From: Mark Rutland <mark.rutland@arm.com>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: cmetcalf@ezchip.com, will.deacon@arm.com,
linux-kernel@vger.kernel.org, luto@amacapital.net,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 2/2] arm64: factor work_pending state machine to C
Date: Wed, 6 Jan 2016 12:47:53 +0000 [thread overview]
Message-ID: <20160106124753.GI563@leverpostej> (raw)
In-Reply-To: <20160106123011.GN6301@e104818-lin.cambridge.arm.com>
On Wed, Jan 06, 2016 at 12:30:11PM +0000, Catalin Marinas wrote:
> On Tue, Jan 05, 2016 at 05:33:35PM +0000, Mark Rutland wrote:
> > Currently ret_fast_syscall, work_pending, and ret_to_user form an ad-hoc
> > state machine that can be difficult to reason about due to duplicated
> > code and a large number of branch targets.
> >
> > This patch factors the common logic out into the existing
> > do_notify_resume function, converting the code to C in the process,
> > making the code more legible.
> >
> > This patch tries to mirror the existing behaviour as closely as possible
> > while using the usual C control flow primitives. There should be no
> > functional change as a result of this patch.
> >
> > Signed-off-by: Mark Rutland <mark.rutland@arm.com>
> > Cc: Catalin Marinas <catalin.marinas@arm.com>
> > Cc: Chris Metcalf <cmetcalf@ezchip.com>
> > Cc: Will Deacon <will.deacon@arm.com>
>
> This is definitely cleaner. The only downside is slightly more expensive
> ret_fast_syscall. I guess it's not noticeable (though we could do some
> quick benchmark like getpid in a loop). Anyway, I'm fine with the patch:
>
> Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cheers!
While any additional overhead hasn't been noticeable, I'll try to get
some numbers out as part of the larger deasm testing/benchmarking.
Thanks,
Mark.
next prev parent reply other threads:[~2016-01-06 12:48 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-04 19:34 [PATCH v9 00/13] support "task_isolation" mode for nohz_full Chris Metcalf
2016-01-04 19:34 ` [PATCH v9 01/13] vmstat: provide a function to quiet down the diff processing Chris Metcalf
2016-01-04 19:34 ` [PATCH v9 02/13] vmstat: add vmstat_idle function Chris Metcalf
2016-01-04 19:34 ` [PATCH v9 03/13] lru_add_drain_all: factor out lru_add_drain_needed Chris Metcalf
2016-01-04 19:34 ` [PATCH v9 04/13] task_isolation: add initial support Chris Metcalf
2016-01-19 15:42 ` Frederic Weisbecker
2016-01-19 20:45 ` Chris Metcalf
2016-01-28 0:28 ` Frederic Weisbecker
2016-01-29 18:18 ` Chris Metcalf
2016-01-30 21:11 ` Frederic Weisbecker
2016-02-11 19:24 ` Chris Metcalf
2016-03-04 12:56 ` Frederic Weisbecker
2016-03-09 19:39 ` Chris Metcalf
2016-04-08 13:56 ` Frederic Weisbecker
2016-04-08 16:34 ` Chris Metcalf
2016-04-12 18:41 ` Chris Metcalf
2016-04-22 13:16 ` Frederic Weisbecker
2016-04-25 20:36 ` Chris Metcalf
2016-05-26 1:07 ` Frederic Weisbecker
2016-06-03 19:32 ` Chris Metcalf
2016-06-29 15:18 ` Frederic Weisbecker
2016-07-01 20:59 ` Chris Metcalf
2016-07-05 14:41 ` Frederic Weisbecker
2016-07-05 17:47 ` Christoph Lameter
2016-01-04 19:34 ` [PATCH v9 05/13] task_isolation: support PR_TASK_ISOLATION_STRICT mode Chris Metcalf
2016-01-04 19:34 ` [PATCH v9 06/13] task_isolation: add debug boot flag Chris Metcalf
2016-01-04 22:52 ` Steven Rostedt
2016-01-04 23:42 ` Chris Metcalf
2016-01-05 13:42 ` Steven Rostedt
2016-01-04 19:34 ` [PATCH v9 07/13] arch/x86: enable task isolation functionality Chris Metcalf
2016-01-04 21:02 ` [PATCH v9bis " Chris Metcalf
2016-01-04 19:34 ` [PATCH v9 08/13] arch/arm64: adopt prepare_exit_to_usermode() model from x86 Chris Metcalf
2016-01-04 20:33 ` Mark Rutland
2016-01-04 21:01 ` Chris Metcalf
2016-01-05 17:21 ` Mark Rutland
2016-01-05 17:33 ` [PATCH 1/2] arm64: entry: remove pointless SPSR mode check Mark Rutland
2016-01-06 12:15 ` Catalin Marinas
2016-01-05 17:33 ` [PATCH 2/2] arm64: factor work_pending state machine to C Mark Rutland
2016-01-05 18:53 ` Chris Metcalf
2016-01-06 12:30 ` Catalin Marinas
2016-01-06 12:47 ` Mark Rutland [this message]
2016-01-06 13:43 ` Mark Rutland
2016-01-06 14:17 ` Catalin Marinas
2016-01-04 22:31 ` [PATCH v9 08/13] arch/arm64: adopt prepare_exit_to_usermode() model from x86 Andy Lutomirski
2016-01-05 18:01 ` Mark Rutland
2016-01-04 19:34 ` [PATCH v9 09/13] arch/arm64: enable task isolation functionality Chris Metcalf
2016-01-04 19:34 ` [PATCH v9 10/13] arch/tile: adopt prepare_exit_to_usermode() model from x86 Chris Metcalf
2016-01-04 19:34 ` [PATCH v9 11/13] arch/tile: move user_exit() to early kernel entry sequence Chris Metcalf
2016-01-04 19:34 ` [PATCH v9 12/13] arch/tile: enable task isolation functionality Chris Metcalf
2016-01-04 19:34 ` [PATCH v9 13/13] arm, tile: turn off timer tick for oneshot_stopped state Chris Metcalf
2016-01-11 21:15 ` [PATCH v9 00/13] support "task_isolation" mode for nohz_full Chris Metcalf
2016-01-12 10:07 ` Will Deacon
2016-01-12 17:49 ` Chris Metcalf
2016-01-13 10:44 ` Ingo Molnar
2016-01-13 21:19 ` Chris Metcalf
2016-01-20 13:27 ` Mark Rutland
2016-01-12 10:53 ` Ingo Molnar
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