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mm, page_alloc: split alloc_pages_nodemask()

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alloc_pages_nodemask does a number of preperation steps that determine
what zones can be used for the allocation depending on a variety of
factors.  This is fine but a hypothetical caller that wanted multiple
order-0 pages has to do the preparation steps multiple times.  This
patch structures __alloc_pages_nodemask such that it's relatively easy
to build a bulk order-0 page allocator.  There is no functional change.

Link: http://lkml.kernel.org/r/20170123153906.3122-3-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Jesper Dangaard Brouer <brouer@redhat.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 2017-02-24 14:56:29 -08:00 committed by Linus Torvalds
parent 066b239355
commit 9cd7555875
1 changed files with 57 additions and 40 deletions
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97
mm/page_alloc.c
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@ -3855,6 +3855,60 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
return page;
}
static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order,
struct zonelist *zonelist, nodemask_t *nodemask,
struct alloc_context *ac, gfp_t *alloc_mask,
unsigned int *alloc_flags)
{
ac->high_zoneidx = gfp_zone(gfp_mask);
ac->zonelist = zonelist;
ac->nodemask = nodemask;
ac->migratetype = gfpflags_to_migratetype(gfp_mask);
if (cpusets_enabled()) {
*alloc_mask |= __GFP_HARDWALL;
*alloc_flags |= ALLOC_CPUSET;
if (!ac->nodemask)
ac->nodemask = &cpuset_current_mems_allowed;
}
lockdep_trace_alloc(gfp_mask);
might_sleep_if(gfp_mask & __GFP_DIRECT_RECLAIM);
if (should_fail_alloc_page(gfp_mask, order))
return false;
/*
* Check the zones suitable for the gfp_mask contain at least one
* valid zone. It's possible to have an empty zonelist as a result
* of __GFP_THISNODE and a memoryless node
*/
if (unlikely(!ac->zonelist->_zonerefs->zone))
return false;
if (IS_ENABLED(CONFIG_CMA) && ac->migratetype == MIGRATE_MOVABLE)
*alloc_flags |= ALLOC_CMA;
return true;
}
/* Determine whether to spread dirty pages and what the first usable zone */
static inline void finalise_ac(gfp_t gfp_mask,
unsigned int order, struct alloc_context *ac)
{
/* Dirty zone balancing only done in the fast path */
ac->spread_dirty_pages = (gfp_mask & __GFP_WRITE);
/*
* The preferred zone is used for statistics but crucially it is
* also used as the starting point for the zonelist iterator. It
* may get reset for allocations that ignore memory policies.
*/
ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
ac->high_zoneidx, ac->nodemask);
}
/*
* This is the 'heart' of the zoned buddy allocator.
*/
@ -3865,50 +3919,13 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
struct page *page;
unsigned int alloc_flags = ALLOC_WMARK_LOW;
gfp_t alloc_mask = gfp_mask; /* The gfp_t that was actually used for allocation */
struct alloc_context ac = {
.high_zoneidx = gfp_zone(gfp_mask),
.zonelist = zonelist,
.nodemask = nodemask,
.migratetype = gfpflags_to_migratetype(gfp_mask),
};
if (cpusets_enabled()) {
alloc_mask |= __GFP_HARDWALL;
alloc_flags |= ALLOC_CPUSET;
if (!ac.nodemask)
ac.nodemask = &cpuset_current_mems_allowed;
}
struct alloc_context ac = { };
gfp_mask &= gfp_allowed_mask;
lockdep_trace_alloc(gfp_mask);
might_sleep_if(gfp_mask & __GFP_DIRECT_RECLAIM);
if (should_fail_alloc_page(gfp_mask, order))
if (!prepare_alloc_pages(gfp_mask, order, zonelist, nodemask, &ac, &alloc_mask, &alloc_flags))
return NULL;
/*
* Check the zones suitable for the gfp_mask contain at least one
* valid zone. It's possible to have an empty zonelist as a result
* of __GFP_THISNODE and a memoryless node
*/
if (unlikely(!zonelist->_zonerefs->zone))
return NULL;
if (IS_ENABLED(CONFIG_CMA) && ac.migratetype == MIGRATE_MOVABLE)
alloc_flags |= ALLOC_CMA;
/* Dirty zone balancing only done in the fast path */
ac.spread_dirty_pages = (gfp_mask & __GFP_WRITE);
/*
* The preferred zone is used for statistics but crucially it is
* also used as the starting point for the zonelist iterator. It
* may get reset for allocations that ignore memory policies.
*/
ac.preferred_zoneref = first_zones_zonelist(ac.zonelist,
ac.high_zoneidx, ac.nodemask);
finalise_ac(gfp_mask, order, &ac);
if (!ac.preferred_zoneref->zone) {
page = NULL;
/*