From 5ac048bb7ea6e87b06504b999017cfa1f38f4092 Mon Sep 17 00:00:00 2001 From: Steven Whitehouse Date: Wed, 30 Mar 2011 16:25:51 +0100 Subject: GFS2: Use filemap_fdatawrite() to write back the AIL In order to ensure that the mapping stats (and thus the bdi) are correctly updated, this patch changes the AIL writeback to use the filemap_datawrite function. This helps prevent stalls in balance_dirty_pages() due to large amounts of dirty metadata when there is little or no dirty data around. Signed-off-by: Steven Whitehouse --- fs/gfs2/log.c | 15 +++++---------- 1 file changed, 5 insertions(+), 10 deletions(-) (limited to 'fs/gfs2/log.c') diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c index 5b102c1887fd..3ebafa1efad0 100644 --- a/fs/gfs2/log.c +++ b/fs/gfs2/log.c @@ -91,6 +91,7 @@ static void gfs2_ail1_start_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai) __releases(&sdp->sd_ail_lock) __acquires(&sdp->sd_ail_lock) { + struct gfs2_glock *gl = NULL; struct gfs2_bufdata *bd, *s; struct buffer_head *bh; int retry; @@ -113,19 +114,13 @@ __acquires(&sdp->sd_ail_lock) if (!buffer_dirty(bh)) continue; - + if (gl == bd->bd_gl) + continue; + gl = bd->bd_gl; list_move(&bd->bd_ail_st_list, &ai->ai_ail1_list); - get_bh(bh); spin_unlock(&sdp->sd_ail_lock); - lock_buffer(bh); - if (test_clear_buffer_dirty(bh)) { - bh->b_end_io = end_buffer_write_sync; - submit_bh(WRITE_SYNC, bh); - } else { - unlock_buffer(bh); - brelse(bh); - } + filemap_fdatawrite(gfs2_glock2aspace(gl)); spin_lock(&sdp->sd_ail_lock); retry = 1; -- cgit v1.2.1 From 4667a0ec32867865fd4deccf834594b3ea831baf Mon Sep 17 00:00:00 2001 From: Steven Whitehouse Date: Mon, 18 Apr 2011 14:18:09 +0100 Subject: GFS2: Make writeback more responsive to system conditions This patch adds writeback_control to writing back the AIL list. This means that we can then take advantage of the information we get in ->write_inode() in order to set off some pre-emptive writeback. In addition, the AIL code is cleaned up a bit to make it a bit simpler to understand. There is still more which can usefully be done in this area, but this is a good start at least. Signed-off-by: Steven Whitehouse --- fs/gfs2/log.c | 165 ++++++++++++++++++++++++++++++---------------------------- 1 file changed, 85 insertions(+), 80 deletions(-) (limited to 'fs/gfs2/log.c') diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c index 3ebafa1efad0..03e00417061b 100644 --- a/fs/gfs2/log.c +++ b/fs/gfs2/log.c @@ -18,6 +18,7 @@ #include #include #include +#include #include "gfs2.h" #include "incore.h" @@ -83,50 +84,90 @@ void gfs2_remove_from_ail(struct gfs2_bufdata *bd) /** * gfs2_ail1_start_one - Start I/O on a part of the AIL * @sdp: the filesystem - * @tr: the part of the AIL + * @wbc: The writeback control structure + * @ai: The ail structure * */ -static void gfs2_ail1_start_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai) +static void gfs2_ail1_start_one(struct gfs2_sbd *sdp, + struct writeback_control *wbc, + struct gfs2_ail *ai) __releases(&sdp->sd_ail_lock) __acquires(&sdp->sd_ail_lock) { struct gfs2_glock *gl = NULL; + struct address_space *mapping; struct gfs2_bufdata *bd, *s; struct buffer_head *bh; - int retry; - do { - retry = 0; +restart: + list_for_each_entry_safe_reverse(bd, s, &ai->ai_ail1_list, bd_ail_st_list) { + bh = bd->bd_bh; - list_for_each_entry_safe_reverse(bd, s, &ai->ai_ail1_list, - bd_ail_st_list) { - bh = bd->bd_bh; + gfs2_assert(sdp, bd->bd_ail == ai); - gfs2_assert(sdp, bd->bd_ail == ai); + if (!buffer_busy(bh)) { + if (!buffer_uptodate(bh)) + gfs2_io_error_bh(sdp, bh); + list_move(&bd->bd_ail_st_list, &ai->ai_ail2_list); + continue; + } + + if (!buffer_dirty(bh)) + continue; + if (gl == bd->bd_gl) + continue; + gl = bd->bd_gl; + list_move(&bd->bd_ail_st_list, &ai->ai_ail1_list); + mapping = bh->b_page->mapping; + spin_unlock(&sdp->sd_ail_lock); + generic_writepages(mapping, wbc); + spin_lock(&sdp->sd_ail_lock); + if (wbc->nr_to_write <= 0) + break; + goto restart; + } +} - if (!buffer_busy(bh)) { - if (!buffer_uptodate(bh)) - gfs2_io_error_bh(sdp, bh); - list_move(&bd->bd_ail_st_list, &ai->ai_ail2_list); - continue; - } - if (!buffer_dirty(bh)) - continue; - if (gl == bd->bd_gl) - continue; - gl = bd->bd_gl; - list_move(&bd->bd_ail_st_list, &ai->ai_ail1_list); +/** + * gfs2_ail1_flush - start writeback of some ail1 entries + * @sdp: The super block + * @wbc: The writeback control structure + * + * Writes back some ail1 entries, according to the limits in the + * writeback control structure + */ - spin_unlock(&sdp->sd_ail_lock); - filemap_fdatawrite(gfs2_glock2aspace(gl)); - spin_lock(&sdp->sd_ail_lock); +void gfs2_ail1_flush(struct gfs2_sbd *sdp, struct writeback_control *wbc) +{ + struct list_head *head = &sdp->sd_ail1_list; + struct gfs2_ail *ai; - retry = 1; + spin_lock(&sdp->sd_ail_lock); + list_for_each_entry_reverse(ai, head, ai_list) { + if (wbc->nr_to_write <= 0) break; - } - } while (retry); + gfs2_ail1_start_one(sdp, wbc, ai); /* This may drop ail lock */ + } + spin_unlock(&sdp->sd_ail_lock); +} + +/** + * gfs2_ail1_start - start writeback of all ail1 entries + * @sdp: The superblock + */ + +static void gfs2_ail1_start(struct gfs2_sbd *sdp) +{ + struct writeback_control wbc = { + .sync_mode = WB_SYNC_NONE, + .nr_to_write = LONG_MAX, + .range_start = 0, + .range_end = LLONG_MAX, + }; + + return gfs2_ail1_flush(sdp, &wbc); } /** @@ -136,7 +177,7 @@ __acquires(&sdp->sd_ail_lock) * */ -static int gfs2_ail1_empty_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai, int flags) +static void gfs2_ail1_empty_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai) { struct gfs2_bufdata *bd, *s; struct buffer_head *bh; @@ -144,71 +185,37 @@ static int gfs2_ail1_empty_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai, int fl list_for_each_entry_safe_reverse(bd, s, &ai->ai_ail1_list, bd_ail_st_list) { bh = bd->bd_bh; - gfs2_assert(sdp, bd->bd_ail == ai); - - if (buffer_busy(bh)) { - if (flags & DIO_ALL) - continue; - else - break; - } - + if (buffer_busy(bh)) + continue; if (!buffer_uptodate(bh)) gfs2_io_error_bh(sdp, bh); - list_move(&bd->bd_ail_st_list, &ai->ai_ail2_list); } - return list_empty(&ai->ai_ail1_list); } -static void gfs2_ail1_start(struct gfs2_sbd *sdp) -{ - struct list_head *head; - u64 sync_gen; - struct gfs2_ail *ai; - int done = 0; - - spin_lock(&sdp->sd_ail_lock); - head = &sdp->sd_ail1_list; - if (list_empty(head)) { - spin_unlock(&sdp->sd_ail_lock); - return; - } - sync_gen = sdp->sd_ail_sync_gen++; - - while(!done) { - done = 1; - list_for_each_entry_reverse(ai, head, ai_list) { - if (ai->ai_sync_gen >= sync_gen) - continue; - ai->ai_sync_gen = sync_gen; - gfs2_ail1_start_one(sdp, ai); /* This may drop ail lock */ - done = 0; - break; - } - } - - spin_unlock(&sdp->sd_ail_lock); -} +/** + * gfs2_ail1_empty - Try to empty the ail1 lists + * @sdp: The superblock + * + * Tries to empty the ail1 lists, starting with the oldest first + */ -static int gfs2_ail1_empty(struct gfs2_sbd *sdp, int flags) +static int gfs2_ail1_empty(struct gfs2_sbd *sdp) { struct gfs2_ail *ai, *s; int ret; spin_lock(&sdp->sd_ail_lock); - list_for_each_entry_safe_reverse(ai, s, &sdp->sd_ail1_list, ai_list) { - if (gfs2_ail1_empty_one(sdp, ai, flags)) + gfs2_ail1_empty_one(sdp, ai); + if (list_empty(&ai->ai_ail1_list)) list_move(&ai->ai_list, &sdp->sd_ail2_list); - else if (!