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Commit 47a25380 authored by Steven Whitehouse's avatar Steven Whitehouse
Browse files

GFS2: Merge glock state fields into a bitfield 



We can only merge the fields into a bitfield if the locking
rules for them are the same. In this case gl_spin covers all
of the fields (write side) but a couple of them are used
with GLF_LOCK as the read side lock, which should be ok
since we know that the field in question won't be changing
at the time.

The gl_req setting has to be done earlier (in glock.c) in order
to place it under gl_spin. The gl_reply setting also has to be
brought under gl_spin in order to comply with the new rules.

This saves 4*sizeof(unsigned int) per glock.

Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
Cc: Bob Peterson <rpeterso@redhat.com>
parent e06dfc49

fs/gfs2/glock.c

+7 −2
Original line number Diff line number Diff line
@@ -567,6 +567,7 @@ __acquires(&gl->gl_spin) 
		set_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);

		do_error(gl, 0); /* Fail queued try locks */

	}

	gl->gl_req = target;

	spin_unlock(&gl->gl_spin);

	if (glops->go_xmote_th)

		glops->go_xmote_th(gl);
@@ -1353,24 +1354,28 @@ static int gfs2_should_freeze(const struct gfs2_glock *gl) 
 * @gl: Pointer to the glock

 * @ret: The return value from the dlm

 *

 * The gl_reply field is under the gl_spin lock so that it is ok

 * to use a bitfield shared with other glock state fields.

 */



void gfs2_glock_complete(struct gfs2_glock *gl, int ret)

{

	struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct;



	spin_lock(&gl->gl_spin);

	gl->gl_reply = ret;



	if (unlikely(test_bit(DFL_BLOCK_LOCKS, &ls->ls_flags))) {

		spin_lock(&gl->gl_spin);

		if (gfs2_should_freeze(gl)) {

			set_bit(GLF_FROZEN, &gl->gl_flags);

			spin_unlock(&gl->gl_spin);

			return;

		}

		spin_unlock(&gl->gl_spin);

	}



	spin_unlock(&gl->gl_spin);

	set_bit(GLF_REPLY_PENDING, &gl->gl_flags);

	smp_wmb();

	gfs2_glock_hold(gl);

	if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)

		gfs2_glock_put(gl);

fs/gfs2/incore.h

+7 −5
Original line number Diff line number Diff line
@@ -207,12 +207,14 @@ struct gfs2_glock { 


	spinlock_t gl_spin;



	unsigned int gl_state;

	unsigned int gl_target;

	unsigned int gl_reply;

	/* State fields protected by gl_spin */

	unsigned int gl_state:2,	/* Current state */

		     gl_target:2,	/* Target state */

		     gl_demote_state:2,	/* State requested by remote node */

		     gl_req:2,		/* State in last dlm request */

		     gl_reply:8;	/* Last reply from the dlm */



	unsigned int gl_hash;

	unsigned int gl_req;

	unsigned int gl_demote_state; /* state requested by remote node */

	unsigned long gl_demote_time; /* time of first demote request */

	struct list_head gl_holders;

fs/gfs2/lock_dlm.c

+0 −1
Original line number Diff line number Diff line
@@ -153,7 +153,6 @@ static int gdlm_lock(struct gfs2_glock *gl, unsigned int req_state, 
	int req;

	u32 lkf;



	gl->gl_req = req_state;

	req = make_mode(req_state);

	lkf = make_flags(gl->gl_lksb.sb_lkid, flags, req);