From: Michal Hocko <mhocko@kernel.org>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mgorman@suse.de>,
Johannes Weiner <hannes@cmpxchg.org>,
Rik van Riel <riel@redhat.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 3/7] mm, vmscan: show the number of skipped pages in mm_vmscan_lru_isolate
Date: Tue, 3 Jan 2017 21:43:33 +0100 [thread overview]
Message-ID: <20170103204331.GB13873@dhcp22.suse.cz> (raw)
In-Reply-To: <f4ca13b7-c4ce-eb4c-8314-c710d93785d3@suse.cz>
On Tue 03-01-17 18:21:48, Vlastimil Babka wrote:
> On 12/28/2016 04:30 PM, Michal Hocko wrote:
> > --- a/mm/vmscan.c
> > +++ b/mm/vmscan.c
> > @@ -1428,6 +1428,7 @@ 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 scan, nr_pages;
> > LIST_HEAD(pages_skipped);
> >
> > @@ -1479,14 +1480,13 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
> > */
> > if (!list_empty(&pages_skipped)) {
> > int zid;
> > - unsigned long total_skipped = 0;
> >
> > for (zid = 0; zid < MAX_NR_ZONES; zid++) {
> > if (!nr_skipped[zid])
> > continue;
> >
> > __count_zid_vm_events(PGSCAN_SKIP, zid, nr_skipped[zid]);
> > - total_skipped += nr_skipped[zid];
> > + skipped += nr_skipped[zid];
> > }
> >
> > /*
> > @@ -1494,13 +1494,13 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
> > * close to unreclaimable. If the LRU list is empty, account
> > * skipped pages as a full scan.
> > */
> > - scan += list_empty(src) ? total_skipped : total_skipped >> 2;
> > + total_skipped = list_empty(src) ? skipped : skipped >> 2;
>
> Should the tracepoint output reflect this halving heuristic or rather report
> the raw data? Or is each variant inferrable from the other?
I would rather see the raw data because you can always go and check the
_current_ implementation and calculate the heuristic.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2017-01-03 20:44 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-28 15:30 [PATCH 0/7] vm, vmscan: enahance vmscan tracepoints Michal Hocko
2016-12-28 15:30 ` [PATCH 1/7] mm, vmscan: remove unused mm_vmscan_memcg_isolate Michal Hocko
2016-12-29 7:33 ` Hillf Danton
2016-12-28 15:30 ` [PATCH 2/7] mm, vmscan: add active list aging tracepoint Michal Hocko
2016-12-29 5:33 ` Minchan Kim
2016-12-29 7:52 ` Michal Hocko
2016-12-30 1:48 ` Minchan Kim
2016-12-30 9:26 ` Michal Hocko
2016-12-30 9:38 ` Hillf Danton
2016-12-30 16:04 ` Minchan Kim
2016-12-30 16:37 ` Michal Hocko
2016-12-30 17:30 ` Michal Hocko
2017-01-03 5:03 ` Minchan Kim
2017-01-03 8:21 ` Michal Hocko
2017-01-04 5:07 ` Minchan Kim
2017-01-04 7:28 ` Vlastimil Babka
2017-01-04 7:50 ` Michal Hocko
2016-12-29 7:44 ` Hillf Danton
2016-12-28 15:30 ` [PATCH 3/7] mm, vmscan: show the number of skipped pages in mm_vmscan_lru_isolate Michal Hocko
2016-12-29 5:53 ` Minchan Kim
2016-12-29 7:49 ` Hillf Danton
2017-01-03 17:21 ` Vlastimil Babka
2017-01-03 20:43 ` Michal Hocko [this message]
2016-12-28 15:30 ` [PATCH 4/7] mm, vmscan: show LRU name in mm_vmscan_lru_isolate tracepoint Michal Hocko
2016-12-28 15:50 ` Nikolay Borisov
2016-12-28 16:00 ` Michal Hocko
2016-12-28 16:40 ` Nikolay Borisov
2016-12-28 16:49 ` Michal Hocko
2016-12-29 6:02 ` Minchan Kim
2016-12-29 7:56 ` Michal Hocko
2016-12-30 1:56 ` Minchan Kim
2016-12-30 9:33 ` Michal Hocko
2016-12-29 7:53 ` Hillf Danton
2017-01-03 17:08 ` Vlastimil Babka
2017-01-03 20:47 ` Michal Hocko
2017-01-03 20:52 ` Michal Hocko
2017-01-03 21:24 ` Michal Hocko
2017-01-03 21:40 ` Vlastimil Babka
2017-01-03 21:48 ` Michal Hocko
2016-12-28 15:30 ` [PATCH 5/7] mm, vmscan: extract shrink_page_list reclaim counters into a struct Michal Hocko
2016-12-29 8:00 ` Hillf Danton
2016-12-28 15:30 ` [PATCH 6/7] mm, vmscan: enhance mm_vmscan_lru_shrink_inactive tracepoint Michal Hocko
2016-12-29 8:05 ` Hillf Danton
2016-12-28 15:30 ` [PATCH 7/7] mm, vmscan: add mm_vmscan_inactive_list_is_low tracepoint Michal Hocko
2016-12-29 8:19 ` Hillf Danton
2016-12-30 9:11 ` [PATCH 0/7] vm, vmscan: enahance vmscan tracepoints Mel Gorman
2016-12-30 9:36 ` Michal Hocko
2016-12-30 10:20 ` Mel Gorman
2017-01-04 10:19 [PATCH 0/7 v2] " Michal Hocko
2017-01-04 10:19 ` [PATCH 3/7] mm, vmscan: show the number of skipped pages in mm_vmscan_lru_isolate Michal Hocko
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