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b=afuAoHsUSSaWfJ0EVXtxzDQO6En30JUuysIxxye+1XlE7NzesjZW3wnqpEN2FrDtARb9lI 4S7yvOd/HQFJBl1UxmTMW5kIpZadEtwjFy0A+I9tYfBE/JNAML1+1Lf59G6qpcjrFcOUOO Su8w6yWg3z3u/eVP4Rk3OE6UQpU8ACc= Received: from imap2.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap2.dmz-prg2.suse.org (Postfix) with ESMTPS id BCB7013A92; Fri, 5 Apr 2024 17:05:50 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap2.dmz-prg2.suse.org with ESMTPSA id WMJiLW4vEGYteAAAn2gu4w (envelope-from ); Fri, 05 Apr 2024 17:05:50 +0000 From: =?utf-8?q?Michal_Koutn=C3=BD?= To: cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: Tejun Heo , Zefan Li , Johannes Weiner , Jonathan Corbet , Shuah Khan Subject: [RFC PATCH v3 1/9] cgroup/pids: Remove superfluous zeroing Date: Fri, 5 Apr 2024 19:05:40 +0200 Message-ID: <20240405170548.15234-2-mkoutny@suse.com> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240405170548.15234-1-mkoutny@suse.com> References: <20240405170548.15234-1-mkoutny@suse.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Rspamd-Action: no action X-Rspamd-Server: rspamd1.dmz-prg2.suse.org X-Spam-Level: X-Spamd-Result: default: False [-0.51 / 50.00]; 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They are zeroed already and atomic64_t does not need special initialization (cf kernel/trace/trace_clock.c:trace_counter). Signed-off-by: Michal Koutný --- kernel/cgroup/pids.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/kernel/cgroup/pids.c b/kernel/cgroup/pids.c index 7695e60bcb40..0e5ec7d59b4d 100644 --- a/kernel/cgroup/pids.c +++ b/kernel/cgroup/pids.c @@ -75,9 +75,7 @@ pids_css_alloc(struct cgroup_subsys_state *parent) if (!pids) return ERR_PTR(-ENOMEM); - atomic64_set(&pids->counter, 0); atomic64_set(&pids->limit, PIDS_MAX); - atomic64_set(&pids->events_limit, 0); return &pids->css; } From patchwork Fri Apr 5 17:05:41 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Michal_Koutn=C3=BD?= X-Patchwork-Id: 786605 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.223.130]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B183F171645; Fri, 5 Apr 2024 17:05:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; 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Fri, 5 Apr 2024 17:05:51 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap2.dmz-prg2.suse.org with ESMTPSA id 6JcFAm8vEGYteAAAn2gu4w (envelope-from ); Fri, 05 Apr 2024 17:05:51 +0000 From: =?utf-8?q?Michal_Koutn=C3=BD?= To: cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: Tejun Heo , Zefan Li , Johannes Weiner , Jonathan Corbet , Shuah Khan Subject: [RFC PATCH v3 2/9] cgroup/pids: Separate semantics of pids.events related to pids.max Date: Fri, 5 Apr 2024 19:05:41 +0200 Message-ID: <20240405170548.15234-3-mkoutny@suse.com> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240405170548.15234-1-mkoutny@suse.com> References: <20240405170548.15234-1-mkoutny@suse.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Flag: NO X-Spam-Score: -3.30 X-Spam-Level: X-Spamd-Result: default: False [-3.30 / 50.00]; BAYES_HAM(-3.00)[100.00%]; MID_CONTAINS_FROM(1.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-0.999]; MIME_GOOD(-0.10)[text/plain]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; RCPT_COUNT_SEVEN(0.00)[9]; RCVD_TLS_ALL(0.00)[]; FUZZY_BLOCKED(0.00)[rspamd.com]; TO_DN_SOME(0.00)[]; FROM_HAS_DN(0.00)[]; DKIM_SIGNED(0.00)[suse.com:s=susede1]; FROM_EQ_ENVFROM(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; DBL_BLOCKED_OPENRESOLVER(0.00)[imap2.dmz-prg2.suse.org:helo, imap2.dmz-prg2.suse.org:rdns, suse.com:email, pids.events:url] Currently, when pids.max limit is breached in the hierarchy, the event is counted and reported in the cgroup where the forking task resides. This decouples the limit and the notification caused by the limit making it hard to detect when the actual limit was effected. Let's introduce new events: max The number of times the limit of the cgroup was hit. max.imposed The number of times fork failed in the cgroup because of self or ancestor limit. Since it changes semantics of the original "max" event, we introduce this change only in the v2 API of the controller. Signed-off-by: Michal Koutný --- Documentation/admin-guide/cgroup-v1/pids.rst | 3 +- Documentation/admin-guide/cgroup-v2.rst | 12 ++++ kernel/cgroup/pids.c | 71 ++++++++++++++++---- 3 files changed, 73 insertions(+), 13 deletions(-) diff --git a/Documentation/admin-guide/cgroup-v1/pids.rst b/Documentation/admin-guide/cgroup-v1/pids.rst index 6acebd9e72c8..0f9f9a7b1f6c 100644 --- a/Documentation/admin-guide/cgroup-v1/pids.rst +++ b/Documentation/admin-guide/cgroup-v1/pids.rst @@ -36,7 +36,8 @@ superset of parent/child/pids.current. The pids.events file contains event counters: - - max: Number of times fork failed because limit was hit. + - max: Number of times fork failed in the cgroup because limit was hit in + self or ancestors. Example ------- diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index 17e6e9565156..4f04538d688c 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -2186,6 +2186,18 @@ PID Interface Files The number of processes currently in the cgroup and its descendants. + pids.events + A read-only flat-keyed file which exists on non-root cgroups. Unless + specified otherwise, a value change in this file generates a file modified + event. The following entries are defined. + + max + The number of times the limit of the cgroup was hit. + + max.imposed + The number of times fork failed in the