Re: [PATCH v5 1/8] smp: Introduce a generic on_each_cpu_mask function
From: Andrew Morton <akpm@linux-foundation.org>
Date: 2012-01-03 22:26:24
Also in:
linux-mm, lkml
On Mon, 2 Jan 2012 12:24:12 +0200 Gilad Ben-Yossef [off-list ref] wrote:
quoted hunk ↗ jump to hunk
on_each_cpu_mask calls a function on processors specified my cpumask, which may include the local processor. All the limitation specified in smp_call_function_many apply. ...--- a/include/linux/smp.h +++ b/include/linux/smp.h@@ -102,6 +102,13 @@ static inline void call_function_init(void) { } int on_each_cpu(smp_call_func_t func, void *info, int wait); /* + * Call a function on processors specified by mask, which might include + * the local one. + */ +void on_each_cpu_mask(const struct cpumask *mask, void (*func)(void *), + void *info, bool wait); + +/* * Mark the boot cpu "online" so that it can call console drivers in * printk() and can access its per-cpu storage. */@@ -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. If this code remains as-is, please add a comment here explaining this, so others don't wonder the same thing. -- 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>