From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 54297C433ED for ; Tue, 13 Apr 2021 18:39:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 362E3613C5 for ; Tue, 13 Apr 2021 18:39:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348097AbhDMSjs (ORCPT ); Tue, 13 Apr 2021 14:39:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:55056 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347975AbhDMSjr (ORCPT ); Tue, 13 Apr 2021 14:39:47 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3E10E613C5; Tue, 13 Apr 2021 18:39:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1618339167; bh=faK+eNmZ8G4HjvlBN68jFqX65PE7SsEn7a96rNi/7cg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=AYYxOJ0ceOFNnoksXkcCP1APE3c35tAstDdtBPTRPxFdcn0aZrs/EEEEJK7l273Aj mzZkfot3vQyAfhdsMFvn/EFianh+ppAOQASaE5gdKjbvO8aq36mfifu6iidVwzS8/y 8dWiiP2TTeJg+2+wLMjvP83e4KFj6Q2Ms0FCEFPAZW0VzQu+e4nC4WFiSTlaaCUYcQ LuA3JtCQei8dq3773vkkCqk8U9umX3ZhCBFzZciUh6RPwlPokwZvBp0Ngf3JKIRsC8 iQ9zYmIniTinrD3/O6ftVSlhn5Dyvyz4XLX66uW1nr783zvsim/njl+ZkhlhUHawfF PGEqzabAcIVQw== Received: by quaco.ghostprotocols.net (Postfix, from userid 1000) id 7C43F40647; Tue, 13 Apr 2021 15:39:24 -0300 (-03) Date: Tue, 13 Apr 2021 15:39:24 -0300 From: Arnaldo Carvalho de Melo To: Rob Herring Cc: Peter Zijlstra , Ingo Molnar , Jiri Olsa , linux-kernel@vger.kernel.org, Will Deacon , Catalin Marinas , Mark Rutland , Namhyung Kim , Itaru Kitayama Subject: Re: [PATCH v7 2/4] libperf: Add evsel mmap support Message-ID: References: <20210413171606.1825808-1-robh@kernel.org> <20210413171606.1825808-3-robh@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210413171606.1825808-3-robh@kernel.org> X-Url: http://acmel.wordpress.com Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Tue, Apr 13, 2021 at 12:16:04PM -0500, Rob Herring escreveu: > In order to support usersapce access, an event must be mmapped. While > there's already mmap support for evlist, the usecase is a bit different > than the self monitoring with userspace access. So let's add a new > perf_evsel__mmap() function to mmap an evsel. This allows implementing > userspace access as a fastpath for perf_evsel__read(). > > The mmapped address is returned by perf_evsel__mmap_base() which > primarily for users/tests to check if userspace access is enabled. > > Signed-off-by: Rob Herring > --- > v7: > - Add NULL fd check to perf_evsel__mmap > v6: > - split mmap struct into it's own xyarray > v5: > - Create an mmap for every underlying event opened. Due to this, we > need a different way to get the mmap ptr, so perf_evsel__mmap_base() > is introduced. > v4: > - Change perf_evsel__mmap size to pages instead of bytes > v3: > - New patch split out from user access patch > --- > tools/lib/perf/Documentation/libperf.txt | 2 + > tools/lib/perf/evsel.c | 54 ++++++++++++++++++++++++ > tools/lib/perf/include/internal/evsel.h | 1 + > tools/lib/perf/include/perf/evsel.h | 2 + > tools/lib/perf/libperf.map | 2 + > 5 files changed, 61 insertions(+) > > diff --git a/tools/lib/perf/Documentation/libperf.txt b/tools/lib/perf/Documentation/libperf.txt > index 0c74c30ed23a..a2c73df191ca 100644 > --- a/tools/lib/perf/Documentation/libperf.txt > +++ b/tools/lib/perf/Documentation/libperf.txt > @@ -136,6 +136,8 @@ SYNOPSIS > struct perf_thread_map *threads); > void perf_evsel__close(struct perf_evsel *evsel); > void perf_evsel__close_cpu(struct perf_evsel *evsel, int cpu); > + int perf_evsel__mmap(struct perf_evsel *evsel, int pages); > + void *perf_evsel__mmap_base(struct perf_evsel *evsel, int cpu, int thread); > int perf_evsel__read(struct perf_evsel *evsel, int cpu, int thread, > struct perf_counts_values *count); > int perf_evsel__enable(struct perf_evsel *evsel); > diff --git a/tools/lib/perf/evsel.c b/tools/lib/perf/evsel.c > index 4dc06289f4c7..7e140763552f 100644 > --- a/tools/lib/perf/evsel.c > +++ b/tools/lib/perf/evsel.c > @@ -11,10 +11,12 @@ > #include > #include > #include > +#include > #include > #include > #include > #include > +#include > > void perf_evsel__init(struct perf_evsel *evsel, struct perf_event_attr *attr) > { > @@ -38,6 +40,7 @@ void perf_evsel__delete(struct perf_evsel *evsel) > } > > #define FD(e, x, y) (*(int *) xyarray__entry(e->fd, x, y)) > +#define MMAP(e, x, y) (e->mmap ? ((struct perf_mmap *) xyarray__entry(e->mmap, x, y)) : NULL) > > int perf_evsel__alloc_fd(struct perf_evsel *evsel, int ncpus, int nthreads) > { > @@ -55,6 +58,13 @@ int perf_evsel__alloc_fd(struct perf_evsel *evsel, int ncpus, int nthreads) > return evsel->fd != NULL ? 