From: Goswin von Brederlow <brederlo@informatik.uni-tuebingen.de>
To: Joern Engel <joern@logfs.org>
Cc: Andrea Arcangeli <andrea@suse.de>,
Goswin von Brederlow <brederlo@informatik.uni-tuebingen.de>,
Andrew Morton <akpm@linux-foundation.org>,
Nick Piggin <nickpiggin@yahoo.com.au>,
Christoph Lameter <clameter@sgi.com>,
torvalds@linux-foundation.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
Mel Gorman <mel@skynet.ie>,
William Lee Irwin III <wli@holomorphy.com>,
David Chinner <dgc@sgi.com>, Jens Axboe <jens.axboe@oracle.com>,
Badari Pulavarty <pbadari@gmail.com>,
Maxim Levitsky <maximlevitsky@gmail.com>,
Fengguang Wu <fengguang.wu@gmail.com>,
swin wang <wangswin@gmail.com>,
totty.lu@gmail.com, hugh@veritas.com
Subject: Re: [00/41] Large Blocksize Support V7 (adds memmap support)
Date: Mon, 17 Sep 2007 00:06:24 +0200 [thread overview]
Message-ID: <87d4wi5kpr.fsf@informatik.uni-tuebingen.de> (raw)
In-Reply-To: <20070916174657.GA2393@lazybastard.org> (Joern Engel's message of "Sun, 16 Sep 2007 19:46:58 +0200")
Jörn Engel <joern@logfs.org> writes:
> On Sun, 16 September 2007 00:30:32 +0200, Andrea Arcangeli wrote:
>>
>> Movable? I rather assume all slab allocations aren't movable. Then
>> slab defrag can try to tackle on users like dcache and inodes. Keep in
>> mind that with the exception of updatedb, those inodes/dentries will
>> be pinned and you won't move them, which is why I prefer to consider
>> them not movable too... since there's no guarantee they are.
>
> I have been toying with the idea of having seperate caches for pinned
> and movable dentries. Downside of such a patch would be the number of
> memcpy() operations when moving dentries from one cache to the other.
> Upside is that a fair amount of slab cache can be made movable.
> memcpy() is still faster than reading an object from disk.
How probable is it that the dentry is needed again? If you copy it and
it is not needed then you wasted time. If you throw it out and it is
needed then you wasted time too. Depending on the probability one of
the two is cheaper overall. Idealy I would throw away dentries that
haven't been accessed recently and copy recently used ones.
How much of a systems ram is spend on dentires? How much on task
structures? Does anyone have some stats on that? If it is <10% of the
total ram combined then I don't see much point in moving them. Just
keep them out of the way of users memory so the buddy system can work
effectively.
> Most likely the current reaction to such a patch would be to shoot it
> down due to overhead, so I didn't pursue it. All I have is an old patch
> to seperate never-cached from possibly-cached dentries. It will
> increase the odds of freeing a slab, but provide no guarantee.
>
> But the point here is: dentries/inodes can be made movable if there are
> clear advantages to it. Maybe they should?
