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Unbreak mutex profiling (at least for me).

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o Always check for null when dereferencing the filename component.
	o Implement a try-and-backoff method for allocating memory to
	  dump stats to avoid a spin-lock -> sleep-lock mutex lock order
	  panic with WITNESS.

Approved by:	des, markm (mentor)
Not objected:	jhb
This commit is contained in:
Mike Makonnen 2003-02-25 22:28:46 +00:00
parent e088615df0
commit 0bd5f7979d
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=111508
2 changed files with 30 additions and 6 deletions
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18
sys/kern/kern_mutex.c
View File

@ -235,6 +235,8 @@ static struct mutex_prof mprof_buf[NUM_MPROF_BUFFERS];
static int first_free_mprof_buf;
#define MPROF_HASH_SIZE 1009
static struct mutex_prof *mprof_hash[MPROF_HASH_SIZE];
/* SWAG: sbuf size = avg stat. line size * number of locks */
#define MPROF_SBUF_SIZE 256 * 400
static int mutex_prof_acquisitions;
SYSCTL_INT(_debug_mutex_prof, OID_AUTO, acquisitions, CTLFLAG_RD,
@ -275,12 +277,14 @@ dump_mutex_prof_stats(SYSCTL_HANDLER_ARGS)
{
struct sbuf *sb;
int error, i;
static int multiplier = 1;
if (first_free_mprof_buf == 0)
return (SYSCTL_OUT(req, "No locking recorded",
sizeof("No locking recorded")));
sb = sbuf_new(NULL, NULL, 1024, SBUF_AUTOEXTEND);
retry_sbufops:
sb = sbuf_new(NULL, NULL, MPROF_SBUF_SIZE * multiplier, SBUF_FIXEDLEN);
sbuf_printf(sb, "%6s %12s %11s %5s %s\n",
"max", "total", "count", "avg", "name");
/*
@ -290,7 +294,7 @@ dump_mutex_prof_stats(SYSCTL_HANDLER_ARGS)
* computation here).
*/
mtx_lock_spin(&mprof_mtx);
for (i = 0; i < first_free_mprof_buf; ++i)
for (i = 0; i < first_free_mprof_buf; ++i) {
sbuf_printf(sb, "%6ju %12ju %11ju %5ju %s:%d (%s)\n",
mprof_buf[i].cnt_max / 1000,
mprof_buf[i].cnt_tot / 1000,
@ -298,6 +302,13 @@ dump_mutex_prof_stats(SYSCTL_HANDLER_ARGS)
mprof_buf[i].cnt_cur == 0 ? (uintmax_t)0 :
mprof_buf[i].cnt_tot / (mprof_buf[i].cnt_cur * 1000),
mprof_buf[i].file, mprof_buf[i].line, mprof_buf[i].name);
if (sbuf_overflowed(sb)) {
mtx_unlock_spin(&mprof_mtx);
sbuf_delete(sb);
multiplier++;
goto retry_sbufops;
}
}
mtx_unlock_spin(&mprof_mtx);
sbuf_finish(sb);
error = SYSCTL_OUT(req, sbuf_data(sb), sbuf_len(sb) + 1);
@ -360,7 +371,8 @@ _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line)
m->mtx_acqtime = 0;
if (now <= acqtime)
goto out;
for (p = m->mtx_filename; strncmp(p, "../", 3) == 0; p += 3)
for (p = m->mtx_filename;
p != NULL && strncmp(p, "../", 3) == 0; p += 3)
/* nothing */ ;
if (p == NULL || *p == '\0')
p = unknown;

18
sys/kern/subr_turnstile.c
View File

@ -235,6 +235,8 @@ static struct mutex_prof mprof_buf[NUM_MPROF_BUFFERS];
static int first_free_mprof_buf;
#define MPROF_HASH_SIZE 1009
static struct mutex_prof *mprof_hash[MPROF_HASH_SIZE];
/* SWAG: sbuf size = avg stat. line size * number of locks */
#define MPROF_SBUF_SIZE 256 * 400
static int mutex_prof_acquisitions;
SYSCTL_INT(_debug_mutex_prof, OID_AUTO, acquisitions, CTLFLAG_RD,
@ -275,12 +277,14 @@ dump_mutex_prof_stats(SYSCTL_HANDLER_ARGS)
{
struct sbuf *sb;
int error, i;
static int multiplier = 1;
if (first_free_mprof_buf == 0)
return (SYSCTL_OUT(req, "No locking recorded",
sizeof("No locking recorded")));
sb = sbuf_new(NULL, NULL, 1024, SBUF_AUTOEXTEND);
retry_sbufops:
sb = sbuf_new(NULL, NULL, MPROF_SBUF_SIZE * multiplier, SBUF_FIXEDLEN);
sbuf_printf(sb, "%6s %12s %11s %5s %s\n",
"max", "total", "count", "avg", "name");
/*
@ -290,7 +294,7 @@ dump_mutex_prof_stats(SYSCTL_HANDLER_ARGS)
* computation here).
*/
mtx_lock_spin(&mprof_mtx);
for (i = 0; i < first_free_mprof_buf; ++i)
for (i = 0; i < first_free_mprof_buf; ++i) {
sbuf_printf(sb, "%6ju %12ju %11ju %5ju %s:%d (%s)\n",
mprof_buf[i].cnt_max / 1000,
mprof_buf[i].cnt_tot / 1000,
@ -298,6 +302,13 @@ dump_mutex_prof_stats(SYSCTL_HANDLER_ARGS)
mprof_buf[i].cnt_cur == 0 ? (uintmax_t)0 :
mprof_buf[i].cnt_tot / (mprof_buf[i].cnt_cur * 1000),
mprof_buf[i].file, mprof_buf[i].line, mprof_buf[i].name);
if (sbuf_overflowed(sb)) {
mtx_unlock_spin(&mprof_mtx);
sbuf_delete(sb);
multiplier++;
goto retry_sbufops;
}
}
mtx_unlock_spin(&mprof_mtx);
sbuf_finish(sb);
error = SYSCTL_OUT(req, sbuf_data(sb), sbuf_len(sb) + 1);
@ -360,7 +371,8 @@ _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line)
m->mtx_acqtime = 0;
if (now <= acqtime)
goto out;
for (p = m->mtx_filename; strncmp(p, "../", 3) == 0; p += 3)
for (p = m->mtx_filename;
p != NULL && strncmp(p, "../", 3) == 0; p += 3)
/* nothing */ ;
if (p == NULL || *p == '\0')
p = unknown;