From: Gioh Kim <gioh.kim@lge.com>
To: Peter Zijlstra <peterz@infradead.org>, Jan Kara <jack@suse.cz>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
Theodore Ts'o <tytso@mit.edu>,
Andreas Dilger <adilger.kernel@dilger.ca>,
linux-ext4@vger.kernel.org, linux-mm@kvack.org,
Minchan Kim <minchan@kernel.org>, Joonsoo Kim <js1304@gmail.com>
Subject: Re: [PATCH 0/2] new API to allocate buffer-cache for superblock in non-movable area
Date: Wed, 06 Aug 2014 15:15:17 +0900 [thread overview]
Message-ID: <53E1C7F5.7040901@lge.com> (raw)
In-Reply-To: <20140801160415.GD9918@twins.programming.kicks-ass.net>
2014-08-02 i??i ? 1:04, Peter Zijlstra i?' e,?:
> On Fri, Aug 01, 2014 at 05:24:59PM +0200, Jan Kara wrote:
>
>> OK, makes sense. But then if there's heavy IO going on, anything that has
>> IO pending on it is pinned and IO completion can easily take something
>> close to a second or more. So meeting subsecond deadlines may be tough even
>> for ordinary data pages under heavy load, even more so for metadata where
>> there are further constraints. OTOH phones aren't usually IO bound so in
>> practice it needn't be so bad ;).
>
> Yeah, typically phones are not IO bound :-)
>
>> So if it is sub-second unless someone
>> loads the storage, then that sounds doable even for metadata. But we'll
>> need to attach ->migratepage callback to blkdev pages and at least in ext4
>> case teach it how to move pages tracked by the journal.
>
> Right, making it possible at all if of course much prefered over not
> possible, regardless of timeliness :-)
>
>>> Sadly its not only mobile devices that excel in crappy hardware, there's
>>> plenty desktop stuff that could use this too, like some of the v4l
>>> devices iirc.
>> Yeah, but in such usecases the guarantees we can offer for completion of
>> migration are even more vague :(.
>
> Yeah, lets start by making it possible, after that we can maybe look at
> making it better, who knows.
>
Is my patch applicable? Or what do I have to do now?
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next prev parent reply other threads:[~2014-08-06 6:16 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <53CDF437.4090306@lge.com>
[not found] ` <20140722073005.GT3935@laptop>
2014-07-22 9:38 ` Jan Kara
2014-07-30 7:44 ` Gioh Kim
2014-07-30 7:57 ` Kyungmin Park
2014-07-30 10:11 ` Jan Kara
2014-07-30 10:19 ` Peter Zijlstra
2014-07-30 23:45 ` Gioh Kim
2014-07-30 23:54 ` Gioh Kim
2014-07-31 0:03 ` Jan Kara
2014-07-31 0:37 ` Gioh Kim
2014-07-31 12:21 ` Jan Kara
2014-08-01 0:07 ` Gioh Kim
2014-08-01 1:06 ` Gioh Kim
2014-08-01 9:57 ` Jan Kara
2014-08-01 13:36 ` Peter Zijlstra
2014-08-01 15:24 ` Jan Kara
2014-08-01 16:04 ` Peter Zijlstra
2014-08-06 6:15 ` Gioh Kim [this message]
2014-08-01 8:34 ` Joonsoo Kim
2014-08-01 9:15 ` Jan Kara
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