>
> Jörn
MfG
Goswin
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next prev parent reply other threads:[~2007-09-16 22:35 UTC|newest]
Thread overview: 187+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-11 6:03 [00/41] Large Blocksize Support V7 (adds memmap support) Christoph Lameter
2007-09-10 18:52 ` Nick Piggin
2007-09-11 12:05 ` Andrea Arcangeli
2007-09-11 20:03 ` Christoph Lameter
2007-09-11 12:12 ` Jörn Engel
2007-09-10 21:13 ` Nick Piggin
2007-09-11 16:02 ` Goswin von Brederlow
2007-09-11 20:07 ` Christoph Lameter
2007-09-11 20:29 ` Jörn Engel
2007-09-11 20:41 ` Christoph Lameter
2007-09-11 23:26 ` Andrea Arcangeli
2007-09-12 0:04 ` Christoph Lameter
2007-09-12 8:20 ` Andrea Arcangeli
2007-09-15 8:44 ` Andrew Morton
2007-09-15 12:14 ` Goswin von Brederlow
2007-09-15 15:51 ` Andrea Arcangeli
2007-09-15 20:14 ` Goswin von Brederlow
2007-09-15 22:30 ` Andrea Arcangeli
2007-09-16 13:54 ` Goswin von Brederlow
2007-09-16 15:08 ` Andrea Arcangeli
2007-09-16 21:08 ` Mel Gorman
2007-09-16 22:48 ` Goswin von Brederlow
2007-09-17 9:30 ` Mel Gorman
2007-09-16 17:46 ` Jörn Engel
2007-09-16 18:15 ` Linus Torvalds
2007-09-16 18:21 ` Jörn Engel
2007-09-16 18:44 ` Linus Torvalds
2007-09-16 22:51 ` Goswin von Brederlow
2007-09-23 17:44 ` Jörn Engel
2007-09-16 22:06 ` Goswin von Brederlow [this message]
2007-09-16 22:40 ` Jörn Engel
2007-09-16 18:15 ` Mel Gorman
2007-09-16 18:50 ` Andrea Arcangeli
2007-09-16 20:54 ` Mel Gorman
2007-09-16 21:31 ` Andrea Arcangeli
2007-09-17 10:13 ` Mel Gorman
2007-09-23 5:50 ` Goswin von Brederlow
2007-09-16 22:56 ` Goswin von Brederlow
2007-09-18 19:31 ` Andrea Arcangeli
2007-09-23 6:56 ` Goswin von Brederlow
2007-09-24 15:39 ` Andrea Arcangeli
2007-09-16 18:13 ` Mel Gorman
2007-09-16 9:03 ` Nick Piggin
2007-09-17 22:00 ` Christoph Lameter
2007-09-18 0:11 ` Nick Piggin
2007-09-18 20:36 ` Christoph Lameter
2007-09-18 10:00 ` Mel Gorman
2007-09-18 10:49 ` Jörn Engel
2007-09-18 12:31 ` David Chinner
2007-09-16 21:58 ` Goswin von Brederlow
2007-09-17 10:03 ` Mel Gorman
2007-09-23 6:22 ` Goswin von Brederlow
2007-09-24 12:32 ` Kyle Moffett
2007-09-16 17:53 ` Jörn Engel
2007-09-16 21:31 ` Mel Gorman
2007-09-17 22:03 ` Christoph Lameter
2007-09-11 15:36 ` Mel Gorman
2007-09-11 1:44 ` Nick Piggin
2007-09-11 20:11 ` Christoph Lameter
2007-09-11 4:53 ` Nick Piggin
2007-09-11 20:42 ` Christoph Lameter
2007-09-11 5:30 ` Nick Piggin
2007-09-11 21:41 ` Christoph Lameter
2007-09-11 6:06 ` Nick Piggin
2007-09-11 21:52 ` Christoph Lameter
2007-09-11 18:07 ` Nick Piggin
2007-09-12 23:06 ` Christoph Lameter
2007-09-13 20:51 ` Nick Piggin
2007-09-14 17:52 ` Christoph Lameter
2007-09-16 8:22 ` Nick Piggin
2007-09-17 22:05 ` Christoph Lameter
2007-09-18 0:10 ` Nick Piggin
2007-09-18 20:42 ` Christoph Lameter
2007-09-17 11:10 ` Bernd Schmidt
2007-09-17 22:10 ` Christoph Lameter
2007-09-14 16:10 ` Goswin von Brederlow