cgroup because of self + or ancestor limit. + Organisational operations are not blocked by cgroup policies, so it is possible to have pids.current > pids.max. This can be done by either setting the limit to be smaller than pids.current, or attaching enough diff --git a/kernel/cgroup/pids.c b/kernel/cgroup/pids.c index 0e5ec7d59b4d..471562609eef 100644 --- a/kernel/cgroup/pids.c +++ b/kernel/cgroup/pids.c @@ -38,6 +38,14 @@ #define PIDS_MAX (PID_MAX_LIMIT + 1ULL) #define PIDS_MAX_STR "max" +enum pidcg_event { + /* Fork failed in subtree because this pids_cgroup limit was hit. */ + PIDCG_MAX, + /* Fork failed in this pids_cgroup because ancestor limit was hit. */ + PIDCG_MAX_IMPOSED, + NR_PIDCG_EVENTS, +}; + struct pids_cgroup { struct cgroup_subsys_state css; @@ -52,8 +60,7 @@ struct pids_cgroup { /* Handle for "pids.events" */ struct cgroup_file events_file; - /* Number of times fork failed because limit was hit. */ - atomic64_t events_limit; + atomic64_t events[NR_PIDCG_EVENTS]; }; static struct pids_cgroup *css_pids(struct cgroup_subsys_state *css) @@ -148,12 +155,13 @@ static void pids_charge(struct pids_cgroup *pids, int num) * pids_try_charge - hierarchically try to charge the pid count * @pids: the pid cgroup state * @num: the number of pids to charge + * @fail: storage of pid cgroup causing the fail * * This function follows the set limit. It will fail if the charge would cause * the new value to exceed the hierarchical limit. Returns 0 if the charge * succeeded, otherwise -EAGAIN. */ -static int pids_try_charge(struct pids_cgroup *pids, int num) +static int pids_try_charge(struct pids_cgroup *pids, int num, struct pids_cgroup **fail) { struct pids_cgroup *p, *q; @@ -166,9 +174,10 @@ static int pids_try_charge(struct pids_cgroup *pids, int num) * p->limit is %PIDS_MAX then we know that this test will never * fail. */ - if (new > limit) + if (new > limit) { + *fail = p; goto revert; - + } /* * Not technically accurate if we go over limit somewhere up * the hierarchy, but that's tolerable for the watermark. @@ -236,7 +245,7 @@ static void pids_cancel_attach(struct cgroup_taskset *tset) static int pids_can_fork(struct task_struct *task, struct css_set *cset) { struct cgroup_subsys_state *css; - struct pids_cgroup *pids; + struct pids_cgroup *pids, *pids_over_limit; int err; if (cset) @@ -244,15 +253,23 @@ static int pids_can_fork(struct task_struct *task, struct css_set *cset) else css = task_css_check(current, pids_cgrp_id, true); pids = css_pids(css); - err = pids_try_charge(pids, 1); + err = pids_try_charge(pids, 1, &pids_over_limit); if (err) { - /* Only log the first time events_limit is incremented. */ - if (atomic64_inc_return(&pids->events_limit) == 1) { + /* compatibility on v1 where events were notified in leaves. */ + if (!cgroup_subsys_on_dfl(pids_cgrp_subsys)) + pids_over_limit = pids; + + /* Only log the first time limit is hit. */ + if (atomic64_inc_return(&pids->events[PIDCG_MAX_IMPOSED]) == 1) { pr_info("cgroup: fork rejected by pids controller in "); - pr_cont_cgroup_path(css->cgroup); + pr_cont_cgroup_path(pids->css.cgroup); pr_cont("\n"); } + atomic64_inc(&pids_over_limit->events[PIDCG_MAX]); + cgroup_file_notify(&pids->events_file); + if (pids_over_limit != pids) + cgroup_file_notify(&pids_over_limit->events_file); } return err; } @@ -341,7 +358,16 @@ static int pids_events_show(struct seq_file *sf, void *v) { struct pids_cgroup *pids = css_pids(seq_css(sf)); - seq_printf(sf, "max %lld\n", (s64)atomic64_read(&pids->events_limit)); + seq_printf(sf, "max %lld\n", (s64)atomic64_read(&pids->events[PIDCG_MAX])); + seq_printf(sf, "max.imposed %lld\n", (s64)atomic64_read(&pids->events[PIDCG_MAX_IMPOSED])); + return 0; +} + +static int pids_events_show_legacy(struct seq_file *sf, void *v) +{ + struct pids_cgroup *pids = css_pids(seq_css(sf)); + + seq_printf(sf, "max%lld\n", (s64)atomic64_read(&pids->events[PIDCG_MAX_IMPOSED])); return 0; } @@ -371,6 +397,27 @@ static struct cftype pids_files[] = { { } /* terminate */ }; +static struct cftype pids_files_legacy[] = { + { + .name = "max", + .write = pids_max_write, + .seq_show = pids_max_show, + .flags = CFTYPE_NOT_ON_ROOT, + }, + { + .name = "current", + .read_s64 = pids_current_read, + .flags = CFTYPE_NOT_ON_ROOT, + }, + { + .name = "events", + .seq_show = pids_events_show_legacy, + .file_offset = offsetof(struct pids_cgroup, events_file), + .flags = CFTYPE_NOT_ON_ROOT, + }, + { } /* terminate */ +}; + struct cgroup_subsys pids_cgrp_subsys = { .css_alloc = pids_css_alloc, .css_free = pids_css_free, @@ -379,7 +426,7 @@ struct cgroup_subsys pids_cgrp_subsys = { .can_fork = pids_can_fork, .cancel_fork = pids_cancel_fork, .release = pids_release, - .legacy_cftypes = pids_files, .dfl_cftypes = pids_files, + .legacy_cftypes = pids_files_legacy, .threaded = true, }; 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Fri, 5 Apr 2024 17:05:51 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap2.dmz-prg2.suse.org with ESMTPSA id QGa1DW8vEGYteAAAn2gu4w (envelope-from ); Fri, 05 Apr 2024 17:05:51 +0000 From: =?utf-8?q?Michal_Koutn=C3=BD?= To: cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: Tejun Heo , Zefan Li , Johannes Weiner , Jonathan Corbet , Shuah Khan Subject: [RFC PATCH v3 3/9] cgroup/pids: Make event counters hierarchical Date: Fri, 5 Apr 2024 19:05:42 +0200 Message-ID: <20240405170548.15234-4-mkoutny@suse.com> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240405170548.15234-1-mkoutny@suse.com> References: <20240405170548.15234-1-mkoutny@suse.