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lockfile: convert retry timeout computations to millisecond

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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 n = 1;
int multiplier = 1; int multiplier = 1;
long remaining_us = 0; long remaining_ms = 0;
static int random_initialized = 0; static int random_initialized = 0;
if (timeout_ms == 0) if (timeout_ms == 0)
@ -195,16 +195,11 @@ static int lock_file_timeout(struct lock_file *lk, const char *path,
random_initialized = 1; random_initialized = 1;
} }
if (timeout_ms > 0) { if (timeout_ms > 0)
/* avoid overflow */ remaining_ms = timeout_ms;
if (timeout_ms <= LONG_MAX / 1000)
remaining_us = timeout_ms * 1000;
else
remaining_us = LONG_MAX;
}
while (1) { while (1) {
long backoff_ms, wait_us; long backoff_ms, wait_ms;
int fd; int fd;
fd = lock_file(lk, path, flags); 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 */ return fd; /* success */
else if (errno != EEXIST) else if (errno != EEXIST)
return -1; /* failure other than lock held */ 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 */ return -1; /* failure due to timeout */
backoff_ms = multiplier * INITIAL_BACKOFF_MS; backoff_ms = multiplier * INITIAL_BACKOFF_MS;
/* back off for between 0.75*backoff_ms and 1.25*backoff_ms */ /* back off for between 0.75*backoff_ms and 1.25*backoff_ms */
wait_us = (750 + rand() % 500) * backoff_ms; wait_ms = (750 + rand() % 500) * backoff_ms / 1000;
sleep_microseconds(wait_us); sleep_microseconds(wait_ms*1000);
remaining_us -= wait_us; remaining_ms -= wait_ms;
/* Recursion: (n+1)^2 = n^2 + 2n + 1 */ /* Recursion: (n+1)^2 = n^2 + 2n + 1 */
multiplier += 2*n + 1; multiplier += 2*n + 1;