From: Theodore Tso <tytso@mit.edu>
To: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>,
Herbert Xu <herbert@gondor.apana.org.au>,
akpm@osdl.org, lkml <linux-kernel@vger.kernel.org>,
ext2-devel <Ext2-devel@lists.sourceforge.net>
Subject: Re: [Ext2-devel] [RFC][PATCH] Manage jbd allocations from its own slabs
Date: Thu, 24 Aug 2006 22:24:05 -0400 [thread overview]
Message-ID: <20060825022405.GA3692@thunk.org> (raw)
In-Reply-To: <44EDF9DD.3040904@us.ibm.com>
On Thu, Aug 24, 2006 at 12:11:25PM -0700, Badari Pulavarty wrote:
> > Why can't you just use alloc_page? I bet the whole slab overhead
> > eats more memory than what's wasted when using alloc_pages. Especially
> > as the typical usecase is a 4k blocks filesystem with 4k pagesize
> > where the overhead of alloc_page is non-existant.
>
> Yes. That was what proposed earlier. But for 1k, 2k allocations we
> end up wasting whole page. Isn't it ? Thats why I created right
> sized slabs and disable slab-debug. I guess, I can do this only for
> 1k, 2k filesystems and directly use alloc_page() for 4k and 8k - but
> that would make code ugly and also it doesn't handle cases for
> bigger base pagesize systems (64k power).
Is there some way we can cleanly have a shortcut case where we use
alloc_page() if fs_blocksize == PAGE_SIZE? The efficiency gains for
what will be the common case on many architectures will probably make
this worthwhile....
- Ted
prev parent reply other threads:[~2006-08-25 2:24 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-08-23 23:08 [RFC][PATCH] Manage jbd allocations from its own slabs Badari Pulavarty
2006-08-23 23:34 ` Andrew Morton
2006-08-24 12:41 ` [Ext2-devel] " Dave Kleikamp
2006-08-25 0:00 ` Badari Pulavarty
2006-08-24 12:29 ` [Ext2-devel] " Dave Kleikamp
2006-08-24 17:12 ` Badari Pulavarty
2006-08-24 18:53 ` Christoph Hellwig
2006-08-24 19:11 ` Badari Pulavarty
2006-08-25 2:24 ` Theodore Tso [this message]
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