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-rw-r--r--fs/gfs2/lock_dlm.c123
1 files changed, 118 insertions, 5 deletions
diff --git a/fs/gfs2/lock_dlm.c b/fs/gfs2/lock_dlm.c
index 8944d1e..f8411bd 100644
--- a/fs/gfs2/lock_dlm.c
+++ b/fs/gfs2/lock_dlm.c
@@ -18,14 +18,106 @@
#include "glock.h"
#include "util.h"
#include "sys.h"
+#include "trace_gfs2.h"
extern struct workqueue_struct *gfs2_control_wq;
+/**
+ * gfs2_update_stats - Update time based stats
+ * @mv: Pointer to mean/variance structure to update
+ * @sample: New data to include
+ *
+ * @delta is the difference between the current rtt sample and the
+ * running average srtt. We add 1/8 of that to the srtt in order to
+ * update the current srtt estimate. The varience estimate is a bit
+ * more complicated. We subtract the abs value of the @delta from
+ * the current variance estimate and add 1/4 of that to the running
+ * total.
+ *
+ * Note that the index points at the array entry containing the smoothed
+ * mean value, and the variance is always in the following entry
+ *
+ * Reference: TCP/IP Illustrated, vol 2, p. 831,832
+ * All times are in units of integer nanoseconds. Unlike the TCP/IP case,
+ * they are not scaled fixed point.
+ */
+
+static inline void gfs2_update_stats(struct gfs2_lkstats *s, unsigned index,
+ s64 sample)
+{
+ s64 delta = sample - s->stats[index];
+ s->stats[index] += (delta >> 3);
+ index++;
+ s->stats[index] += ((abs64(delta) - s->stats[index]) >> 2);
+}
+
+/**
+ * gfs2_update_reply_times - Update locking statistics
+ * @gl: The glock to update
+ *
+ * This assumes that gl->gl_dstamp has been set earlier.
+ *
+ * The rtt (lock round trip time) is an estimate of the time
+ * taken to perform a dlm lock request. We update it on each
+ * reply from the dlm.
+ *
+ * The blocking flag is set on the glock for all dlm requests
+ * which may potentially block due to lock requests from other nodes.
+ * DLM requests where the current lock state is exclusive, the
+ * requested state is null (or unlocked) or where the TRY or
+ * TRY_1CB flags are set are classified as non-blocking. All
+ * other DLM requests are counted as (potentially) blocking.
+ */
+static inline void gfs2_update_reply_times(struct gfs2_glock *gl)
+{
+ struct gfs2_pcpu_lkstats *lks;
+ const unsigned gltype = gl->gl_name.ln_type;
+ unsigned index = test_bit(GLF_BLOCKING, &gl->gl_flags) ?
+ GFS2_LKS_SRTTB : GFS2_LKS_SRTT;
+ s64 rtt;
+
+ preempt_disable();
+ rtt = ktime_to_ns(ktime_sub(ktime_get_real(), gl->gl_dstamp));
+ lks = this_cpu_ptr(gl->gl_sbd->sd_lkstats);
+ gfs2_update_stats(&gl->gl_stats, index, rtt); /* Local */
+ gfs2_update_stats(&lks->lkstats[gltype], index, rtt); /* Global */
+ preempt_enable();
+
+ trace_gfs2_glock_lock_time(gl, rtt);
+}
+
+/**
+ * gfs2_update_request_times - Update locking statistics
+ * @gl: The glock to update
+ *
+ * The irt (lock inter-request times) measures the average time
+ * between requests to the dlm. It is updated immediately before
+ * each dlm call.
+ */
+
+static inline void gfs2_update_request_times(struct gfs2_glock *gl)
+{
+ struct gfs2_pcpu_lkstats *lks;
+ const unsigned gltype = gl->gl_name.ln_type;
+ ktime_t dstamp;
+ s64 irt;
+
+ preempt_disable();
+ dstamp = gl->gl_dstamp;
+ gl->gl_dstamp = ktime_get_real();
+ irt = ktime_to_ns(ktime_sub(gl->gl_dstamp, dstamp));
+ lks = this_cpu_ptr(gl->gl_sbd->sd_lkstats);
+ gfs2_update_stats(&gl->gl_stats, GFS2_LKS_SIRT, irt); /* Local */
+ gfs2_update_stats(&lks->lkstats[gltype], GFS2_LKS_SIRT, irt); /* Global */
+ preempt_enable();
+}
+
static void gdlm_ast(void *arg)
{
struct gfs2_glock *gl = arg;
unsigned ret = gl->gl_state;
+ gfs2_update_reply_times(gl);
BUG_ON(gl->gl_lksb.sb_flags & DLM_SBF_DEMOTED);
if (gl->gl_lksb.sb_flags & DLM_SBF_VALNOTVALID)
@@ -111,7 +203,7 @@ static int make_mode(const unsigned int lmstate)
static u32 make_flags(const u32 lkid, const unsigned int gfs_flags,
const int req)
{
- u32 lkf = 0;
+ u32 lkf = DLM_LKF_VALBLK;
if (gfs_flags & LM_FLAG_TRY)
lkf |= DLM_LKF_NOQUEUE;
@@ -138,26 +230,43 @@ static u32 make_flags(const u32 lkid, const unsigned int gfs_flags,
if (lkid != 0)
lkf |= DLM_LKF_CONVERT;
- lkf |= DLM_LKF_VALBLK;
-
return lkf;
}
+static void gfs2_reverse_hex(char *c, u64 value)
+{
+ while (value) {
+ *c-- = hex_asc[value & 0x0f];
+ value >>= 4;
+ }
+}
+
static int gdlm_lock(struct gfs2_glock *gl, unsigned int req_state,
unsigned int flags)
{
struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct;
int req;
u32 lkf;
+ char strname[GDLM_STRNAME_BYTES] = "";
req = make_mode(req_state);
lkf = make_flags(gl->gl_lksb.sb_lkid, flags, req);
-
+ gfs2_glstats_inc(gl, GFS2_LKS_DCOUNT);
+ gfs2_sbstats_inc(gl, GFS2_LKS_DCOUNT);
+ if (gl->gl_lksb.sb_lkid) {
+ gfs2_update_request_times(gl);
+ } else {
+ memset(strname, ' ', GDLM_STRNAME_BYTES - 1);
+ strname[GDLM_STRNAME_BYTES - 1] = '\0';
+ gfs2_reverse_hex(strname + 7, gl->gl_name.ln_type);
+ gfs2_reverse_hex(strname + 23, gl->gl_name.ln_number);
+ gl->gl_dstamp = ktime_get_real();
+ }
/*
* Submit the actual lock request.
*/
- return dlm_lock(ls->ls_dlm, req, &gl->gl_lksb, lkf, gl->gl_strname,
+ return dlm_lock(ls->ls_dlm, req, &gl->gl_lksb, lkf, strname,
GDLM_STRNAME_BYTES - 1, 0, gdlm_ast, gl, gdlm_bast);
}
@@ -172,6 +281,10 @@ static void gdlm_put_lock(struct gfs2_glock *gl)
return;
}
+ clear_bit(GLF_BLOCKING, &gl->gl_flags);
+ gfs2_glstats_inc(gl, GFS2_LKS_DCOUNT);
+ gfs2_sbstats_inc(gl, GFS2_LKS_DCOUNT);
+ gfs2_update_request_times(gl);
error = dlm_unlock(ls->ls_dlm, gl->gl_lksb.sb_lkid, DLM_LKF_VALBLK,
NULL, gl);
if (error) {
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