From: Jiri Gaisler <jiri@gaisler.com>
To: Jan Kara <jack@suse.cz>
Cc: Alexander Beregalov <a.beregalov@gmail.com>,
Theodore Tso <tytso@mit.edu>,
"linux-next@vger.kernel.org" <linux-next@vger.kernel.org>,
linux-ext4@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
sparclinux@vger.kernel.org
Subject: Re: next-20090310: ext4 hangs
Date: Thu, 26 Mar 2009 01:17:06 +0100 [thread overview]
Message-ID: <49CAC982.4050507@gaisler.com> (raw)
In-Reply-To: <20090326000035.GB11024@duck.suse.cz>
Jan Kara wrote:
> Hi,
>
> thanks for the updated disassembly.
>
>> 55bab0: 82 10 60 01 or %g1, 1, %g1
>> spin_unlock(&journal->j_list_lock);
>> 55bab4: 40 06 4b 20 call 6ee734 <_spin_unlock>
>> 55bab8: c2 24 e0 28 st %g1, [ %l3 + 0x28 ]
> OK, so it really seems that:
> jinode->i_flags |= JI_COMMIT_RUNNING;
> spin_unlock(&journal->j_list_lock);
>
> has been compiled to
> ld [ %l3 + 0x28 ], %g1
> or %g1, 1, %g1
> call 6ee734 <_spin_unlock>
> st %g1, [ %l3 + 0x28 ]
>
> Which seems like a bug in the compiler or in the way implement compiler
> barriers in spin_unlock() on UP sparc. Or is there some sparc magic by which
> this is correct code? Any clever sparc guy?
>
> Honza
Looks fine to me - the store is made in the branch delay slot
of the call, so it will occur before the first instruction at
the call target address executes.
Jiri.
WARNING: multiple messages have this Message-ID (diff)
From: Jiri Gaisler <jiri@gaisler.com>
To: Jan Kara <jack@suse.cz>
Cc: Alexander Beregalov <a.beregalov@gmail.com>,
Theodore Tso <tytso@mit.edu>,
"linux-next@vger.kernel.org" <linux-next@vger.kernel.org>,
linux-ext4@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
sparclinux@vger.kernel.org
Subject: Re: next-20090310: ext4 hangs
Date: Thu, 26 Mar 2009 00:17:06 +0000 [thread overview]
Message-ID: <49CAC982.4050507@gaisler.com> (raw)
In-Reply-To: <20090326000035.GB11024@duck.suse.cz>
Jan Kara wrote:
> Hi,
>
> thanks for the updated disassembly.
>
>> 55bab0: 82 10 60 01 or %g1, 1, %g1
>> spin_unlock(&journal->j_list_lock);
>> 55bab4: 40 06 4b 20 call 6ee734 <_spin_unlock>
>> 55bab8: c2 24 e0 28 st %g1, [ %l3 + 0x28 ]
> OK, so it really seems that:
> jinode->i_flags |= JI_COMMIT_RUNNING;
> spin_unlock(&journal->j_list_lock);
>
> has been compiled to
> ld [ %l3 + 0x28 ], %g1
> or %g1, 1, %g1
> call 6ee734 <_spin_unlock>
> st %g1, [ %l3 + 0x28 ]
>
> Which seems like a bug in the compiler or in the way implement compiler
> barriers in spin_unlock() on UP sparc. Or is there some sparc magic by which
> this is correct code? Any clever sparc guy?
>
> Honza
Looks fine to me - the store is made in the branch delay slot
of the call, so it will occur before the first instruction at
the call target address executes.
Jiri.
next prev parent reply other threads:[~2009-03-26 0:17 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-10 12:17 next-20090310: ext4 hangs Alexander Beregalov
2009-03-10 12:46 ` Theodore Tso
2009-03-10 12:54 ` Alexander Beregalov
2009-03-10 12:54 ` Alexander Beregalov
2009-03-10 12:54 ` Alexander Beregalov
2009-03-10 14:18 ` Alexander Beregalov
2009-03-10 15:47 ` Theodore Tso
2009-03-11 16:07 ` Alexander Beregalov
2009-03-11 16:07 ` Alexander Beregalov
2009-03-11 16:07 ` Alexander Beregalov
2009-03-25 15:11 ` Jan Kara
2009-03-25 15:15 ` Jan Kara
2009-03-25 15:15 ` Jan Kara
2009-03-25 15:18 ` Alexander Beregalov
2009-03-25 15:18 ` Alexander Beregalov
2009-03-25 15:22 ` Jan Kara
2009-03-25 15:29 ` Alexander Beregalov
2009-03-25 16:15 ` Jan Kara
2009-03-25 16:15 ` Jan Kara
2009-03-25 17:07 ` Alexander Beregalov
2009-03-25 19:43 ` Jan Kara
2009-03-25 19:43 ` Jan Kara
2009-03-25 19:43 ` Jan Kara
2009-03-25 22:38 ` Alexander Beregalov
2009-03-25 22:38 ` Alexander Beregalov
2009-03-26 0:00 ` Jan Kara
2009-03-26 0:00 ` Jan Kara
2009-03-26 0:17 ` Jiri Gaisler [this message]
2009-03-26 0:17 ` Jiri Gaisler
2009-03-26 0:25 ` Jan Kara
2009-03-26 0:25 ` Jan Kara
2009-03-31 10:01 ` Jan Kara
2009-03-31 10:01 ` Jan Kara
2009-03-31 10:01 ` Jan Kara
2009-03-31 10:07 ` Alexander Beregalov
2009-03-31 10:07 ` Alexander Beregalov
2009-03-31 12:33 ` Jan Kara
2009-03-31 12:33 ` Jan Kara
2009-04-02 18:50 ` Alexander Beregalov
2009-04-02 18:50 ` Alexander Beregalov
2009-04-02 18:50 ` Alexander Beregalov
2009-04-04 21:09 ` Alexander Beregalov
2009-04-04 21:09 ` Alexander Beregalov
2009-04-06 9:20 ` Jan Kara
2009-04-06 9:20 ` Jan Kara
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