diff options
Diffstat (limited to 'fs/gfs2/lock_dlm.c')
| -rw-r--r-- | fs/gfs2/lock_dlm.c | 123 |
1 files changed, 118 insertions, 5 deletions
diff --git a/fs/gfs2/lock_dlm.c b/fs/gfs2/lock_dlm.c index 8944d1e32ab5..f8411bd1b805 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) { |