From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bombadil.infradead.org ([65.50.211.133]:60712 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751215AbdA2Sov (ORCPT ); Sun, 29 Jan 2017 13:44:51 -0500 Received: from clnet-p099-196.ikbnet.co.at ([83.175.99.196] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.87 #1 (Red Hat Linux)) id 1cXuS6-00019v-CG for linux-xfs@vger.kernel.org; Sun, 29 Jan 2017 18:43:50 +0000 From: Christoph Hellwig Subject: [PATCH 2/4] xfs: improve handling of busy extents in the low-level allocator Date: Sun, 29 Jan 2017 19:43:39 +0100 Message-Id: <1485715421-17182-3-git-send-email-hch@lst.de> In-Reply-To: <1485715421-17182-1-git-send-email-hch@lst.de> References: <1485715421-17182-1-git-send-email-hch@lst.de> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: linux-xfs@vger.kernel.org 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 --- fs/xfs/libxfs/xfs_alloc.c | 93 +++++++++++++++++++++++--------------------- fs/xfs/xfs_extent_busy.c | 98 ++++++++++++++++++++++++++++++++++------------- fs/xfs/xfs_extent_busy.h | 8 +++- fs/xfs/xfs_mount.c | 1 + fs/xfs/xfs_mount.h | 2 + 5 files changed, 129 insertions(+), 73 deletions(-) diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c index 9f06a21..fe98fbc 100644 --- a/fs/xfs/libxfs/xfs_alloc.c +++ b/fs/xfs/libxfs/xfs_alloc.c @@ -221,20 +221,22 @@ xfs_alloc_get_rec( * Compute aligned version of the found extent. * Takes alignment and min length into account. */ -STATIC void +STATIC bool xfs_alloc_compute_aligned( xfs_alloc_arg_t *args, /* allocation argument structure */ xfs_agblock_t foundbno, /* starting block in found extent */ xfs_extlen_t foundlen, /* length in found extent */ xfs_agblock_t *resbno, /* result block number */ - xfs_extlen_t *reslen) /* result length */ + xfs_extlen_t *reslen, /* result length */ + unsigned *busy_gen) { - xfs_agblock_t bno; - xfs_extlen_t len; + xfs_agblock_t bno = foundbno; + xfs_extlen_t len = foundlen; xfs_extlen_t diff; + bool busy; /* Trim busy sections out of found extent */ - xfs_extent_busy_trim(args, foundbno, foundlen, &bno, &len); + busy = xfs_extent_busy_trim(args, &bno, &len, busy_gen); /* * If we have a largish extent that happens to start before min_agbno, @@ -259,6 +261,8 @@ xfs_alloc_compute_aligned( *resbno = bno; *reslen = len; } + + return busy; } /* @@ -737,10 +741,11 @@ xfs_alloc_ag_vextent_exact( int error; xfs_agblock_t fbno; /* start block of found extent */ xfs_extlen_t flen; /* length of found extent */ - xfs_agblock_t tbno; /* start block of trimmed extent */ - xfs_extlen_t tlen; /* length of trimmed extent */ - xfs_agblock_t tend; /* end block of trimmed extent */ + xfs_agblock_t tbno; /* start block of busy extent */ + xfs_extlen_t tlen; /* length of busy extent */ + xfs_agblock_t tend; /* end block of busy extent */ int i; /* success/failure of operation */ + unsigned busy_gen; ASSERT(args->alignment == 1); @@ -773,7 +778,9 @@ xfs_alloc_ag_vextent_exact( /* * Check for overlapping busy extents. */ - xfs_extent_busy_trim(args, fbno, flen, &tbno, &tlen); + tbno = fbno; + tlen = flen; + xfs_extent_busy_trim(args, &tbno, &tlen, &busy_gen); /* * Give up if the start of the extent is busy, or the freespace isn't @@ -853,6 +860,7 @@ xfs_alloc_find_best_extent( xfs_agblock_t sdiff; int error; int i; + unsigned busy_gen; /* The good extent is perfect, no need to search. */ if (!gdiff) @@ -866,7 +874,8 @@ xfs_alloc_find_best_extent( if (error) goto error0; XFS_WANT_CORRUPTED_GOTO(args->mp, i == 1, error0); - xfs_alloc_compute_aligned(args, *sbno, *slen, sbnoa, slena); + xfs_alloc_compute_aligned(args, *sbno, *slen, + sbnoa, slena, &busy_gen); /* * The good extent is closer than this one. @@ -955,7 +964,8 @@ xfs_alloc_ag_vextent_near( xfs_extlen_t ltlena; /* aligned ... */ xfs_agblock_t ltnew; /* useful start bno of left side */ xfs_extlen_t rlen; /* length of returned extent */ - int forced = 0; + bool busy; + unsigned busy_gen; #ifdef DEBUG /* * Randomly don't execute the first algorithm. @@ -982,6 +992,7 @@ xfs_alloc_ag_vextent_near( ltlen = 0; gtlena = 0; ltlena = 0; + busy = false; /* * Get a cursor for the by-size btree. @@ -1064,8 +1075,8 @@ xfs_alloc_ag_vextent_near( if ((error = xfs_alloc_get_rec(cnt_cur, <bno, <len, &i))) goto error0; XFS_WANT_CORRUPTED_GOTO(args->mp, i == 1, error0); - xfs_alloc_compute_aligned(args, ltbno, ltlen, - <bnoa, <lena); + busy = xfs_alloc_compute_aligned(args, ltbno, ltlen, + <bnoa, <lena, &busy_gen); if (ltlena < args->minlen) continue; if (ltbnoa < args->min_agbno || ltbnoa > args->max_agbno) @@ -1183,8 +1194,8 @@ xfs_alloc_ag_vextent_near( if ((error = xfs_alloc_get_rec(bno_cur_lt, <bno, <len, &i))) goto error0; XFS_WANT_CORRUPTED_GOTO(args->mp, i == 1, error0); - xfs_alloc_compute_aligned(args, ltbno, ltlen, - <bnoa, <lena); + busy |= xfs_alloc_compute_aligned(args, ltbno, ltlen, + <bnoa, <lena, &busy_gen); if (ltlena >= args->minlen && ltbnoa >= args->min_agbno) break; if ((error = xfs_btree_decrement(bno_cur_lt, 0, &i))) @@ -1199,8 +1210,8 @@ xfs_alloc_ag_vextent_near( if ((error = xfs_alloc_get_rec(bno_cur_gt, >bno, >len, &i))) goto error0; XFS_WANT_CORRUPTED_GOTO(args->mp, i == 1, error0); - xfs_alloc_compute_aligned(args, gtbno, gtlen, - >bnoa, >lena); + busy |= xfs_alloc_compute_aligned(args, gtbno, gtlen, + >bnoa, >lena, &busy_gen); if (gtlena >= args->minlen && gtbnoa <= args->max_agbno) break; if ((error = xfs_btree_increment(bno_cur_gt, 0, &i))) @@ -1261,9 +1272,9 @@ xfs_alloc_ag_vextent_near( if (bno_cur_lt == NULL && bno_cur_gt == NULL) { xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR); - if (!forced++) { + if (busy) { trace_xfs_alloc_near_busy(args); - xfs_log_force(args->mp, XFS_LOG_SYNC); + xfs_extent_busy_flush(args->mp, args->pag, busy_gen); goto restart; } trace_xfs_alloc_size_neither(args); @@ -1344,7 +1355,8 @@ xfs_alloc_ag_vextent_size( int i; /* temp status variable */ xfs_agblock_t rbno; /* returned block number */ xfs_extlen_t rlen; /* length of returned extent */ - int forced = 0; + bool busy; + unsigned busy_gen; restart: /* @@ -1353,6 +1365,7 @@ xfs_alloc_ag_vextent_size( cnt_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp, args->agno, XFS_BTNUM_CNT); bno_cur = NULL; + busy = false; /* * Look for an entry >= maxlen+alignment-1 blocks. @@ -1362,14 +1375,13 @@ xfs_alloc_ag_vextent_size( goto error0; /* - * If none or we have busy extents that we cannot allocate from, then - * we have to settle for a smaller extent. In the case that there are - * no large extents, this will return the last entry in the tree unless - * the tree is empty. In the case that there are only busy large - * extents, this will return the largest small extent unless there + * If none then we have to settle for a smaller extent. In the case that + * there are no large extents, this will return the last entry in the + * tree unless the tree is empty. In the case that there are only busy + * large extents, this will return the largest small extent unless there * are no smaller extents available. */ - if (!i || forced > 1) { + if (!i) { error = xfs_alloc_ag_vextent_small(args, cnt_cur, &fbno, &flen, &i); if (error) @@ -1380,13 +1392,11 @@ xfs_alloc_ag_vextent_size( return 0; } ASSERT(i == 1); - xfs_alloc_compute_aligned(args, fbno, flen, &rbno, &rlen); + busy = xfs_alloc_compute_aligned(args, fbno, flen, &rbno, + &rlen, &busy_gen); } else { /* * Search for a non-busy extent that is large enough. - * If we are at low space, don't check, or if we fall of - * the end of the btree, turn off the busy check and - * restart. */ for (;;) { error = xfs_alloc_get_rec(cnt_cur, &fbno, &flen, &i); @@ -1394,8 +1404,8 @@ xfs_alloc_ag_vextent_size( goto error0; XFS_WANT_CORRUPTED_GOTO(args->mp, i == 1, error0); - xfs_alloc_compute_aligned(args, fbno, flen, - &rbno, &rlen); + busy = xfs_alloc_compute_aligned(args, fbno, flen, + &rbno, &rlen, &busy_gen); if (rlen >= args->maxlen) break; @@ -1407,18 +1417,13 @@ xfs_alloc_ag_vextent_size( /* * Our only valid extents must have been busy. * Make it unbusy by forcing the log out and - * retrying. If we've been here before, forcing - * the log isn't making the extents available, - * which means they have probably been freed in - * this transaction. In that case, we have to - * give up on them and we'll attempt a minlen - * allocation the next time around. + * retrying. */ xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR); trace_xfs_alloc_size_busy(args); - if (!forced++) - xfs_log_force(args->mp, XFS_LOG_SYNC); + xfs_extent_busy_flush(args->mp, + args->pag, busy_gen); goto restart; } } @@ -1454,8 +1459,8 @@ xfs_alloc_ag_vextent_size( XFS_WANT_CORRUPTED_GOTO(args->mp, i == 1, error0); if (flen < bestrlen) break; - xfs_alloc_compute_aligned(args, fbno, flen, - &rbno, &rlen); + busy = xfs_alloc_compute_aligned(args, fbno, flen, + &rbno, &rlen, &busy_gen); rlen = XFS_EXTLEN_MIN(args->maxlen, rlen); XFS_WANT_CORRUPTED_GOTO(args->mp, rlen == 0 || (rlen <= flen && rbno + rlen <= fbno + flen), @@ -1484,10 +1489,10 @@ xfs_alloc_ag_vextent_size( */ args->len = rlen; if (rlen < args->minlen) { - if (!forced++) { + if (busy) { xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR); trace_xfs_alloc_size_busy(args); - xfs_log_force(args->mp, XFS_LOG_SYNC); + xfs_extent_busy_flush(args->mp, args->pag, busy_gen); goto restart; } goto out_nominleft; diff --git a/fs/xfs/xfs_extent_busy.c b/fs/xfs/xfs_extent_busy.c index 29c2f99..8251359 100644 --- a/fs/xfs/xfs_extent_busy.c +++ b/fs/xfs/xfs_extent_busy.c @@ -334,14 +334,18 @@ xfs_extent_busy_reuse( * 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 discard generation for the AG if the file system + * has online discard enabled. This value can be used to wait for + * the trimmed extent to become fully available if the AG is running out + * of space. */ -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; @@ -351,8 +355,8 @@ xfs_extent_busy_trim( 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 +508,25 @@ xfs_extent_busy_trim( flen = fend - fbno; } +out: spin_unlock(&args->pag->pagb_lock); - 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; + return true; } - *rbno = fbno; - *rlen = flen; - return; + return false; 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 +545,21 @@ 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 @@ -554,29 +574,53 @@ 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); - xfs_perag_put(pag); + 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; + + while (busy_gen == READ_ONCE(pag->pagb_gen)) { + prepare_to_wait(&pag->pagb_wait, &wait, TASK_KILLABLE); + schedule(); } + finish_wait(&pag->pagb_wait, &wait); } /* diff --git a/fs/xfs/xfs_extent_busy.h b/fs/xfs/xfs_extent_busy.h index bfff284..bcb99463 100644 --- a/fs/xfs/xfs_extent_busy.h +++ b/fs/xfs/xfs_extent_busy.h @@ -58,9 +58,13 @@ void xfs_extent_busy_reuse(struct xfs_mount *mp, xfs_agnumber_t agno, xfs_agblock_t fbno, xfs_extlen_t flen, bool userdata); +bool +xfs_extent_busy_trim(struct xfs_alloc_arg *args, xfs_agblock_t *bno, + xfs_extlen_t *len, unsigned *busy_gen); + void -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_extent_busy_flush(struct xfs_mount *mp, struct xfs_perag *pag, + unsigned discards); int xfs_extent_busy_ag_cmp(void *priv, struct list_head *a, struct list_head *b); diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c index 9b9540d..4e9feb1 100644 --- a/fs/xfs/xfs_mount.c +++ b/fs/xfs/xfs_mount.c @@ -215,6 +215,7 @@ xfs_initialize_perag( INIT_RADIX_TREE(&pag->pag_ici_root, GFP_ATOMIC); if (xfs_buf_hash_init(pag)) goto out_unwind; + init_waitqueue_head(&pag->pagb_wait); if (radix_tree_preload(GFP_NOFS)) goto out_unwind; diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h index 7f351f7..7363499 100644 --- a/fs/xfs/xfs_mount.h +++ b/fs/xfs/xfs_mount.h @@ -384,6 +384,8 @@ typedef struct xfs_perag { xfs_agino_t pagl_rightrec; spinlock_t pagb_lock; /* lock for pagb_tree */ struct rb_root pagb_tree; /* ordered tree of busy extents */ + unsigned int pagb_gen; + wait_queue_head_t pagb_wait; atomic_t pagf_fstrms; /* # of filestreams active in this AG */ -- 2.1.4