2007-09-14 17:42 ` Mel Gorman
2007-09-15 0:31 ` Goswin von Brederlow
2007-09-16 21:16 ` Mel Gorman
2007-09-16 22:38 ` Goswin von Brederlow
2007-09-17 8:57 ` Mel Gorman
2007-09-23 6:49 ` Goswin von Brederlow
2007-09-11 20:53 ` Mel Gorman
2007-09-11 6:00 ` Nick Piggin
2007-09-11 21:48 ` Christoph Lameter
2007-09-11 6:17 ` Nick Piggin
2007-09-12 0:00 ` Christoph Lameter
2007-09-12 2:46 ` Nick Piggin
2007-09-12 23:17 ` Christoph Lameter
2007-09-13 9:40 ` Mel Gorman
2007-09-14 2:38 ` Christoph Lameter
2007-09-13 21:20 ` Nick Piggin
2007-09-14 18:08 ` Christoph Lameter
2007-09-14 18:15 ` Christoph Lameter
2007-09-15 0:33 ` Goswin von Brederlow
2007-09-16 8:53 ` Nick Piggin
2007-09-17 22:21 ` Christoph Lameter
2007-09-18 1:16 ` Nick Piggin
2007-09-18 18:30 ` Linus Torvalds
2007-09-18 17:53 ` Nick Piggin
2007-09-18 19:18 ` Andrea Arcangeli
2007-09-18 19:44 ` Linus Torvalds
2007-09-19 0:58 ` Nathan Scott
2007-09-19 1:06 ` Linus Torvalds
2007-09-19 2:45 ` Nathan Scott
2007-09-19 5:09 ` David Chinner
2007-09-19 9:41 ` Alex Tomas
2007-09-19 14:04 ` Andrea Arcangeli
2007-09-20 1:38 ` David Chinner
2007-09-20 14:54 ` Andrea Arcangeli
2007-09-20 18:11 ` Christoph Lameter
2007-09-20 18:07 ` Christoph Lameter
2007-09-21 20:41 ` Hugh Dickins
2007-09-24 21:13 ` Christoph Lameter
2007-09-28 2:46 ` Nick Piggin
2007-09-19 3:41 ` Rene Herman
2007-09-19 3:50 ` Linus Torvalds
2007-09-19 4:26 ` Rene Herman
2007-09-19 4:33 ` Linus Torvalds
2007-09-19 4:56 ` Rene Herman
2007-09-11 21:54 ` Mel Gorman
2007-09-12 14:29 ` Martin J. Bligh
2007-09-12 1:49 ` David Chinner
2007-09-11 15:27 ` Nick Piggin
2007-09-13 1:49 ` David Chinner
2007-09-12 17:23 ` Nick Piggin
2007-09-13 13:03 ` David Chinner
2007-09-13 2:01 ` Nick Piggin
2007-09-13 20:48 ` Nick Piggin
2007-09-17 4:07 ` David Chinner
2007-09-16 21:13 ` Nick Piggin
2007-09-12 2:01 ` Nick Piggin
2007-09-11 21:35 ` Christoph Lameter
2007-09-11 16:47 ` Andrea Arcangeli
2007-09-11 18:31 ` Mel Gorman
2007-09-11 2:26 ` Nick Piggin
2007-09-11 18:25 ` Maxim Levitsky
2007-09-11 3:05 ` Nick Piggin
2007-09-11 21:03 ` Mel Gorman
2007-09-11 19:20 ` Andrea Arcangeli
2007-09-11 20:19 ` Jörn Engel
2007-09-11 20:13 ` Christoph Lameter
2007-09-11 20:01 ` Christoph Lameter
2007-09-11 4:43 ` Nick Piggin
2007-09-11 5:17 ` Nick Piggin
2007-09-11 21:27 ` Mel Gorman
2007-09-11 6:03 ` [01/41] Pagecache zeroing: zero_user_segment, zero_user_segments and zero_user Christoph Lameter
2007-09-11 6:03 ` [02/41] Define functions for page cache handling Christoph Lameter
2007-09-11 6:03 ` [03/41] Use page_cache_xxx functions in mm/filemap.c Christoph Lameter
2007-09-11 6:03 ` [04/41] Use page_cache_xxx in mm/page-writeback.c Christoph Lameter
2007-09-11 6:03 ` [05/41] Use page_cache_xxx in mm/truncate.c Christoph Lameter
2007-09-11 6:03 ` [06/41] Use page_cache_xxx in mm/rmap.c Christoph Lameter
2007-09-11 6:03 ` [07/41] Use page_cache_xxx in mm/filemap_xip.c Christoph Lameter
