From nobody Tue Dec 16 20:00:43 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C0F64CDB47E for ; Fri, 13 Oct 2023 18:41:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231450AbjJMSl2 (ORCPT ); Fri, 13 Oct 2023 14:41:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43578 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229518AbjJMSl1 (ORCPT ); Fri, 13 Oct 2023 14:41:27 -0400 Received: from mx1.sberdevices.ru (mx1.sberdevices.ru [37.18.73.165]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3CD0BC0; Fri, 13 Oct 2023 11:41:23 -0700 (PDT) Received: from p-infra-ksmg-sc-msk01 (localhost [127.0.0.1]) by mx1.sberdevices.ru (Postfix) with ESMTP id D549A100006; Fri, 13 Oct 2023 21:41:19 +0300 (MSK) DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.sberdevices.ru D549A100006 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=salutedevices.com; s=mail; t=1697222479; bh=8QIY7MI/xX/BChuarEslhWbVX0P4jo1X9m5opcLx4p8=; h=From:To:Subject:Date:Message-ID:MIME-Version:Content-Type:From; b=GXX7Q0O4xMMBb+EwhZVsQvtUewh+HJUSqjR9DdHt4eNLdwS8iPF2d7EkiH1eH1S3Q XOB4yAQqlPWmBV4ZmJ6doZGh+ZDR9Rk4ooH1GJ4LpVq0qwkbmVCn1nwL/WapRlqob+ 62JMxW2z6d5n4zoZTNBu750rtaJdJLQy4J02qLjnm2nHWzBo75vD1SyEGVz31z4G4m I8dfnoznp8JmX2IUVGlEEzjlwhb3fc7VPtkYXSgRvoIn9cfPj5yGTC8DUChXN6ySvi vi/xGSTWmbyyT0izXDPIfup/WoTDWDF/5DJ67MbdGnDmdjHgv37GhoHaA98PIIImvu gEVPuhaf3jbaA== Received: from p-i-exch-sc-m01.sberdevices.ru (p-i-exch-sc-m01.sberdevices.ru [172.16.192.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.sberdevices.ru (Postfix) with ESMTPS; Fri, 13 Oct 2023 21:41:18 +0300 (MSK) Received: from localhost.localdomain (100.64.160.123) by p-i-exch-sc-m01.sberdevices.ru (172.16.192.107) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.30; Fri, 13 Oct 2023 21:41:17 +0300 From: Dmitry Rokosov To: , , , , , CC: , , , , , , Dmitry Rokosov Subject: [PATCH v1] tools/cgroup: introduce cgroup v2 memory.events listener Date: Fri, 13 Oct 2023 21:41:07 +0300 Message-ID: <20231013184107.28734-1-ddrokosov@salutedevices.com> X-Mailer: git-send-email 2.36.0 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [100.64.160.123] X-ClientProxiedBy: p-i-exch-sc-m01.sberdevices.ru (172.16.192.107) To p-i-exch-sc-m01.sberdevices.ru (172.16.192.107) X-KSMG-Rule-ID: 10 X-KSMG-Message-Action: clean X-KSMG-AntiSpam-Lua-Profiles: 180616 [Oct 13 2023] X-KSMG-AntiSpam-Version: 6.0.0.2 X-KSMG-AntiSpam-Envelope-From: ddrokosov@salutedevices.com X-KSMG-AntiSpam-Rate: 0 X-KSMG-AntiSpam-Status: not_detected X-KSMG-AntiSpam-Method: none X-KSMG-AntiSpam-Auth: dkim=none X-KSMG-AntiSpam-Info: LuaCore: 539 539 807534d9021bfe9ca369c363d15ac993cd93d4d9, {Tracking_from_domain_doesnt_match_to}, d41d8cd98f00b204e9800998ecf8427e.com:7.1.1;127.0.0.199:7.1.2;p-i-exch-sc-m01.sberdevices.ru:7.1.1,5.0.1;100.64.160.123:7.1.2;salutedevices.com:7.1.1, FromAlignment: s, ApMailHostAddress: 100.64.160.123 X-MS-Exchange-Organization-SCL: -1 X-KSMG-AntiSpam-Interceptor-Info: scan successful X-KSMG-AntiPhishing: Clean X-KSMG-LinksScanning: Clean X-KSMG-AntiVirus: Kaspersky Secure Mail Gateway, version 2.0.1.6960, bases: 2023/10/13 17:38:00 #22183193 X-KSMG-AntiVirus-Status: Clean, skipped Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" This is a simple listener for memory events that handles counter changes in runtime. It can be set up for a specific memory cgroup v2. The output example: =3D=3D=3D=3D=3D $ /tmp/cgroup_v2_event_listener test Initialized MEMCG events with counters: MEMCG events: low: 0 high: 0 max: 0 oom: 0 oom_kill: 0 oom_group_kill: 0 Started monitoring memory events from '/sys/fs/cgroup/test/memory.events'... Received event in /sys/fs/cgroup/test/memory.events: *** 1 MEMCG oom_kill event, change counter 0 =3D> 1 Received event in /sys/fs/cgroup/test/memory.events: *** 1 MEMCG oom_kill event, change counter 1 =3D> 2 Received event in /sys/fs/cgroup/test/memory.events: *** 1 MEMCG oom_kill event, change counter 2 =3D> 3 Received event in /sys/fs/cgroup/test/memory.events: *** 1 MEMCG oom_kill event, change counter 3 =3D> 4 Received event in /sys/fs/cgroup/test/memory.events: *** 2 MEMCG max events, change counter 0 =3D> 2 Received event in /sys/fs/cgroup/test/memory.events: *** 8 MEMCG max events, change counter 2 =3D> 10 *** 1 MEMCG oom event, change counter 0 =3D> 1 Received event in /sys/fs/cgroup/test/memory.events: *** 1 MEMCG oom_kill event, change counter 4 =3D> 5 ^CExiting cgroup v2 event listener... =3D=3D=3D=3D=3D Signed-off-by: Dmitry Rokosov --- tools/cgroup/Makefile | 4 +- tools/cgroup/cgroup_v2_event_listener.c | 330 ++++++++++++++++++++++++ 2 files changed, 332 insertions(+), 2 deletions(-) create mode 100644 tools/cgroup/cgroup_v2_event_listener.c diff --git a/tools/cgroup/Makefile b/tools/cgroup/Makefile index ffca068e4a76..86bd357a8f54 100644 --- a/tools/cgroup/Makefile +++ b/tools/cgroup/Makefile @@ -3,9 +3,9 @@ =20 CFLAGS =3D -Wall -Wextra =20 -all: cgroup_event_listener +all: cgroup_event_listener cgroup_v2_event_listener %: %.c $(CC) $(CFLAGS) -o $@ $^ =20 clean: - $(RM) cgroup_event_listener + $(RM) cgroup_event_listener cgroup_v2_event_listener diff --git a/tools/cgroup/cgroup_v2_event_listener.c b/tools/cgroup/cgroup_= v2_event_listener.c new file mode 100644 index 000000000000..987261db5369 --- /dev/null +++ b/tools/cgroup/cgroup_v2_event_listener.c @@ -0,0 +1,330 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * cgroup_v2_event_listener.c - Simple listener of cgroup v2 memory.events + * + * Copyright (c) 2023, SaluteDevices. All Rights Reserved. + * + * Author: Dmitry Rokosov + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define MEMCG_EVENTS "memory.events" + +/* Size of buffer to use when reading inotify events */ +#define INOTIFY_BUFFER_SIZE 8192 + +#define INOTIFY_EVENT_NEXT(event, length) ({ \ + (length) -=3D sizeof(*(event)) + (event)->len; \ + (event)++; \ +}) + +#define INOTIFY_EVENT_OK(event, length) ((length) >=3D (ssize_t)sizeof(*(e= vent))) + +#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof(arr[0])) + +struct memcg_counters { + long low; + long high; + long max; + long oom; + long oom_kill; + long oom_group_kill; +}; + +struct memcg_events { + struct memcg_counters counters; + char path[PATH_MAX]; + int inotify_fd; + int inotify_wd; +}; + +static void print_memcg_counters(const struct