dm raid1: switch read_record from kmalloc to slab to save memory

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With my previous patch to save bi_io_vec, the size of dm_raid1_read_record
is significantly increased (the vector list takes 3072 bytes on 32-bit machines
and 4096 bytes on 64-bit machines).

The structure dm_raid1_read_record used to be allocated with kmalloc,
but kmalloc aligns the size on the next power-of-two so an object
slightly greater than 4096 will allocate 8192 bytes of memory and half of
that memory will be wasted.

This patch turns kmalloc into a slab cache which doesn't have this
padding so it will reduce the memory consumed.

Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

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Mikulas Patocka 2009-04-02 19:55:24 +01:00 • committed by Alasdair G Kergon

parent a920f6b3ac

commit 95f8fac8dc

1 changed files with 21 additions and 4 deletions

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drivers/md/dm-raid1.c

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