From: Michal Hocko <mhocko@kernel.org>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Minchan Kim <minchan@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
linux-api@vger.kernel.org, Johannes Weiner <hannes@cmpxchg.org>,
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>,
oleksandr@redhat.com, hdanton@sina.com, lizeb@google.com,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [PATCH v3 1/5] mm: introduce MADV_COLD
Date: Thu, 27 Jun 2019 16:02:03 +0200 [thread overview]
Message-ID: <20190627140203.GB5303@dhcp22.suse.cz> (raw)
In-Reply-To: <343599f9-3d99-b74f-1732-368e584fa5ef@intel.com>
On Thu 27-06-19 06:13:36, Dave Hansen wrote:
> On 6/27/19 4:54 AM, Minchan Kim wrote:
> > This patch introduces the new MADV_COLD hint to madvise(2) syscall.
> > MADV_COLD can be used by a process to mark a memory range as not expected
> > to be used in the near future. The hint can help kernel in deciding which
> > pages to evict early during memory pressure.
> >
> > It works for every LRU pages like MADV_[DONTNEED|FREE]. IOW, It moves
> >
> > active file page -> inactive file LRU
> > active anon page -> inacdtive anon LRU
>
> Is the LRU behavior part of the interface or the implementation?
>
> I ask because we've got something in between tossing something down the
> LRU and swapping it: page migration. Specifically, on a system with
> slower memory media (like persistent memory) we just migrate a page
> instead of discarding it at reclaim:
But we already do have interfaces for migrating the memory
(move_pages(2)). Why should this interface duplicate that interface?
I believe the only purpose of these two new madvise modes is to provide
a non-destructive MADV_{DONTNEED,FREE} alteternatives. In other words,
pageout vs. age interface.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2019-06-27 14:02 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-27 11:54 [PATCH v3 0/5] Introduce MADV_COLD and MADV_PAGEOUT Minchan Kim
2019-06-27 11:54 ` [PATCH v3 1/5] mm: introduce MADV_COLD Minchan Kim
2019-06-27 13:13 ` Dave Hansen
2019-06-27 14:02 ` Michal Hocko [this message]
2019-06-27 14:36 ` Dave Hansen
2019-06-27 14:53 ` Michal Hocko
2019-06-27 23:56 ` Minchan Kim
2019-07-01 7:35 ` Minchan Kim
2019-07-09 9:19 ` Michal Hocko
2019-06-27 23:46 ` Minchan Kim
2019-06-27 11:54 ` [PATCH v3 2/5] mm: change PAGEREF_RECLAIM_CLEAN with PAGE_REFRECLAIM Minchan Kim
2019-06-27 11:54 ` [PATCH v3 3/5] mm: account nr_isolated_xxx in [isolate|putback]_lru_page Minchan Kim
2019-07-09 9:38 ` Michal Hocko
2019-06-27 11:54 ` [PATCH v3 4/5] mm: introduce MADV_PAGEOUT Minchan Kim
2019-07-09 9:55 ` Michal Hocko
2019-07-10 10:48 ` Minchan Kim
2019-07-10 11:16 ` Michal Hocko
2019-07-10 11:53 ` Minchan Kim
2019-07-10 19:47 ` Michal Hocko
2019-07-11 0:25 ` Minchan Kim
2019-06-27 11:54 ` [PATCH v3 5/5] mm: factor out pmd young/dirty bit handling and THP split Minchan Kim
2019-07-09 14:10 ` Michal Hocko
2019-07-10 10:56 ` Minchan Kim
2019-06-27 18:06 ` [PATCH v3 0/5] Introduce MADV_COLD and MADV_PAGEOUT Kirill A. Shutemov
2019-06-27 23:12 ` Minchan Kim
2019-07-01 7:38 ` Minchan Kim
2019-07-01 10:22 ` Michal Hocko
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