From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752473AbbERAmY (ORCPT ); Sun, 17 May 2015 20:42:24 -0400 Received: from LGEMRELSE6Q.lge.com ([156.147.1.121]:55788 "EHLO lgemrelse6q.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752389AbbERAmH (ORCPT ); Sun, 17 May 2015 20:42:07 -0400 X-Original-SENDERIP: 10.177.220.203 X-Original-MAILFROM: namhyung@kernel.org From: Namhyung Kim To: Arnaldo Carvalho de Melo Cc: Ingo Molnar , Peter Zijlstra , Jiri Olsa , LKML , David Ahern , Adrian Hunter , Andi Kleen , Frederic Weisbecker , Stephane Eranian Subject: [PATCH 26/40] perf tools: Protect dso cache tree using dso->lock Date: Mon, 18 May 2015 09:30:41 +0900 Message-Id: <1431909055-21442-27-git-send-email-namhyung@kernel.org> X-Mailer: git-send-email 2.4.0 In-Reply-To: <1431909055-21442-1-git-send-email-namhyung@kernel.org> References: <1431909055-21442-1-git-send-email-namhyung@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The dso cache is accessed during dwarf callchain unwind and it might be processed concurrently when multi-thread report is enabled. Protect it under dso->lock. Note that it doesn't protect dso_cache__find(). I think it's safe to access to the cache tree without the lock since we don't delete nodes. It it missed an existing node due to rotation, it'll find it during dso_cache__insert() anyway. Signed-off-by: Namhyung Kim --- tools/perf/util/dso.c | 34 +++++++++++++++++++++++++++------- 1 file changed, 27 insertions(+), 7 deletions(-) diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c index c14d981568fd..425989e85302 100644 --- a/tools/perf/util/dso.c +++ b/tools/perf/util/dso.c @@ -495,10 +495,12 @@ bool dso__data_status_seen(struct dso *dso, enum dso_data_status_seen by) } static void -dso_cache__free(struct rb_root *root) +dso_cache__free(struct dso *dso) { + struct rb_root *root = &dso->data.cache; struct rb_node *next = rb_first(root); + pthread_mutex_lock(&dso->lock); while (next) { struct dso_cache *cache; @@ -507,10 +509,12 @@ dso_cache__free(struct rb_root *root) rb_erase(&cache->rb_node, root); free(cache); } + pthread_mutex_unlock(&dso->lock); } -static struct dso_cache *dso_cache__find(const struct rb_root *root, u64 offset) +static struct dso_cache *dso_cache__find(struct dso *dso, u64 offset) { + const struct rb_root *root = &dso->data.cache; struct rb_node * const *p = &root->rb_node; const struct rb_node *parent = NULL; struct dso_cache *cache; @@ -529,17 +533,20 @@ static struct dso_cache *dso_cache__find(const struct rb_root *root, u64 offset) else return cache; } + return NULL; } -static void -dso_cache__insert(struct rb_root *root, struct dso_cache *new) +static struct dso_cache * +dso_cache__insert(struct dso *dso, struct dso_cache *new) { + struct rb_root *root = &dso->data.cache; struct rb_node **p = &root->rb_node; struct rb_node *parent = NULL; struct dso_cache *cache; u64 offset = new->offset; + pthread_mutex_lock(&dso->lock); while (*p != NULL) { u64 end; @@ -551,10 +558,17 @@ dso_cache__insert(struct rb_root *root, struct dso_cache *new) p = &(*p)->rb_left; else if (offset >= end) p = &(*p)->rb_right; + else + goto out; } rb_link_node(&new->rb_node, parent, p); rb_insert_color(&new->rb_node, root); + + cache = NULL; +out: + pthread_mutex_unlock(&dso->lock); + return cache; } static ssize_t @@ -572,6 +586,7 @@ static ssize_t dso_cache__read(struct dso *dso, u64 offset, u8 *data, ssize_t size) { struct dso_cache *cache; + struct dso_cache *old; ssize_t ret; do { @@ -591,7 +606,12 @@ dso_cache__read(struct dso *dso, u64 offset, u8 *data, ssize_t size) cache->offset = cache_offset; cache->size = ret; - dso_cache__insert(&dso->data.cache, cache); + old = dso_cache__insert(dso, cache); + if (old) { + /* we lose the race */ + free(cache); + cache = old; + } ret = dso_cache__memcpy(cache, offset, data, size); @@ -608,7 +628,7 @@ static ssize_t dso_cache_read(struct dso *dso, u64 offset, { struct dso_cache *cache; - cache = dso_cache__find(&dso->data.cache, offset); + cache = dso_cache__find(dso, offset); if (cache) return dso_cache__memcpy(cache, offset, data, size); else @@ -964,7 +984,7 @@ void dso__delete(struct dso *dso) dso__data_close(dso); auxtrace_cache__free(dso->auxtrace_cache); - dso_cache__free(&dso->data.cache); + dso_cache__free(dso); dso__free_a2l(dso); zfree(&dso->symsrc_filename); pthread_mutex_destroy(&dso->lock); -- 2.4.0