diff options
| -rw-r--r-- | fs/gfs2/glock.c | 90 |
1 files changed, 67 insertions, 23 deletions
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c index 3ad8fd36f8da..cf3515546739 100644 --- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -30,6 +30,7 @@ #include <linux/rculist_bl.h> #include <linux/bit_spinlock.h> #include <linux/percpu.h> +#include <linux/list_sort.h> #include "gfs2.h" #include "incore.h" @@ -1376,50 +1377,93 @@ void gfs2_glock_complete(struct gfs2_glock *gl, int ret) gfs2_glock_put(gl); } +static int glock_cmp(void *priv, struct list_head *a, struct list_head *b) +{ + struct gfs2_glock *gla, *glb; + + gla = list_entry(a, struct gfs2_glock, gl_lru); + glb = list_entry(b, struct gfs2_glock, gl_lru); + + if (gla->gl_name.ln_number > glb->gl_name.ln_number) + return 1; + if (gla->gl_name.ln_number < glb->gl_name.ln_number) + return -1; + + return 0; +} + +/** + * gfs2_dispose_glock_lru - Demote a list of glocks + * @list: The list to dispose of + * + * Disposing of glocks may involve disk accesses, so that here we sort + * the glocks by number (i.e. disk location of the inodes) so that if + * there are any such accesses, they'll be sent in order (mostly). + * + * Must be called under the lru_lock, but may drop and retake this + * lock. While the lru_lock is dropped, entries may vanish from the + * list, but no new entries will appear on the list (since it is + * private) + */ + +static void gfs2_dispose_glock_lru(struct list_head *list) +__releases(&lru_lock) +__acquires(&lru_lock) +{ + struct gfs2_glock *gl; + + list_sort(NULL, list, glock_cmp); + + while(!list_empty(list)) { + gl = list_entry(list->next, struct gfs2_glock, gl_lru); + list_del_init(&gl->gl_lru); + clear_bit(GLF_LRU, &gl->gl_flags); + gfs2_glock_hold(gl); + spin_unlock(&lru_lock); + spin_lock(&gl->gl_spin); + if (demote_ok(gl)) + handle_callback(gl, LM_ST_UNLOCKED, 0); + WARN_ON(!test_and_clear_bit(GLF_LOCK, &gl->gl_flags)); + smp_mb__after_clear_bit(); + if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0) + gfs2_glock_put_nolock(gl); + spin_unlock(&gl->gl_spin); + spin_lock(&lru_lock); + } +} + /** * gfs2_scan_glock_lru - Scan the LRU looking for locks to demote * @nr: The number of entries to scan * + * This function selects the entries on the LRU which are able to + * be demoted, and then kicks off the process by calling + * gfs2_dispose_glock_lru() above. */ static void gfs2_scan_glock_lru(int nr) { struct gfs2_glock *gl; - int may_demote; - int nr_skipped = 0; LIST_HEAD(skipped); + LIST_HEAD(dispose); spin_lock(&lru_lock); while(nr && !list_empty(&lru_list)) { gl = list_entry(lru_list.next, struct gfs2_glock, gl_lru); - list_del_init(&gl->gl_lru); - clear_bit(GLF_LRU, &gl->gl_flags); - atomic_dec(&lru_count); /* Test for being demotable */ if (!test_and_set_bit(GLF_LOCK, &gl->gl_flags)) { - gfs2_glock_hold(gl); - spin_unlock(&lru_lock); - spin_lock(&gl->gl_spin); - may_demote = demote_ok(gl); - if (may_demote) { - handle_callback(gl, LM_ST_UNLOCKED, 0); - nr--; - } - clear_bit(GLF_LOCK, &gl->gl_flags); - smp_mb__after_clear_bit(); - if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0) - gfs2_glock_put_nolock(gl); - spin_unlock(&gl->gl_spin); - spin_lock(&lru_lock); + list_move(&gl->gl_lru, &dispose); + atomic_dec(&lru_count); + nr--; continue; } - nr_skipped++; - list_add(&gl->gl_lru, &skipped); - set_bit(GLF_LRU, &gl->gl_flags); + + list_move(&gl->gl_lru, &skipped); } list_splice(&skipped, &lru_list); - atomic_add(nr_skipped, &lru_count); + if (!list_empty(&dispose)) + gfs2_dispose_glock_lru(&dispose); spin_unlock(&lru_lock); } |