From: David Howells <dhowells@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: dhowells@redhat.com, Al Viro <viro@zeniv.linux.org.uk>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [git pull] more vfs bits
Date: Sun, 22 Feb 2015 12:44:12 +0000 [thread overview]
Message-ID: <27542.1424609052@warthog.procyon.org.uk> (raw)
In-Reply-To: <CA+55aFzEhrqOBJcJAocD=iqY6FKYro8k03D9=dE=AO4CFZ51fw@mail.gmail.com>
Linus Torvalds <torvalds@linux-foundation.org> wrote:
> So the ACCESS_ONCE() thing is more special than just "done under RCU".
> It's more like "really special case done without any of the normal
> locking _or_ any of the normal RCU checks".
>
> That said, the overhead of using ACCESS_ONCE() is basically nil, so
> it's not like we couldn't just start doing more of them, and make it
> be more of a "any time we're under RCU" kind of thing.
Some functions access ->d_inode more than once. Wouldn't that potentially
increase the number of load instructions? Admittedly, calls to
dentry->d_inode could be replaced with inode = dentry->d_inode, then use
inode.
> Yeah, I think "d_backing_store_inode()" would probably be more along
> the lines, but that's a mouthful. Maybe shortened to
> "d_backing_inode()"?
Sounds more reasonable than d_opened_inode(). d_actual_inode() might also
work. d_lower_inode() might work too.
David
next prev parent reply other threads:[~2015-02-22 12:44 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-21 3:34 [git pull] more vfs bits Al Viro
2015-02-21 22:45 ` Linus Torvalds
2015-02-21 22:48 ` Linus Torvalds
2015-02-22 0:23 ` David Howells
2015-02-22 0:59 ` Al Viro
2015-02-22 0:51 ` Al Viro
2015-02-22 1:34 ` Linus Torvalds
2015-02-22 2:02 ` Al Viro
2015-02-22 2:11 ` Al Viro
2015-02-22 2:19 ` Linus Torvalds
2015-02-22 2:51 ` Al Viro
2015-02-22 3:16 ` Linus Torvalds
2015-02-22 8:51 ` Al Viro
2015-02-22 9:32 ` Sedat Dilek
2015-02-22 9:37 ` Al Viro
2015-02-22 10:36 ` Sedat Dilek
2015-02-22 15:05 ` Sedat Dilek
2015-02-22 15:12 ` Sedat Dilek
2015-02-22 13:22 ` Sedat Dilek
2015-02-22 13:23 ` Sedat Dilek
2015-02-22 12:54 ` David Howells
2015-02-22 16:46 ` [git pull] more vfs bits, updated Al Viro
2015-02-22 20:10 ` Sedat Dilek
2015-02-22 12:44 ` David Howells [this message]
2015-02-22 12:39 ` [git pull] more vfs bits David Howells
2015-02-22 12:30 ` David Howells
2015-02-22 0:18 ` David Howells
2015-02-22 1:14 ` Linus Torvalds
2015-02-22 1:32 ` Al Viro
-- strict thread matches above, loose matches on Subject: below --
2013-03-03 16:04 Al Viro
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