From: Michal Hocko <mhocko@kernel.org>
To: Aaron Lu <aaron.lu@intel.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Huang Ying <ying.huang@intel.com>,
Dave Hansen <dave.hansen@intel.com>,
Kemi Wang <kemi.wang@intel.com>,
Tim Chen <tim.c.chen@linux.intel.com>,
Andi Kleen <ak@linux.intel.com>, Vlastimil Babka <vbabka@suse.cz>,
Mel Gorman <mgorman@techsingularity.net>,
Matthew Wilcox <willy@infradead.org>,
David Rientjes <rientjes@google.com>
Subject: Re: [PATCH v4 1/3] mm/free_pcppages_bulk: update pcp->count inside
Date: Thu, 1 Mar 2018 14:45:12 +0100 [thread overview]
Message-ID: <20180301134512.GI15057@dhcp22.suse.cz> (raw)
In-Reply-To: <20180301062845.26038-2-aaron.lu@intel.com>
On Thu 01-03-18 14:28:43, Aaron Lu wrote:
> 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 <willy@infradead.org>
> Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Makes a lot of sense to me.
Acked-by: Michal Hocko <mhocko@suse.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
>
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2018-03-01 13:45 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-01 6:28 [PATCH v4 0/3] mm: improve zone->lock scalability Aaron Lu
2018-03-01 6:28 ` [PATCH v4 1/3] mm/free_pcppages_bulk: update pcp->count inside Aaron Lu
2018-03-01 12:11 ` David Rientjes
2018-03-01 13:45 ` Michal Hocko [this message]
2018-03-12 13:22 ` Vlastimil Babka
2018-03-13 2:11 ` Aaron Lu
2018-03-01 6:28 ` [PATCH v4 2/3] mm/free_pcppages_bulk: do not hold lock when picking pages to free Aaron Lu
2018-03-01 13:55 ` Michal Hocko
2018-03-02 7:15 ` Aaron Lu
2018-03-02 15:34 ` Dave Hansen
2018-03-02 7:31 ` Huang, Ying
2018-03-02 0:01 ` Andrew Morton
2018-03-02 8:01 ` Aaron Lu
2018-03-02 21:23 ` Andrew Morton
2018-03-02 21:25 ` Dave Hansen
2018-03-12 14:22 ` Vlastimil Babka
2018-03-13 3:34 ` Aaron Lu
2018-03-22 15:17 ` Matthew Wilcox
2018-03-26 3:03 ` Aaron Lu
2018-03-01 6:28 ` [PATCH v4 3/3] mm/free_pcppages_bulk: prefetch buddy while not holding lock Aaron Lu
2018-03-01 14:00 ` Michal Hocko
2018-03-02 8:31 ` Aaron Lu
2018-03-02 17:55 ` Vlastimil Babka
2018-03-02 18:00 ` Dave Hansen
2018-03-02 18:08 ` Vlastimil Babka
2018-03-05 11:41 ` Aaron Lu
2018-03-05 11:48 ` Aaron Lu
2018-03-06 7:55 ` Vlastimil Babka
2018-03-06 12:27 ` Aaron Lu
2018-03-06 12:53 ` Matthew Wilcox
2018-03-02 0:09 ` Andrew Morton
2018-03-02 8:27 ` Aaron Lu
2018-03-09 8:24 ` [PATCH v4 3/3 update] " Aaron Lu
2018-03-09 21:58 ` Andrew Morton
2018-03-10 14:46 ` Aaron Lu
2018-03-12 15:05 ` Vlastimil Babka
2018-03-12 17:32 ` Dave Hansen
2018-03-13 3:35 ` Aaron Lu
2018-03-13 7:04 ` Aaron Lu
2018-03-20 9:50 ` Vlastimil Babka
2018-03-20 11:31 ` [PATCH v4 3/3 update2] " Aaron Lu
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