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Flag: NO X-Spam-Score: -3.30 X-Spam-Level: X-Spamd-Result: default: False [-3.30 / 50.00]; BAYES_HAM(-3.00)[100.00%]; MID_CONTAINS_FROM(1.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-0.999]; MIME_GOOD(-0.10)[text/plain]; RCPT_COUNT_SEVEN(0.00)[9]; RCVD_VIA_SMTP_AUTH(0.00)[]; MIME_TRACE(0.00)[0:+]; TO_DN_SOME(0.00)[]; ARC_NA(0.00)[]; RCVD_TLS_ALL(0.00)[]; DKIM_SIGNED(0.00)[suse.com:s=susede1]; FUZZY_BLOCKED(0.00)[rspamd.com]; FROM_HAS_DN(0.00)[]; R_RATELIMIT(0.00)[to_ip_from(RLqco6ghhk4ot65weiawc5nc38)]; FROM_EQ_ENVFROM(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.com:email, pids.events:url, imap2.dmz-prg2.suse.org:helo, imap2.dmz-prg2.suse.org:rdns] The pids.events file should honor the hierarchy, so make the events propagate from their origin up to the root on the unified hierarchy. The v1 behavior remains non-hierarchical. Signed-off-by: Michal Koutný --- Documentation/admin-guide/cgroup-v2.rst | 4 ++- kernel/cgroup/pids.c | 46 ++++++++++++++++--------- 2 files changed, 33 insertions(+), 17 deletions(-) diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index 4f04538d688c..5d4c505cae06 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -2189,7 +2189,9 @@ PID Interface Files pids.events A read-only flat-keyed file which exists on non-root cgroups. Unless specified otherwise, a value change in this file generates a file modified - event. The following entries are defined. + event. Fields in this file are hierarchical and the file modified event + can be generated due to an event down the hierarchy. The following + entries are defined. max The number of times the limit of the cgroup was hit. diff --git a/kernel/cgroup/pids.c b/kernel/cgroup/pids.c index 471562609eef..76c0a97e42da 100644 --- a/kernel/cgroup/pids.c +++ b/kernel/cgroup/pids.c @@ -238,6 +238,34 @@ static void pids_cancel_attach(struct cgroup_taskset *tset) } } +static void pids_event(struct pids_cgroup *pids_forking, + struct pids_cgroup *pids_over_limit) +{ + struct pids_cgroup *p = pids_forking; + bool limit = false; + + /* Only log the first time limit is hit. */ + if (atomic64_inc_return(&p->events[PIDCG_MAX_IMPOSED]) == 1) { + pr_info("cgroup: fork rejected by pids controller in "); + pr_cont_cgroup_path(p->css.cgroup); + pr_cont("\n"); + } + /* Events are only notified in pids_forking on v1 */ + if (!cgroup_subsys_on_dfl(pids_cgrp_subsys)) + return; + + for (; parent_pids(p); p = parent_pids(p)) { + atomic64_inc(&p->events[PIDCG_MAX_IMPOSED]); + + if (p == pids_over_limit) + limit = true; + if (limit) + atomic64_inc(&p->events[PIDCG_MAX]); + + cgroup_file_notify(&p->events_file); + } +} + /* * task_css_check(true) in pids_can_fork() and pids_cancel_fork() relies * on cgroup_threadgroup_change_begin() held by the copy_process(). @@ -254,23 +282,9 @@ static int pids_can_fork(struct task_struct *task, struct css_set *cset) css = task_css_check(current, pids_cgrp_id, true); pids = css_pids(css); err = pids_try_charge(pids, 1, &pids_over_limit); - if (err) { - /* compatibility on v1 where events were notified in leaves. */ - if (!cgroup_subsys_on_dfl(pids_cgrp_subsys)) - pids_over_limit = pids; - - /* Only log the first time limit is hit. */ - if (atomic64_inc_return(&pids->events[PIDCG_MAX_IMPOSED]) == 1) { - pr_info("cgroup: fork rejected by pids controller in "); - pr_cont_cgroup_path(pids->css.cgroup); - pr_cont("\n"); - } - atomic64_inc(&pids_over_limit->events[PIDCG_MAX]); + if (err) + pids_event(pids, pids_over_limit); - cgroup_file_notify(&pids->events_file); - if (pids_over_limit != pids) - cgroup_file_notify(&pids_over_limit->events_file); 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b=BQG5QlckHEHyiAAX6helwYcS4V/BH/xIjs9yrntAOiUJeU1PyVnqK47jpolQB8xiGCl7Zg HF1np1ayrdYwkpU0f95+c4/0Afl6ze4BdqLN6H2J5vq4KvOlSVgvdpG1zZC2E8g5Cf2j7Y eIq1ShwduaI59ymFPoxpyrsfCusVNi4= Received: from imap2.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap2.dmz-prg2.suse.org (Postfix) with ESMTPS id 6969E13AAE; Fri, 5 Apr 2024 17:05:51 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap2.dmz-prg2.suse.org with ESMTPSA id aBEEGW8vEGYteAAAn2gu4w (envelope-from ); Fri, 05 Apr 2024 17:05:51 +0000 From: =?utf-8?q?Michal_Koutn=C3=BD?= To: cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: Tejun Heo , Zefan Li , Johannes Weiner , Jonathan Corbet , Shuah Khan Subject: [RFC PATCH v3 4/9] cgroup/pids: Add pids.events.local Date: Fri, 5 Apr 2024 19:05:43 +0200 Message-ID: <20240405170548.15234-5-mkoutny@suse.com> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240405170548.15234-1-mkoutny@suse.com> References: <20240405170548.15234-1-mkoutny@suse.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Level: X-Spamd-Result: default: False [-0.53 / 50.00]; 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Therefore introduce .local flavor of events file (akin to memory controller) that collects only events relevant to given cgroup. Signed-off-by: Michal Koutný --- kernel/cgroup/pids.c | 41 +++++++++++++++++++++++++++++++++-------- 1 file changed, 33 insertions(+), 8 deletions(-) diff --git a/kernel/cgroup/pids.c b/kernel/cgroup/pids.c index 76c0a97e42da..f5f81274658e 100644 --- a/kernel/cgroup/pids.c +++ b/kernel/cgroup/pids.c @@ -57,10 +57,12 @@ struct pids_cgroup { atomic64_t limit; int64_t watermark; - /* Handle for "pids.events" */ + /* Handles for pids.events[.local] */ struct cgroup_file events_file; + struct cgroup_file events_local_file; atomic64_t events[NR_PIDCG_EVENTS]; + atomic64_t