From fc0a75ce4835187a3f76d6b35f0644d1b168eef5 Mon Sep 17 00:00:00 2001 From: Nathan Scott Date: Thu, 6 Jul 2006 09:56:30 +0200 Subject: [PATCH 1/3] [PATCH] blktrace: fix barrier vs sync typo Signed-off-by: Nathan Scott Signed-off-by: Jens Axboe --- include/linux/blktrace_api.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h index a7e8cef73d15..d95615fc6da5 100644 --- a/include/linux/blktrace_api.h +++ b/include/linux/blktrace_api.h @@ -11,7 +11,7 @@ enum blktrace_cat { BLK_TC_READ = 1 << 0, /* reads */ BLK_TC_WRITE = 1 << 1, /* writes */ BLK_TC_BARRIER = 1 << 2, /* barrier */ - BLK_TC_SYNC = 1 << 3, /* barrier */ + BLK_TC_SYNC = 1 << 3, /* sync IO */ BLK_TC_QUEUE = 1 << 4, /* queueing/merging */ BLK_TC_REQUEUE = 1 << 5, /* requeueing */ BLK_TC_ISSUE = 1 << 6, /* issue */ From 40359ccb836866435b03a0cb57345002b587d875 Mon Sep 17 00:00:00 2001 From: Nathan Scott Date: Thu, 6 Jul 2006 10:03:28 +0200 Subject: [PATCH 2/3] [PATCH] blktrace: readahead support Provide the needed kernel support for distinguishing readahead from regular read requests when tracing block devices. Signed-off-by: Nathan Scott Signed-off-by: Jens Axboe --- block/blktrace.c | 5 ++++- include/linux/blktrace_api.h | 1 + 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/block/blktrace.c b/block/blktrace.c index 92925e7d9e6c..b8c0702777ff 100644 --- a/block/blktrace.c +++ b/block/blktrace.c @@ -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))) diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h index d95615fc6da5..2346a1db8561 100644 --- a/include/linux/blktrace_api.h +++ b/include/linux/blktrace_api.h @@ -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 */ }; From 1959d21232931dfa686769a21161413f10d6652f Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 6 Jul 2006 10:18:05 +0200 Subject: [PATCH 3/3] [PATCH] Only the first two bits in bio->bi_rw and rq->flags match Not three, as assumed. This causes the barrier bit to be needlessly set for some IO. Signed-off-by: Jens Axboe --- block/ll_rw_blk.c | 4 ++-- include/linux/blktrace_api.h | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c index ab17c7224bb6..61d6b3c65b66 100644 --- a/block/ll_rw_blk.c +++ b/block/ll_rw_blk.c @@ -3491,8 +3491,8 @@ EXPORT_SYMBOL(end_request); void blk_rq_bio_prep(request_queue_t *q, struct request *rq, struct bio *bio) { - /* first three bits are identical in rq->flags and bio->bi_rw */ - rq->flags |= (bio->bi_rw & 7); + /* first two bits are identical in rq->flags and bio->bi_rw */ + rq->flags |= (bio->bi_rw & 3); rq->nr_phys_segments = bio_phys_segments(q, bio); rq->nr_hw_segments = bio_hw_segments(q, bio); diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h index 2346a1db8561..7520cc1ff9e2 100644 --- a/include/linux/blktrace_api.h +++ b/include/linux/blktrace_api.h @@ -148,7 +148,7 @@ static inline void blk_add_trace_rq(struct request_queue *q, struct request *rq, u32 what) { struct blk_trace *bt = q->blk_trace; - int rw = rq->flags & 0x07; + int rw = rq->flags & 0x03; if (likely(!bt)) return;