From: Yang Shi <shy828301@gmail.com>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Linux MM <linux-mm@kvack.org>, Thomas Gleixner <tglx@linutronix.de>
Subject: Re: Memory compaction and mlockall()
Date: Thu, 11 Jul 2019 09:23:31 -0700 [thread overview]
Message-ID: <CAHbLzkr5fJ-eEhAtbubLyoEvHzjfJ3hkwbGmbiUaOVrPH_uDtw@mail.gmail.com> (raw)
In-Reply-To: <20190711094324.ninnmarx5r3amz4p@linutronix.de>
On Thu, Jul 11, 2019 at 2:43 AM Sebastian Andrzej Siewior
<bigeasy@linutronix.de> wrote:
>
> On 2019-07-10 11:21:19 [-0700], Yang Shi wrote:
> >
> > compaction should not isolate unevictable pages unless you have
> > /proc/sys/vm/compact_unevictable_allowed set.
>
> Thank you. This is enabled by default. The documentation for this says
> | … compaction is allowed to examine the unevictable lru (mlocked pages) for
> | pages to compact.…
>
> so it is actually clear once you know where to look.
> If I read this correct, the default behavior was to ignore mlock()ed
> pages for compaction then commit
> 5bbe3547aa3ba ("mm: allow compaction of unevictable pages")
Yes, before this commit compaction doesn't migrate unevictable pages.
But, other types of migration always do.
>
> came along in v4.1-rc1 and changed that behaviour. Is it too late to
> flip it back?
Disabling it via proc knob isn't fine?
>
> Sebastian
next prev parent reply other threads:[~2019-07-11 16:23 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-10 14:41 Memory compaction and mlockall() Sebastian Andrzej Siewior
2019-07-10 16:20 ` Dave Hansen
2019-07-10 16:45 ` Sebastian Andrzej Siewior
2019-07-10 17:02 ` Dave Hansen
2019-07-10 18:21 ` Yang Shi
2019-07-11 9:43 ` Sebastian Andrzej Siewior
2019-07-11 16:23 ` Yang Shi [this message]
2019-08-12 14:59 ` Vlastimil Babka
2019-08-12 15:54 ` Sebastian Andrzej Siewior
2019-08-13 8:23 ` Vlastimil Babka
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