events_local[NR_PIDCG_EVENTS]; }; static struct pids_cgroup *css_pids(struct cgroup_subsys_state *css) @@ -245,11 +247,12 @@ static void pids_event(struct pids_cgroup *pids_forking, bool limit = false; /* Only log the first time limit is hit. */ - if (atomic64_inc_return(&p->events[PIDCG_MAX_IMPOSED]) == 1) { + if (atomic64_inc_return(&p->events_local[PIDCG_MAX_IMPOSED]) == 1) { pr_info("cgroup: fork rejected by pids controller in "); pr_cont_cgroup_path(p->css.cgroup); pr_cont("\n"); } + cgroup_file_notify(&p->events_local_file); /* Events are only notified in pids_forking on v1 */ if (!cgroup_subsys_on_dfl(pids_cgrp_subsys)) return; @@ -257,8 +260,11 @@ static void pids_event(struct pids_cgroup *pids_forking, for (; parent_pids(p); p = parent_pids(p)) { atomic64_inc(&p->events[PIDCG_MAX_IMPOSED]); - if (p == pids_over_limit) + if (p == pids_over_limit) { limit = true; + atomic64_inc(&p->events_local[PIDCG_MAX]); + cgroup_file_notify(&p->events_local_file); + } if (limit) atomic64_inc(&p->events[PIDCG_MAX]); @@ -368,12 +374,25 @@ static s64 pids_peak_read(struct cgroup_subsys_state *css, return READ_ONCE(pids->watermark); } -static int pids_events_show(struct seq_file *sf, void *v) +static int __pids_events_show(struct seq_file *sf, bool local) { struct pids_cgroup *pids = css_pids(seq_css(sf)); + atomic64_t *events = local ? pids->events_local : pids->events; + + seq_printf(sf, "max %lld\n", (s64)atomic64_read(&events[PIDCG_MAX])); + seq_printf(sf, "max.imposed %lld\n", (s64)atomic64_read(&events[PIDCG_MAX_IMPOSED])); + return 0; +} + +static int pids_events_show(struct seq_file *sf, void *v) +{ + __pids_events_show(sf, false); + return 0; +} - seq_printf(sf, "max %lld\n", (s64)atomic64_read(&pids->events[PIDCG_MAX])); - seq_printf(sf, "max.imposed %lld\n", (s64)atomic64_read(&pids->events[PIDCG_MAX_IMPOSED])); +static int pids_events_local_show(struct seq_file *sf, void *v) +{ + __pids_events_show(sf, true); return 0; } @@ -381,7 +400,7 @@ static int pids_events_show_legacy(struct seq_file *sf, void *v) { struct pids_cgroup *pids = css_pids(seq_css(sf)); - seq_printf(sf, "max%lld\n", (s64)atomic64_read(&pids->events[PIDCG_MAX_IMPOSED])); + seq_printf(sf, "max%lld\n", (s64)atomic64_read(&pids->events_local[PIDCG_MAX_IMPOSED])); return 0; } @@ -408,6 +427,12 @@ static struct cftype pids_files[] = { .file_offset = offsetof(struct pids_cgroup, events_file), .flags = CFTYPE_NOT_ON_ROOT, }, + { + .name = "events.local", + .seq_show = pids_events_local_show, + .file_offset = offsetof(struct pids_cgroup, events_file), + .flags = CFTYPE_NOT_ON_ROOT, + }, { } /* terminate */ }; @@ -426,7 +451,7 @@ static struct cftype pids_files_legacy[] = { { .name = "events", .seq_show = pids_events_show_legacy, - .file_offset = offsetof(struct pids_cgroup, events_file), + .file_offset = offsetof(struct pids_cgroup, events_local_file), .flags = CFTYPE_NOT_ON_ROOT, }, { } /* terminate */ From patchwork Fri Apr 5 17:05:44 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Michal_Koutn=C3=BD?= X-Patchwork-Id: 786360 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.223.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 04F79171654; Fri, 5 Apr 2024 17:05:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=195.135.223.131 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712336757; cv=none; b=mZtJp9KNrsTiD/t+pznfVhkQZN4dNzhJ29fWM3rxvkZsUcHQmead0VzR8T2NFDmImSi6+R2OqJy+aJLuI6cXX0g+yJY4ZKhg5SNEU+GYIrLtg1xUjLB+rIqQum669P+7ATS6VdUEyktG79ALFyM4kwe3YnLC+sWIc87JNSPKFgo= ARC-Message-Signature: i=1; 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Signed-off-by: Michal Koutný --- tools/testing/selftests/cgroup/Makefile | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-) diff --git a/tools/testing/selftests/cgroup/Makefile b/tools/testing/selftests/cgroup/Makefile index 00b441928909..f3e1ef69e88d 100644 --- a/tools/testing/selftests/cgroup/Makefile +++ b/tools/testing/selftests/cgroup/Makefile @@ -6,26 +6,27 @@ all: ${HELPER_PROGS} TEST_FILES := with_stress.sh TEST_PROGS := test_stress.sh test_cpuset_prs.sh TEST_GEN_FILES := wait_inotify -TEST_GEN_PROGS = test_memcontrol -TEST_GEN_PROGS += test_kmem -TEST_GEN_PROGS += test_core -TEST_GEN_PROGS += test_freezer -TEST_GEN_PROGS += test_kill +# Keep the lists lexicographically sorted +TEST_GEN_PROGS = test_core TEST_GEN_PROGS += test_cpu TEST_GEN_PROGS += test_cpuset -TEST_GEN_PROGS += test_zswap +TEST_GEN_PROGS += test_freezer TEST_GEN_PROGS += test_hugetlb_memcg +TEST_GEN_PROGS += test_kill +TEST_GEN_PROGS += test_kmem +TEST_GEN_PROGS += test_memcontrol +TEST_GEN_PROGS += test_zswap LOCAL_HDRS += $(selfdir)/clone3/clone3_selftests.h $(selfdir)/pidfd/pidfd.h include ../lib.mk -$(OUTPUT)/test_memcontrol: cgroup_util.c -$(OUTPUT)/test_kmem: cgroup_util.c $(OUTPUT)/test_core: cgroup_util.c -$(OUTPUT)/test_freezer: cgroup_util.c -$(OUTPUT)/test_kill: cgroup_util.c $(OUTPUT)/test_cpu: cgroup_util.c $(OUTPUT)/test_cpuset: cgroup_util.c -$(OUTPUT)/test_zswap: cgroup_util.c +$(OUTPUT)/test_freezer: cgroup_util.c $(OUTPUT)/test_hugetlb_memcg: cgroup_util.c +$(OUTPUT)/test_kill: cgroup_util.c +$(OUTPUT)/test_kmem: cgroup_util.c +$(OUTPUT)/test_memcontrol: cgroup_util.c +$(OUTPUT)/test_zswap: cgroup_util.c From patchwork Fri Apr 5 17:05:45 2024 Content-Type: text/plain; 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Signed-off-by: Michal Koutný --- tools/testing/selftests/cgroup/Makefile | 2 + tools/testing/selftests/cgroup/test_pids.c | 187 +++++++++++++++++++++ 2 files