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| author | David Woodhouse <David.Woodhouse@intel.com> | 2008-08-10 13:33:00 +0200 |
|---|---|---|
| committer | Jens Axboe <jens.axboe@oracle.com> | 2008-10-09 08:56:01 +0200 |
| commit | 35ba8f7083e87602b695d6eaca38a6464d5b74db (patch) | |
| tree | dd9e515480ec307cf12378f13b01c7922cf3266c /block/blktrace.c | |
| parent | blktrace: support discard requests (diff) | |
| download | linux-35ba8f7083e87602b695d6eaca38a6464d5b74db.tar.xz linux-35ba8f7083e87602b695d6eaca38a6464d5b74db.zip | |
blktrace: simplify flags handling in __blk_add_trace
Let the compiler see what's going on, and it can all get a lot simpler.
On PPC64 this reduces the size of the code calculating these bits by
about 60%. On x86_64 it's less of a win -- only 40%.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/blktrace.c')
| -rw-r--r-- | block/blktrace.c | 38 |
1 files changed, 8 insertions, 30 deletions
diff --git a/block/blktrace.c b/block/blktrace.c index 7495a84353e4..9e0212c90b29 100644 --- a/block/blktrace.c +++ b/block/blktrace.c @@ -111,31 +111,9 @@ static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector, */ static u32 ddir_act[2] __read_mostly = { BLK_TC_ACT(BLK_TC_READ), BLK_TC_ACT(BLK_TC_WRITE) }; -/* - * Bio action bits of interest - */ -static u32 bio_act[17] __read_mostly = { - [1] = BLK_TC_ACT(BLK_TC_BARRIER), - [2] = BLK_TC_ACT(BLK_TC_SYNC), - [4] = BLK_TC_ACT(BLK_TC_AHEAD), - [8] = BLK_TC_ACT(BLK_TC_META), - [16] = BLK_TC_ACT(BLK_TC_DISCARD) -}; - -/* - * More could be added as needed, taking care to increment the decrementer - * to get correct indexing - */ -#define trace_barrier_bit(rw) \ - (((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)) << (2 - BIO_RW_AHEAD)) -#define trace_meta_bit(rw) \ - (((rw) & (1 << BIO_RW_META)) >> (BIO_RW_META - 3)) -#define trace_discard_bit(rw) \ - (((rw) & (1 << BIO_RW_DISCARD)) >> (BIO_RW_DISCARD - 4)) +/* The ilog2() calls fall out because they're constant */ +#define MASK_TC_BIT(rw, __name) ( (rw & (1 << BIO_RW_ ## __name)) << \ + (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - BIO_RW_ ## __name) ) /* * The worker for the various blk_add_trace*() types. Fills out a @@ -155,11 +133,11 @@ void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, return; 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)]; - what |= bio_act[trace_meta_bit(rw)]; - what |= bio_act[trace_discard_bit(rw)]; + what |= MASK_TC_BIT(rw, BARRIER); + what |= MASK_TC_BIT(rw, SYNC); + what |= MASK_TC_BIT(rw, AHEAD); + what |= MASK_TC_BIT(rw, META); + what |= MASK_TC_BIT(rw, DISCARD); pid = tsk->pid; if (unlikely(act_log_check(bt, what, sector, pid))) |