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From: yc_zhou <yc_zhou@ncic.ac.cn>
To: axboe@kernel.dk, linux-kernel@vger.kernel.org, axboe@suse.de
Subject: [PATCH  2.6.19] Adding branch to remove possible unnecessary inst
Date: Sun, 31 Dec 2006 14:03:34 +0800	[thread overview]
Message-ID: <459752B6.1020904@ncic.ac.cn> (raw)

Function blk_queue_bounce_limit using dma flag to determine whether
assigned a certain value for member of request_queue_t. But the
assignment is unconditionally after the flag is set. It introduce
possible unnecessary instructions.


Signed-Off-By: Yingchao Zhou <yc_zhou@ncic.ac.cn>

---
--- linux-2.6.19/block/ll_rw_blk.c.orig 2006-12-31 13:35:22.307742904 +0800
+++ linux-2.6.19/block/ll_rw_blk.c 2006-12-31 13:34:05.032490528 +0800
@@ -606,11 +606,13 @@ void blk_queue_bounce_limit(request_queu
know of a way to test this here. */
if (bounce_pfn < (min_t(u64,0xffffffff,BLK_BOUNCE_HIGH) >> PAGE_SHIFT))
dma = 1;
- q->bounce_pfn = max_low_pfn;
+ else
+ q->bounce_pfn = max_low_pfn;
#else
if (bounce_pfn < blk_max_low_pfn)
dma = 1;
- q->bounce_pfn = bounce_pfn;
+ else
+ q->bounce_pfn = bounce_pfn;
#endif
if (dma) {
init_emergency_isa_pool();


             reply	other threads:[~2006-12-31  6:27 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-12-31  6:03 yc_zhou [this message]
2007-01-02  8:32 ` [PATCH 2.6.19] Adding branch to remove possible unnecessary inst Jens Axboe

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