The patch titled
Subject: mm, page_alloc: set alloc_flags only once in slowpath
has been removed from the -mm tree. Its filename was
mm-page_alloc-set-alloc_flags-only-once-in-slowpath.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Vlastimil Babka <vbabka@xxxxxxx>
Subject: mm, page_alloc: set alloc_flags only once in slowpath
In __alloc_pages_slowpath(), alloc_flags doesn't change after it's
initialized, so move the initialization above the retry: label. Also make
the comment above the initialization more descriptive.
The only exception in the alloc_flags being constant is
ALLOC_NO_WATERMARKS, which may change due to TIF_MEMDIE being set on the
allocating thread. We can fix this, and make the code simpler and a bit
more effective at the same time, by moving the part that determines
ALLOC_NO_WATERMARKS from gfp_to_alloc_flags() to gfp_pfmemalloc_allowed().
This means we don't have to mask out ALLOC_NO_WATERMARKS in numerous
places in __alloc_pages_slowpath() anymore. The only two tests for the
flag can instead call gfp_pfmemalloc_allowed().
Link: http://lkml.kernel.org/r/20160721073614.24395-3-vbabka@xxxxxxx
Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Acked-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 52 +++++++++++++++++++++++-----------------------
1 file changed, 26 insertions(+), 26 deletions(-)
diff -puN mm/page_alloc.c~mm-page_alloc-set-alloc_flags-only-once-in-slowpath mm/page_alloc.c
--- a/mm/page_alloc.c~mm-page_alloc-set-alloc_flags-only-once-in-slowpath
+++ a/mm/page_alloc.c
@@ -3119,8 +3119,7 @@ __alloc_pages_direct_compact(gfp_t gfp_m
*/
count_vm_event(COMPACTSTALL);
- page = get_page_from_freelist(gfp_mask, order,
- alloc_flags & ~ALLOC_NO_WATERMARKS, ac);
+ page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
if (page) {
struct zone *zone = page_zone(page);
@@ -3288,8 +3287,7 @@ __alloc_pages_direct_reclaim(gfp_t gfp_m
return NULL;
retry:
- page = get_page_from_freelist(gfp_mask, order,
- alloc_flags & ~ALLOC_NO_WATERMARKS, ac);
+ page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
/*
* If an allocation failed after direct reclaim, it could be because
@@ -3351,16 +3349,6 @@ gfp_to_alloc_flags(gfp_t gfp_mask)
} else if (unlikely(rt_task(current)) && !in_interrupt())
alloc_flags |= ALLOC_HARDER;
- if (likely(!(gfp_mask & __GFP_NOMEMALLOC))) {
- if (gfp_mask & __GFP_MEMALLOC)
- alloc_flags |= ALLOC_NO_WATERMARKS;
- else if (in_serving_softirq() && (current->flags & PF_MEMALLOC))
- alloc_flags |= ALLOC_NO_WATERMARKS;
- else if (!in_interrupt() &&
- ((current->flags & PF_MEMALLOC) ||
- unlikely(test_thread_flag(TIF_MEMDIE))))
- alloc_flags |= ALLOC_NO_WATERMARKS;
- }
#ifdef CONFIG_CMA
if (gfpflags_to_migratetype(gfp_mask) == MIGRATE_MOVABLE)
alloc_flags |= ALLOC_CMA;
@@ -3370,7 +3358,19 @@ gfp_to_alloc_flags(gfp_t gfp_mask)
bool gfp_pfmemalloc_allowed(gfp_t gfp_mask)
{
- return !!(gfp_to_alloc_flags(gfp_mask) & ALLOC_NO_WATERMARKS);
+ if (unlikely(gfp_mask & __GFP_NOMEMALLOC))
+ return false;
+
+ if (gfp_mask & __GFP_MEMALLOC)
+ return true;
+ if (in_serving_softirq() && (current->flags & PF_MEMALLOC))
+ return true;
+ if (!in_interrupt() &&
+ ((current->flags & PF_MEMALLOC) ||
+ unlikely(test_thread_flag(TIF_MEMDIE))))
+ return true;
+
+ return false;
}
static inline bool is_thp_gfp_mask(gfp_t gfp_mask)
@@ -3503,36 +3503,36 @@ __alloc_pages_slowpath(gfp_t gfp_mask, u
(__GFP_ATOMIC|__GFP_DIRECT_RECLAIM)))
gfp_mask &= ~__GFP_ATOMIC;
-retry:
- if (gfp_mask & __GFP_KSWAPD_RECLAIM)
- wake_all_kswapds(order, ac);
-
/*
- * OK, we're below the kswapd watermark and have kicked background
- * reclaim. Now things get more complex, so set up alloc_flags according
- * to how we want to proceed.
+ * The fast path uses conservative alloc_flags to succeed only until
+ * kswapd needs to be woken up, and to avoid the cost of setting up
+ * alloc_flags precisely. So we do that now.
*/
alloc_flags = gfp_to_alloc_flags(gfp_mask);
+retry:
+ if (gfp_mask & __GFP_KSWAPD_RECLAIM)
+ wake_all_kswapds(order, ac);
+
/*
* Reset the zonelist iterators if memory policies can be ignored.
* These allocations are high priority and system rather than user
* orientated.
*/
- if ((alloc_flags & ALLOC_NO_WATERMARKS) || !(alloc_flags & ALLOC_CPUSET)) {
+ if (!(alloc_flags & ALLOC_CPUSET) || gfp_pfmemalloc_allowed(gfp_mask)) {
ac->zonelist = node_zonelist(numa_node_id(), gfp_mask);
ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
ac->high_zoneidx, ac->nodemask);
}
/* This is the last chance, in general, before the goto nopage. */
- page = get_page_from_freelist(gfp_mask, order,
- alloc_flags & ~ALLOC_NO_WATERMARKS, ac);
+ page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
if (page)
goto got_pg;
/* Allocate without watermarks if the context allows */
- if (alloc_flags & ALLOC_NO_WATERMARKS) {
+ if (gfp_pfmemalloc_allowed(gfp_mask)) {
+
page = get_page_from_freelist(gfp_mask, order,
ALLOC_NO_WATERMARKS, ac);
if (page)
_
Patches currently in -mm which might be from vbabka@xxxxxxx are
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