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author | Tina Ruchandani <ruchandani.tina@gmail.com> | 2015-09-04 22:44:43 (GMT) |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-09-04 23:54:41 (GMT) |
commit | 40476b8294466d40e7db57b4cbf69a831a4486b8 (patch) | |
tree | e1675104a4b34137ce7cf31c83b67672a08f4600 /fs/ocfs2/cluster | |
parent | ad694821224634d46b6571f0161e85ac2e397396 (diff) | |
download | linux-40476b8294466d40e7db57b4cbf69a831a4486b8.tar.xz |
ocfs2: use 64bit variables to track heartbeat time
o2hb_elapsed_msecs computes the time taken for a disk heartbeat.
'struct timeval' variables are used to store start and end times. On
32-bit systems, the 'tv_sec' component of 'struct timeval' will overflow
in year 2038 and beyond.
This patch solves the overflow with the following:
1. Replace o2hb_elapsed_msecs using 'ktime_t' values to measure start
and end time, and built-in function 'ktime_ms_delta' to compute the
elapsed time. ktime_get_real() is used since the code prints out the
wallclock time.
2. Changes format string to print time as a single 64-bit nanoseconds
value ("%lld") instead of seconds and microseconds. This simplifies
the code since converting ktime_t to that format would need expensive
computation. However, the debug log string is less readable than the
previous format.
Signed-off-by: Tina Ruchandani <ruchandani.tina@gmail.com>
Suggested by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/ocfs2/cluster')
-rw-r--r-- | fs/ocfs2/cluster/heartbeat.c | 49 |
1 files changed, 9 insertions, 40 deletions
diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c index f973064..fa15deb 100644 --- a/fs/ocfs2/cluster/heartbeat.c +++ b/fs/ocfs2/cluster/heartbeat.c @@ -36,7 +36,7 @@ #include <linux/debugfs.h> #include <linux/slab.h> #include <linux/bitmap.h> - +#include <linux/ktime.h> #include "heartbeat.h" #include "tcp.h" #include "nodemanager.h" @@ -1060,37 +1060,6 @@ bail: return ret; } -/* Subtract b from a, storing the result in a. a *must* have a larger - * value than b. */ -static void o2hb_tv_subtract(struct timeval *a, - struct timeval *b) -{ - /* just return 0 when a is after b */ - if (a->tv_sec < b->tv_sec || - (a->tv_sec == b->tv_sec && a->tv_usec < b->tv_usec)) { - a->tv_sec = 0; - a->tv_usec = 0; - return; - } - - a->tv_sec -= b->tv_sec; - a->tv_usec -= b->tv_usec; - while ( a->tv_usec < 0 ) { - a->tv_sec--; - a->tv_usec += 1000000; - } -} - -static unsigned int o2hb_elapsed_msecs(struct timeval *start, - struct timeval *end) -{ - struct timeval res = *end; - - o2hb_tv_subtract(&res, start); - - return res.tv_sec * 1000 + res.tv_usec / 1000; -} - /* * we ride the region ref that the region dir holds. before the region * dir is removed and drops it ref it will wait to tear down this @@ -1101,7 +1070,7 @@ static int o2hb_thread(void *data) int i, ret; struct o2hb_region *reg = data; struct o2hb_bio_wait_ctxt write_wc; - struct timeval before_hb, after_hb; + ktime_t before_hb, after_hb; unsigned int elapsed_msec; mlog(ML_HEARTBEAT|ML_KTHREAD, "hb thread running\n"); @@ -1118,18 +1087,18 @@ static int o2hb_thread(void *data) * hr_timeout_ms between disk writes. On busy systems * this should result in a heartbeat which is less * likely to time itself out. */ - do_gettimeofday(&before_hb); + before_hb = ktime_get_real(); ret = o2hb_do_disk_heartbeat(reg); - do_gettimeofday(&after_hb); - elapsed_msec = o2hb_elapsed_msecs(&before_hb, &after_hb); + after_hb = ktime_get_real(); + + elapsed_msec = (unsigned int) + ktime_ms_delta(after_hb, before_hb); mlog(ML_HEARTBEAT, - "start = %lu.%lu, end = %lu.%lu, msec = %u, ret = %d\n", - before_hb.tv_sec, (unsigned long) before_hb.tv_usec, - after_hb.tv_sec, (unsigned long) after_hb.tv_usec, - elapsed_msec, ret); + "start = %lld, end = %lld, msec = %u, ret = %d\n", + before_hb.tv64, after_hb.tv64, elapsed_msec, ret); if (!kthread_should_stop() && elapsed_msec < reg->hr_timeout_ms) { |