memcg_counters *counters) +{ + printf("MEMCG events:\n"); + printf("\tlow: %ld\n", counters->low); + printf("\thigh: %ld\n", counters->high); + printf("\tmax: %ld\n", counters->max); + printf("\toom: %ld\n", counters->oom); + printf("\toom_kill: %ld\n", counters->oom_kill); + printf("\toom_group_kill: %ld\n", counters->oom_group_kill); +} + +static int get_memcg_counter(char *line, const char *name, long *counter) +{ + size_t len =3D strlen(name); + char *endptr; + long tmp; + + if (memcmp(line, name, len)) { + warnx("Counter line %s has wrong name, %s is expected", + line, name); + return -EINVAL; + } + + /* skip the whitespace delimiter */ + len +=3D 1; + + errno =3D 0; + tmp =3D strtol(&line[len], &endptr, 10); + if (((tmp =3D=3D LONG_MAX || tmp =3D=3D LONG_MIN) && errno =3D=3D ERANGE)= || + (errno && !tmp)) { + warnx("Failed to parse: %s", &line[len]); + return -ERANGE; + } + + if (endptr =3D=3D &line[len]) { + warnx("Not digits were found in line %s", &line[len]); + return -EINVAL; + } + + if (!(*endptr =3D=3D '\0' || (*endptr =3D=3D '\n' && *++endptr =3D=3D '\0= '))) { + warnx("Further characters after number: %s", endptr); + return -EINVAL; + } + + *counter =3D tmp; + + return 0; +} + +static int read_memcg_events(struct memcg_events *events, bool show_diff) +{ + FILE *fp =3D fopen(events->path, "re"); + size_t i; + int ret =3D 0; + bool any_new_events =3D false; + char *line =3D NULL; + size_t len =3D 0; + struct memcg_counters new_counters; + struct memcg_counters *counters =3D &events->counters; + struct { + const char *name; + long *new; + long *old; + } map[] =3D { + { + .name =3D "low", + .new =3D &new_counters.low, + .old =3D &counters->low, + }, + { + .name =3D "high", + .new =3D &new_counters.high, + .old =3D &counters->high, + }, + { + .name =3D "max", + .new =3D &new_counters.max, + .old =3D &counters->max, + }, + { + .name =3D "oom", + .new =3D &new_counters.oom, + .old =3D &counters->oom, + }, + { + .name =3D "oom_kill", + .new =3D &new_counters.oom_kill, + .old =3D &counters->oom_kill, + }, + { + .name =3D "oom_group_kill", + .new =3D &new_counters.oom_group_kill, + .old =3D &counters->oom_group_kill, + }, + }; + + if (!fp) { + warn("Failed to open memcg events file %s", events->path); + return -EBADF; + } + + /* Read new values for memcg counters */ + for (i =3D 0; i < ARRAY_SIZE(map); ++i) { + ssize_t nread; + + errno =3D 0; + nread =3D getline(&line, &len, fp); + if (nread =3D=3D -1) { + if (errno) { + warn("Failed to read line for counter %s", + map[i].name); + ret =3D -EIO; + goto exit; + } + + break; + } + + ret =3D get_memcg_counter(line, map[i].name, map[i].new); + if (ret) { + warnx("Failed to get counter value from line %s", line); + goto exit; + } + } + + for (i =3D 0; i < ARRAY_SIZE(map); ++i) { + long diff; + + if (*map[i].new > *map[i].old) { + diff =3D *map[i].new - *map[i].old; + + if (show_diff) + printf("*** %ld MEMCG %s event%s, " + "change counter %ld =3D> %ld\n", + diff, map[i].name, + (diff =3D=3D 1) ? "" : "s", + *map[i].old, *map[i].new); + + *map[i].old +=3D diff; + any_new_events =3D true; + } + } + + if (show_diff && !any_new_events) + printf("*** No new untracked memcg events available\n"); + +exit: + free(line); + fclose(fp); + + return ret; +} + +static void process_memcg_events(struct memcg_events *events, + struct inotify_event *event) +{ + int ret; + + if (events->inotify_wd !