From: Waiman Long <longman@redhat.com>
To: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Petr Mladek <pmladek@suse.com>,
Steven Rostedt <rostedt@goodmis.org>,
Sergey Senozhatsky <senozhatsky@chromium.org>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
linux-mm@kvack.org, Ira Weiny <ira.weiny@intel.com>,
Mike Rapoport <rppt@kernel.org>,
David Rientjes <rientjes@google.com>,
Roman Gushchin <guro@fb.com>, Rafael Aquini <aquini@redhat.com>,
Vlastimil Babka <vbabka@suse.cz>
Subject: Re: [PATCH v4 4/4] mm/page_owner: Record task command name
Date: Wed, 2 Feb 2022 11:53:52 -0500 [thread overview]
Message-ID: <4ba66abe-5c6d-26a7-f11c-c3b8514bfb34@redhat.com> (raw)
In-Reply-To: <YflRjeoC0jbzArDG@dhcp22.suse.cz>
On 2/1/22 10:28, Michal Hocko wrote:
> Cc Vlastimil
>
> On Mon 31-01-22 17:03:28, Waiman Long wrote:
>> The page_owner information currently includes the pid of the calling
>> task. That is useful as long as the task is still running. Otherwise,
>> the number is meaningless. To have more information about the allocating
>> tasks that had exited by the time the page_owner information is
>> retrieved, we need to store the command name of the task.
>>
>> Add a new comm field into page_owner structure to store the command name
>> and display it when the page_owner information is retrieved.
> I completely agree that pid is effectivelly useless (if not misleading)
> but is comm really telling all that much to compensate for the
> additional storage required for _each_ page in the system?
Yes, it does add an extra 16 bytes per page overhead. The command name
can be useful if one want to find out which userspace command is
responsible for a problematic page allocation. Maybe we can remove pid
from page_owner to save 8 bytes as you also agree that this number is
not that useful.
Cheers,
Longman
next prev parent reply other threads:[~2022-02-02 16:54 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-31 19:23 [PATCH v3 0/4] mm/page_owner: Extend page_owner to show memcg information Waiman Long
2022-01-31 19:23 ` [PATCH v3 1/4] lib/vsprintf: Avoid redundant work with 0 size Waiman Long
2022-01-31 20:42 ` Mike Rapoport
2022-01-31 19:23 ` [PATCH v3 2/4] mm/page_owner: Use scnprintf() to avoid excessive buffer overrun check Waiman Long
2022-01-31 20:38 ` Roman Gushchin
2022-01-31 20:43 ` Mike Rapoport
2022-01-31 19:23 ` [PATCH v3 3/4] mm/page_owner: Print memcg information Waiman Long
2022-01-31 20:51 ` Mike Rapoport
2022-01-31 21:43 ` Waiman Long
2022-02-01 6:23 ` Mike Rapoport
2022-01-31 20:51 ` Roman Gushchin
2022-02-01 10:54 ` Michal Hocko
2022-02-01 17:04 ` Waiman Long
2022-02-02 8:49 ` Michal Hocko
2022-02-02 16:12 ` Waiman Long
2022-01-31 19:23 ` [PATCH v3 4/4] mm/page_owner: Record task command name Waiman Long
2022-01-31 20:54 ` Roman Gushchin
2022-01-31 21:46 ` Waiman Long
2022-01-31 22:03 ` [PATCH v4 " Waiman Long
2022-02-01 15:28 ` Michal Hocko
2022-02-02 16:53 ` Waiman Long [this message]
2022-02-03 12:10 ` Vlastimil Babka
2022-02-03 18:53 ` Waiman Long
2022-02-02 20:30 ` [PATCH v4 0/4] mm/page_owner: Extend page_owner to show memcg information Waiman Long
2022-02-02 23:06 ` Rafael Aquini
2022-02-02 20:30 ` [PATCH v4 1/4] lib/vsprintf: Avoid redundant work with 0 size Waiman Long
2022-02-08 10:08 ` Petr Mladek
2022-02-02 20:30 ` [PATCH v4 2/4] mm/page_owner: Use scnprintf() to avoid excessive buffer overrun check Waiman Long
2022-02-03 15:46 ` Vlastimil Babka
2022-02-03 18:49 ` Waiman Long
2022-02-08 10:51 ` Petr Mladek
2022-02-02 20:30 ` [PATCH v4 3/4] mm/page_owner: Print memcg information Waiman Long
2022-02-03 6:53 ` Mike Rapoport
2022-02-03 12:46 ` Michal Hocko
2022-02-03 19:03 ` Waiman Long
2022-02-07 17:20 ` Michal Hocko
2022-02-07 19:09 ` Andrew Morton
2022-02-07 19:33 ` Waiman Long
2022-02-02 20:30 ` [PATCH v4 4/4] mm/page_owner: Record task command name Waiman Long
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