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Commit 63872f87 authored by Eric Dumazet's avatar Eric Dumazet Committed by Linus Torvalds
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[PATCH] Only allocate percpu data for possible CPUs 



percpu_data blindly allocates bootmem memory to store NR_CPUS instances of
cpudata, instead of allocating memory only for possible cpus.

This patch saves ram, allocating num_possible_cpus() (instead of NR_CPUS)
instances.

Signed-off-by: default avatarEric Dumazet <dada1@cosmosbay.com>
Acked-by: default avatar"David S. Miller" <davem@davemloft.net>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Jens Axboe <axboe@suse.de>
Acked-by: default avatarIngo Molnar <mingo@elte.hu>
Cc: Jens Axboe <axboe@suse.de>
Cc: Anton Blanchard <anton@samba.org>
Acked-by: default avatarWilliam Irwin <wli@holomorphy.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 5a6b7951

init/main.c

+8 −3
Original line number Diff line number Diff line
@@ -333,6 +333,7 @@ static void __init setup_per_cpu_areas(void) 
{

	unsigned long size, i;

	char *ptr;

	unsigned long nr_possible_cpus = num_possible_cpus();



	/* Copy section for each CPU (we discard the original) */

	size = ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES);
@@ -340,12 +341,16 @@ static void __init setup_per_cpu_areas(void) 
	if (size < PERCPU_ENOUGH_ROOM)

		size = PERCPU_ENOUGH_ROOM;

#endif

	ptr = alloc_bootmem(size * nr_possible_cpus);



	ptr = alloc_bootmem(size * NR_CPUS);



	for (i = 0; i < NR_CPUS; i++, ptr += size) {

	for (i = 0; i < NR_CPUS; i++) {

		if (!cpu_possible(i)) {

			__per_cpu_offset[i] = (char*)0 - __per_cpu_start;

			continue;

		}

		__per_cpu_offset[i] = ptr - __per_cpu_start;

		memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);

		ptr += size;

	}

}

#endif /* !__GENERIC_PER_CPU */