From: Michal Hocko <mhocko@kernel.org>
To: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
"David S. Miller" <davem@davemloft.net>,
Tony Luck <tony.luck@intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Chris Zankel <chris@zankel.net>,
Max Filippov <jcmvbkbc@gmail.com>,
x86@kernel.org, linux-alpha@vger.kernel.org,
linux-ia64@vger.kernel.org, linux-s390@vger.kernel.org,
linux-sh@vger.kernel.org, sparclinux@vger.kernel.org,
linux-xtensa@linux-xtensa.org, linux-arch@vger.kernel.org,
Josh Poimboeuf <jpoimboe@redhat.com>
Subject: Re: [PATCH 10/11] x86, rwsem: provide __down_write_killable
Date: Wed, 20 Apr 2016 16:58:26 -0400 [thread overview]
Message-ID: <20160420205825.GB4771@dhcp22.suse.cz> (raw)
In-Reply-To: <20160420204501.GA6815@pd.tnic>
On Wed 20-04-16 22:45:01, Borislav Petkov wrote:
> On Wed, Apr 20, 2016 at 11:04:05AM -0700, H. Peter Anvin wrote:
> > The reason it breaks is because the same register can't be an
> > input-output register and a separate input. However, the input side of
> > the input-output is probably undefined, and so gcc may not notice.
>
> So Michal and I talked about this a while ago. Why do we need the '"a"
> (sem)' input dependency if '"+a" (ret)' already supplies the same thing?
>
> There's also that "=d" (tmp) thing which we don't really need as an
> output, right?
>
> I.e., can we simplify like this?
I am for any simplification, my gcc-asm-foo is just too weak and I
wanted my change to be as minimal as possible. So if you feel you can
clean up this I would more than welcome that. Maybe a follow up patch
would be a better approach so that we can check that the generated code
hasn't changed.
Thanks!
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2016-04-20 20:58 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-07 15:12 [PATCH 0/11] introduce down_write_killable for rw_semaphore v3 Michal Hocko
2016-04-07 15:12 ` [PATCH 01/11] locking, rwsem: get rid of __down_write_nested Michal Hocko
2016-04-13 11:32 ` [tip:locking/rwsem] locking/rwsem: Get rid of __down_write_nested() tip-bot for Michal Hocko
2016-04-07 15:12 ` [PATCH 02/11] locking, rwsem: drop explicit memory barriers Michal Hocko
2016-04-13 11:32 ` [tip:locking/rwsem] locking/rwsem: Drop " tip-bot for Michal Hocko
2016-04-07 15:12 ` [PATCH 03/11] xtensa, rwsem: drop superfluous arch specific implementation Michal Hocko
2016-04-13 11:33 ` [tip:locking/rwsem] locking/rwsem, xtensa: Drop " tip-bot for Michal Hocko
2016-04-07 15:12 ` [PATCH 04/11] sh, rwsem: drop " Michal Hocko
2016-04-13 11:33 ` [tip:locking/rwsem] locking/rwsem, sh: Drop " tip-bot for Michal Hocko
2016-04-07 15:12 ` [PATCH 05/11] sparc, rwsem: drop " Michal Hocko
2016-04-13 11:33 ` [tip:locking/rwsem] locking/rwsem, sparc: Drop " tip-bot for Michal Hocko
2016-04-07 15:12 ` [PATCH 06/11] locking, rwsem: introduce basis for down_write_killable Michal Hocko
2016-04-13 11:34 ` [tip:locking/rwsem] locking/rwsem: Introduce basis for down_write_killable() tip-bot for Michal Hocko
2016-04-07 15:12 ` [PATCH 07/11] alpha, rwsem: provide __down_write_killable Michal Hocko
2016-04-22 9:42 ` [tip:locking/rwsem] locking/rwsem, alpha: Provide __down_write_killable() tip-bot for Michal Hocko
2016-04-07 15:12 ` [PATCH 08/11] ia64, rwsem: provide __down_write_killable Michal Hocko
2016-04-07 17:28 ` Sergei Shtylyov
2016-04-08 6:22 ` Michal Hocko
2016-04-22 9:43 ` [tip:locking/rwsem] locking/rwsem, ia64: Provide __down_write_killable() tip-bot for Michal Hocko
2016-04-07 15:12 ` [PATCH 09/11] s390, rwsem: provide __down_write_killable Michal Hocko
2016-04-22 9:43 ` [tip:locking/rwsem] locking/rwsem, s390: Provide __down_write_killable() tip-bot for Michal Hocko
2016-04-07 15:12 ` [PATCH 10/11] x86, rwsem: provide __down_write_killable Michal Hocko
2016-04-13 9:08 ` Ingo Molnar
2016-04-13 9:16 ` Michal Hocko
2016-04-13 9:19 ` Ingo Molnar
2016-04-13 10:27 ` Ingo Molnar
2016-04-13 12:49 ` Michal Hocko
2016-04-17 16:59 ` Michal Hocko
2016-04-20 13:40 ` Peter Zijlstra
2016-04-20 18:04 ` H. Peter Anvin
2016-04-20 20:45 ` Borislav Petkov
2016-04-20 20:58 ` Michal Hocko [this message]
2016-04-20 21:06 ` H. Peter Anvin
2016-04-20 21:36 ` Borislav Petkov
2016-04-20 22:29 ` H. Peter Anvin
2016-04-21 11:35 ` Borislav Petkov
2016-04-21 13:09 ` Michal Hocko
2016-04-21 13:21 ` Borislav Petkov
2016-04-27 12:02 ` [PATCH] x86/locking/rwsem: Cleanup ____down_write() Borislav Petkov
2016-04-28 10:27 ` [tip:locking/rwsem] locking/rwsem, x86: Clean up ____down_write() tip-bot for Borislav Petkov
2016-04-22 6:53 ` [PATCH 10/11] x86, rwsem: provide __down_write_killable Ingo Molnar
2016-04-13 9:57 ` [PATCH] x86: add frame annotation for call_rwsem_down_write_failed_killable Michal Hocko
2016-04-22 9:44 ` [tip:locking/rwsem] locking/rwsem, x86: Add frame annotation for call_rwsem_down_write_failed_killable() tip-bot for Michal Hocko
2016-04-22 9:43 ` [tip:locking/rwsem] locking/rwsem, x86: Provide __down_write_killable() tip-bot for Michal Hocko
2016-04-07 15:12 ` [PATCH 11/11] locking, rwsem: provide down_write_killable Michal Hocko
2016-04-22 9:44 ` [tip:locking/rwsem] locking/rwsem: Provide down_write_killable() tip-bot for Michal Hocko
2016-04-12 9:37 ` [PATCH 0/11] introduce down_write_killable for rw_semaphore v3 Michal Hocko
2016-04-12 15:40 ` Peter Zijlstra
2016-04-12 18:01 ` Michal Hocko
-- strict thread matches above, loose matches on Subject: below --
2016-04-01 11:04 [PATCH 0/11] introduce down_write_killable for rw_semaphore v2 Michal Hocko
2016-04-01 11:04 ` [PATCH 10/11] x86, rwsem: provide __down_write_killable Michal Hocko
2016-04-06 18:31 ` Peter Zijlstra
2016-02-29 12:58 [PATCH 0/11] introduce down_write_killable for rw_semaphore Michal Hocko
2016-02-29 12:58 ` [PATCH 10/11] x86, rwsem: provide __down_write_killable Michal Hocko
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