[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: Eric Dumazet <dada1@cosmosbay.com>
Acked-by: "David S. Miller" <davem@davemloft.net>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Jens Axboe <axboe@suse.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Jens Axboe <axboe@suse.de>
Cc: Anton Blanchard <anton@samba.org>
Acked-by: William Irwin <wli@holomorphy.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/init/main.c b/init/main.c
index 141e889..9cf6b30 100644
--- a/init/main.c
+++ b/init/main.c
@@ -333,6 +333,7 @@
{
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 @@
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 */