2007-09-11 6:03 ` [08/41] Use page_cache_xxx in mm/migrate.c Christoph Lameter
2007-09-11 6:03 ` [09/41] Use page_cache_xxx in fs/libfs.c Christoph Lameter
2007-09-11 6:04 ` [10/41] Use page_cache_xxx in fs/sync Christoph Lameter
2007-09-11 6:04 ` [11/41] Use page_cache_xxx in fs/buffer.c Christoph Lameter
2007-09-11 6:04 ` [12/41] Use page_cache_xxx in mm/mpage.c Christoph Lameter
2007-09-11 6:04 ` [13/41] Use page_cache_xxx in mm/fadvise.c Christoph Lameter
2007-09-11 6:04 ` [14/41] Use page_cache_xxx in fs/splice.c Christoph Lameter
2007-09-11 6:04 ` [15/41] Use page_cache_xxx in ext2 Christoph Lameter
2007-09-11 6:04 ` [16/41] Use page_cache_xxx in fs/ext3 Christoph Lameter
2007-09-11 6:04 ` [17/41] Use page_cache_xxx in fs/ext4 Christoph Lameter
2007-09-11 6:04 ` [18/41] Use page_cache_xxx in fs/reiserfs Christoph Lameter
2007-09-11 6:04 ` [19/41] Use page_cache_xxx for fs/xfs Christoph Lameter
2007-09-11 6:04 ` [20/41] Use page_cache_xxx in drivers/block/rd.c Christoph Lameter
2007-09-11 6:04 ` [21/41] compound pages: Better PageHead/PageTail handling Christoph Lameter
2007-09-11 6:04 ` [22/41] compound pages: Add new support functions Christoph Lameter
2007-09-11 6:04 ` [23/41] compound pages: vmstat support Christoph Lameter
2007-09-11 6:04 ` [24/41] compound pages: Use new compound vmstat functions in SLUB Christoph Lameter
2007-09-11 6:04 ` [25/41] compound pages: Allow use of get_page_unless_zero with compound pages Christoph Lameter
2007-09-11 6:04 ` [26/41] compound pages: Allow freeing of compound pages via pagevec Christoph Lameter
2007-09-11 6:04 ` [27/41] Large page order operations, zeroing and flushing Christoph Lameter
2007-09-11 6:04 ` [28/41] Futex: Fix PAGE SIZE assumption Christoph Lameter
2007-09-11 6:04 ` [29/41] Fix up reclaim counters Christoph Lameter
2007-09-11 6:04 ` [30/41] Add VM_BUG_ONs to check for correct page order Christoph Lameter
2007-09-11 6:04 ` [31/41] Large Blocksize: Core piece Christoph Lameter
2007-09-11 6:04 ` [32/41] Readahead changes to support large blocksize Christoph Lameter
2007-09-11 6:04 ` [33/41] Large blocksize support in ramfs Christoph Lameter
2007-09-11 6:04 ` [34/41] Large blocksize support for XFS Christoph Lameter
2007-09-11 6:04 ` [35/41] Reiserfs: Fix up mapping_set_gfp_mask() Christoph Lameter
2007-09-11 6:04 ` [36/41] 64k block size support for Ext2/3/4 Christoph Lameter
2007-09-11 6:04 ` [37/41] ext2: fix rec_len overflow for 64KB block size Christoph Lameter
2007-09-11 6:04 ` [38/41] ext3: fix rec_len overflow with " Christoph Lameter
2007-09-11 6:04 ` [39/41] ext4: fix rec_len overflow for " Christoph Lameter
2007-09-11 6:04 ` [40/41] Do not use f_mapping in simple_prepare_write() Christoph Lameter
2007-09-11 6:04 ` [41/41] Mmap support using pte PAGE_SIZE mappings Christoph Lameter
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