GFS2: Instruct DLM to avoid queue convert slowdown (4c569a72) · Commits · 戴 / test

This patch instructs DLM to prevent an "in place" conversion, where the lock just stays on the granted queue, and instead forces the conversion to the back of the convert queue. This is done on upward conversions only. This is useful in cases where, for example, a lock is frequently needed in PR on one node, but another node needs it temporarily in EX to update it. This may happen, for example, when the rindex is being updated by gfs2_grow. The gfs2_grow needs to have the lock in EX, but the other nodes need to re-read it to retrieve the updates. The glock is already granted in PR on the non-growing nodes, so this prevents them from continually re-granting the lock in PR, and forces the EX from gfs2_grow to go through. Signed-off-by:

Bob Peterson <rpeterso@redhat.com> Signed-off-by:

Steven Whitehouse <swhiteho@redhat.com>

fs/gfs2/lock_dlm.c

+7 −3

Original line number	Diff line number	Diff line
		@@ -200,10 +200,11 @@ static int make_mode(const unsigned int lmstate)
		return -1;
		}

		static u32 make_flags(const u32 lkid, const unsigned int gfs_flags,
		static u32 make_flags(struct gfs2_glock *gl, const unsigned int gfs_flags,
		const int req)
		{
		u32 lkf = DLM_LKF_VALBLK;
		u32 lkid = gl->gl_lksb.sb_lkid;

		if (gfs_flags & LM_FLAG_TRY)
		lkf \|= DLM_LKF_NOQUEUE;
		@@ -227,8 +228,11 @@ static u32 make_flags(const u32 lkid, const unsigned int gfs_flags,
		BUG();
		}

		if (lkid != 0)
		if (lkid != 0) {
		lkf \|= DLM_LKF_CONVERT;
		if (test_bit(GLF_BLOCKING, &gl->gl_flags))
		lkf \|= DLM_LKF_QUECVT;
		}

		return lkf;
		}
		@@ -250,7 +254,7 @@ static int gdlm_lock(struct gfs2_glock *gl, unsigned int req_state,
		char strname[GDLM_STRNAME_BYTES] = "";

		req = make_mode(req_state);
		lkf = make_flags(gl->gl_lksb.sb_lkid, flags, req);
		lkf = make_flags(gl, flags, req);
		gfs2_glstats_inc(gl, GFS2_LKS_DCOUNT);
		gfs2_sbstats_inc(gl, GFS2_LKS_DCOUNT);
		if (gl->gl_lksb.sb_lkid) {

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