From: Michal Hocko <mhocko@kernel.org>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Jia He <hejianet@gmail.com>, Mel Gorman <mgorman@suse.de>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
kernel-team@fb.com
Subject: Re: [PATCH 8/9] Revert "mm, vmscan: account for skipped pages as a partial scan"
Date: Wed, 1 Mar 2017 16:51:38 +0100 [thread overview]
Message-ID: <20170301155138.GH11730@dhcp22.suse.cz> (raw)
In-Reply-To: <20170228214007.5621-9-hannes@cmpxchg.org>
On Tue 28-02-17 16:40:06, Johannes Weiner wrote:
> This reverts commit d7f05528eedb047efe2288cff777676b028747b6.
>
> Now that reclaimability of a node is no longer based on the ratio
> between pages scanned and theoretically reclaimable pages, we can
> remove accounting tricks for pages skipped due to zone constraints.
>
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
> ---
> mm/vmscan.c | 22 ++++------------------
> 1 file changed, 4 insertions(+), 18 deletions(-)
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 35b791a8922b..ddcff8a11c1e 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -1471,12 +1471,12 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
> unsigned long nr_taken = 0;
> unsigned long nr_zone_taken[MAX_NR_ZONES] = { 0 };
> unsigned long nr_skipped[MAX_NR_ZONES] = { 0, };
> - unsigned long skipped = 0, total_skipped = 0;
> + unsigned long skipped = 0;
> unsigned long scan, nr_pages;
> LIST_HEAD(pages_skipped);
>
> for (scan = 0; scan < nr_to_scan && nr_taken < nr_to_scan &&
> - !list_empty(src);) {
> + !list_empty(src); scan++) {
> struct page *page;
>
> page = lru_to_page(src);
> @@ -1490,12 +1490,6 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
> continue;
> }
>
> - /*
> - * Account for scanned and skipped separetly to avoid the pgdat
> - * being prematurely marked unreclaimable by pgdat_reclaimable.
> - */
> - scan++;
> -
> switch (__isolate_lru_page(page, mode)) {
> case 0:
> nr_pages = hpage_nr_pages(page);
> @@ -1524,6 +1518,7 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
> if (!list_empty(&pages_skipped)) {
> int zid;
>
> + list_splice(&pages_skipped, src);
> for (zid = 0; zid < MAX_NR_ZONES; zid++) {
> if (!nr_skipped[zid])
> continue;
> @@ -1531,17 +1526,8 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
> __count_zid_vm_events(PGSCAN_SKIP, zid, nr_skipped[zid]);
> skipped += nr_skipped[zid];
> }
> -
> - /*
> - * Account skipped pages as a partial scan as the pgdat may be
> - * close to unreclaimable. If the LRU list is empty, account
> - * skipped pages as a full scan.
> - */
> - total_skipped = list_empty(src) ? skipped : skipped >> 2;
> -
> - list_splice(&pages_skipped, src);
> }
> - *nr_scanned = scan + total_skipped;
> + *nr_scanned = scan;
> trace_mm_vmscan_lru_isolate(sc->reclaim_idx, sc->order, nr_to_scan,
> scan, skipped, nr_taken, mode, lru);
> update_lru_sizes(lruvec, lru, nr_zone_taken);
> --
> 2.11.1
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2017-03-01 15:52 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-28 21:39 [PATCH 0/9] mm: kswapd spinning on unreclaimable nodes - fixes and cleanups Johannes Weiner
2017-02-28 21:39 ` [PATCH 1/9] mm: fix 100% CPU kswapd busyloop on unreclaimable nodes Johannes Weiner
2017-03-02 3:23 ` Hillf Danton
2017-03-02 23:30 ` Shakeel Butt
2017-03-03 1:26 ` Minchan Kim
2017-03-03 7:59 ` Michal Hocko
2017-03-06 1:37 ` Minchan Kim
2017-03-06 16:24 ` Johannes Weiner
2017-03-07 0:59 ` Hillf Danton
2017-03-07 7:28 ` Minchan Kim
2017-03-07 10:17 ` Michal Hocko
2017-03-07 16:56 ` Johannes Weiner
2017-03-09 14:20 ` Mel Gorman
2017-02-28 21:40 ` [PATCH 2/9] mm: fix check for reclaimable pages in PF_MEMALLOC reclaim throttling Johannes Weiner
2017-03-01 15:02 ` Michal Hocko
2017-03-02 3:25 ` Hillf Danton
2017-02-28 21:40 ` [PATCH 3/9] mm: remove seemingly spurious reclaimability check from laptop_mode gating Johannes Weiner
2017-03-01 15:06 ` Michal Hocko
2017-03-01 15:17 ` Mel Gorman
2017-03-02 3:27 ` Hillf Danton
2017-02-28 21:40 ` [PATCH 4/9] mm: remove unnecessary reclaimability check from NUMA balancing target Johannes Weiner
2017-03-01 15:14 ` Michal Hocko
2017-03-02 3:28 ` Hillf Danton
2017-02-28 21:40 ` [PATCH 5/9] mm: don't avoid high-priority reclaim on unreclaimable nodes Johannes Weiner
2017-03-01 15:21 ` Michal Hocko
2017-03-02 3:31 ` Hillf Danton
2017-02-28 21:40 ` [PATCH 6/9] mm: don't avoid high-priority reclaim on memcg limit reclaim Johannes Weiner
2017-03-01 15:40 ` Michal Hocko
2017-03-01 17:36 ` Johannes Weiner
2017-03-01 19:13 ` Michal Hocko
2017-03-02 3:32 ` Hillf Danton
2017-02-28 21:40 ` [PATCH 7/9] mm: delete NR_PAGES_SCANNED and pgdat_reclaimable() Johannes Weiner
2017-03-01 15:41 ` Michal Hocko
2017-03-02 3:34 ` Hillf Danton
2017-02-28 21:40 ` [PATCH 8/9] Revert "mm, vmscan: account for skipped pages as a partial scan" Johannes Weiner
2017-03-01 15:51 ` Michal Hocko [this message]
2017-03-02 3:36 ` Hillf Danton
2017-02-28 21:40 ` [PATCH 9/9] mm: remove unnecessary back-off function when retrying page reclaim Johannes Weiner
2017-03-01 14:56 ` Michal Hocko
2017-03-02 3:37 ` Hillf Danton
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