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dtrace: depessimize dtmalloc when dtrace is active

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Each malloc/free was testing dtrace_malloc_enabled and forcing
extra reads from the malloc type struct to see if perhaps a
dtmalloc probe was on.

Treat it like lockstat and sdt: have a global bolean.
This commit is contained in:
Mateusz Guzik 2018-04-24 01:06:20 +00:00
parent 4c5209cb21
commit 7cd794214a
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=332901
2 changed files with 13 additions and 3 deletions
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9
sys/cddl/dev/dtmalloc/dtmalloc.c
View File

@ -36,6 +36,9 @@
#include <sys/dtrace.h>
#include <sys/dtrace_bsd.h>
extern bool dtrace_malloc_enabled;
static uint32_t dtrace_malloc_enabled_count;
static d_open_t dtmalloc_open;
static int dtmalloc_unload(void);
static void dtmalloc_getargdesc(void *, dtrace_id_t, void *, dtrace_argdesc_t *);
@ -152,6 +155,9 @@ dtmalloc_enable(void *arg, dtrace_id_t id, void *parg)
{
uint32_t *p = parg;
*p = id;
dtrace_malloc_enabled_count++;
if (dtrace_malloc_enabled_count == 1)
dtrace_malloc_enabled = true;
}
static void
@ -159,6 +165,9 @@ dtmalloc_disable(void *arg, dtrace_id_t id, void *parg)
{
uint32_t *p = parg;
*p = 0;
dtrace_malloc_enabled_count--;
if (dtrace_malloc_enabled_count == 0)
dtrace_malloc_enabled = false;
}
static void

7
sys/kern/kern_malloc.c
View File

@ -93,7 +93,8 @@ __FBSDID("$FreeBSD$");
#ifdef KDTRACE_HOOKS
#include <sys/dtrace_bsd.h>
dtrace_malloc_probe_func_t dtrace_malloc_probe;
bool __read_frequently dtrace_malloc_enabled;
dtrace_malloc_probe_func_t __read_mostly dtrace_malloc_probe;
#endif
#if defined(INVARIANTS) || defined(MALLOC_MAKE_FAILURES) || \
@ -376,7 +377,7 @@ malloc_type_zone_allocated(struct malloc_type *mtp, unsigned long size,
mtsp->mts_size |= 1 << zindx;
#ifdef KDTRACE_HOOKS
if (dtrace_malloc_probe != NULL) {
if (__predict_false(dtrace_malloc_enabled)) {
uint32_t probe_id = mtip->mti_probes[DTMALLOC_PROBE_MALLOC];
if (probe_id != 0)
(dtrace_malloc_probe)(probe_id,
@ -415,7 +416,7 @@ malloc_type_freed(struct malloc_type *mtp, unsigned long size)
mtsp->mts_numfrees++;
#ifdef KDTRACE_HOOKS
if (dtrace_malloc_probe != NULL) {
if (__predict_false(dtrace_malloc_enabled)) {
uint32_t probe_id = mtip->mti_probes[DTMALLOC_PROBE_FREE];
if (probe_id != 0)
(dtrace_malloc_probe)(probe_id,