From: Johannes Weiner <hannes@cmpxchg.org>
To: Minchan Kim <minchan@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>, Michal Hocko <mhocko@suse.com>,
Tim Murray <timmurray@google.com>,
Joel Fernandes <joel@joelfernandes.org>,
Suren Baghdasaryan <surenb@google.com>,
Daniel Colascione <dancol@google.com>,
Shakeel Butt <shakeelb@google.com>,
Sonny Rao <sonnyrao@google.com>,
Brian Geffon <bgeffon@google.com>
Subject: Re: [RFC 0/7] introduce memory hinting API for external process
Date: Mon, 20 May 2019 12:46:05 -0400 [thread overview]
Message-ID: <20190520164605.GA11665@cmpxchg.org> (raw)
In-Reply-To: <20190520035254.57579-1-minchan@kernel.org>
On Mon, May 20, 2019 at 12:52:47PM +0900, Minchan Kim wrote:
> - Approach
>
> The approach we chose was to use a new interface to allow userspace to
> proactively reclaim entire processes by leveraging platform information.
> This allowed us to bypass the inaccuracy of the kernel’s LRUs for pages
> that are known to be cold from userspace and to avoid races with lmkd
> by reclaiming apps as soon as they entered the cached state. Additionally,
> it could provide many chances for platform to use much information to
> optimize memory efficiency.
>
> IMHO we should spell it out that this patchset complements MADV_WONTNEED
> and MADV_FREE by adding non-destructive ways to gain some free memory
> space. MADV_COLD is similar to MADV_WONTNEED in a way that it hints the
> kernel that memory region is not currently needed and should be reclaimed
> immediately; MADV_COOL is similar to MADV_FREE in a way that it hints the
> kernel that memory region is not currently needed and should be reclaimed
> when memory pressure rises.
I agree with this approach and the semantics. But these names are very
vague and extremely easy to confuse since they're so similar.
MADV_COLD could be a good name, but for deactivating pages, not
reclaiming them - marking memory "cold" on the LRU for later reclaim.
For the immediate reclaim one, I think there is a better option too:
In virtual memory speak, putting a page into secondary storage (or
ensuring it's already there), and then freeing its in-memory copy, is
called "paging out". And that's what this flag is supposed to do. So
how about MADV_PAGEOUT?
With that, we'd have:
MADV_FREE: Mark data invalid, free memory when needed
MADV_DONTNEED: Mark data invalid, free memory immediately
MADV_COLD: Data is not used for a while, free memory when needed
MADV_PAGEOUT: Data is not used for a while, free memory immediately
What do you think?
next prev parent reply other threads:[~2019-05-20 16:46 UTC|newest]
Thread overview: 132+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-20 3:52 [RFC 0/7] introduce memory hinting API for external process Minchan Kim
2019-05-20 3:52 ` [RFC 1/7] mm: introduce MADV_COOL Minchan Kim
2019-05-20 8:16 ` Michal Hocko
2019-05-20 8:19 ` Michal Hocko
2019-05-20 15:08 ` Suren Baghdasaryan
2019-05-20 22:55 ` Minchan Kim
2019-05-20 22:54 ` Minchan Kim
2019-05-21 6:04 ` Michal Hocko
2019-05-21 9:11 ` Minchan Kim
2019-05-21 10:05 ` Michal Hocko
2019-05-28 10:58 ` Minchan Kim
2019-05-20 3:52 ` [RFC 2/7] mm: change PAGEREF_RECLAIM_CLEAN with PAGE_REFRECLAIM Minchan Kim
2019-05-20 16:50 ` Johannes Weiner
2019-05-20 22:57 ` Minchan Kim
2019-05-20 3:52 ` [RFC 3/7] mm: introduce MADV_COLD Minchan Kim
2019-05-20 8:27 ` Michal Hocko
2019-05-20 23:00 ` Minchan Kim
2019-05-21 6:08 ` Michal Hocko
2019-05-21 9:13 ` Minchan Kim
2019-05-30 0:45 ` Minchan Kim
2019-05-20 3:52 ` [RFC 4/7] mm: factor out madvise's core functionality Minchan Kim
2019-05-20 14:26 ` Oleksandr Natalenko
2019-05-21 1:26 ` Minchan Kim
2019-05-21 6:36 ` Oleksandr Natalenko
2019-05-21 6:50 ` Michal Hocko
2019-05-21 7:06 ` Oleksandr Natalenko
2019-05-21 10:52 ` Minchan Kim
