From c1ab059a21015f2e33547f5efb4bd92099999b58 Mon Sep 17 00:00:00 2001
From: Aaron Lu <aaron.lu@intel.com>
Date: Fri, 2 Mar 2018 11:08:02 +0000
Subject: [PATCH] mm/free_pcppages_bulk: update pcp->count inside
References: bnc#971975 VM performance -- page allocator
Patch-mainline: v4.17-rc1
Git-commit: 77ba9062e43c7e4966d9ff3afd87dca86542f86a
Matthew Wilcox found that all callers of free_pcppages_bulk() currently
update pcp->count immediately after so it's natural to do it inside
free_pcppages_bulk().
No functionality or performance change is expected from this patch.
Link: http://lkml.kernel.org/r/20180301062845.26038-2-aaron.lu@intel.com
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Kemi Wang <kemi.wang@intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
mm/page_alloc.c | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 05fb17ec8e7f..787958f28993 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1145,6 +1145,7 @@ static void free_pcppages_bulk(struct zone *zone, int count,
page = list_last_entry(list, struct page, lru);
/* must delete as __free_one_page list manipulates */
list_del(&page->lru);
+ pcp->count--;
mt = get_pcppage_migratetype(page);
/* MIGRATE_ISOLATE page should not go to pcplists */
@@ -2343,10 +2344,8 @@ void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
local_irq_save(flags);
batch = READ_ONCE(pcp->batch);
to_drain = min(pcp->count, batch);
- if (to_drain > 0) {
+ if (to_drain > 0)
free_pcppages_bulk(zone, to_drain, pcp);
- pcp->count -= to_drain;
- }
local_irq_restore(flags);
}
#endif
@@ -2368,10 +2367,8 @@ static void drain_pages_zone(unsigned int cpu, struct zone *zone)
pset = per_cpu_ptr(zone->pageset, cpu);
pcp = &pset->pcp;
- if (pcp->count) {
+ if (pcp->count)
free_pcppages_bulk(zone, pcp->count, pcp);
- pcp->count = 0;
- }
local_irq_restore(flags);
}
@@ -2595,7 +2592,6 @@ static void free_unref_page_commit(struct page *page, unsigned long pfn)
if (pcp->count >= pcp->high) {
unsigned long batch = READ_ONCE(pcp->batch);
free_pcppages_bulk(zone, batch, pcp);
- pcp->count -= batch;
}
}