Author: pfg Date: Sun Jun 7 20:45:13 2015 New Revision: 284136 URL: https://svnweb.freebsd.org/changeset/base/284136
Log: MFC r278166, MFV r266993: 4469 DTrace helper tracing should be dynamic Reference: https://illumos.org/issues/4469 Obtained from: Illumos Phabric: D1551 Reviewed by: markj Modified: stable/10/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c stable/10/sys/cddl/dev/dtrace/dtrace_load.c stable/10/sys/cddl/dev/dtrace/dtrace_unload.c Directory Properties: stable/10/ (props changed) Modified: stable/10/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c ============================================================================== --- stable/10/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c Sun Jun 7 20:44:06 2015 (r284135) +++ stable/10/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c Sun Jun 7 20:45:13 2015 (r284136) @@ -351,17 +351,22 @@ dtrace_id_t dtrace_probeid_error; /* sp /* * DTrace Helper Tracing Variables - */ -uint32_t dtrace_helptrace_next = 0; -uint32_t dtrace_helptrace_nlocals; -char *dtrace_helptrace_buffer; -int dtrace_helptrace_bufsize = 512 * 1024; - -#ifdef DEBUG -int dtrace_helptrace_enabled = 1; -#else -int dtrace_helptrace_enabled = 0; -#endif + * + * These variables should be set dynamically to enable helper tracing. The + * only variables that should be set are dtrace_helptrace_enable (which should + * be set to a non-zero value to allocate helper tracing buffers on the next + * open of /dev/dtrace) and dtrace_helptrace_disable (which should be set to a + * non-zero value to deallocate helper tracing buffers on the next close of + * /dev/dtrace). When (and only when) helper tracing is disabled, the + * buffer size may also be set via dtrace_helptrace_bufsize. + */ +int dtrace_helptrace_enable = 0; +int dtrace_helptrace_disable = 0; +int dtrace_helptrace_bufsize = 16 * 1024 * 1024; +uint32_t dtrace_helptrace_nlocals; +static dtrace_helptrace_t *dtrace_helptrace_buffer; +static uint32_t dtrace_helptrace_next = 0; +static int dtrace_helptrace_wrapped = 0; /* * DTrace Error Hashing @@ -15203,10 +15208,10 @@ dtrace_helper_trace(dtrace_helper_action dtrace_mstate_t *mstate, dtrace_vstate_t *vstate, int where) { uint32_t size, next, nnext, i; - dtrace_helptrace_t *ent; + dtrace_helptrace_t *ent, *buffer; uint16_t flags = cpu_core[curcpu].cpuc_dtrace_flags; - if (!dtrace_helptrace_enabled) + if ((buffer = dtrace_helptrace_buffer) == NULL) return; ASSERT(vstate->dtvs_nlocals <= dtrace_helptrace_nlocals); @@ -15234,10 +15239,12 @@ dtrace_helper_trace(dtrace_helper_action /* * We have our slot; fill it in. */ - if (nnext == size) + if (nnext == size) { + dtrace_helptrace_wrapped++; next = 0; + } - ent = (dtrace_helptrace_t *)&dtrace_helptrace_buffer[next]; + ent = (dtrace_helptrace_t *)((uintptr_t)buffer + next); ent->dtht_helper = helper; ent->dtht_where = where; ent->dtht_nlocals = vstate->dtvs_nlocals; @@ -15271,7 +15278,7 @@ dtrace_helper(int which, dtrace_mstate_t dtrace_helper_action_t *helper; dtrace_vstate_t *vstate; dtrace_difo_t *pred; - int i, trace = dtrace_helptrace_enabled; + int i, trace = dtrace_helptrace_buffer != NULL; ASSERT(which >= 0 && which < DTRACE_NHELPER_ACTIONS); @@ -16674,17 +16681,6 @@ dtrace_attach(dev_info_t *devi, ddi_atta mutex_exit(&cpu_lock); /* - * If DTrace helper tracing is enabled, we need to allocate the - * trace buffer and initialize the values. - */ - if (dtrace_helptrace_enabled) { - ASSERT(dtrace_helptrace_buffer == NULL); - dtrace_helptrace_buffer = - kmem_zalloc(dtrace_helptrace_bufsize, KM_SLEEP); - dtrace_helptrace_next = 0; - } - - /* * If there are already providers, we must ask them to provide their * probes, and then match any anonymous enabling against them. Note * that there should be no other retained enablings at this time: @@ -16797,6 +16793,18 @@ dtrace_open(struct cdev *dev, int oflags return (EBUSY); } + if (dtrace_helptrace_enable && dtrace_helptrace_buffer == NULL) { + /* + * If DTrace helper tracing is enabled, we need to allocate the + * trace buffer and initialize the values. + */ + dtrace_helptrace_buffer = + kmem_zalloc(dtrace_helptrace_bufsize, KM_SLEEP); + dtrace_helptrace_next = 0; + dtrace_helptrace_wrapped = 0; + dtrace_helptrace_enable = 0; + } + state = dtrace_state_create(devp, cred_p); #else state = dtrace_state_create(dev); @@ -16833,7 +16841,10 @@ dtrace_dtr(void *data) #if defined(sun) minor_t minor = getminor(dev); dtrace_state_t *state; +#endif + dtrace_helptrace_t *buf = NULL; +#ifdef illumos if (minor == DTRACEMNRN_HELPER) return (0); @@ -16858,6 +16869,18 @@ dtrace_dtr(void *data) dtrace_state_destroy(state->dts_anon); } + if (dtrace_helptrace_disable) { + /* + * If we have been told to disable helper tracing, set the + * buffer to NULL before calling into dtrace_state_destroy(); + * we take advantage of its dtrace_sync() to know that no + * CPU is in probe context with enabled helper tracing + * after it returns. + */ + buf = dtrace_helptrace_buffer; + dtrace_helptrace_buffer = NULL; + } + #ifdef illumos dtrace_state_destroy(state); #else @@ -16879,6 +16902,11 @@ dtrace_dtr(void *data) --dtrace_opens; #endif + if (buf != NULL) { + kmem_free(buf, dtrace_helptrace_bufsize); + dtrace_helptrace_disable = 0; + } + mutex_exit(&dtrace_lock); mutex_exit(&cpu_lock); @@ -17776,11 +17804,6 @@ dtrace_detach(dev_info_t *dip, ddi_detac mutex_exit(&cpu_lock); - if (dtrace_helptrace_enabled) { - kmem_free(dtrace_helptrace_buffer, dtrace_helptrace_bufsize); - dtrace_helptrace_buffer = NULL; - } - kmem_free(dtrace_probes, dtrace_nprobes * sizeof (dtrace_probe_t *)); dtrace_probes = NULL; dtrace_nprobes = 0; Modified: stable/10/sys/cddl/dev/dtrace/dtrace_load.c ============================================================================== --- stable/10/sys/cddl/dev/dtrace/dtrace_load.c Sun Jun 7 20:44:06 2015 (r284135) +++ stable/10/sys/cddl/dev/dtrace/dtrace_load.c Sun Jun 7 20:45:13 2015 (r284136) @@ -137,17 +137,6 @@ dtrace_load(void *dummy) mutex_exit(&cpu_lock); - /* - * If DTrace helper tracing is enabled, we need to allocate the - * trace buffer and initialize the values. - */ - if (dtrace_helptrace_enabled) { - ASSERT(dtrace_helptrace_buffer == NULL); - dtrace_helptrace_buffer = - kmem_zalloc(dtrace_helptrace_bufsize, KM_SLEEP); - dtrace_helptrace_next = 0; - } - mutex_exit(&dtrace_lock); mutex_exit(&dtrace_provider_lock); Modified: stable/10/sys/cddl/dev/dtrace/dtrace_unload.c ============================================================================== --- stable/10/sys/cddl/dev/dtrace/dtrace_unload.c Sun Jun 7 20:44:06 2015 (r284135) +++ stable/10/sys/cddl/dev/dtrace/dtrace_unload.c Sun Jun 7 20:45:13 2015 (r284136) @@ -69,11 +69,6 @@ dtrace_unload() mutex_exit(&cpu_lock); - if (dtrace_helptrace_enabled) { - kmem_free(dtrace_helptrace_buffer, 0); - dtrace_helptrace_buffer = NULL; - } - if (dtrace_probes != NULL) { kmem_free(dtrace_probes, 0); dtrace_probes = NULL; _______________________________________________ svn-src-stable-10@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-stable-10 To unsubscribe, send any mail to "svn-src-stable-10-unsubscr...@freebsd.org"
