From: Daniel Colascione <dancol@google.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>,
linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Oleg Nesterov <oleg@redhat.com>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH] Synchronize task mm counters on context switch
Date: Fri, 23 Feb 2018 08:34:19 -0800 [thread overview]
Message-ID: <CAKOZueurwrSZWbKKUTx+LOSKEWFnfMYbarDc++pEKHD3xyQbmA@mail.gmail.com> (raw)
In-Reply-To: <20180223081147.GD30773@dhcp22.suse.cz>
On Fri, Feb 23, 2018 at 12:11 AM, Michal Hocko <mhocko@kernel.org> wrote:
> On Wed 21-02-18 18:49:35, Daniel Colascione wrote:
> [...]
>> For more context: on Android, we've historically scanned each processes's
>> address space using /proc/pid/smaps (and /proc/pid/smaps_rollup more
>> recently) to extract memory management statistics. We're looking at
>> replacing this mechanism with the new /proc/pid/status per-memory-type
>> (e.g., anonymous, file-backed) counters so that we can be even more
>> efficient, but we'd like the counts we collect to be accurate.
>
> If you need the accuracy then why don't you simply make
> SPLIT_RSS_COUNTING configurable and disable it in your setup?
I considered that option, but it feels like a last resort. I think
agreement between /proc/pid/status and /proc/pid/smaps is a
correctness issue, and I'd prefer to fix the correctness issue
globally.
That said, *deleting* the SPLIT_RSS_COUNTING code would be nice and
simple. How sure are we that the per-task accounting is really needed?
Maybe I'm wrong, but I feel like taking page faults will touch per-mm
data structures anyway, so one additional atomic update on the mm
shouldn't hurt all that much.
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next prev parent reply other threads:[~2018-02-23 16:34 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-05 22:03 [PATCH] Synchronize task mm counters on context switch Daniel Colascione
2018-02-21 19:05 ` Daniel Colascione
2018-02-22 0:16 ` Minchan Kim
2018-02-22 0:23 ` Daniel Colascione
2018-02-22 2:06 ` Minchan Kim
2018-02-22 2:46 ` [PATCH] Synchronize task mm counters on demand Daniel Colascione
2018-02-23 2:01 ` Minchan Kim
2018-02-23 2:09 ` Daniel Colascione
2018-02-23 2:24 ` Daniel Colascione
2018-02-23 2:28 ` Minchan Kim
2018-02-23 2:43 ` Daniel Colascione
2018-02-23 3:12 ` Minchan Kim
2018-02-23 9:50 ` f66871fb4c: WARNING:inconsistent_lock_state kernel test robot
2018-02-22 2:49 ` [PATCH] Synchronize task mm counters on context switch Daniel Colascione
2018-02-23 8:11 ` Michal Hocko
2018-02-23 16:34 ` Daniel Colascione [this message]
2018-02-23 17:50 ` Michal Hocko
2018-02-23 18:47 ` Daniel Colascione
2018-02-27 10:02 ` Michal Hocko
2018-02-22 9:40 ` Peter Zijlstra
2018-02-22 13:06 ` Minchan Kim
2018-02-22 16:23 ` Daniel Colascione
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