From: Peter Zijlstra <peterz@infradead.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Hans Liljestrand <ishkamiel@gmail.com>,
Al Viro <viro@zeniv.linux.org.uk>,
linux-kernel@vger.kernel.org, dwindsor@gmail.com,
David Howells <dhowells@redhat.com>,
linux-fsdevel@vger.kernel.org, Chris Mason <clm@fb.com>,
gregkh@linuxfoundation.org, elena.reshetova@intel.com
Subject: Re: [RFC][PATCH 02/10] fs: Avoid looking at i_count without i_lock held
Date: Fri, 24 Feb 2017 18:06:06 +0100 [thread overview]
Message-ID: <20170224170606.GR6515@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <CA+55aFxLw8FXf61rsGYDjA1tS=joDeaF7OSgaepLWwcz4zt=dg@mail.gmail.com>
On Fri, Feb 24, 2017 at 08:56:06AM -0800, Linus Torvalds wrote:
> This one looks very questionable.
>
> Taking the lock for every single inode, even when we can tell that it's
> pointless, is horrid.
>
> Even if you really think you found a race, i think it would be better to
> leave the unlocked read around as an optimistic check, and then do a safe
> double check read inside the lock (together with the i_state checks)
>
> Hmm?
Yeah, pretty dumb that.
next prev parent reply other threads:[~2017-02-24 17:06 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-24 15:43 [RFC][PATCH 00/10] On inode::i_count and the usage vs reference count issue Peter Zijlstra
2017-02-24 15:43 ` [RFC][PATCH 01/10] fs: Use lockdep_assert_held() instead of comments Peter Zijlstra
2017-02-24 15:43 ` [RFC][PATCH 02/10] fs: Avoid looking at i_count without i_lock held Peter Zijlstra
[not found] ` <CA+55aFxLw8FXf61rsGYDjA1tS=joDeaF7OSgaepLWwcz4zt=dg@mail.gmail.com>
2017-02-24 17:06 ` Peter Zijlstra [this message]
2017-02-24 15:43 ` [RFC][PATCH 03/10] fs: Introduce i_count() Peter Zijlstra
2017-02-24 15:43 ` [RFC][PATCH 04/10] fs: Restructure iput() Peter Zijlstra
2017-02-24 15:43 ` [RFC][PATCH 05/10] fs: Remove iput_final() Peter Zijlstra
2017-02-24 15:43 ` [RFC][PATCH 06/10] fs: Rework i_count Peter Zijlstra
2017-02-24 20:49 ` Al Viro
2017-02-24 15:43 ` [RFC][PATCH 07/10] orangefs: Use RCU for destroy_inode Peter Zijlstra
2017-02-24 20:52 ` Al Viro
2017-02-24 23:00 ` Mike Marshall
2017-02-25 20:31 ` Mike Marshall
2017-02-27 0:34 ` Mike Marshall
2017-02-27 1:20 ` Linus Torvalds
2017-02-27 8:44 ` David Howells
2017-02-27 14:44 ` Mike Marshall
2017-02-24 15:43 ` [RFC][PATCH 08/10] fs: Do RCU versions for find_inode() Peter Zijlstra
2017-02-24 15:43 ` [RFC][PATCH 09/10] locking/refcount: Provide refcount_dec_unless() Peter Zijlstra
2017-02-27 9:28 ` Reshetova, Elena
2017-02-24 15:43 ` [RFC][PATCH 10/10] fs: Convert i_count over to refcount_t Peter Zijlstra
2017-02-24 16:43 ` [RFC][PATCH 00/10] On inode::i_count and the usage vs reference count issue Christoph Hellwig
2017-02-24 17:07 ` Peter Zijlstra
2017-02-24 20:59 ` David Windsor
[not found] ` <CA+55aFy1bNbsX_3T-s_EUwTP-r_SmJJMvB3=-2nffehFVP=EdQ@mail.gmail.com>
[not found] ` <CA+55aFz0DbAGZ8gc+s35nm1N5frXjK_NOh7QzuSfZeJbjsT6Sg@mail.gmail.com>
[not found] ` <CA+55aFyR8wkHps5_AqUqzx8MDMNxRZZ7+MYH9g=ZCUi=4Oey8w@mail.gmail.com>
2017-02-24 19:24 ` Fwd: " Linus Torvalds
2017-02-24 20:42 ` Al Viro
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