mirror of https://gitee.com/openkylin/linux.git
[GFS2] delay glock demote for a minimum hold time
When a lot of IO, with some distributed mmap IO, is run on a GFS2 filesystem in a cluster, it will deadlock. The reason is that do_no_page() will repeatedly call gfs2_sharewrite_nopage(), because each node keeps giving up the glock too early, and is forced to call unmap_mapping_range(). This bumps the mapping->truncate_count sequence count, forcing do_no_page() to retry. This patch institutes a minimum glock hold time a tenth a second. This insures that even in heavy contention cases, the node has enough time to get some useful work done before it gives up the glock. A second issue is that when gfs2_glock_dq() is called from within a page fault to demote a lock, and the associated page needs to be written out, it will try to acqire a lock on it, but it has already been locked at a higher level. This patch puts makes gfs2_glock_dq() use the work queue as well, to avoid this issue. This is the same patch as Steve Whitehouse originally proposed to fix this issue, execpt that gfs2_glock_dq() now grabs a reference to the glock before it queues up the work on it. Signed-off-by: Benjamin E. Marzinski <bmarzins@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This commit is contained in:
Benjamin Marzinski
Steven Whitehouse
parent
d1e2777d4f
commit
c4f68a130f
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@ -27,6 +27,8 @@
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#include <linux/debugfs.h>
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#include <linux/kthread.h>
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#include <linux/freezer.h>
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#include <linux/workqueue.h>
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#include <linux/jiffies.h>
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#include "gfs2.h"
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#include "incore.h"
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@ -58,10 +60,13 @@ static int gfs2_dump_lockstate(struct gfs2_sbd *sdp);
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static int dump_glock(struct glock_iter *gi, struct gfs2_glock *gl);
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static void gfs2_glock_xmote_th(struct gfs2_glock *gl, struct gfs2_holder *gh);
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static void gfs2_glock_drop_th(struct gfs2_glock *gl);
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static void run_queue(struct gfs2_glock *gl);
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static DECLARE_RWSEM(gfs2_umount_flush_sem);
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static struct dentry *gfs2_root;
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static struct task_struct *scand_process;
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static unsigned int scand_secs = 5;
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static struct workqueue_struct *glock_workqueue;
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#define GFS2_GL_HASH_SHIFT 15
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#define GFS2_GL_HASH_SIZE (1 << GFS2_GL_HASH_SHIFT)
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@ -277,6 +282,18 @@ static struct gfs2_glock *gfs2_glock_find(const struct gfs2_sbd *sdp,
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return gl;
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}
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static void glock_work_func(struct work_struct *work)
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{
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struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_work.work);
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spin_lock(&gl->gl_spin);
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if (test_and_clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags))
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set_bit(GLF_DEMOTE, &gl->gl_flags);
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run_queue(gl);
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spin_unlock(&gl->gl_spin);
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gfs2_glock_put(gl);
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}
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/**
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* gfs2_glock_get() - Get a glock, or create one if one doesn't exist
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* @sdp: The GFS2 superblock
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@ -316,6 +333,7 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
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gl->gl_name = name;
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atomic_set(&gl->gl_ref, 1);
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gl->gl_state = LM_ST_UNLOCKED;
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gl->gl_demote_state = LM_ST_EXCLUSIVE;
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gl->gl_hash = hash;
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gl->gl_owner_pid = 0;
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gl->gl_ip = 0;
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@ -324,10 +342,12 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
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gl->gl_req_bh = NULL;
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gl->gl_vn = 0;
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gl->gl_stamp = jiffies;
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gl->gl_tchange = jiffies;
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gl->gl_object = NULL;
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gl->gl_sbd = sdp;
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gl->gl_aspace = NULL;
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lops_init_le(&gl->gl_le, &gfs2_glock_lops);
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INIT_DELAYED_WORK(&gl->gl_work, glock_work_func);
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/* If this glock protects actual on-disk data or metadata blocks,
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create a VFS inode to manage the pages/buffers holding them. */
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@ -441,6 +461,8 @@ static void wait_on_holder(struct gfs2_holder *gh)
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static void gfs2_demote_wake(struct gfs2_glock *gl)
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{
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BUG_ON(!spin_is_locked(&gl->gl_spin));
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gl->gl_demote_state = LM_ST_EXCLUSIVE;
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clear_bit(GLF_DEMOTE, &gl->gl_flags);
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smp_mb__after_clear_bit();
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wake_up_bit(&gl->gl_flags, GLF_DEMOTE);
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@ -682,10 +704,14 @@ static void gfs2_glmutex_unlock(struct gfs2_glock *gl)
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* practise: LM_ST_SHARED and LM_ST_UNLOCKED
