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MFC r278619: Make WRITE SAME commands respect physical block size.

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This change by 2-3 times improves performance of misaligned WRITE SAME
commands by avoiding unneeded read-modify-write cycles inside ZFS.
This commit is contained in:
mav 2015-02-19 13:06:38 +00:00
parent 01fc097c17
commit 8fc5fb008d
1 changed files with 12 additions and 2 deletions
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14
sys/cam/ctl/ctl_backend_block.c
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@ -1190,7 +1190,7 @@ ctl_be_block_cw_dispatch_ws(struct ctl_be_block_lun *be_lun,
struct ctl_be_block_io *beio;
struct ctl_be_block_softc *softc;
struct ctl_lba_len_flags *lbalen;
uint64_t len_left, lba;
uint64_t len_left, lba, pb, pbo, adj;
int i, seglen;
uint8_t *buf, *end;
@ -1244,6 +1244,8 @@ ctl_be_block_cw_dispatch_ws(struct ctl_be_block_lun *be_lun,
DPRINTF("WRITE SAME at LBA %jx len %u\n",
(uintmax_t)lbalen->lba, lbalen->len);
pb = (uint64_t)be_lun->blocksize << be_lun->pblockexp;
pbo = pb - (uint64_t)be_lun->blocksize * be_lun->pblockoff;
len_left = (uint64_t)lbalen->len * be_lun->blocksize;
for (i = 0, lba = 0; i < CTLBLK_MAX_SEGS && len_left > 0; i++) {
@ -1251,7 +1253,15 @@ ctl_be_block_cw_dispatch_ws(struct ctl_be_block_lun *be_lun,
* Setup the S/G entry for this chunk.
*/
seglen = MIN(CTLBLK_MAX_SEG, len_left);
seglen -= seglen % be_lun->blocksize;
if (pb > be_lun->blocksize) {
adj = ((lbalen->lba + lba) * be_lun->blocksize +
seglen - pbo) % pb;
if (seglen > adj)
seglen -= adj;
else
seglen -= seglen % be_lun->blocksize;
} else
seglen -= seglen % be_lun->blocksize;
beio->sg_segs[i].len = seglen;
beio->sg_segs[i].addr = uma_zalloc(be_lun->lun_zone, M_WAITOK);