From patchwork Fri Apr 2 05:57:45 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Manish Varma X-Patchwork-Id: 12180311 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=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL 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 29015C433B4 for ; Fri, 2 Apr 2021 05:57:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E2A1B610CE for ; Fri, 2 Apr 2021 05:57:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229742AbhDBF5v (ORCPT ); Fri, 2 Apr 2021 01:57:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48366 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229518AbhDBF5u (ORCPT ); Fri, 2 Apr 2021 01:57:50 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E557EC0613E6 for ; Thu, 1 Apr 2021 22:57:49 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id d1so8261578ybj.15 for ; Thu, 01 Apr 2021 22:57:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=LPDjYVsuuz78ydcsF2TccRXebl6RyftwNS4xQthlRJU=; b=AW7AFbFdCw9ZjpwVkLM9vCH4RzMUNjrWeyDwr+/rCz/5buvedH8Y8rVLgFmcvMSqLA dsX4p/CXRV3lsUYOi4SeM+902Qecnohw7Bl5hHCHzQLqnpxSu+SGSaAQ6yViYFqHPH9L kOdBq+pTBHTuI/1SFKZJtVT0t582Wqz/RNh3uQlO6XEDdRFkBK1fW3TGbgnW1B5cXnpL P2OV7pXyMA/Q/TnvS28INtn2OrRrbwOfh7cjke6EUG1Qmsh0n2aEBl7/0fmx0+4Qfk2r sU5BBfKHBYivpVDDPDCBj3rz0jpP90iNw5TpaMtJlwEsKfFizFTTTiTVjP4A+FwtAFwJ yOHA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=LPDjYVsuuz78ydcsF2TccRXebl6RyftwNS4xQthlRJU=; b=Yit/GEyjJsvxIq25Y0d7KJAUoIrCVHGQYdqKrjBpg/XlH9siJ5ICvYWMjBq+XGrDHk ZsafXCzn2Q4oV8tNXeIh6n6nFcF41wGWz4OPerNdUOhlQUjvpeQe/s9Hl/UbOnzzMMZ/ ulAXlRTIgBbflqwd/eZ77hLHtkZ4clNdwZWbObwVmofYweBvSM/k5Atrj3xUWmgkx2hq fOqNn0rTtRvyxfThvTpOmpppBoDDe04WDAqXHkqOFTAobQbzZ/6S1OqamSnYFd6Eoj4T kP+qWVOs1dx3/NvE5f56340byH/Aar4Tc8Dm1hiB0FYFHHR/Xuh7ZKUwIWbtZMbSdw1T +3Kw== X-Gm-Message-State: AOAM533bt5/pE1QL/qPDiW5lKAlpgzvAIoic31JuQXFT/LQPfD3bo0Jc DsYM9jCcKVwayq9LdQMoHjh5Ht7riI4= X-Google-Smtp-Source: ABdhPJwYotMzhZ8ORbnpzqZuNWOWQ37DFSMdjl0rEsL7ha5ML/+joadSegq1SKDrQJJxJiwlE3ViuaCMC/E= X-Received: from legoland2.mtv.corp.google.com ([2620:15c:211:1:857d:472:1e7f:a7fe]) (user=varmam job=sendgmr) by 2002:a25:34d2:: with SMTP id b201mr3432474yba.307.1617343068996; Thu, 01 Apr 2021 22:57:48 -0700 (PDT) Date: Thu, 1 Apr 2021 22:57:45 -0700 Message-Id: <20210402055745.3690281-1-varmam@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.31.0.208.g409f899ff0-goog Subject: [PATCH v3] fs: Improve eventpoll logging to stop indicting timerfd From: Manish Varma To: Alexander Viro , Thomas Gleixner Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@android.com, Manish Varma , kernel test robot , Kelly Rossmoyer Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org timerfd doesn't create any wakelocks, but eventpoll can. When it does, it names them after the underlying file descriptor, and since all timerfd file descriptors are named "[timerfd]" (which saves memory on systems like desktops with potentially many timerfd instances), all wakesources created as a result of using the eventpoll-on-timerfd idiom are called... "[timerfd]". However, it becomes impossible to tell which "[timerfd]" wakesource is affliated with which process and hence troubleshooting is difficult. This change addresses this problem by changing the way eventpoll wakesources are named: 1) the top-level per-process eventpoll wakesource is now named "epoll:P" (instead of just "eventpoll"), where P, is the PID of the creating process. 