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*/
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static void handle_callback(struct gfs2_glock *gl, unsigned int state, int remote)
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static void handle_callback(struct gfs2_glock *gl, unsigned int state,
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int remote, unsigned long delay)
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{
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int bit = delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE;
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spin_lock(&gl->gl_spin);
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if (test_and_set_bit(GLF_DEMOTE, &gl->gl_flags) == 0) {
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set_bit(bit, &gl->gl_flags);
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if (gl->gl_demote_state == LM_ST_EXCLUSIVE) {
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gl->gl_demote_state = state;
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gl->gl_demote_time = jiffies;
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if (remote && gl->gl_ops->go_type == LM_TYPE_IOPEN &&
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@ -727,6 +753,7 @@ static void state_change(struct gfs2_glock *gl, unsigned int new_state)
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}
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gl->gl_state = new_state;
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gl->gl_tchange = jiffies;
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}
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/**
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@ -813,7 +840,6 @@ static void xmote_bh(struct gfs2_glock *gl, unsigned int ret)
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gl->gl_req_gh = NULL;
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gl->gl_req_bh = NULL;
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clear_bit(GLF_LOCK, &gl->gl_flags);
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run_queue(gl);
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spin_unlock(&gl->gl_spin);
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}
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@ -885,7 +911,6 @@ static void drop_bh(struct gfs2_glock *gl, unsigned int ret)
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gfs2_assert_warn(sdp, !ret);
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state_change(gl, LM_ST_UNLOCKED);
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gfs2_demote_wake(gl);
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if (glops->go_inval)
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glops->go_inval(gl, DIO_METADATA);
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@ -898,10 +923,10 @@ static void drop_bh(struct gfs2_glock *gl, unsigned int ret)
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}
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spin_lock(&gl->gl_spin);
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gfs2_demote_wake(gl);
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gl->gl_req_gh = NULL;
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gl->gl_req_bh = NULL;
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clear_bit(GLF_LOCK, &gl->gl_flags);
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run_queue(gl);
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spin_unlock(&gl->gl_spin);
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gfs2_glock_put(gl);
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@ -1209,9 +1234,10 @@ void gfs2_glock_dq(struct gfs2_holder *gh)
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{
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struct gfs2_glock *gl = gh->gh_gl;
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const struct gfs2_glock_operations *glops = gl->gl_ops;
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unsigned delay = 0;
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if (gh->gh_flags & GL_NOCACHE)
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handle_callback(gl, LM_ST_UNLOCKED, 0);
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handle_callback(gl, LM_ST_UNLOCKED, 0, 0);
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gfs2_glmutex_lock(gl);
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@ -1229,8 +1255,14 @@ void gfs2_glock_dq(struct gfs2_holder *gh)
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}
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clear_bit(GLF_LOCK, &gl->gl_flags);
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run_queue(gl);
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spin_unlock(&gl->gl_spin);
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gfs2_glock_hold(gl);
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if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
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!test_bit(GLF_DEMOTE, &gl->gl_flags))
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delay = gl->gl_ops->go_min_hold_time;
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if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
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gfs2_glock_put(gl);
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}
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void gfs2_glock_dq_wait(struct gfs2_holder *gh)
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@ -1457,18 +1489,21 @@ static void blocking_cb(struct gfs2_sbd *sdp, struct lm_lockname *name,
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unsigned int state)
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{
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struct gfs2_glock *gl;
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unsigned long delay = 0;
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unsigned long holdtime;
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unsigned long now = jiffies;
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gl = gfs2_glock_find(sdp, name);
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if (!gl)
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return;
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handle_callback(gl, state, 1);
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holdtime = gl->gl_tchange + gl->gl_ops->go_min_hold_time;
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if (time_before(now, holdtime))
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delay = holdtime - now;
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spin_lock(&gl->gl_spin);
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run_queue(gl);
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spin_unlock(&gl->gl_spin);
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gfs2_glock_put(gl);
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handle_callback(gl, state, 1, delay);
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if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
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gfs2_glock_put(gl);
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}
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/**
