are pinned on the per-cpu lists. Drain them and try again + */ + if (!page && !drained) { + drain_all_pages(); + drained = true; + goto retry; + } + return page; } -- 1.7.3.3 _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