(flags & DIO_ALL)) + else break; } - ret = list_empty(&sdp->sd_ail1_list); - spin_unlock(&sdp->sd_ail_lock); return ret; @@ -569,7 +576,7 @@ static void log_write_header(struct gfs2_sbd *sdp, u32 flags, int pull) set_buffer_uptodate(bh); clear_buffer_dirty(bh); - gfs2_ail1_empty(sdp, 0); + gfs2_ail1_empty(sdp); tail = current_tail(sdp); lh = (struct gfs2_log_header *)bh->b_data; @@ -864,7 +871,7 @@ void gfs2_meta_syncfs(struct gfs2_sbd *sdp) gfs2_log_flush(sdp, NULL); for (;;) { gfs2_ail1_start(sdp); - if (gfs2_ail1_empty(sdp, DIO_ALL)) + if (gfs2_ail1_empty(sdp)) break; msleep(10); } @@ -900,17 +907,15 @@ int gfs2_logd(void *data) preflush = atomic_read(&sdp->sd_log_pinned); if (gfs2_jrnl_flush_reqd(sdp) || t == 0) { - gfs2_ail1_empty(sdp, DIO_ALL); + gfs2_ail1_empty(sdp); gfs2_log_flush(sdp, NULL); - gfs2_ail1_empty(sdp, DIO_ALL); } if (gfs2_ail_flush_reqd(sdp)) { gfs2_ail1_start(sdp); io_schedule(); - gfs2_ail1_empty(sdp, 0); + gfs2_ail1_empty(sdp); gfs2_log_flush(sdp, NULL); - gfs2_ail1_empty(sdp, DIO_ALL); } wake_up(&sdp->sd_log_waitq); -- cgit v1.2.1 From c83ae9cad8776bab153a05cc466be39f14011091 Mon Sep 17 00:00:00 2001 From: Steven Whitehouse Date: Mon, 18 Apr 2011 14:18:38 +0100 Subject: GFS2: Add an AIL writeback tracepoint Add a tracepoint for monitoring writeback of the AIL. Signed-off-by: Steven Whitehouse --- fs/gfs2/log.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'fs/gfs2/log.c') diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c index 03e00417061b..ad1f1887633f 100644 --- a/fs/gfs2/log.c +++ b/fs/gfs2/log.c @@ -144,6 +144,7 @@ void gfs2_ail1_flush(struct gfs2_sbd *sdp, struct writeback_control *wbc) struct list_head *head = &sdp->sd_ail1_list; struct gfs2_ail *ai; + trace_gfs2_ail_flush(sdp, wbc, 1); spin_lock(&sdp->sd_ail_lock); list_for_each_entry_reverse(ai, head, ai_list) { if (wbc->nr_to_write <= 0) @@ -151,6 +152,7 @@ void gfs2_ail1_flush(struct gfs2_sbd *sdp, struct writeback_control *wbc) gfs2_ail1_start_one(sdp, wbc, ai); /* This may drop ail lock */ } spin_unlock(&sdp->sd_ail_lock); + trace_gfs2_ail_flush(sdp, wbc, 0); } /** -- cgit v1.2.1 From 4f1de018215fb56940ce5793e11becd1e8cd6e44 Mon Sep 17 00:00:00 2001 From: Steven Whitehouse Date: Tue, 26 Apr 2011 10:23:56 +0100 Subject: GFS2: Fix ail list traversal In the recent patches to update the AIL list code, I managed to forget that the ail list lock got dropped, even though I added a comment specifically to remind myself :( Reported-by: Barry Marson Signed-off-by: Steven Whitehouse --- fs/gfs2/log.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) (limited to 'fs/gfs2/log.c') diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c index ad1f1887633f..cec26c00b50d 100644 --- a/fs/gfs2/log.c +++ b/fs/gfs2/log.c @@ -89,9 +89,9 @@ void gfs2_remove_from_ail(struct gfs2_bufdata *bd) * */ -static void gfs2_ail1_start_one(struct gfs2_sbd *sdp, - struct writeback_control *wbc, - struct gfs2_ail *ai) +static int gfs2_ail1_start_one(struct gfs2_sbd *sdp, + struct writeback_control *wbc, + struct gfs2_ail *ai) __releases(&sdp->sd_ail_lock) __acquires(&sdp->sd_ail_lock) { @@ -100,7 +100,6 @@ __acquires(&sdp->sd_ail_lock) struct gfs2_bufdata *bd, *s; struct buffer_head *bh; -restart: list_for_each_entry_safe_reverse(bd, s, &ai->ai_ail1_list, bd_ail_st_list) { bh = bd->bd_bh; @@ -120,13 +119,17 @@ restart: gl = bd->bd_gl; list_move(&bd->bd_ail_st_list, &ai->ai_ail1_list); mapping = bh->b_page->mapping; + if (!mapping) + continue; spin_unlock(&sdp->sd_ail_lock); generic_writepages(mapping, wbc); spin_lock(&sdp->sd_ail_lock); if (wbc->nr_to_write <= 0) break; - goto restart; + return 1; } + + return 0; } @@ -146,10 +149,12 @@ void gfs2_ail1_flush(struct gfs2_sbd *sdp, struct writeback_control *wbc) trace_gfs2_ail_flush(sdp, wbc, 1); spin_lock(&sdp->sd_ail_lock); +restart: list_for_each_entry_reverse(ai, head, ai_list) { if (wbc->nr_to_write <= 0) break; - gfs2_ail1_start_one(sdp, wbc, ai); /* This may drop ail lock */ + if (gfs2_ail1_start_one(sdp, wbc, ai)) + goto restart; } spin_unlock(&sdp->sd_ail_lock); trace_gfs2_ail_flush(sdp, wbc, 0); -- cgit v1.2.1