Date: Tue, 24 Apr 2018 01:06:20 +0000 (UTC) From: Mateusz Guzik <mjg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r332901 - in head/sys: cddl/dev/dtmalloc kern Message-ID: <201804240106.w3O16KY3046619@repo.freebsd.org>
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Author: mjg Date: Tue Apr 24 01:06:20 2018 New Revision: 332901 URL: https://svnweb.freebsd.org/changeset/base/332901 Log: dtrace: depessimize dtmalloc when dtrace is active 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. Modified: head/sys/cddl/dev/dtmalloc/dtmalloc.c head/sys/kern/kern_malloc.c Modified: head/sys/cddl/dev/dtmalloc/dtmalloc.c ============================================================================== --- head/sys/cddl/dev/dtmalloc/dtmalloc.c Tue Apr 24 01:04:10 2018 (r332900) +++ head/sys/cddl/dev/dtmalloc/dtmalloc.c Tue Apr 24 01:06:20 2018 (r332901) @@ -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 Modified: head/sys/kern/kern_malloc.c ============================================================================== --- head/sys/kern/kern_malloc.c Tue Apr 24 01:04:10 2018 (r332900) +++ head/sys/kern/kern_malloc.c Tue Apr 24 01:06:20 2018 (r332901) @@ -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, un 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 lo 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,
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