From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752364AbaIJOKn (ORCPT ); Wed, 10 Sep 2014 10:10:43 -0400 Received: from mail.kernel.org ([198.145.19.201]:38683 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752221AbaIJOKh (ORCPT ); Wed, 10 Sep 2014 10:10:37 -0400 From: Arnaldo Carvalho de Melo To: Jiri Olsa Cc: linux-kernel@vger.kernel.org, Arnaldo Carvalho de Melo , Adrian Hunter , Borislav Petkov , Corey Ashford , David Ahern , Frederic Weisbecker , Ingo Molnar , Jean Pihet , Jiri Olsa , Namhyung Kim , Paul Mackerras , Peter Zijlstra Subject: [PATCH 12/14] perf evlist: Refcount mmaps Date: Wed, 10 Sep 2014 11:08:47 -0300 Message-Id: <1410358129-9965-13-git-send-email-acme@kernel.org> X-Mailer: git-send-email 1.9.3 In-Reply-To: <1410358129-9965-1-git-send-email-acme@kernel.org> References: <1410358129-9965-1-git-send-email-acme@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Arnaldo Carvalho de Melo We need to know how many fds are using a perf mmap via PERF_EVENT_IOC_SET_OUTPUT, so that we can know when to ditch an mmap, refcount it. Cc: Adrian Hunter Cc: Borislav Petkov Cc: Corey Ashford Cc: David Ahern Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Jean Pihet Cc: Jiri Olsa Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20140908153824.GG2773@kernel.org Link: http://lkml.kernel.org/n/tip-9ymfcxmk52sb7u1g0i3aiovh@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/evlist.c | 21 ++++++++++++++++++++- tools/perf/util/evlist.h | 6 ++++++ 2 files changed, 26 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c index 477ede5367ee..662057a44126 100644 --- a/tools/perf/util/evlist.c +++ b/tools/perf/util/evlist.c @@ -664,6 +664,7 @@ static void __perf_evlist__munmap(struct perf_evlist *evlist, int idx) if (evlist->mmap[idx].base != NULL) { munmap(evlist->mmap[idx].base, evlist->mmap_len); evlist->mmap[idx].base = NULL; + evlist->mmap[idx].nfds = 0; } } @@ -697,6 +698,7 @@ struct mmap_params { static int __perf_evlist__mmap(struct perf_evlist *evlist, int idx, struct mmap_params *mp, int fd) { + evlist->mmap[idx].nfds = 1; evlist->mmap[idx].prev = 0; evlist->mmap[idx].mask = mp->mask; evlist->mmap[idx].base = mmap(NULL, evlist->mmap_len, mp->prot, @@ -711,6 +713,19 @@ static int __perf_evlist__mmap(struct perf_evlist *evlist, int idx, return 0; } +static void perf_evlist__mmap_get(struct perf_evlist *evlist, int idx) +{ + ++evlist->mmap[idx].nfds; +} + +static void perf_evlist__mmap_put(struct perf_evlist *evlist, int idx) +{ + BUG_ON(evlist->mmap[idx].nfds == 0); + + if (--evlist->mmap[idx].nfds == 0) + __perf_evlist__munmap(evlist, idx); +} + static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx, struct mmap_params *mp, int cpu, int thread, int *output) @@ -732,10 +747,14 @@ static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx, } else { if (ioctl(fd, PERF_EVENT_IOC_SET_OUTPUT, *output) != 0) return -1; + + perf_evlist__mmap_get(evlist, idx); } - if (perf_evlist__add_pollfd(evlist, fd) < 0) + if (perf_evlist__add_pollfd(evlist, fd) < 0) { + perf_evlist__mmap_put(evlist, idx); return -1; + } if ((evsel->attr.read_format & PERF_FORMAT_ID) && perf_evlist__id_add_fd(evlist, evsel, cpu, thread, fd) < 0) diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h index fc013704d903..19bbe0410827 100644 --- a/tools/perf/util/evlist.h +++ b/tools/perf/util/evlist.h @@ -18,9 +18,15 @@ struct record_opts; #define PERF_EVLIST__HLIST_BITS 8 #define PERF_EVLIST__HLIST_SIZE (1 << PERF_EVLIST__HLIST_BITS) +/** + * struct perf_mmap - perf's ring buffer mmap details + * + * @nfds - file descriptors pointing here via PERF_EVENT_IOC_SET_OUTPUT + */ struct perf_mmap { void *base; int mask; + int nfds; unsigned int prev; char event_copy[PERF_SAMPLE_MAX_SIZE]; }; -- 1.9.3