2019-05-21 11:00 ` Michal Hocko
2019-05-21 11:24 ` Minchan Kim
2019-05-21 11:32 ` Michal Hocko
2019-05-21 10:49 ` Minchan Kim
2019-05-21 10:55 ` Michal Hocko
2019-05-20 3:52 ` [RFC 5/7] mm: introduce external memory hinting API Minchan Kim
2019-05-20 9:18 ` Michal Hocko
2019-05-21 2:41 ` Minchan Kim
2019-05-21 6:17 ` Michal Hocko
2019-05-21 10:32 ` Minchan Kim
2019-05-21 9:01 ` Christian Brauner
2019-05-21 11:35 ` Minchan Kim
2019-05-21 11:51 ` Christian Brauner
2019-05-21 15:31 ` Oleg Nesterov
2019-05-27 7:43 ` Minchan Kim
2019-05-27 15:12 ` Oleg Nesterov
2019-05-27 23:33 ` Minchan Kim
2019-05-28 7:23 ` Michal Hocko
2019-05-30 0:38 ` Minchan Kim
2019-05-20 3:52 ` [RFC 6/7] mm: extend process_madvise syscall to support vector arrary Minchan Kim
2019-05-20 9:22 ` Michal Hocko
2019-05-21 2:48 ` Minchan Kim
2019-05-21 6:24 ` Michal Hocko
2019-05-21 10:26 ` Minchan Kim
2019-05-21 10:37 ` Michal Hocko
2019-05-27 7:49 ` Minchan Kim
2019-05-29 10:08 ` Daniel Colascione
2019-05-29 10:33 ` Michal Hocko
2019-05-30 2:17 ` Minchan Kim
2019-05-30 6:57 ` Michal Hocko
2019-05-30 8:02 ` Minchan Kim
2019-05-30 16:19 ` Daniel Colascione
2019-05-30 18:47 ` Michal Hocko
2019-05-30 0:35 ` Minchan Kim
2019-05-20 3:52 ` [RFC 7/7] mm: madvise support MADV_ANONYMOUS_FILTER and MADV_FILE_FILTER Minchan Kim
2019-05-20 9:28 ` Michal Hocko
2019-05-21 2:55 ` Minchan Kim
2019-05-21 6:26 ` Michal Hocko
2019-05-27 7:58 ` Minchan Kim
2019-05-27 12:44 ` Michal Hocko
2019-05-28 3:26 ` Minchan Kim
2019-05-28 6:29 ` Michal Hocko
2019-05-28 8:13 ` Minchan Kim
2019-05-28 8:31 ` Daniel Colascione
2019-05-28 8:49 ` Minchan Kim
2019-05-28 9:08 ` Michal Hocko
2019-05-28 9:39 ` Daniel Colascione
2019-05-28 10:33 ` Michal Hocko
2019-05-28 11:21 ` Daniel Colascione
2019-05-28 11:49 ` Michal Hocko
2019-05-28 12:11 ` Daniel Colascione
2019-05-28 12:32 ` Michal Hocko
2019-05-28 10:32 ` Minchan Kim
2019-05-28 10:41 ` Michal Hocko
2019-05-28 11:12 ` Minchan Kim
2019-05-28 11:28 ` Michal Hocko
2019-05-28 11:42 ` Daniel Colascione
2019-05-28 11:56 ` Michal Hocko
2019-05-28 12:18 ` Daniel Colascione
2019-05-28 12:38 ` Michal Hocko
2019-05-28 12:10 ` Minchan Kim
2019-05-28 11:44 ` Minchan Kim
2019-05-28 11:51 ` Daniel Colascione
2019-05-28 12:06 ` Michal Hocko
2019-05-28 12:22 ` Minchan Kim
2019-05-28 11:28 ` Daniel Colascione
2019-05-21 15:33 ` Johannes Weiner
2019-05-22 1:50 ` Minchan Kim
2019-05-30 1:00 ` Minchan Kim
2019-05-20 6:37 ` [RFC 0/7] introduce memory hinting API for external process Anshuman Khandual
2019-05-20 16:59 ` Tim Murray
2019-05-21 2:55 ` Anshuman Khandual
2019-05-21 5:14 ` Minchan Kim
2019-05-21 10:34 ` Michal Hocko
2019-05-28 10:50 ` Anshuman Khandual
2019-05-21 12:56 ` Shakeel Butt
2019-05-22 4:23 ` Brian Geffon
2019-05-20 9:28 ` Michal Hocko
2019-05-20 14:42 ` Oleksandr Natalenko
2019-05-21 2:56 ` Minchan Kim
2019-05-20 16:46 ` Johannes Weiner [this message]
2019-05-21 4:39 ` Minchan Kim
2019-05-21 6:32 ` Michal Hocko
2019-05-21 1:44 ` Matthew Wilcox
2019-05-21 5:01 ` Minchan Kim
2019-05-21 6:34 ` Michal Hocko
2019-05-21 8:42 ` Christian Brauner
2019-05-21 11:05 ` Minchan Kim
2019-05-21 11:30 ` Christian Brauner
2019-05-21 11:39 ` Christian Brauner
2019-05-22 5:11 ` Daniel Colascione
2019-05-22 8:22 ` Christian Brauner
2019-05-22 13:16 ` Daniel Colascione
2019-05-22 14:52 ` Christian Brauner
2019-05-22 15:17 ` Daniel Colascione
2019-05-22 15:48 ` Christian Brauner
2019-05-22 15:57 ` Daniel Colascione
2019-05-22 16:01 ` Christian Brauner
2019-05-22 16:01 ` Daniel Colascione
2019-05-23 13:07 ` Minchan Kim
2019-05-27 8:06 ` Minchan Kim
2019-05-21 11:41 ` Minchan Kim
2019-05-21 12:04 ` Christian Brauner
2019-05-21 12:15 ` Oleksandr Natalenko
2019-05-21 12:53 ` Shakeel Butt
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