Messages in this thread | | | Date | Tue, 25 Jul 2006 23:02:59 -0700 | From | Andrew Morton <> | Subject | Re: [Patch 1/2] CPU hotplug compatible alloc_percpu |
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On Mon, 24 Jul 2006 19:16:54 +0200 Martin Peschke <mp3@de.ibm.com> wrote:
> This patch splits alloc_percpu() up into two phases. Likewise for > free_percpu(). This allows clients to limit initial allocations to > online cpu's, and to populate or depopulate per-cpu data at run time as > needed: > > struct my_struct *obj; > > /* initial allocation for online cpu's */ > obj = percpu_alloc(sizeof(struct my_struct), GFP_KERNEL); > > ... > > /* populate per-cpu data for cpu coming online */ > ptr = percpu_populate(obj, sizeof(struct my_struct), GFP_KERNEL, cpu); > > ... > > /* access per-cpu object */ > ptr = percpu_ptr(obj, smp_processor_id()); > > ... > > /* depopulate per-cpu data for cpu going offline */ > percpu_depopulate(obj, cpu); > > ... > > /* final removal */ > percpu_free(obj);
That looks pretty thorough.
The one little nit I'd have is that the code passes cpumasks by value. See the tricks in <linux/cpumask.h> which pretend to take the caller's cpumask by value but which instead pass it via const reference to the callee.
CONFIG_NR_CPUS=1024 leads to a 128-byte cpumask_t. It's worth doing. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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