Re: [PATCH v5 1/8] smp: Introduce a generic on_each_cpu_mask function
From: Michal Nazarewicz <hidden>
Date: 2012-01-05 13:17:54
Also in:
linux-mm, lkml
On Tue, 03 Jan 2012 23:26:24 +0100, Andrew Morton [off-list ref] wrote:
On Mon, 2 Jan 2012 12:24:12 +0200 Gilad Ben-Yossef [off-list ref] wrote:quoted
on_each_cpu_mask calls a function on processors specified my cpumask, which may include the local processor.
quoted
@@ -132,6 +139,15 @@ static inline int up_smp_call_function(smp_call_func_t func, void *info) local_irq_enable(); \ 0; \ }) +#define on_each_cpu_mask(mask, func, info, wait) \ + do { \ + if (cpumask_test_cpu(0, (mask))) { \ + local_irq_disable(); \ + (func)(info); \ + local_irq_enable(); \ + } \ + } while (0)Why is the cpumask_test_cpu() call there? It's hard to think of a reason why "mask" would specify any CPU other than "0" in a uniprocessor kernel.
It may specify none. For instance, in drain_all_pages() case, if the CPU has no pages on PCP lists, the mask will be empty and so the cpumask_test_cpu() will return zero. -- Best regards, _ _ .o. | Liege of Serenely Enlightened Majesty of o' \,=./ `o ..o | Computer Science, Michał “mina86” Nazarewicz (o o) ooo +----<email/xmpp: mpn@google.com>--------------ooO--(_)--Ooo-- -- 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: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>