From 73118ca8baf78dddd1f9c8ac67c1d80b47d9830e Mon Sep 17 00:00:00 2001 From: Bob Peterson Date: Fri, 5 Apr 2019 04:41:38 +0100 Subject: gfs2: Replace gl_revokes with a GLF flag The gl_revokes value determines how many outstanding revokes a glock has on the superblock revokes list; this is used to avoid unnecessary log flushes. However, gl_revokes is only ever tested for being zero, and it's only decremented in revoke_lo_after_commit, which removes all revokes from the list, so we know that the gl_revoke values of all the glocks on the list will reach zero. Therefore, we can replace gl_revokes with a bit flag. This saves an atomic counter in struct gfs2_glock. Signed-off-by: Bob Peterson Signed-off-by: Andreas Gruenbacher --- fs/gfs2/glock.c | 4 ++-- fs/gfs2/incore.h | 2 +- fs/gfs2/log.c | 4 +++- fs/gfs2/lops.c | 33 ++++++++++++++++++++++++--------- fs/gfs2/main.c | 1 - fs/gfs2/super.c | 2 +- 6 files changed, 31 insertions(+), 15 deletions(-) (limited to 'fs/gfs2') diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c index 71c28ff98b56..15c605cfcfc8 100644 --- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -140,7 +140,7 @@ void gfs2_glock_free(struct gfs2_glock *gl) { struct gfs2_sbd *sdp = gl->gl_name.ln_sbd; - BUG_ON(atomic_read(&gl->gl_revokes)); + BUG_ON(test_bit(GLF_REVOKES, &gl->gl_flags)); rhashtable_remove_fast(&gl_hash_table, &gl->gl_node, ht_parms); smp_mb(); wake_up_glock(gl); @@ -1801,7 +1801,7 @@ void gfs2_dump_glock(struct seq_file *seq, struct gfs2_glock *gl) state2str(gl->gl_target), state2str(gl->gl_demote_state), dtime, atomic_read(&gl->gl_ail_count), - atomic_read(&gl->gl_revokes), + test_bit(GLF_REVOKES, &gl->gl_flags) ? 1 : 0, (int)gl->gl_lockref.count, gl->gl_hold_time); list_for_each_entry(gh, &gl->gl_holders, gh_list) diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h index 86840a70ee1a..6a94b094a904 100644 --- a/fs/gfs2/incore.h +++ b/fs/gfs2/incore.h @@ -345,6 +345,7 @@ enum { GLF_OBJECT = 14, /* Used only for tracing */ GLF_BLOCKING = 15, GLF_INODE_CREATING = 16, /* Inode creation occurring */ + GLF_REVOKES = 17, /* Glock has revokes in queue */ }; struct gfs2_glock { @@ -374,7 +375,6 @@ struct gfs2_glock { struct list_head gl_lru; struct list_head gl_ail_list; atomic_t gl_ail_count; - atomic_t gl_revokes; struct delayed_work gl_work; union { /* For inode and iopen glocks only */ diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c index 7ba94b66c91b..d55315a46ece 100644 --- a/fs/gfs2/log.c +++ b/fs/gfs2/log.c @@ -606,8 +606,10 @@ void gfs2_add_revoke(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd) gfs2_remove_from_ail(bd); /* drops ref on bh */ bd->bd_bh = NULL; sdp->sd_log_num_revoke++; - if (atomic_inc_return(&gl->gl_revokes) == 1) + if (!test_bit(GLF_REVOKES, &gl->gl_flags)) { + set_bit(GLF_REVOKES, &gl->gl_flags); gfs2_glock_hold(gl); + } set_bit(GLF_LFLUSH, &gl->gl_flags); list_add(&bd->bd_list, &sdp->sd_log_le_revoke); } diff --git a/fs/gfs2/lops.c b/fs/gfs2/lops.c index b4f0a6a3ba59..2fd61853ba63 100644 --- a/fs/gfs2/lops.c +++ b/fs/gfs2/lops.c @@ -662,19 +662,34 @@ static void revoke_lo_before_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr) static void revoke_lo_after_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr) { struct list_head *head = &sdp->sd_log_le_revoke; - struct gfs2_bufdata *bd; - struct gfs2_glock *gl; + struct gfs2_bufdata *bd, *tmp; - while (!list_empty(head)) { - bd = list_entry(head->next, struct gfs2_bufdata, bd_list); - list_del_init(&bd->bd_list); - gl = bd->bd_gl; - if (atomic_dec_return(&gl->gl_revokes) == 0) { - clear_bit(GLF_LFLUSH, &gl->gl_flags); - gfs2_glock_queue_put(gl); + /* + * Glocks can be referenced repeatedly on the revoke list, but the list + * only holds one reference. All glocks on the list will have the + * GLF_REVOKES flag set initially. + */ + + list_for_each_entry_safe(bd, tmp, head, bd_list) { + struct gfs2_glock *gl = bd->bd_gl; + + if (test_bit(GLF_REVOKES, &gl->gl_flags)) { + /* Keep each glock on the list exactly once. */ + clear_bit(GLF_REVOKES, &gl->gl_flags); + continue; } + list_del(&bd->bd_list); + kmem_cache_free(gfs2_bufdata_cachep, bd); + } + list_for_each_entry_safe(bd, tmp, head, bd_list) { + struct gfs2_glock *gl = bd->bd_gl; + + list_del(&bd->bd_list); kmem_cache_free(gfs2_bufdata_cachep, bd); + clear_bit(GLF_LFLUSH, &gl->gl_flags); + gfs2_glock_queue_put(gl); } + /* the list is empty now */ } static void revoke_lo_before_scan(struct gfs2_jdesc *jd, diff --git a/fs/gfs2/main.c b/fs/gfs2/main.c index 136484ef35d3..c700738de1f7 100644 --- a/fs/gfs2/main.c +++ b/fs/gfs2/main.c @@ -59,7 +59,6 @@ static void gfs2_init_glock_once(void *foo) INIT_LIST_HEAD(&gl->gl_lru); INIT_LIST_HEAD(&gl->gl_ail_list); atomic_set(&gl->gl_ail_count, 0); - atomic_set(&gl->gl_revokes, 0); } static void gfs2_init_gl_aspace_once(void *foo) diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c index 7b8d2306b3d3..2a7692d70394 100644 --- a/fs/gfs2/super.c +++ b/fs/gfs2/super.c @@ -1474,7 +1474,7 @@ static void gfs2_final_release_pages(struct gfs2_inode *ip) truncate_inode_pages(gfs2_glock2aspace(ip->i_gl), 0); truncate_inode_pages(&inode->i_data, 0); - if (atomic_read(&gl->gl_revokes) == 0) { + if (!test_bit(GLF_REVOKES, &gl->gl_flags)) { clear_bit(GLF_LFLUSH, &gl->gl_flags); clear_bit(GLF_DIRTY, &gl->gl_flags); } -- cgit v1.2.3-55-g7522