diff options
author | Christoph Hellwig <hch@lst.de> | 2017-02-07 14:06:57 -0800 |
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committer | Darrick J. Wong <darrick.wong@oracle.com> | 2017-02-09 10:50:25 -0800 |
commit | ebf55872616c7d4754db5a318591a72a8d5e6896 (patch) | |
tree | fd88d14b7765f0834273807a14ee931519029438 /fs/xfs/xfs_extent_busy.c | |
parent | 5e30c23d13919a718b22d4921dc5c0accc59da27 (diff) | |
download | linux-ebf55872616c7d4754db5a318591a72a8d5e6896.tar.gz linux-ebf55872616c7d4754db5a318591a72a8d5e6896.tar.xz |
xfs: improve handling of busy extents in the low-level allocator
Currently we force the log and simply try again if we hit a busy extent,
but especially with online discard enabled it might take a while after
the log force for the busy extents to disappear, and we might have
already completed our second pass.
So instead we add a new waitqueue and a generation counter to the pag
structure so that we can do wakeups once we've removed busy extents,
and we replace the single retry with an unconditional one - after
all we hold the AGF buffer lock, so no other allocations or frees
can be racing with us in this AG.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Diffstat (limited to 'fs/xfs/xfs_extent_busy.c')
-rw-r--r-- | fs/xfs/xfs_extent_busy.c | 125 |
1 files changed, 98 insertions, 27 deletions
diff --git a/fs/xfs/xfs_extent_busy.c b/fs/xfs/xfs_extent_busy.c index 29c2f997aedf..4d850e27095e 100644 --- a/fs/xfs/xfs_extent_busy.c +++ b/fs/xfs/xfs_extent_busy.c @@ -334,25 +334,31 @@ restart: * subset of the extent that is not busy. If *rlen is smaller than * args->minlen no suitable extent could be found, and the higher level * code needs to force out the log and retry the allocation. + * + * Return the current busy generation for the AG if the extent is busy. This + * value can be used to wait for at least one of the currently busy extents + * to be cleared. Note that the busy list is not guaranteed to be empty after + * the gen is woken. The state of a specific extent must always be confirmed + * with another call to xfs_extent_busy_trim() before it can be used. */ -void +bool xfs_extent_busy_trim( struct xfs_alloc_arg *args, - xfs_agblock_t bno, - xfs_extlen_t len, - xfs_agblock_t *rbno, - xfs_extlen_t *rlen) + xfs_agblock_t *bno, + xfs_extlen_t *len, + unsigned *busy_gen) { xfs_agblock_t fbno; xfs_extlen_t flen; struct rb_node *rbp; + bool ret = false; ASSERT(len > 0); spin_lock(&args->pag->pagb_lock); restart: - fbno = bno; - flen = len; + fbno = *bno; + flen = *len; rbp = args->pag->pagb_tree.rb_node; while (rbp && flen >= args->minlen) { struct xfs_extent_busy *busyp = @@ -504,24 +510,25 @@ restart: flen = fend - fbno; } - spin_unlock(&args->pag->pagb_lock); +out: - if (fbno != bno || flen != len) { - trace_xfs_extent_busy_trim(args->mp, args->agno, bno, len, + if (fbno != *bno || flen != *len) { + trace_xfs_extent_busy_trim(args->mp, args->agno, *bno, *len, fbno, flen); + *bno = fbno; + *len = flen; + *busy_gen = args->pag->pagb_gen; + ret = true; } - *rbno = fbno; - *rlen = flen; - return; + spin_unlock(&args->pag->pagb_lock); + return ret; fail: /* * Return a zero extent length as failure indications. All callers * re-check if the trimmed extent satisfies the minlen requirement. */ - spin_unlock(&args->pag->pagb_lock); - trace_xfs_extent_busy_trim(args->mp, args->agno, bno, len, fbno, 0); - *rbno = fbno; - *rlen = 0; + flen = 0; + goto out; } STATIC void @@ -540,6 +547,21 @@ xfs_extent_busy_clear_one( kmem_free(busyp); } +static void +xfs_extent_busy_put_pag( + struct xfs_perag *pag, + bool wakeup) + __releases(pag->pagb_lock) +{ + if (wakeup) { + pag->pagb_gen++; + wake_up_all(&pag->pagb_wait); + } + + spin_unlock(&pag->pagb_lock); + xfs_perag_put(pag); +} + /* * Remove all extents on the passed in list from the busy extents tree. * If do_discard is set skip extents that need to be discarded, and mark @@ -554,27 +576,76 @@ xfs_extent_busy_clear( struct xfs_extent_busy *busyp, *n; struct xfs_perag *pag = NULL; xfs_agnumber_t agno = NULLAGNUMBER; + bool wakeup = false; list_for_each_entry_safe(busyp, n, list, list) { if (busyp->agno != agno) { - if (pag) { - spin_unlock(&pag->pagb_lock); - xfs_perag_put(pag); - } - pag = xfs_perag_get(mp, busyp->agno); - spin_lock(&pag->pagb_lock); + if (pag) + xfs_extent_busy_put_pag(pag, wakeup); agno = busyp->agno; + pag = xfs_perag_get(mp, agno); + spin_lock(&pag->pagb_lock); + wakeup = false; } if (do_discard && busyp->length && - !(busyp->flags & XFS_EXTENT_BUSY_SKIP_DISCARD)) + !(busyp->flags & XFS_EXTENT_BUSY_SKIP_DISCARD)) { busyp->flags = XFS_EXTENT_BUSY_DISCARDED; - else + } else { xfs_extent_busy_clear_one(mp, pag, busyp); + wakeup = true; + } } - if (pag) { - spin_unlock(&pag->pagb_lock); + if (pag) + xfs_extent_busy_put_pag(pag, wakeup); +} + +/* + * Flush out all busy extents for this AG. + */ +void +xfs_extent_busy_flush( + struct xfs_mount *mp, + struct xfs_perag *pag, + unsigned busy_gen) +{ + DEFINE_WAIT (wait); + int log_flushed = 0, error; + + trace_xfs_log_force(mp, 0, _THIS_IP_); + error = _xfs_log_force(mp, XFS_LOG_SYNC, &log_flushed); + if (error) + return; + + do { + prepare_to_wait(&pag->pagb_wait, &wait, TASK_KILLABLE); + if (busy_gen != READ_ONCE(pag->pagb_gen)) + break; + schedule(); + } while (1); + + finish_wait(&pag->pagb_wait, &wait); +} + +void +xfs_extent_busy_wait_all( + struct xfs_mount *mp) +{ + DEFINE_WAIT (wait); + xfs_agnumber_t agno; + + for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) { + struct xfs_perag *pag = xfs_perag_get(mp, agno); + + do { + prepare_to_wait(&pag->pagb_wait, &wait, TASK_KILLABLE); + if (RB_EMPTY_ROOT(&pag->pagb_tree)) + break; + schedule(); + } while (1); + finish_wait(&pag->pagb_wait, &wait); + xfs_perag_put(pag); } } |