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From: Mel Gorman <mgorman@suse.de>
To: Michal Hocko <mhocko@kernel.org>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Vlastimil Babka <vbabka@suse.cz>, Rik van Riel <riel@redhat.com>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/7] vm, vmscan: enahance vmscan tracepoints
Date: Fri, 30 Dec 2016 09:11:17 +0000	[thread overview]
Message-ID: <20161230091117.nkxn3bnhle3bofhw@suse.de> (raw)
In-Reply-To: <20161228153032.10821-1-mhocko@kernel.org>

On Wed, Dec 28, 2016 at 04:30:25PM +0100, Michal Hocko wrote:
> Hi,
> while debugging [1] I've realized that there is some room for
> improvements in the tracepoints set we offer currently. I had hard times
> to make any conclusion from the existing ones. The resulting problem
> turned out to be active list aging [2] and we are missing at least two
> tracepoints to debug such a problem.
> 
> Some existing tracepoints could export more information to see _why_ the
> reclaim progress cannot be made not only _how much_ we could reclaim.
> The later could be seen quite reasonably from the vmstat counters
> already. It can be argued that we are showing too many implementation
> details in those tracepoints but I consider them way too lowlevel
> already to be usable by any kernel independent userspace. I would be
> _really_ surprised if anything but debugging tools have used them.
> 
> Any feedback is highly appreciated.
> 

There is some minor overhead introduced in some paths regardless of
whether the tracepoints are active or not but I suspect it's negligible
in the context of the overhead of reclaim in general so;

Acked-by: Mel Gorman <mgorman@suse.de>

-- 
Mel Gorman
SUSE Labs

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  parent reply	other threads:[~2016-12-30  9:11 UTC|newest]

Thread overview: 48+ 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
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 ` Mel Gorman [this message]
2016-12-30  9:36   ` [PATCH 0/7] vm, vmscan: enahance vmscan tracepoints Michal Hocko
2016-12-30 10:20     ` Mel Gorman

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