From: Hillf Danton <hdanton@sina.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.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>,
Brian Geffon <bgeffon@google.com>
Subject: Re: [RFC 1/7] mm: introduce MADV_COOL
Date: Wed, 29 May 2019 10:40:33 +0800 [thread overview]
Message-ID: <20190529024033.13500-1-hdanton@sina.com> (raw)
On Wed, 29 May 2019 00:11:15 +0800 Michal Hocko wrote:
> On Tue 28-05-19 23:38:11, Hillf Danton wrote:
> >
> > In short, I prefer to skip IO mapping since any kind of address range
> > can be expected from userspace, and it may probably cover an IO mapping.
> > And things can get out of control, if we reclaim some IO pages while
> > underlying device is trying to fill data into any of them, for instance.
>
> What do you mean by IO pages why what is the actual problem?
>
Io pages are the backing-store pages of a mapping whose vm_flags has
VM_IO set, and the comment in mm/memory.c says:
/*
* Physically remapped pages are special. Tell the
* rest of the world about it:
* VM_IO tells people not to look at these pages
* (accesses can have side effects).
BR
Hillf
next reply other threads:[~2019-05-29 2:40 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-29 2:40 Hillf Danton [this message]
2019-05-29 5:05 ` [RFC 1/7] mm: introduce MADV_COOL Michal Hocko
-- strict thread matches above, loose matches on Subject: below --
2019-05-29 8:52 Hillf Danton
2019-05-28 15:38 Hillf Danton
2019-05-28 16:11 ` Michal Hocko
2019-05-28 12:15 Hillf Danton
2019-05-28 12:39 ` Minchan Kim
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 8:53 ` Hillf Danton
2019-05-28 10:58 ` Minchan Kim
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