0 : -ENOMEM; > } > > +static int perf_evsel__alloc_mmap(struct perf_evsel *evsel, int ncpus, int nthreads) > +{ > + evsel->mmap = xyarray__new(ncpus, nthreads, sizeof(struct perf_mmap)); > + > + return evsel->mmap != NULL ? 0 : -ENOMEM; > +} > + > static int > sys_perf_event_open(struct perf_event_attr *attr, > pid_t pid, int cpu, int group_fd, > @@ -137,6 +147,8 @@ void perf_evsel__free_fd(struct perf_evsel *evsel) > { > xyarray__delete(evsel->fd); > evsel->fd = NULL; > + xyarray__delete(evsel->mmap); > + evsel->mmap = NULL; > } > > void perf_evsel__close(struct perf_evsel *evsel) > @@ -156,6 +168,48 @@ void perf_evsel__close_cpu(struct perf_evsel *evsel, int cpu) > perf_evsel__close_fd_cpu(evsel, cpu); > } > > +int perf_evsel__mmap(struct perf_evsel *evsel, int pages) > +{ > + int ret, cpu, thread; > + struct perf_mmap_param mp = { > + .prot = PROT_READ | PROT_WRITE, > + .mask = (pages * page_size) - 1, > + }; > + > + if (evsel->fd == NULL) > + return -EINVAL; > + > + if (evsel->mmap == NULL && > + perf_evsel__alloc_mmap(evsel, xyarray__max_x(evsel->fd), xyarray__max_y(evsel->fd)) < 0) > + return -ENOMEM; > + > + for (cpu = 0; cpu < xyarray__max_x(evsel->fd); cpu++) { > + for (thread = 0; thread < xyarray__max_y(evsel->fd); thread++) { > + int fd = FD(evsel, cpu, thread); > + struct perf_mmap *map = MMAP(evsel, cpu, thread); > + > + if (fd < 0) > + continue; > + > + perf_mmap__init(map, NULL, false, NULL); > + > + ret = perf_mmap__mmap(map, &mp, fd, cpu); > + if (ret) > + return -1; > + } > + } > + > + return 0; > +} Where is the counterpart? I.e. perf_evsel__munmap(), and it should be called if perf_evsel__mmap() fails, right? - Arnaldo > +void *perf_evsel__mmap_base(struct perf_evsel *evsel, int cpu, int thread) > +{ > + if (FD(evsel, cpu, thread) < 0 || MMAP(evsel, cpu, thread) == NULL) > + return NULL; > + > + return MMAP(evsel, cpu, thread)->base; > +} > + > int perf_evsel__read_size(struct perf_evsel *evsel) > { > u64 read_format = evsel->attr.read_format; > diff --git a/tools/lib/perf/include/internal/evsel.h b/tools/lib/perf/include/internal/evsel.h > index 1ffd083b235e..1c067d088bc6 100644 > --- a/tools/lib/perf/include/internal/evsel.h > +++ b/tools/lib/perf/include/internal/evsel.h > @@ -41,6 +41,7 @@ struct perf_evsel { > struct perf_cpu_map *own_cpus; > struct perf_thread_map *threads; > struct xyarray *fd; > + struct xyarray *mmap; > struct xyarray *sample_id; > u64 *id; > u32 ids; > diff --git a/tools/lib/perf/include/perf/evsel.h b/tools/lib/perf/include/perf/evsel.h > index c82ec39a4ad0..9f5265f2f39f 100644 > --- a/tools/lib/perf/include/perf/evsel.h > +++ b/tools/lib/perf/include/perf/evsel.h > @@ -27,6 +27,8 @@ LIBPERF_API int perf_evsel__open(struct perf_evsel *evsel, struct perf_cpu_map * > struct perf_thread_map *threads); > LIBPERF_API void perf_evsel__close(struct perf_evsel *evsel); > LIBPERF_API void perf_evsel__close_cpu(struct perf_evsel *evsel, int cpu); > +LIBPERF_API int perf_evsel__mmap(struct perf_evsel *evsel, int pages); > +LIBPERF_API void *perf_evsel__mmap_base(struct perf_evsel *evsel, int cpu, int thread); > LIBPERF_API int perf_evsel__read(struct perf_evsel *evsel, int cpu, int thread, > struct perf_counts_values *count); > LIBPERF_API int perf_evsel__enable(struct perf_evsel *evsel); > diff --git a/tools/lib/perf/libperf.map b/tools/lib/perf/libperf.map > index 7be1af8a546c..0b993de15830 100644 > --- a/tools/lib/perf/libperf.map > +++ b/tools/lib/perf/libperf.map > @@ -23,6 +23,8 @@ LIBPERF_0.0.1 { > perf_evsel__disable; > perf_evsel__open; > perf_evsel__close; > + perf_evsel__mmap; > + perf_evsel__mmap_base; > perf_evsel__read; > perf_evsel__cpus; > perf_evsel__threads; > -- > 2.27.0 > -- - Arnaldo