2) individual per-underlying-filedescriptor eventpoll wakesources are now named "epollitemN:P.F", where N is a unique ID token and P is PID of the creating process and F is the name of the underlying file descriptor. All together that should be splitted up into a change to eventpoll and timerfd (or other file descriptors). Reported-by: kernel test robot Co-developed-by: Kelly Rossmoyer Signed-off-by: Kelly Rossmoyer Signed-off-by: Manish Varma --- drivers/base/power/wakeup.c | 10 ++++++++-- fs/eventpoll.c | 10 ++++++++-- include/linux/pm_wakeup.h | 4 ++-- 3 files changed, 18 insertions(+), 6 deletions(-) diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c index 01057f640233..3628536c67a5 100644 --- a/drivers/base/power/wakeup.c +++ b/drivers/base/power/wakeup.c @@ -216,13 +216,19 @@ EXPORT_SYMBOL_GPL(wakeup_source_remove); /** * wakeup_source_register - Create wakeup source and add it to the list. * @dev: Device this wakeup source is associated with (or NULL if virtual). - * @name: Name of the wakeup source to register. + * @fmt: format string for the wakeup source name */ struct wakeup_source *wakeup_source_register(struct device *dev, - const char *name) + const char *fmt, ...) { struct wakeup_source *ws; int ret; + char name[128]; + va_list args; + + va_start(args, fmt); + vsnprintf(name, sizeof(name), fmt, args); + va_end(args); ws = wakeup_source_create(name); if (ws) { diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 7df8c0fa462b..7c35987a8887 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -312,6 +312,7 @@ struct ctl_table epoll_table[] = { }; #endif /* CONFIG_SYSCTL */ +static atomic_t wakesource_create_id = ATOMIC_INIT(0); static const struct file_operations eventpoll_fops; static inline int is_file_epoll(struct file *f) @@ -1451,15 +1452,20 @@ static int ep_create_wakeup_source(struct epitem *epi) { struct name_snapshot n; struct wakeup_source *ws; + pid_t task_pid; + int id; + + task_pid = task_pid_nr(current); if (!epi->ep->ws) { - epi->ep->ws = wakeup_source_register(NULL, "eventpoll"); + epi->ep->ws = wakeup_source_register(NULL, "epoll:%d", task_pid); if (!epi->ep->ws) return -ENOMEM; } + id = atomic_inc_return(&wakesource_create_id); take_dentry_name_snapshot(&n, epi->ffd.file->f_path.dentry); - ws = wakeup_source_register(NULL, n.name.name); + ws = wakeup_source_register(NULL, "epollitem%d:%d.%s", id, task_pid, n.name.name); release_dentry_name_snapshot(&n); if (!ws) diff --git a/include/linux/pm_wakeup.h b/include/linux/pm_wakeup.h index aa3da6611533..cb91c84f6f08 100644 --- a/include/linux/pm_wakeup.h +++ b/include/linux/pm_wakeup.h @@ -95,7 +95,7 @@ extern void wakeup_source_destroy(struct wakeup_source *ws); extern void wakeup_source_add(struct wakeup_source *ws); extern void wakeup_source_remove(struct wakeup_source *ws); extern struct wakeup_source *wakeup_source_register(struct device *dev, - const char *name); + const char *fmt, ...); extern void wakeup_source_unregister(struct wakeup_source *ws); extern int wakeup_sources_read_lock(void); extern void wakeup_sources_read_unlock(int idx); @@ -137,7 +137,7 @@ static inline void wakeup_source_add(struct wakeup_source *ws) {} static inline void wakeup_source_remove(struct wakeup_source *ws) {} static inline struct wakeup_source *wakeup_source_register(struct device *dev, - const char *name) + const char *fmt, ...) { return NULL; }