From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx153.postini.com [74.125.245.153]) by kanga.kvack.org (Postfix) with SMTP id 7539C6B13F0 for ; Thu, 9 Feb 2012 17:26:27 -0500 (EST) Date: Thu, 9 Feb 2012 14:26:25 -0800 From: Andrew Morton Subject: Re: [PATCH v9 4/8] smp: add func to IPI cpus based on parameter func Message-Id: <20120209142625.0664e055.akpm@linux-foundation.org> In-Reply-To: <1328776585-22518-5-git-send-email-gilad@benyossef.com> References: <1328776585-22518-1-git-send-email-gilad@benyossef.com> <1328776585-22518-5-git-send-email-gilad@benyossef.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Gilad Ben-Yossef Cc: linux-kernel@vger.kernel.org, Chris Metcalf , Christoph Lameter , Frederic Weisbecker , Russell King , linux-mm@kvack.org, Pekka Enberg , Matt Mackall , Sasha Levin , Rik van Riel , Andi Kleen , Alexander Viro , linux-fsdevel@vger.kernel.org, Avi Kivity , Kosaki Motohiro , Milton Miller On Thu, 9 Feb 2012 10:36:21 +0200 Gilad Ben-Yossef wrote: > @@ -153,6 +162,22 @@ static inline int up_smp_call_function(smp_call_func_t func, void *info) > local_irq_enable(); \ > } \ > } while (0) > +/* > + * Preemption is disabled here to make sure the > + * cond_func is called under the same condtions in UP > + * and SMP. > + */ > +#define on_each_cpu_cond(cond_func, func, info, wait, gfp_flags) \ > + do { > + void *__info = (info); \ > + preempt_disable(); \ > + if ((cond_func)(0, __info)) { \ > + local_irq_disable(); \ > + (func)(__info); \ > + local_irq_enable(); \ > + } \ > + preempt_enable(); \ > + } while (0) That wasn't compile-tested! This is one of the many reasons why I convert replacement patches into incremental patches - so I can see what was done. Here's what I queued after converting this patch into a delta: --- a/kernel/smp.c~smp-add-func-to-ipi-cpus-based-on-parameter-func-v9 +++ a/kernel/smp.c @@ -771,7 +771,9 @@ EXPORT_SYMBOL(on_each_cpu_mask); * The function might sleep if the GFP flags indicates a non * atomic allocation is allowed. * - * Preemption is disabled to protect against a hotplug event. + * Preemption is disabled to protect against CPU going offline but not + * online. CPUs going online during the call will not be seen or sent + * an IPI. * * You must not call this function with disabled interrupts or * from a hardware interrupt handler or from a bottom half handler. _ And I queued a small fix to that: From: Andrew Morton Subject: smp-add-func-to-ipi-cpus-based-on-parameter-func-v9-fix s/CPU/CPUs, use all 80 cols in comment Cc: Gilad Ben-Yossef Signed-off-by: Andrew Morton --- kernel/smp.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) --- a/kernel/smp.c~smp-add-func-to-ipi-cpus-based-on-parameter-func-v9-fix +++ a/kernel/smp.c @@ -771,9 +771,8 @@ EXPORT_SYMBOL(on_each_cpu_mask); * The function might sleep if the GFP flags indicates a non * atomic allocation is allowed. * - * Preemption is disabled to protect against CPU going offline but not - * online. CPUs going online during the call will not be seen or sent - * an IPI. + * Preemption is disabled to protect against CPUs going offline but not online. + * CPUs going online during the call will not be seen or sent an IPI. * * You must not call this function with disabled interrupts or * from a hardware interrupt handler or from a bottom half handler. _ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org