From: Fengguang Wu <wfg@mail.ustc.edu.cn>
To: Andi Kleen <andi@firstfloor.org>
Cc: Andrew Morton <akpm@osdl.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/6] compacting file_ra_state
Date: Fri, 20 Jul 2007 20:11:43 +0800 [thread overview]
Message-ID: <384933499.09699@ustc.edu.cn> (raw)
Message-ID: <20070720121143.GA8584@mail.ustc.edu.cn> (raw)
In-Reply-To: <p73y7hbux4d.fsf@bingen.suse.de>
On Fri, Jul 20, 2007 at 01:34:42PM +0200, Andi Kleen wrote:
> Fengguang Wu <wfg@mail.ustc.edu.cn> writes:
>
> > Use 'unsigned int' instead of 'unsigned long' for the readahead indexes/sizes.
> >
> > This helps reduce memory consumption on 64bit CPU when
> > a lot of files are opened.
> >
> > Note that the (smaller) 32bit index can support up to 16PB file.
~~~~
sorry, it's 16TB ;)
> > Which should be sufficient large at least for now.
>
> This would add a new limit to 64bit architectures. Surely keeping
> start at pgoff_t will not be a big issue? The other fields can be
> 32bit.
Yeah, it counts for about 4MB memory for 1M opened files.
But, the filp size is now 296 on x86_64, so slab-objects-per-page = 13.
Adding another 4bytes, it remains in 13;
Taking 4bytes more, it increases to 14.
So pgoff_t consumes no more memory actually.
next prev parent reply other threads:[~2007-07-20 12:12 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20070720100740.106917381@mail.ustc.edu.cn>
2007-07-20 10:07 ` [PATCH 0/6] readahead cleanups and interleaved readahead Fengguang Wu
[not found] ` <20070720101123.936159499@mail.ustc.edu.cn>
2007-07-20 10:07 ` [PATCH 1/6] compacting file_ra_state Fengguang Wu
[not found] ` <p73y7hbux4d.fsf@bingen.suse.de>
[not found] ` <20070720121143.GA8584@mail.ustc.edu.cn>
2007-07-20 12:11 ` Fengguang Wu [this message]
2007-07-20 16:02 ` Linus Torvalds
[not found] ` <1184927207.20032.168.camel@twins>
2007-07-20 10:48 ` Peter Zijlstra
[not found] ` <20070720112409.GB6300@mail.ustc.edu.cn>
2007-07-20 11:24 ` Fengguang Wu
[not found] ` <20070720101124.083676724@mail.ustc.edu.cn>
2007-07-20 10:07 ` [PATCH 2/6] mmap read-around simplification Fengguang Wu
[not found] ` <20070720101124.221472134@mail.ustc.edu.cn>
2007-07-20 10:07 ` [PATCH 3/6] remove several readahead macros Fengguang Wu
[not found] ` <20070720101124.350754890@mail.ustc.edu.cn>
2007-07-20 10:07 ` [PATCH 4/6] remove the limit max_sectors_kb imposed on max_readahead_kb Fengguang Wu
2007-07-20 11:07 ` Jens Axboe
[not found] ` <20070720112528.GC6300@mail.ustc.edu.cn>
2007-07-20 11:25 ` Fengguang Wu
[not found] ` <20070720101124.470940735@mail.ustc.edu.cn>
2007-07-20 10:07 ` [PATCH 5/6] introduce radix_tree_scan_hole() Fengguang Wu
[not found] ` <20070720101124.600141268@mail.ustc.edu.cn>
2007-07-20 10:07 ` [PATCH 6/6] basic support of interleaved reads Fengguang Wu
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