[PATCH] blk-throttle: Fix calculation of max number of WRITES to bedispatched

From: Vivek Goyal
Date: Wed Oct 27 2010 - 13:29:51 EST


o Currently we try to dispatch more READS and less WRITES (75%, 25%) in one
dispatch round. ummy pointed out that there is a bug in max_nr_writes
calculation. This patch fixes it.

Reported-by: ummy y <yummylln@xxxxxxxxxxxx>
Signed-off-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
---
block/blk-throttle.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-2.6/block/blk-throttle.c
===================================================================
--- linux-2.6.orig/block/blk-throttle.c 2010-10-27 10:57:25.000000000 -0400
+++ linux-2.6/block/blk-throttle.c 2010-10-27 11:02:33.733048194 -0400
@@ -645,7 +645,7 @@ static int throtl_dispatch_tg(struct thr
{
unsigned int nr_reads = 0, nr_writes = 0;
unsigned int max_nr_reads = throtl_grp_quantum*3/4;
- unsigned int max_nr_writes = throtl_grp_quantum - nr_reads;
+ unsigned int max_nr_writes = throtl_grp_quantum - max_nr_reads;
struct bio *bio;

/* Try to dispatch 75% READS and 25% WRITES */
--
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