[PATCH] fix creating zero sized bio mempools in low memory system

[Milan Broz <mbroz@redhat.com>]

In the very low memory systems is in the init_bio call
scale parameter set to zero and it leads to creating
zero sized mempool.

This patch prevents pool_entries parameter become zero,
so the created pool have at least 1 entry.

Mempool with 0 entries lead to incorrect behaviour 
of mempool_free. (Alloc requests are not waken up
and system stalls in mempool_alloc->ioschedule). 


Signed-off-by: Milan Broz <mbroz@redhat.com>

Index: linux-2.6.18-rc6/fs/bio.c
===================================================================
--- linux-2.6.18-rc6.orig/fs/bio.c
+++ linux-2.6.18-rc6/fs/bio.c
@@ -1142,7 +1142,7 @@ static int biovec_create_pools(struct bi
		struct biovec_slab *bp = bvec_slabs + i;
		mempool_t **bvp = bs->bvec_pools + i;

-		if (i >= scale)
+		if (pool_entries > 1 && i >= scale)
			pool_entries >>= 1;

		*bvp = mempool_create_slab_pool(pool_entries, bp->slab);



--
VGER BF report: U 0.493705
-
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