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mm: introduce __GFP_MEMALLOC to allow access to emergency reserves

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__GFP_MEMALLOC will allow the allocation to disregard the watermarks, much
like PF_MEMALLOC.  It allows one to pass along the memalloc state in
object related allocation flags as opposed to task related flags, such as
sk->sk_allocation.  This removes the need for ALLOC_PFMEMALLOC as callers
using __GFP_MEMALLOC can get the ALLOC_NO_WATERMARK flag which is now
enough to identify allocations related to page reclaim.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: David Miller <davem@davemloft.net>
Cc: Neil Brown <neilb@suse.de>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mel Gorman
2012-07-31 16:44:03 -07:00
committed by Linus Torvalds
parent 5091b74a95
commit b37f1dd0f5
5 changed files with 21 additions and 16 deletions
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22
mm/page_alloc.c
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@@ -1513,7 +1513,6 @@ failed:
#define ALLOC_HARDER 0x10 /* try to alloc harder */
#define ALLOC_HIGH 0x20 /* __GFP_HIGH set */
#define ALLOC_CPUSET 0x40 /* check for correct cpuset */
#define ALLOC_PFMEMALLOC 0x80 /* Caller has PF_MEMALLOC set */
#ifdef CONFIG_FAIL_PAGE_ALLOC
@@ -2294,11 +2293,10 @@ gfp_to_alloc_flags(gfp_t gfp_mask)
} else if (unlikely(rt_task(current)) && !in_interrupt())
alloc_flags |= ALLOC_HARDER;
if ((current->flags & PF_MEMALLOC) ||
unlikely(test_thread_flag(TIF_MEMDIE))) {
alloc_flags |= ALLOC_PFMEMALLOC;
if (likely(!(gfp_mask & __GFP_NOMEMALLOC)) && !in_interrupt())
if (likely(!(gfp_mask & __GFP_NOMEMALLOC))) {
if (gfp_mask & __GFP_MEMALLOC)
alloc_flags |= ALLOC_NO_WATERMARKS;
else if (likely(!(gfp_mask & __GFP_NOMEMALLOC)) && !in_interrupt())
alloc_flags |= ALLOC_NO_WATERMARKS;
}
@@ -2307,7 +2305,7 @@ gfp_to_alloc_flags(gfp_t gfp_mask)
bool gfp_pfmemalloc_allowed(gfp_t gfp_mask)
{
return !!(gfp_to_alloc_flags(gfp_mask) & ALLOC_PFMEMALLOC);
return !!(gfp_to_alloc_flags(gfp_mask) & ALLOC_NO_WATERMARKS);
}
static inline struct page *
@@ -2498,12 +2496,12 @@ nopage:
return page;
got_pg:
/*
* page->pfmemalloc is set when the caller had PFMEMALLOC set or is
* been OOM killed. The expectation is that the caller is taking
* steps that will free more memory. The caller should avoid the
* page being used for !PFMEMALLOC purposes.
* page->pfmemalloc is set when the caller had PFMEMALLOC set, is
* been OOM killed or specified __GFP_MEMALLOC. The expectation is
* that the caller is taking steps that will free more memory. The
* caller should avoid the page being used for !PFMEMALLOC purposes.
*/
page->pfmemalloc = !!(alloc_flags & ALLOC_PFMEMALLOC);
page->pfmemalloc = !!(alloc_flags & ALLOC_NO_WATERMARKS);
if (kmemcheck_enabled)
kmemcheck_pagealloc_alloc(page, order, gfp_mask);