From: Vlastimil Babka <vbabka@suse.cz>
To: Mel Gorman <mgorman@techsingularity.net>,
Andrew Morton <akpm@linux-foundation.org>
Cc: Aaron Lu <aaron.lu@intel.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Michal Hocko <mhocko@kernel.org>,
Jesper Dangaard Brouer <brouer@redhat.com>,
LKML <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>
Subject: Re: [PATCH 2/6] mm/page_alloc: Track range of active PCP lists during bulk free
Date: Thu, 17 Feb 2022 10:41:50 +0100 [thread overview]
Message-ID: <83d6e082-9289-e8cb-2e40-77650e2bb375@suse.cz> (raw)
In-Reply-To: <20220217002227.5739-3-mgorman@techsingularity.net>
On 2/17/22 01:22, Mel Gorman wrote:
> free_pcppages_bulk() frees pages in a round-robin fashion. Originally,
> this was dealing only with migratetypes but storing high-order pages
> means that there can be many more empty lists that are uselessly
> checked. Track the minimum and maximum active pindex to reduce the
> search space.
>
> Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
> ---
> mm/page_alloc.c | 17 +++++++++++++----
> 1 file changed, 13 insertions(+), 4 deletions(-)
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 08de32cfd9bb..85cc1fe8bcc5 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -1450,6 +1450,8 @@ static void free_pcppages_bulk(struct zone *zone, int count,
> struct per_cpu_pages *pcp)
> {
> int pindex = 0;
> + int min_pindex = 0;
> + int max_pindex = NR_PCP_LISTS - 1;
> int batch_free = 0;
> int nr_freed = 0;
> unsigned int order;
> @@ -1475,13 +1477,20 @@ static void free_pcppages_bulk(struct zone *zone, int count,
> */
> do {
> batch_free++;
> - if (++pindex == NR_PCP_LISTS)
> - pindex = 0;
> + if (++pindex > max_pindex)
> + pindex = min_pindex;
> list = &pcp->lists[pindex];
> - } while (list_empty(list));
> + if (!list_empty(list))
> + break;
> +
> + if (pindex == max_pindex)
> + max_pindex--;
> + if (pindex == min_pindex)
> + min_pindex++;
> + } while (1);
>
> /* This is the only non-empty list. Free them all. */
> - if (batch_free == NR_PCP_LISTS)
> + if (batch_free >= max_pindex - min_pindex)
> batch_free = count;
>
> order = pindex_to_order(pindex);
next prev parent reply other threads:[~2022-02-17 9:41 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-17 0:22 [PATCH v2 0/6] Follow-up on high-order PCP caching Mel Gorman
2022-02-17 0:22 ` [PATCH 1/6] mm/page_alloc: Fetch the correct pcp buddy during bulk free Mel Gorman
2022-02-17 1:43 ` Aaron Lu
2022-02-17 0:22 ` [PATCH 2/6] mm/page_alloc: Track range of active PCP lists " Mel Gorman
2022-02-17 9:41 ` Vlastimil Babka [this message]
2022-02-17 0:22 ` [PATCH 3/6] mm/page_alloc: Simplify how many pages are selected per pcp list " Mel Gorman
2022-02-17 0:22 ` [PATCH 4/6] mm/page_alloc: Drain the requested list first " Mel Gorman
2022-02-17 9:42 ` Vlastimil Babka
2022-02-17 0:22 ` [PATCH 5/6] mm/page_alloc: Free pages in a single pass " Mel Gorman
2022-02-17 1:53 ` Aaron Lu
2022-02-17 8:49 ` Aaron Lu
2022-02-17 9:31 ` Mel Gorman
2022-02-18 4:20 ` Aaron Lu
2022-02-18 9:20 ` Mel Gorman
2022-02-21 13:38 ` Aaron Lu
2022-02-23 11:30 ` Aaron Lu
2022-02-23 13:05 ` Mel Gorman
2022-02-24 1:34 ` Lu, Aaron
2022-02-18 6:07 ` Aaron Lu
2022-02-18 9:47 ` Mel Gorman
2022-02-18 12:13 ` Aaron Lu
2022-02-17 0:22 ` [PATCH 6/6] mm/page_alloc: Limit number of high-order pages on PCP " Mel Gorman
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