From: Chris Wedgwood <cw@f00f.org>
To: Ingo Molnar <mingo@elte.hu>, Andrew Morton <akpm@osdl.org>,
torvalds@osdl.org, benh@kernel.crashing.org,
linux-kernel@vger.kernel.org,
Ia64 Linux <linux-ia64@vger.kernel.org>
Subject: Re: Horrible regression with -CURRENT from "Don't busy-lock-loop in preemptable spinlocks" patch
Date: Tue, 18 Jan 2005 07:08:52 +0000 [thread overview]
Message-ID: <20050118070852.GA26049@taniwha.stupidest.org> (raw)
In-Reply-To: <20050118042858.GD14709@cse.unsw.EDU.AU>
On Tue, Jan 18, 2005 at 03:28:58PM +1100, Darren Williams wrote:
> On top of Ingo's patch I attempt a solution that failed:
> +#define read_is_locked(x) (*(volatile int *) (x) > 0)
> +#define write_is_locked(x) (*(volatile int *) (x) < 0)
how about something like:
#define read_is_locked(x) (*(volatile int *) (x) != 0)
#define write_is_locked(x) (*(volatile int *) (x) & (1<<31))
I'm not masking the write-bit for read_is_locked here, I'm not sure is
we should?
--cw
next prev parent reply other threads:[~2005-01-18 7:08 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20050117055044.GA3514@taniwha.stupidest.org>
[not found] ` <20050116230922.7274f9a2.akpm@osdl.org>
[not found] ` <20050117143301.GA10341@elte.hu>
2005-01-18 1:47 ` Horrible regression with -CURRENT from "Don't busy-lock-loop in preemptable spinlocks" patch Darren Williams
2005-01-18 4:28 ` Darren Williams
2005-01-18 7:08 ` Chris Wedgwood [this message]
2005-01-19 0:14 ` Peter Chubb
2005-01-19 8:04 ` Ingo Molnar
2005-01-19 9:18 ` Peter Chubb
2005-01-19 9:20 ` Ingo Molnar
2005-01-19 21:43 ` Paul Mackerras
2005-01-20 2:34 ` [PATCH RFC] 'spinlock/rwlock fixes' V3 [1/1] Chris Wedgwood
2005-01-20 3:01 ` Andrew Morton
2005-01-20 3:18 ` Chris Wedgwood
2005-01-20 3:33 ` Andrew Morton
2005-01-20 8:59 ` Peter Chubb
2005-01-20 13:04 ` Ingo Molnar
2005-01-20 15:51 ` Linus Torvalds
2005-01-20 16:08 ` [patch 1/3] spinlock fix #1, *_can_lock() primitives Ingo Molnar
2005-01-20 16:11 ` [patch 2/3] spinlock fix #2: generalize [spin|rw]lock yielding Ingo Molnar
2005-01-20 16:12 ` [patch 3/3] spinlock fix #3: type-checking spinlock primitives, x86 Ingo Molnar
2005-01-20 16:14 ` [patch] stricter type-checking rwlock " Ingo Molnar
2005-01-20 16:16 ` [patch] minor spinlock cleanups Ingo Molnar
2005-01-20 16:31 ` [patch 1/3] spinlock fix #1, *_can_lock() primitives Linus Torvalds
2005-01-20 16:40 ` Ingo Molnar
2005-01-20 17:48 ` Linus Torvalds
2005-01-20 17:53 ` Ingo Molnar
2005-01-20 18:22 ` [patch, BK-curr] nonintrusive spin-polling loop in kernel/spinlock.c Ingo Molnar
2005-01-20 18:25 ` [patch, BK-curr] rename 'lock' to 'slock' in asm-i386/spinlock.h Ingo Molnar
2005-01-20 23:45 ` [patch, BK-curr] nonintrusive spin-polling loop in kernel/spinlock.c Linus Torvalds
2005-01-20 16:44 ` [patch 1/3] spinlock fix #1, *_can_lock() primitives Ingo Molnar
2005-01-20 16:59 ` Ingo Molnar
2005-01-20 16:47 ` Ingo Molnar
2005-01-20 16:57 ` Ingo Molnar
2005-01-20 16:05 ` [PATCH RFC] 'spinlock/rwlock fixes' V3 [1/1] Linus Torvalds
2005-01-20 16:20 ` Ingo Molnar
2005-01-20 16:18 ` Linus Torvalds
2005-01-20 16:23 ` Ingo Molnar
2005-01-20 17:30 ` Linus Torvalds
2005-01-20 17:38 ` Ingo Molnar
2005-01-20 16:28 ` Ingo Molnar
2005-01-20 5:49 ` Horrible regression with -CURRENT from "Don't busy-lock-loop in preemptable spinlocks" patch Grant Grundler
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20050118070852.GA26049@taniwha.stupidest.org \
--to=cw@f00f.org \
--cc=akpm@osdl.org \
--cc=benh@kernel.crashing.org \
--cc=linux-ia64@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=torvalds@osdl.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox