diff options
Diffstat (limited to 'usr/src/uts/common/dtrace/dtrace.c')
| -rw-r--r-- | usr/src/uts/common/dtrace/dtrace.c | 79 |
1 files changed, 64 insertions, 15 deletions
diff --git a/usr/src/uts/common/dtrace/dtrace.c b/usr/src/uts/common/dtrace/dtrace.c index ea1ac53d44..2a9df6d403 100644 --- a/usr/src/uts/common/dtrace/dtrace.c +++ b/usr/src/uts/common/dtrace/dtrace.c @@ -20,8 +20,7 @@ */ /* - * Copyright 2009 Sun Microsystems, Inc. All rights reserved. - * Use is subject to license terms. + * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved. */ /* @@ -186,6 +185,7 @@ static dtrace_helpers_t *dtrace_deferred_pid; /* deferred helper list */ static dtrace_enabling_t *dtrace_retained; /* list of retained enablings */ static dtrace_genid_t dtrace_retained_gen; /* current retained enab gen */ static dtrace_dynvar_t dtrace_dynhash_sink; /* end of dynamic hash chains */ +static int dtrace_dynvar_failclean; /* dynvars failed to clean */ /* * DTrace Locking @@ -1188,12 +1188,12 @@ dtrace_dynvar_clean(dtrace_dstate_t *dstate) { dtrace_dynvar_t *dirty; dtrace_dstate_percpu_t *dcpu; - int i, work = 0; + dtrace_dynvar_t **rinsep; + int i, j, work = 0; for (i = 0; i < NCPU; i++) { dcpu = &dstate->dtds_percpu[i]; - - ASSERT(dcpu->dtdsc_rinsing == NULL); + rinsep = &dcpu->dtdsc_rinsing; /* * If the dirty list is NULL, there is no dirty work to do. @@ -1201,14 +1201,62 @@ dtrace_dynvar_clean(dtrace_dstate_t *dstate) if (dcpu->dtdsc_dirty == NULL) continue; - /* - * If the clean list is non-NULL, then we're not going to do - * any work for this CPU -- it means that there has not been - * a dtrace_dynvar() allocation on this CPU (or from this CPU) - * since the last time we cleaned house. - */ - if (dcpu->dtdsc_clean != NULL) + if (dcpu->dtdsc_rinsing != NULL) { + /* + * If the rinsing list is non-NULL, then it is because + * this CPU was selected to accept another CPU's + * dirty list -- and since that time, dirty buffers + * have accumulated. This is a highly unlikely + * condition, but we choose to ignore the dirty + * buffers -- they'll be picked up a future cleanse. + */ continue; + } + + if (dcpu->dtdsc_clean != NULL) { + /* + * If the clean list is non-NULL, then we're in a + * situation where a CPU has done deallocations (we + * have a non-NULL dirty list) but no allocations (we + * also have a non-NULL clean list). We can't simply + * move the dirty list into the clean list on this + * CPU, yet we also don't want to allow this condition + * to persist, lest a short clean list prevent a + * massive dirty list from being cleaned (which in + * turn could lead to otherwise avoidable dynamic + * drops). To deal with this, we look for some CPU + * with a NULL clean list, NULL dirty list, and NULL + * rinsing list -- and then we borrow this CPU to + * rinse our dirty list. + */ + for (j = 0; j < NCPU; j++) { + dtrace_dstate_percpu_t *rinser; + + rinser = &dstate->dtds_percpu[j]; + + if (rinser->dtdsc_rinsing != NULL) + continue; + + if (rinser->dtdsc_dirty != NULL) + continue; + + if (rinser->dtdsc_clean != NULL) + continue; + + rinsep = &rinser->dtdsc_rinsing; + break; + } + + if (j == NCPU) { + /* + * We were unable to find another CPU that + * could accept this dirty list -- we are + * therefore unable to clean it now. + */ + dtrace_dynvar_failclean++; + continue; + } + } work = 1; @@ -1225,7 +1273,7 @@ dtrace_dynvar_clean(dtrace_dstate_t *dstate) * on a hash chain, either the dirty list or the * rinsing list for some CPU must be non-NULL.) */ - dcpu->dtdsc_rinsing = dirty; + *rinsep = dirty; dtrace_membar_producer(); } while (dtrace_casptr(&dcpu->dtdsc_dirty, dirty, NULL) != dirty); @@ -1656,7 +1704,7 @@ retry: ASSERT(clean->dtdv_hashval == DTRACE_DYNHASH_FREE); /* - * Now we'll move the clean list to the free list. + * Now we'll move the clean list to our free list. * It's impossible for this to fail: the only way * the free list can be updated is through this * code path, and only one CPU can own the clean list. @@ -1669,6 +1717,7 @@ retry: * owners of the clean lists out before resetting * the clean lists. */ + dcpu = &dstate->dtds_percpu[me]; rval = dtrace_casptr(&dcpu->dtdsc_free, NULL, clean); ASSERT(rval == NULL); goto retry; @@ -3606,7 +3655,7 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs, int64_t index = (int64_t)tupregs[1].dttk_value; int64_t remaining = (int64_t)tupregs[2].dttk_value; size_t len = dtrace_strlen((char *)s, size); - int64_t i = 0; + int64_t i; if (!dtrace_canload(s, len + 1, mstate, vstate)) { regs[rd] = NULL; |