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lockfile: convert retry timeout computations to millisecond 

When the goal is to wait for some random amount of time up to one
second, it is not necessary to compute with microsecond precision.
This is a preparation to re-use sleep_millisec().

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Johannes Sixt 2015-06-05 21:45:06 +02:00 committed by Junio C Hamano
parent 2024d31765
commit a8a17756bb
1 changed files with 8 additions and 13 deletions
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21
lockfile.c
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@ -184,7 +184,7 @@ static int lock_file_timeout(struct lock_file *lk, const char *path,
{
int n = 1;
int multiplier = 1;
long remaining_us = 0;
long remaining_ms = 0;
static int random_initialized = 0;
if (timeout_ms == 0)
@ -195,16 +195,11 @@ static int lock_file_timeout(struct lock_file *lk, const char *path,
random_initialized = 1;
}
if (timeout_ms > 0) {
/* avoid overflow */
if (timeout_ms <= LONG_MAX / 1000)
remaining_us = timeout_ms * 1000;
else
remaining_us = LONG_MAX;
}
if (timeout_ms > 0)
remaining_ms = timeout_ms;
while (1) {
long backoff_ms, wait_us;
long backoff_ms, wait_ms;
int fd;
fd = lock_file(lk, path, flags);
@ -213,14 +208,14 @@ static int lock_file_timeout(struct lock_file *lk, const char *path,
return fd; /* success */
else if (errno != EEXIST)
return -1; /* failure other than lock held */
else if (timeout_ms > 0 && remaining_us <= 0)
else if (timeout_ms > 0 && remaining_ms <= 0)
return -1; /* failure due to timeout */
backoff_ms = multiplier * INITIAL_BACKOFF_MS;
/* back off for between 0.75*backoff_ms and 1.25*backoff_ms */
wait_us = (750 + rand() % 500) * backoff_ms;
sleep_microseconds(wait_us);
remaining_us -= wait_us;
wait_ms = (750 + rand() % 500) * backoff_ms / 1000;
sleep_microseconds(wait_ms*1000);
remaining_ms -= wait_ms;
/* Recursion: (n+1)^2 = n^2 + 2n + 1 */
multiplier += 2*n + 1;