diff options
| -rw-r--r-- | module/zfs/dmu_zfetch.c | 24 |
1 files changed, 19 insertions, 5 deletions
diff --git a/module/zfs/dmu_zfetch.c b/module/zfs/dmu_zfetch.c index 1bf5c4e34..e72e9ef9c 100644 --- a/module/zfs/dmu_zfetch.c +++ b/module/zfs/dmu_zfetch.c @@ -228,19 +228,33 @@ dmu_zfetch(zfetch_t *zf, uint64_t blkid, uint64_t nblks, boolean_t fetch_data) rw_enter(&zf->zf_rwlock, RW_READER); + /* + * Find matching prefetch stream. Depending on whether the accesses + * are block-aligned, first block of the new access may either follow + * the last block of the previous access, or be equal to it. + */ for (zs = list_head(&zf->zf_stream); zs != NULL; zs = list_next(&zf->zf_stream, zs)) { - if (blkid == zs->zs_blkid) { + if (blkid == zs->zs_blkid || blkid + 1 == zs->zs_blkid) { mutex_enter(&zs->zs_lock); /* * zs_blkid could have changed before we * acquired zs_lock; re-check them here. */ - if (blkid != zs->zs_blkid) { - mutex_exit(&zs->zs_lock); - continue; + if (blkid == zs->zs_blkid) { + break; + } else if (blkid + 1 == zs->zs_blkid) { + blkid++; + nblks--; + if (nblks == 0) { + /* Already prefetched this before. */ + mutex_exit(&zs->zs_lock); + rw_exit(&zf->zf_rwlock); + return; + } + break; } - break; + mutex_exit(&zs->zs_lock); } } |