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Commit 40359ccb authored by Nathan Scott's avatar Nathan Scott Committed by Jens Axboe
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[PATCH] blktrace: readahead support 



Provide the needed kernel support for distinguishing readahead
from regular read requests when tracing block devices.

Signed-off-by: default avatarNathan Scott <nathans@sgi.com>
Signed-off-by: default avatarJens Axboe <axboe@suse.de>
parent fc0a75ce

block/blktrace.c

+4 −1
Original line number Diff line number Diff line
@@ -69,7 +69,7 @@ static u32 ddir_act[2] __read_mostly = { BLK_TC_ACT(BLK_TC_READ), BLK_TC_ACT(BLK 
/*

 * Bio action bits of interest

 */

static u32 bio_act[3] __read_mostly = { 0, BLK_TC_ACT(BLK_TC_BARRIER), BLK_TC_ACT(BLK_TC_SYNC) };

static u32 bio_act[5] __read_mostly = { 0, BLK_TC_ACT(BLK_TC_BARRIER), BLK_TC_ACT(BLK_TC_SYNC), 0, BLK_TC_ACT(BLK_TC_AHEAD) };



/*

 * More could be added as needed, taking care to increment the decrementer
@@ -79,6 +79,8 @@ static u32 bio_act[3] __read_mostly = { 0, BLK_TC_ACT(BLK_TC_BARRIER), BLK_TC_AC 
	(((rw) & (1 << BIO_RW_BARRIER)) >> (BIO_RW_BARRIER - 0))

#define trace_sync_bit(rw)	\

	(((rw) & (1 << BIO_RW_SYNC)) >> (BIO_RW_SYNC - 1))

#define trace_ahead_bit(rw)	\

	(((rw) & (1 << BIO_RW_AHEAD)) << (BIO_RW_AHEAD - 0))



/*

 * The worker for the various blk_add_trace*() types. Fills out a
@@ -100,6 +102,7 @@ void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, 
	what |= ddir_act[rw & WRITE];

	what |= bio_act[trace_barrier_bit(rw)];

	what |= bio_act[trace_sync_bit(rw)];

	what |= bio_act[trace_ahead_bit(rw)];



	pid = tsk->pid;

	if (unlikely(act_log_check(bt, what, sector, pid)))

include/linux/blktrace_api.h

+1 −0
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ enum blktrace_cat { 
	BLK_TC_FS	= 1 << 8,	/* fs requests */

	BLK_TC_PC	= 1 << 9,	/* pc requests */

	BLK_TC_NOTIFY	= 1 << 10,	/* special message */

	BLK_TC_AHEAD	= 1 << 11,	/* readahead */



	BLK_TC_END	= 1 << 15,	/* only 16-bits, reminder */

};