changed, 189 insertions(+) create mode 100644 tools/testing/selftests/cgroup/test_pids.c diff --git a/tools/testing/selftests/cgroup/Makefile b/tools/testing/selftests/cgroup/Makefile index f3e1ef69e88d..f5f0886a2c4a 100644 --- a/tools/testing/selftests/cgroup/Makefile +++ b/tools/testing/selftests/cgroup/Makefile @@ -15,6 +15,7 @@ TEST_GEN_PROGS += test_hugetlb_memcg TEST_GEN_PROGS += test_kill TEST_GEN_PROGS += test_kmem TEST_GEN_PROGS += test_memcontrol +TEST_GEN_PROGS += test_pids TEST_GEN_PROGS += test_zswap LOCAL_HDRS += $(selfdir)/clone3/clone3_selftests.h $(selfdir)/pidfd/pidfd.h @@ -29,4 +30,5 @@ $(OUTPUT)/test_hugetlb_memcg: cgroup_util.c $(OUTPUT)/test_kill: cgroup_util.c $(OUTPUT)/test_kmem: cgroup_util.c $(OUTPUT)/test_memcontrol: cgroup_util.c +$(OUTPUT)/test_pids: cgroup_util.c $(OUTPUT)/test_zswap: cgroup_util.c diff --git a/tools/testing/selftests/cgroup/test_pids.c b/tools/testing/selftests/cgroup/test_pids.c new file mode 100644 index 000000000000..c1c3a3965624 --- /dev/null +++ b/tools/testing/selftests/cgroup/test_pids.c @@ -0,0 +1,187 @@ +// SPDX-License-Identifier: GPL-2.0 +#define _GNU_SOURCE + +#include +#include +#include +#include +#include +#include +#include + +#include "../kselftest.h" +#include "cgroup_util.h" + +static int run_success(const char *cgroup, void *arg) +{ + return 0; +} + +static int run_pause(const char *cgroup, void *arg) +{ + return pause(); +} + +/* + * This test checks that pids.max prevents forking new children above the + * specified limit in the cgroup. + */ +static int test_pids_max(const char *root) +{ + int ret = KSFT_FAIL; + char *cg_pids; + int pid; + + + cg_pids = cg_name(root, "pids_test"); + if (!cg_pids) + goto cleanup; + + if (cg_create(cg_pids)) + goto cleanup; + + if (cg_read_strcmp(cg_pids, "pids.max", "max\n")) + goto cleanup; + + if (cg_write(cg_pids, "pids.max", "2")) + goto cleanup; + + if (cg_enter_current(cg_pids)) + goto cleanup; + + pid = cg_run_nowait(cg_pids, run_pause, NULL); + if (pid < 0) + goto cleanup; + + if (cg_run_nowait(cg_pids, run_success, NULL) != -1 || errno != EAGAIN) + goto cleanup; + + if (kill(pid, SIGINT)) + goto cleanup; + + ret = KSFT_PASS; + +cleanup: + cg_enter_current(root); + cg_destroy(cg_pids); + free(cg_pids); + + return ret; +} + +/* + * This test checks that pids.max prevents forking new children above the + * specified limit in the cgroup. + */ +static int test_pids_events(const char *root) +{ + int ret = KSFT_FAIL; + char *cg_parent = NULL, *cg_child = NULL; + int pid; + + + cg_parent = cg_name(root, "pids_parent"); + cg_child = cg_name(cg_parent, "pids_child"); + if (!cg_parent || !cg_child) + goto cleanup; + + if (cg_create(cg_parent)) + goto cleanup; + if (cg_write(cg_parent, "cgroup.subtree_control", "+pids")) + goto cleanup; + if (cg_create(cg_child)) + goto cleanup; + + if (cg_write(cg_parent, "pids.max", "2")) + goto cleanup; + + if (cg_read_strcmp(cg_child, "pids.max", "max\n")) + goto cleanup; + + if (cg_enter_current(cg_child)) + goto cleanup; + + pid = cg_run_nowait(cg_child, run_pause, NULL); + if (pid < 0) + goto cleanup; + + if (cg_run_nowait(cg_child, run_success, NULL) != -1 || errno != EAGAIN) + goto cleanup; + + if (kill(pid, SIGINT)) + goto cleanup; + + + if (cg_read_key_long(cg_child, "pids.events", "max ") != 0) + goto cleanup; + if (cg_read_key_long(cg_child, "pids.events", "max.imposed ") != 1) + goto cleanup; + + if (cg_read_key_long(cg_parent, "pids.events", "max ") != 1) + goto cleanup; + if (cg_read_key_long(cg_parent, "pids.events", "max.imposed ") != 1) + goto cleanup; + + + ret = KSFT_PASS; + +cleanup: + cg_enter_current(root); + if (cg_child) + cg_destroy(cg_child); + if (cg_parent) + cg_destroy(cg_parent); + free(cg_child); + free(cg_parent); + + return ret; +} + + + +#define T(x) { x, #x } +struct pids_test { + int (*fn)(const char *root); + const char *name; +} tests[] = { + T(test_pids_max), + T(test_pids_events), +}; +#undef T + +int main(int argc, char **argv) +{ + char root[PATH_MAX]; + int i, ret = EXIT_SUCCESS; + + if (cg_find_unified_root(root, sizeof(root))) + ksft_exit_skip("cgroup v2 isn't mounted\n"); + + /* + * Check that pids controller is available: + * pids is listed in cgroup.controllers + */ + if (cg_read_strstr(root, "cgroup.controllers", "pids")) + ksft_exit_skip("pids controller isn't available\n"); + + if (cg_read_strstr(root, "cgroup.subtree_control", "pids")) + if (cg_write(root, "cgroup.subtree_control", "+pids")) + ksft_exit_skip("Failed to set pids controller\n"); + + for (i = 0; i < ARRAY_SIZE(tests); i++) { + switch (tests[i].fn(root)) { + case KSFT_PASS: + ksft_test_result_pass("%s\n", tests[i].name); + break; + case KSFT_SKIP: + ksft_test_result_skip("%s\n", tests[i].name); + break; + default: + ret = EXIT_FAILURE; + ksft_test_result_fail("%s\n", tests[i].name); + break; + } + } + + return ret; +} From patchwork Fri Apr 5 17:05:46 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Michal_Koutn=C3=BD?= X-Patchwork-Id: 786364 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.223.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D2DD5171651; Fri, 5 Apr 2024 17:05:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=195.135.223.131 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712336755; 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Fri, 5 Apr 2024 17:05:52 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap2.dmz-prg2.suse.org with ESMTPSA id 2MdBAHAvEGYteAAAn2gu4w (envelope-from ); Fri, 05 Apr 2024 17:05:52 +0000 From: =?utf-8?q?Michal_Koutn=C3=BD?