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Maps fix

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Read complete content of /proc/self/maps into one buffer without
realocation in the middle of reading and before doing any m/unlock
operation with these lines - as some of them gets change.
With previous implementation we've read some mappings twice ([stack])
This commit is contained in:
Zdenek Kabelac 2010-09-30 11:32:40 +00:00
parent c7df0240f9
commit c631be7684
2 changed files with 41 additions and 13 deletions
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1
WHATS_NEW
View File

@ -1,5 +1,6 @@
Version 2.02.75 -
=====================================
Read whole /proc/self/maps file before working with maps entries.
Speed up unquoting of quoted double quotes and backslashes.
Speed up CRC32 calculations by using a larger lookup table.

53
lib/mm/memlock.c
View File

@ -76,7 +76,9 @@ static const char * const _blacklist_maps[] = {
typedef enum { LVM_MLOCK, LVM_MUNLOCK } lvmlock_t;
static unsigned _use_mlockall;
static FILE *_mapsh;
static int _maps_fd;
static size_t _maps_len = 8192; /* Initial buffer size for reading /proc/self/maps */
static char *_maps_buffer;
static char _procselfmaps[PATH_MAX] = "";
#define SELF_MAPS "/self/maps"
@ -193,7 +195,7 @@ static int _maps_line(struct cmd_context *cmd, lvmlock_t lock,
static int _memlock_maps(struct cmd_context *cmd, lvmlock_t lock, size_t *mstats)
{
char *line = NULL;
char *line, *line_end;
size_t len;
ssize_t n;
int ret = 1;
@ -222,15 +224,39 @@ static int _memlock_maps(struct cmd_context *cmd, lvmlock_t lock, size_t *mstats
(void)strerror(0);
/* Reset statistic counters */
*mstats = 0;
rewind(_mapsh);
while ((n = getline(&line, &len, _mapsh)) != -1) {
line[n > 0 ? n - 1 : 0] = '\0'; /* remove \n */
if (!_maps_line(cmd, lock, line, mstats))
ret = 0;
/* read mapping into a single memory chunk without reallocation
* in the middle of reading maps file */
for (len = 0;;) {
if (!_maps_buffer || len >= _maps_len) {
if (_maps_buffer)
_maps_len *= 2;
if (!(_maps_buffer = dm_realloc(_maps_buffer, _maps_len))) {
log_error("Allocation of maps buffer failed");
return 0;
}
}
lseek(_maps_fd, 0, SEEK_SET);
for (len = 0 ; len < _maps_len; len += n) {
if (!(n = read(_maps_fd, _maps_buffer + len, _maps_len - len))) {
_maps_buffer[len] = '\0';
break; /* EOF */
}
if (n == -1)
return_0;
}
if (len < _maps_len) /* fits in buffer */
break;
}
free(line);
line = _maps_buffer;
while ((line_end = strchr(line, '\n'))) {
*line_end = '\0'; /* remove \n */
if (!_maps_line(cmd, lock, line, mstats))
ret = 0;
line = line_end + 1;
}
log_debug("%socked %ld bytes",
(lock == LVM_MLOCK) ? "L" : "Unl", (long)*mstats);
@ -260,8 +286,8 @@ static void _lock_mem(struct cmd_context *cmd)
return;
}
if (!(_mapsh = fopen(_procselfmaps, "r"))) {
log_sys_error("fopen", _procselfmaps);
if (!(_maps_fd = open(_procselfmaps, O_RDONLY))) {
log_sys_error("open", _procselfmaps);
return;
}
}
@ -289,9 +315,10 @@ static void _unlock_mem(struct cmd_context *cmd)
stack;
if (!_use_mlockall) {
if (fclose(_mapsh))
log_sys_error("fclose", _procselfmaps);
if (close(_maps_fd))
log_sys_error("close", _procselfmaps);
dm_free(_maps_buffer);
_maps_buffer = NULL;
if (_mstats < unlock_mstats)
log_error(INTERNAL_ERROR "Maps lock %ld < unlock %ld",
(long)_mstats, (long)unlock_mstats);