=3D event->wd) { + warnx("Unknown inotify event %d, should be %d", event->wd, + events->inotify_wd); + return; + } + + printf("Received event in %s:\n", events->path); + + if (!(event->mask & IN_MODIFY)) { + warnx("No IN_MODIFY event, skip it"); + return; + } + + ret =3D read_memcg_events(events, /* show_diff =3D */true); + if (ret) + warnx("Can't read memcg events"); +} + +static void monitor_events(struct memcg_events *events) +{ + struct pollfd fds[1]; + int ret; + + printf("Started monitoring memory events from '%s'...\n", events->path); + + fds[0].fd =3D events->inotify_fd; + fds[0].events =3D POLLIN; + + for (;;) { + ret =3D poll(fds, ARRAY_SIZE(fds), -1); + if (ret < 0 && errno !=3D EAGAIN) + err(EXIT_FAILURE, "Can't poll memcg events (%d)", ret); + + if (fds[0].revents & POLLERR) + err(EXIT_FAILURE, "Got POLLERR during monitor events"); + + if (fds[0].revents & POLLIN) { + struct inotify_event *event; + char buffer[INOTIFY_BUFFER_SIZE]; + ssize_t length; + + length =3D read(fds[0].fd, buffer, INOTIFY_BUFFER_SIZE); + if (length <=3D 0) + continue; + + event =3D (struct inotify_event *)buffer; + while (INOTIFY_EVENT_OK(event, length)) { + process_memcg_events(events, event); + event =3D INOTIFY_EVENT_NEXT(event, length); + } + } + } +} + +static int initialize_memcg_events(struct memcg_events *events, + const char *cgroup) +{ + int ret; + + memset(events, 0, sizeof(struct memcg_events)); + + ret =3D snprintf(events->path, PATH_MAX, + "/sys/fs/cgroup/%s/memory.events", cgroup); + if (ret >=3D PATH_MAX) { + warnx("Path to cgroup memory.events is too long"); + return -EMSGSIZE; + } else if (ret < 0) { + warn("Can't generate cgroup event full name"); + return ret; + } + + ret =3D read_memcg_events(events, /* show_diff =3D */false); + if (ret) { + warnx("Failed to read initial memcg events state (%d)", ret); + return ret; + } + + events->inotify_fd =3D inotify_init(); + if (events->inotify_fd < 0) { + warn("Failed to setup new inotify device"); + return -EMFILE; + } + + events->inotify_wd =3D inotify_add_watch(events->inotify_fd, + events->path, IN_MODIFY); + if (events->inotify_wd < 0) { + warn("Couldn't add monitor in dir %s", events->path); + return -EIO; + } + + printf("Initialized MEMCG events with counters:\n"); + print_memcg_counters(&events->counters); + + return 0; +} + +static void cleanup_memcg_events(struct memcg_events *events) +{ + inotify_rm_watch(events->inotify_fd, events->inotify_wd); + close(events->inotify_fd); +} + +int main(int argc, const char **argv) +{ + struct memcg_events events; + ssize_t ret; + + if (argc !=3D 2) + errx(EXIT_FAILURE, "Usage: %s ", argv[0]); + + ret =3D initialize_memcg_events(&events, argv[1]); + if (ret) + errx(EXIT_FAILURE, "Can't initialize memcg events (%zd)", ret); + + monitor_events(&events); + + cleanup_memcg_events(&events); + + printf("Exiting cgroup v2 event listener...\n"); + + return EXIT_SUCCESS; +} --=20 2.36.0