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@ -1509,7 +1544,8 @@ void gfs2_glock_cb(void *cb_data, unsigned int type, void *data)
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return;
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if (!gfs2_assert_warn(sdp, gl->gl_req_bh))
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gl->gl_req_bh(gl, async->lc_ret);
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gfs2_glock_put(gl);
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if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
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gfs2_glock_put(gl);
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up_read(&gfs2_umount_flush_sem);
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return;
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}
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@ -1602,7 +1638,7 @@ void gfs2_reclaim_glock(struct gfs2_sbd *sdp)
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if (gfs2_glmutex_trylock(gl)) {
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if (list_empty(&gl->gl_holders) &&
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gl->gl_state != LM_ST_UNLOCKED && demote_ok(gl))
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handle_callback(gl, LM_ST_UNLOCKED, 0);
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handle_callback(gl, LM_ST_UNLOCKED, 0, 0);
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gfs2_glmutex_unlock(gl);
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}
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@ -1702,7 +1738,7 @@ static void clear_glock(struct gfs2_glock *gl)
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if (gfs2_glmutex_trylock(gl)) {
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if (list_empty(&gl->gl_holders) &&
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gl->gl_state != LM_ST_UNLOCKED)
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handle_callback(gl, LM_ST_UNLOCKED, 0);
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handle_callback(gl, LM_ST_UNLOCKED, 0, 0);
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gfs2_glmutex_unlock(gl);
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}
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}
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@ -2009,11 +2045,18 @@ int __init gfs2_glock_init(void)
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if (IS_ERR(scand_process))
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return PTR_ERR(scand_process);
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glock_workqueue = create_workqueue("glock_workqueue");
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if (IS_ERR(glock_workqueue)) {
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kthread_stop(scand_process);
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return PTR_ERR(glock_workqueue);
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}
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return 0;
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}
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void gfs2_glock_exit(void)
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{
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destroy_workqueue(glock_workqueue);
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kthread_stop(scand_process);
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}
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@ -454,6 +454,7 @@ const struct gfs2_glock_operations gfs2_inode_glops = {
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.go_lock = inode_go_lock,
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.go_unlock = inode_go_unlock,
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.go_type = LM_TYPE_INODE,
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.go_min_hold_time = HZ / 10,
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};
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const struct gfs2_glock_operations gfs2_rgrp_glops = {
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@ -464,6 +465,7 @@ const struct gfs2_glock_operations gfs2_rgrp_glops = {
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.go_lock = rgrp_go_lock,
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.go_unlock = rgrp_go_unlock,
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.go_type = LM_TYPE_RGRP,
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.go_min_hold_time = HZ / 10,
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};
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const struct gfs2_glock_operations gfs2_trans_glops = {
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@ -11,6 +11,7 @@
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#define __INCORE_DOT_H__
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#include <linux/fs.h>
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#include <linux/workqueue.h>
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#define DIO_WAIT 0x00000010
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#define DIO_METADATA 0x00000020
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@ -130,6 +131,7 @@ struct gfs2_glock_operations {
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int (*go_lock) (struct gfs2_holder *gh);
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void (*go_unlock) (struct gfs2_holder *gh);
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const int go_type;
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const unsigned long go_min_hold_time;
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};
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enum {
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@ -161,6 +163,7 @@ enum {
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GLF_LOCK = 1,
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GLF_STICKY = 2,
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GLF_DEMOTE = 3,
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GLF_PENDING_DEMOTE = 4,
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GLF_DIRTY = 5,
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};
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@ -193,6 +196,7 @@ struct gfs2_glock {
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u64 gl_vn;
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unsigned long gl_stamp;
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unsigned long gl_tchange;
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void *gl_object;
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struct list_head gl_reclaim;
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@ -203,6 +207,7 @@ struct gfs2_glock {
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struct gfs2_log_element gl_le;
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struct list_head gl_ail_list;
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atomic_t gl_ail_count;
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struct delayed_work gl_work;
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};
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struct gfs2_alloc {
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