From: Borislav Petkov <bp@alien8.de>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andi Kleen <andi@firstfloor.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
the arch/x86 maintainers <x86@kernel.org>,
Ingo Molnar <mingo@kernel.org>, Andi Kleen <ak@linux.intel.com>
Subject: Re: [PATCH 10/13] x86: Move cond resched for copy_{from,to}_user into low level code 64bit
Date: Sat, 10 Aug 2013 20:23:09 +0200 [thread overview]
Message-ID: <20130810182309.GA5714@pd.tnic> (raw)
In-Reply-To: <CA+55aFw94ow=aYF-y9kJu+2ZsA=YLob5wFe01H+ooQmP6EbJvQ@mail.gmail.com>
On Sat, Aug 10, 2013 at 09:27:33AM -0700, Linus Torvalds wrote:
> Now, the *debug* logic is entirely different, of course. Maybe the
> problem is that we have mixed up the two so badly, and we have
> "might_sleep()" that implies more of a debug issue than a preemption
> issue, and then people add those because they want the debug coverage
> (and then you *absolutely* want it even for a single-byte user
> mode access). And then because the concept is tied together with
> preemption, we end up doing preemption even for that single-byte
> access despite the fact that it makes no sense what-so-ever.
Sounds like the debug aspect and the preemption point addition need
to be sorf-of split into two different functions/macros and each used
separately.
Something like keep the current might_sleep and have debug_sleep or
similar which does only __might_sleep without the resched...
--
Regards/Gruss,
Boris.
Sent from a fat crate under my desk. Formatting is fine.
--
next prev parent reply other threads:[~2013-08-10 18:23 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-09 23:04 Re-tune x86 uaccess code for PREEMPT_VOLUNTARY Andi Kleen
2013-08-09 23:04 ` [PATCH 01/13] x86: Add 1/2/4/8 byte optimization to 64bit __copy_{from,to}_user_inatomic Andi Kleen
2013-08-09 23:04 ` [PATCH 02/13] x86: Include linux/sched.h in asm/uaccess.h Andi Kleen
2013-08-09 23:04 ` [PATCH 03/13] tree-sweep: Include linux/sched.h for might_sleep users Andi Kleen
2013-08-09 23:04 ` [PATCH 04/13] Move might_sleep and friends from kernel.h to sched.h Andi Kleen
2013-08-09 23:04 ` [PATCH 05/13] sched: mark should_resched() __always_inline Andi Kleen
2013-08-09 23:04 ` [PATCH 06/13] x86: Add 32bit versions of SAVE_ALL/RESTORE_ALL to calling.h Andi Kleen
2013-08-09 23:04 ` [PATCH 07/13] Add might_fault_debug_only() Andi Kleen
2013-08-14 18:24 ` Michael S. Tsirkin
2013-08-09 23:04 ` [PATCH 08/13] x86: Move cond_resched into the out of line put_user code Andi Kleen
2013-08-09 23:04 ` [PATCH 09/13] x86: Move cond_resched into the out of line get_user code Andi Kleen
2013-08-09 23:04 ` [PATCH 10/13] x86: Move cond resched for copy_{from,to}_user into low level code 64bit Andi Kleen
2013-08-10 15:42 ` Linus Torvalds
2013-08-10 16:10 ` Andi Kleen
2013-08-10 16:27 ` Linus Torvalds
2013-08-10 18:23 ` Borislav Petkov [this message]
2013-08-10 19:05 ` Jörn Engel
2013-08-20 21:03 ` KOSAKI Motohiro
2013-08-15 5:04 ` Michael S. Tsirkin
2013-08-09 23:04 ` [PATCH 11/13] sched: Inline the need_resched test into the caller for _cond_resched Andi Kleen
2013-08-09 23:04 ` [PATCH 12/13] x86: move __copy_*_nocache might fault check out of line Andi Kleen
2013-08-09 23:04 ` [PATCH 13/13] x86: drop cond rescheds from __copy_{from,to}_user Andi Kleen
2013-08-10 4:42 ` Re-tune x86 uaccess code for PREEMPT_VOLUNTARY H. Peter Anvin
2013-08-10 5:55 ` Mike Galbraith
2013-08-10 16:09 ` H. Peter Anvin
2013-08-10 16:43 ` Linus Torvalds
2013-08-10 17:18 ` H. Peter Anvin
2013-08-10 18:51 ` Linus Torvalds
2013-08-10 19:18 ` H. Peter Anvin
2013-08-10 20:26 ` H. Peter Anvin
2013-08-10 23:00 ` H. Peter Anvin
2013-08-11 4:17 ` Mike Galbraith
2013-08-11 4:27 ` H. Peter Anvin
2013-08-11 4:36 ` Mike Galbraith
2013-08-11 4:57 ` H. Peter Anvin
2013-08-11 5:58 ` Mike Galbraith
2013-08-13 18:09 ` H. Peter Anvin
2013-08-13 18:12 ` Andi Kleen
2013-08-14 18:27 ` Michael S. Tsirkin
2013-08-14 22:08 ` Andi Kleen
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