From: Linus Torvalds <torvalds@linux-foundation.org>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH] VFS: Cut down inode->i_op->xyz accesses in path walking
Date: Tue, 26 Jul 2011 11:45:38 -0700 [thread overview]
Message-ID: <CA+55aFz+5K5T1X6c-9aw3EnpTFXK499sDmwzS7_dcGMhiSHDkQ@mail.gmail.com> (raw)
In-Reply-To: <20110726184122.GI22133@ZenIV.linux.org.uk>
On Tue, Jul 26, 2011 at 11:41 AM, Al Viro <viro@zeniv.linux.org.uk> wrote:
>
> Hmm... We still have 19 spare bits in ->i_flags and at least 22 in ->i_state.
> Do we need to bother with new field at all? ->i_state is unsigned long...
Do we *need* it? No. But it's often in the next cache-line. It would
be beautiful to put the bits right next to i_mode, and basically make
a lot of the common operations just touch those four bytes for doing
the S_ISDIR tests and the "can I use generic_permission()" tests etc.
And the whole point of that is to make for a smaller cacheline
footprint (and admittedly also the few cycles to avoid the dereference
- and that you'd get from using i_state).
Linus
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next prev parent reply other threads:[~2011-07-26 18:46 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-22 17:37 VFS pathname walking cleanups (i_op and ACL access) Linus Torvalds
2011-07-22 17:37 ` [PATCH 1/2] VFS: Cut down inode->i_op->xyz accesses in path walking Linus Torvalds
2011-07-22 17:47 ` Christoph Hellwig
2011-07-22 23:40 ` Al Viro
2011-07-22 23:54 ` Linus Torvalds
2011-07-23 3:55 ` [PATCH] " Linus Torvalds
2011-07-23 13:35 ` Christoph Hellwig
2011-07-23 14:46 ` Al Viro
2011-07-23 14:51 ` Christoph Hellwig
2011-07-23 15:45 ` Linus Torvalds
[not found] ` <alpine.LFD.2.02.1107251852220.13796@i5.linux-foundation.org>
2011-07-26 3:05 ` Al Viro
2011-07-26 3:23 ` Linus Torvalds
2011-07-26 18:41 ` Al Viro
2011-07-26 18:45 ` Linus Torvalds [this message]
2011-08-07 6:06 ` Linus Torvalds
2011-08-07 6:51 ` Al Viro
2011-08-07 23:43 ` Linus Torvalds
2011-07-22 17:40 ` VFS pathname walking cleanups (i_op and ACL access) Christoph Hellwig
2011-07-22 17:45 ` [PATCH 2/2] vfs: move ACL cache lookup into generic code Linus Torvalds
2011-07-22 17:50 ` Christoph Hellwig
2011-07-22 17:54 ` Linus Torvalds
2011-07-23 2:34 ` [PATCH] " Linus Torvalds
2011-07-23 3:29 ` Al Viro
2011-07-23 3:42 ` Linus Torvalds
2011-07-23 4:31 ` Al Viro
2011-07-23 6:06 ` Al Viro
2011-07-25 8:15 ` Aneesh Kumar K.V
2011-07-25 8:16 ` Aneesh Kumar K.V
2011-07-23 7:47 ` Al Viro
2011-07-23 14:50 ` Christoph Hellwig
2011-07-23 15:32 ` Al Viro
2011-07-23 17:02 ` Al Viro
2011-07-23 17:31 ` Linus Torvalds
2011-07-23 18:20 ` Al Viro
2011-07-23 18:29 ` Linus Torvalds
2011-07-23 21:53 ` Al Viro
2011-07-23 22:38 ` Al Viro
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