[PATCH v4 1/3] mm/free_pcppages_bulk: update pcp->count inside

[Aaron Lu]

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.

Suggested-by: Matthew Wilcox <wi...@infradead.org>
Signed-off-by: Aaron Lu <aaron...@intel.com>
---
 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 cb416723538f..faa33eac1635 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1148,6 +1148,7 @@ 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 */
@@ -2416,10 +2417,8 @@ 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
@@ -2441,10 +2440,8 @@ 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);
 }
 
@@ -2668,7 +2665,6 @@ 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;
        }
 }
 
-- 
2.14.3