= To: cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: Tejun Heo , Zefan Li , Johannes Weiner , Jonathan Corbet , Shuah Khan Subject: [RFC PATCH v3 7/9] cgroup/pids: Replace uncharge/charge pair with a single function Date: Fri, 5 Apr 2024 19:05:46 +0200 Message-ID: <20240405170548.15234-8-mkoutny@suse.com> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240405170548.15234-1-mkoutny@suse.com> References: <20240405170548.15234-1-mkoutny@suse.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Flag: NO X-Spam-Score: -3.30 X-Spam-Level: X-Spamd-Result: default: False [-3.30 / 50.00]; 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This rework reduces modifications of pids counters only to a minimal subtree of uncharged/charged cgroups. Signed-off-by: Michal Koutný --- kernel/cgroup/pids.c | 80 ++++++++++++++++++++++++++------------------ 1 file changed, 47 insertions(+), 33 deletions(-) diff --git a/kernel/cgroup/pids.c b/kernel/cgroup/pids.c index f5f81274658e..9df8a209a6e2 100644 --- a/kernel/cgroup/pids.c +++ b/kernel/cgroup/pids.c @@ -133,41 +133,23 @@ static void pids_uncharge(struct pids_cgroup *pids, int num) pids_cancel(p, num); } -/** - * pids_charge - hierarchically charge the pid count - * @pids: the pid cgroup state - * @num: the number of pids to charge - * - * This function does *not* follow the pid limit set. It cannot fail and the new - * pid count may exceed the limit. This is only used for reverting failed - * attaches, where there is no other way out than violating the limit. - */ -static void pids_charge(struct pids_cgroup *pids, int num) -{ - struct pids_cgroup *p; - - for (p = pids; parent_pids(p); p = parent_pids(p)) { - int64_t new = atomic64_add_return(num, &p->counter); - - pids_update_watermark(p, new); - } -} - /** * pids_try_charge - hierarchically try to charge the pid count * @pids: the pid cgroup state * @num: the number of pids to charge + * @root: charge only under this root (NULL is global root) * @fail: storage of pid cgroup causing the fail * * This function follows the set limit. It will fail if the charge would cause - * the new value to exceed the hierarchical limit. Returns 0 if the charge - * succeeded, otherwise -EAGAIN. + * the new value to exceed the hierarchical limit and fail is set. Returns 0 if + * no limit was hit, otherwise -EAGAIN. */ -static int pids_try_charge(struct pids_cgroup *pids, int num, struct pids_cgroup **fail) +static int pids_try_charge(struct pids_cgroup *pids, int num, struct pids_cgroup *root, struct pids_cgroup **fail) { struct pids_cgroup *p, *q; + int ret = 0; - for (p = pids; parent_pids(p); p = parent_pids(p)) { + for (p = pids; parent_pids(p) && p != root; p = parent_pids(p)) { int64_t new = atomic64_add_return(num, &p->counter); int64_t limit = atomic64_read(&p->limit); @@ -177,8 +159,11 @@ static int pids_try_charge(struct pids_cgroup *pids, int num, struct pids_cgroup * fail. */ if (new > limit) { - *fail = p; - goto revert; + ret = -EAGAIN; + if (fail) { + *fail = p; + goto revert; + } } /* * Not technically accurate if we go over limit somewhere up @@ -187,14 +172,45 @@ static int pids_try_charge(struct pids_cgroup *pids, int num, struct pids_cgroup pids_update_watermark(p, new); } - return 0; + return ret; revert: for (q = pids; q != p; q = parent_pids(q)) pids_cancel(q, num); pids_cancel(p, num); - return -EAGAIN; + return ret; +} + +/** + * pids_tranfer_charge - charge/uncharge in subtree betwee src and dst + * @src: pid cgroup state to uncharge + * @dst: pid cgroup state to charge + * @num: the number of pids to transfer + * + * The function updates charged pids in subtree whose root is the closest + * common ancestor of @src and @dst. This root and its ancestors are not + * modified (their limits are not enacted). + * + * Returns 0 if no limit was hit, -EAGAIN if a limit on path [@dst, @comm) was + * hit (charges are transferred despite the limit). + */ +static int pids_tranfer_charge(struct pids_cgroup *src, struct pids_cgroup *dst, int num) +{ + struct pids_cgroup *p, *comm = src; + int ret; + + /* for stable cgroup tree */ + lockdep_assert_held(&cgroup_mutex); + + while (!cgroup_is_descendant(dst->css.cgroup, comm->css.cgroup)) + comm = parent_pids(comm); + + ret = pids_try_charge(dst, num, comm, NULL); + + for (p = src; p != comm; p = parent_pids(p)) + pids_cancel(p, num); + return ret; } static int pids_can_attach(struct cgroup_taskset *tset) @@ -215,8 +231,7 @@ static int pids_can_attach(struct cgroup_taskset *tset) old_css = task_css(task, pids_cgrp_id); old_pids = css_pids(old_css); - pids_charge(pids, 1); - pids_uncharge(old_pids, 1); + (void) pids_tranfer_charge(old_pids, pids, 1); } return 0; @@ -235,8 +250,7 @@ static void pids_cancel_attach(struct cgroup_taskset *tset) old_css = task_css(task, pids_cgrp_id); old_pids = css_pids(old_css); - pids_charge(old_pids, 1); - pids_uncharge(pids, 1); + (void) pids_tranfer_charge(pids, old_pids, 1); } } @@ -287,7 +301,7 @@ static int pids_can_fork(struct task_struct *task, struct css_set *cset) else css = task_css_check(current, pids_cgrp_id, true); pids = css_pids(css); - err = pids_try_charge(pids, 1, &pids_over_limit); + err = pids_try_charge(pids, 1, NULL, &pids_over_limit); if (err) pids_event(pids, pids_over_limit); From patchwork Fri Apr 5 17:05:47 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Michal_Koutn=C3=BD?