From: Jan Kara <jack@suse.cz>
To: Matthew Wilcox <willy@infradead.org>
Cc: lsf-pc@lists.linux-foundation.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: [Lsf-pc] [ATTEND] many topics
Date: Wed, 18 Jan 2017 11:13:43 +0100 [thread overview]
Message-ID: <20170118101343.GC24789@quack2.suse.cz> (raw)
In-Reply-To: <20170118054945.GD18349@bombadil.infradead.org>
On Tue 17-01-17 21:49:45, Matthew Wilcox wrote:
> 1. Exploiting multiorder radix tree entries. I believe we would do well
> to attempt to allocate compound pages, insert them into the page cache,
> and expect filesystems to be able to handle filling compound pages with
> ->readpage. It will be more efficient because alloc_pages() can return
> large entries out of the buddy list rather than breaking them down,
> and it'll help reduce fragmentation.
Kirill has patches to do this and I don't like the complexity it adds to
pagecache handling code and each filesystem that would like to support
this. I don't have objections to the general idea but the complexity of the
current implementation just looks too big to me...
> 2. Supporting filesystem block sizes > page size. Once we do the above
> for efficiency, I think it then becomes trivial to support, eg 16k block
> size filesystems on x86 machines with 4k pages.
Heh, you wish... :) There's a big difference between opportunistically
allocating a huge page and reliably have to provide high order page. Memory
fragmentation issues will be difficult to deal with...
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
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next prev parent reply other threads:[~2017-01-18 10:13 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-18 5:49 [ATTEND] many topics Matthew Wilcox
2017-01-18 10:13 ` Jan Kara [this message]
2017-01-18 11:26 ` [Lsf-pc] " willy
2017-01-18 13:32 ` Michal Hocko
2017-01-19 11:05 ` willy
2017-01-19 11:33 ` Michal Hocko
2017-01-19 11:52 ` willy
2017-01-19 12:11 ` Michal Hocko
2017-01-21 0:11 ` NeilBrown
2017-01-21 13:16 ` Theodore Ts'o
2017-01-22 4:45 ` NeilBrown
2017-01-23 6:05 ` Matthew Wilcox
2017-01-23 6:30 ` NeilBrown
2017-01-23 6:35 ` Matthew Wilcox
2017-01-23 17:09 ` Theodore Ts'o
2017-01-23 19:34 ` NeilBrown
2017-01-25 14:36 ` Vlastimil Babka
2017-01-25 20:36 ` Matthew Wilcox
2017-01-25 21:15 ` Vlastimil Babka
2017-01-25 23:19 ` NeilBrown
2017-01-26 8:56 ` Michal Hocko
2017-01-26 21:20 ` NeilBrown
2017-01-27 13:12 ` Michal Hocko
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