Re: [PATCH] mm: avoid livelock on !__GFP_FS allocations
From: David Rientjes <rientjes@google.com>
Date: 2011-11-15 21:40:46
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lkml
On Mon, 14 Nov 2011, Mel Gorman wrote:
quoted hunk ↗ jump to hunk
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 9dd443d..5402897 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c@@ -127,6 +127,20 @@ void pm_restrict_gfp_mask(void) saved_gfp_mask = gfp_allowed_mask; gfp_allowed_mask &= ~GFP_IOFS; } + +static bool pm_suspending(void) +{ + if ((gfp_allowed_mask & GFP_IOFS) == GFP_IOFS) + return false; + return true; +} + +#else + +static bool pm_suspending(void) +{ + return false; +} #endif /* CONFIG_PM_SLEEP */ #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE@@ -2214,6 +2228,14 @@ rebalance: goto restart; } + + /* + * Suspend converts GFP_KERNEL to __GFP_WAIT which can + * prevent reclaim making forward progress without + * invoking OOM. Bail if we are suspending + */ + if (pm_suspending()) + goto nopage; } /* Check if we should retry the allocation */
This allows all __GFP_NOFAIL allocations to fail while pm_restrict_gfp_mask() is in effect, so I disagree with this unless it is moved into the should_alloc_retry() logic. If you pass did_some_progress into that function and then moved the check for __GFP_NOFAIL right under the check for __GFP_NORETRY and checked for pm_suspending() there (and before the check for PAGE_ALLOC_COSTLY_ORDER) then it would allow the infinite loop for __GFP_NOFAIL which is required if __GFP_WAIT. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>