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author | Christoph Hellwig <hch@lst.de> | 2019-02-28 11:00:18 -0500 |
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committer | Jens Axboe <axboe@kernel.dk> | 2019-02-28 13:49:22 -0700 |
commit | 5b88a17cfdeba75e0092bab2c79aaf7d9e7db482 (patch) | |
tree | 9b4eb6248df2e42fa08c1138fa0c0ca49d48f35b /include/linux/bvec.h | |
parent | 594b9a89af8e7629e95a4cd844d188361be32790 (diff) | |
download | linux-5b88a17cfdeba75e0092bab2c79aaf7d9e7db482.tar.gz linux-5b88a17cfdeba75e0092bab2c79aaf7d9e7db482.tar.bz2 linux-5b88a17cfdeba75e0092bab2c79aaf7d9e7db482.zip |
block: optimize bvec iteration in bvec_iter_advance
There is no need to only iterate in chunks of PAGE_SIZE or less in
bvec_iter_advance, given that the callers pass in the chunk length that
they are operating on - either that already is less than PAGE_SIZE
because they do classic page-based iteration, or it is larger because
the caller operates on multi-page bvecs.
This should help shaving off a few cycles of the I/O hot path.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include/linux/bvec.h')
-rw-r--r-- | include/linux/bvec.h | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/include/linux/bvec.h b/include/linux/bvec.h index 87e82e503a52..f6275c4da13a 100644 --- a/include/linux/bvec.h +++ b/include/linux/bvec.h @@ -112,14 +112,15 @@ static inline bool bvec_iter_advance(const struct bio_vec *bv, } while (bytes) { - unsigned iter_len = bvec_iter_len(bv, *iter); - unsigned len = min(bytes, iter_len); + const struct bio_vec *cur = bv + iter->bi_idx; + unsigned len = min3(bytes, iter->bi_size, + cur->bv_len - iter->bi_bvec_done); bytes -= len; iter->bi_size -= len; iter->bi_bvec_done += len; - if (iter->bi_bvec_done == __bvec_iter_bvec(bv, *iter)->bv_len) { + if (iter->bi_bvec_done == cur->bv_len) { iter->bi_bvec_done = 0; iter->bi_idx++; } |