block/partitions: optimize memory allocation in check_partition()
authorMing Lei <ming.lei@canonical.com>
Thu, 28 Feb 2013 01:05:19 +0000 (17:05 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 28 Feb 2013 03:10:21 +0000 (19:10 -0800)
commitac2e5327a5e4f6477afc6a3b3b0dc6e0476d71d4
treee8193241c1789655f2168013d1ee434c21f12bac
parent06004e6eebdaf101a0f9b533fac77b5768d2c09c
block/partitions: optimize memory allocation in check_partition()

Currently, sizeof(struct parsed_partitions) may be 64KB in 32bit arch, so
it is easy to trigger page allocation failure by check_partition,
especially in hotplug block device situation(such as, USB mass storage,
MMC card, ...), and Felipe Balbi has observed the failure.

This patch does below optimizations on the allocation of struct
parsed_partitions to try to address the issue:

- make parsed_partitions.parts as pointer so that the pointed memory can
  fit in 32KB buffer, then approximate 32KB memory can be saved

- vmalloc the buffer pointed by parsed_partitions.parts because 32KB is
  still a bit big for kmalloc

- given that many devices have the partition count limit, so only
  allocate disk_max_parts() partitions instead of 256 partitions always

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Reported-by: Felipe Balbi <balbi@ti.com>
Cc: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
block/partition-generic.c
block/partitions/check.c
block/partitions/check.h