= X-Patchwork-Id: 786362 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.223.130]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0E1FB171658; Fri, 5 Apr 2024 17:05:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=195.135.223.130 ARC-Seal: i=1; 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Fri, 5 Apr 2024 17:05:52 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap2.dmz-prg2.suse.org with ESMTPSA id qIPoCXAvEGYteAAAn2gu4w (envelope-from ); Fri, 05 Apr 2024 17:05:52 +0000 From: =?utf-8?q?Michal_Koutn=C3=BD?= To: cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: Tejun Heo , Zefan Li , Johannes Weiner , Jonathan Corbet , Shuah Khan Subject: [RFC PATCH v3 8/9] cgroup/pids: Enforce pids.max on task migrations Date: Fri, 5 Apr 2024 19:05:47 +0200 Message-ID: <20240405170548.15234-9-mkoutny@suse.com> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240405170548.15234-1-mkoutny@suse.com> References: <20240405170548.15234-1-mkoutny@suse.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Level: X-Spamd-Result: default: False [-3.51 / 50.00]; BAYES_HAM(-3.00)[100.00%]; MID_CONTAINS_FROM(1.00)[]; 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A manager daemon is in /src and it spawns tasks into /dst. The administrator sets up a limit dst/pids.max while src/pids.max is unlimited. The manager daemon can spawn more than dst/pids.max tasks because they get into their target cgroup via migration (or CLONE_INTO_CGROUP). For this (migration) to work both src and dst must be in the same resource domain so the manager daemon does not honor the limit which is under its control anyway and no excessive resource consumption happens. dst/pids.current > dst/pids.max may come as a surprise when the spawning mechanism is opaque to the administrator of dst/pids.max. Change the behavior of pids controller to take into account limits of target cgroup upon migration (but only below common ancestor src and dst, pids.current of common ancestor and above is not affected by migration, so deliberatly ignore pre-existing pids.current > pids.max). This change of behavior is hidden behind cgroup2 mount option and the default is unchanged, pids.max won't affect migrations. Signed-off-by: Michal Koutný --- Documentation/admin-guide/cgroup-v2.rst | 8 +++++++- include/linux/cgroup-defs.h | 7 ++++++- kernel/cgroup/cgroup.c | 16 +++++++++++++++- kernel/cgroup/pids.c | 8 ++++++-- 4 files changed, 34 insertions(+), 5 deletions(-) diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index 5d4c505cae06..d7e721aed584 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -239,6 +239,11 @@ cgroup v2 currently supports the following mount options. will not be tracked by the memory controller (even if cgroup v2 is remounted later on). + pids_miglimit + Apply pids.max limit also when migrating tasks between cgroups. Only + new destination limit are taken into account, i.e. if subtree has + pids.current > pids.max, migration within that subtree is allowed. + Organizing Processes and Threads -------------------------------- @@ -2204,7 +2209,8 @@ Organisational operations are not blocked by cgroup policies, so it is possible to have pids.current > pids.max. This can be done by either setting the limit to be smaller than pids.current, or attaching enough processes to the cgroup such that pids.current is larger than -pids.max. However, it is not possible to violate a cgroup PID policy +pids.max (unless pids_miglimit mount options is given). +However, it is not possible to violate a cgroup PID policy through fork() or clone(). These will return -EAGAIN if the creation of a new process would cause a cgroup policy to be violated. diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h index ea48c861cd36..a99db24b5496 100644 --- a/include/linux/cgroup-defs.h +++ b/include/linux/cgroup-defs.h @@ -119,7 +119,12 @@ enum { /* * Enable hugetlb accounting for the memory controller. */ - CGRP_ROOT_MEMORY_HUGETLB_ACCOUNTING = (1 << 19), + CGRP_ROOT_MEMORY_HUGETLB_ACCOUNTING = (1 << 19), + + /* + * Enforce pids limit upon task migration + */ + CGRP_ROOT_PIDS_MIGRATION_LIMIT = (1 << 20), }; /* cftype->flags */ diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index a66c088c851c..9aa6428c84c1 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -1922,6 +1922,7 @@ enum cgroup2_param { Opt_memory_localevents, Opt_memory_recursiveprot, Opt_memory_hugetlb_accounting, + Opt_pids_miglimit, nr__cgroup2_params }; @@ -1931,6 +1932,7 @@ static const struct fs_parameter_spec cgroup2_fs_parameters[] = { fsparam_flag("memory_localevents", Opt_memory_localevents), fsparam_flag("memory_recursiveprot", Opt_memory_recursiveprot), fsparam_flag("memory_hugetlb_accounting", Opt_memory_hugetlb_accounting), + fsparam_flag("pids_miglimit", Opt_pids_miglimit), {} }; @@ -1960,6 +1962,9 @@ static int cgroup2_parse_param(struct fs_context *fc, struct fs_parameter *param case Opt_memory_hugetlb_accounting: ctx->flags |= CGRP_ROOT_MEMORY_HUGETLB_ACCOUNTING; return 0; + case Opt_pids_miglimit: + ctx->flags |= CGRP_ROOT_PIDS_MIGRATION_LIMIT; + return 0; } return -EINVAL; } @@ -1989,6 +1994,12 @@ static void apply_cgroup_root_flags(unsigned int root_flags) cgrp_dfl_root.flags |= CGRP_ROOT_MEMORY_HUGETLB_ACCOUNTING; else cgrp_dfl_root.flags &= ~CGRP_ROOT_MEMORY_HUGETLB_ACCOUNTING; + + if (root_flags & CGRP_ROOT_PIDS_MIGRATION_LIMIT) + cgrp_dfl_root.flags |= CGRP_ROOT_PIDS_MIGRATION_LIMIT; + else + cgrp_dfl_root.flags &= ~CGRP_ROOT_PIDS_MIGRATION_LIMIT; + } } @@ -2004,6 +2015,8 @@ static int cgroup_show_options(struct seq_file *seq, struct kernfs_root *kf_root seq_puts(seq, ",memory_recursiveprot"); if (cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_HUGETLB_ACCOUNTING) seq_puts(seq, ",memory_hugetlb_accounting"); + if (cgrp_dfl_root.flags & CGRP_ROOT_PIDS_MIGRATION_LIMIT) + seq_puts(seq, ",pids_miglimit"); return 0; } @@ -7061,7 +7074,8 @@ static ssize_t features_show(struct kobject *kobj, struct kobj_attribute *attr, "favordynmods\n" "memory_localevents\n" "memory_recursiveprot\n" - "memory_hugetlb_accounting\n"); + "memory_hugetlb_accounting\n" + "pids_miglimit\n"); } static struct kobj_attribute cgroup_features_attr = __ATTR_RO(features); diff --git a/kernel/cgroup/pids.c b/kernel/cgroup/pids.c index 9df8a209a6e2..4683629b8168 100644 --- a/kernel/cgroup/pids.c +++ b/kernel/cgroup/pids.c @@ -217,6 +217,7 @@ static int pids_can_attach(struct cgroup_taskset *tset) { struct task_struct *task; struct cgroup_subsys_state *dst_css; + int err, ret = 0; cgroup_taskset_for_each(task, dst_css, tset) { struct pids_cgroup *pids = css_pids(dst_css); @@ -231,10 +232,13 @@ static int pids_can_attach(struct cgroup_taskset *tset) old_css = task_css(task, pids_cgrp_id); old_pids = css_pids(old_css); - (void) pids_tranfer_charge(old_pids, pids, 1); + err = pids_tranfer_charge(old_pids, pids, 1); + + if (!ret && (cgrp_dfl_root.flags & CGRP_ROOT_PIDS_MIGRATION_LIMIT)) + ret = err; 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Fri, 05 Apr 2024 17:05:52 +0000 From: =?utf-8?q?Michal_Koutn=C3=BD?= To: cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: Tejun Heo , Zefan Li , Johannes Weiner , Jonathan Corbet , Shuah Khan Subject: [RFC PATCH v3 9/9] selftests: cgroup: Add tests pids controller Date: Fri, 5 Apr 2024 19:05:48 +0200 Message-ID: <20240405170548.15234-10-mkoutny@suse.com> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240405170548.15234-1-mkoutny@suse.com> References: <20240405170548.15234-1-mkoutny@suse.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Level: X-Spamd-Result: default: False [-3.51 / 50.00]; BAYES_HAM(-3.00)[100.00%]; MID_CONTAINS_FROM(1.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; R_DKIM_ALLOW(-0.20)[suse.com:s=susede1]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; MX_GOOD(-0.01)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; 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When the new option does not exist, the test is skipped. Signed-off-by: Michal Koutný --- tools/testing/selftests/cgroup/test_pids.c | 117 ++++++++++++++++++++- 1 file changed, 116 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/cgroup/test_pids.c b/tools/testing/selftests/cgroup/test_pids.c index c1c3a3965624..a3ad5a495f59 100644 --- a/tools/testing/selftests/cgroup/test_pids.c +++ b/tools/testing/selftests/cgroup/test_pids.c @@ -12,6 +12,8 @@ #include "../kselftest.h" #include "cgroup_util.h" +static bool has_miglimit; + static int run_success(const char *cgroup, void *arg) { return 0; @@ -69,6 +71,112 @@ static int test_pids_max(const char *root) return ret; } +/* + * This test checks that pids.max prevents migrating tasks over limit into the + * cgroup. + */ +static int test_pids_max_migration(const char *root) +{ + int ret = KSFT_FAIL; + char *cg_pids; + int pid; + + if (!has_miglimit) + return KSFT_SKIP; + + cg_pids = cg_name(root, "pids_test"); + if (!cg_pids) + goto cleanup; + + if (cg_create(cg_pids)) + goto cleanup; + + if (cg_write(cg_pids, "pids.max", "1")) + goto cleanup; + + pid = cg_run_nowait(cg_pids, run_pause, NULL); + if (pid < 0) + goto cleanup; + + if (cg_enter_current(cg_pids) >= 0) + goto cleanup; + + if (kill(pid, SIGINT)) + goto cleanup; + + ret = KSFT_PASS; + +cleanup: + cg_enter_current(root); + cg_destroy(cg_pids); + free(cg_pids); + + return ret; +} + +/* + * This test checks that pids.max does not prevent migrating existing tasks + * inside subtree. + */ +static int test_pids_max_overcommit(const char *root) +{ + int ret = KSFT_FAIL; + char *cg_parent = NULL, *cg_src = NULL, *cg_dst = NULL; + int pid; + + if (!has_miglimit) + return KSFT_SKIP; + + cg_parent = cg_name(root, "pids_test"); + if (!cg_parent) + goto cleanup; + cg_src = cg_name(cg_parent, "src"); + if (!cg_src) + goto cleanup; + cg_dst = cg_name(cg_parent, "dst"); + if (!cg_dst) + goto cleanup; + + if (cg_create(cg_parent)) + goto cleanup; + if (cg_write(cg_parent, "cgroup.subtree_control", "+pids")) + goto cleanup; + if (cg_create(cg_src)) + goto cleanup; + if (cg_create(cg_dst)) + goto cleanup; + + if (cg_enter_current(cg_src) < 0) + goto cleanup; + + pid = cg_run_nowait(cg_src, run_pause, NULL); + if (pid < 0) + goto cleanup; + + if (cg_write(cg_parent, "pids.max", "1")) + goto cleanup; + + if (cg_enter(cg_dst, pid) < 0) + goto cleanup; + + if (kill(pid, SIGINT)) + goto cleanup; + + ret = KSFT_PASS; + +cleanup: + cg_enter_current(root); + cg_destroy(cg_dst); + cg_destroy(cg_src); + cg_destroy(cg_parent); + free(cg_dst); + free(cg_src); + free(cg_parent); + + return ret; +} + + /* * This test checks that pids.max prevents forking new children above the * specified limit in the cgroup. @@ -145,6 +253,8 @@ struct pids_test { const char *name; } tests[] = { T(test_pids_max), + T(test_pids_max_migration), + T(test_pids_max_overcommit), T(test_pids_events), }; #undef T @@ -152,7 +262,7 @@ struct pids_test { int main(int argc, char **argv) { char root[PATH_MAX]; - int i, ret = EXIT_SUCCESS; + int i, proc_status, ret = EXIT_SUCCESS; if (cg_find_unified_root(root, sizeof(root))) ksft_exit_skip("cgroup v2 isn't mounted\n"); @@ -168,6 +278,11 @@ int main(int argc, char **argv) if (cg_write(root, "cgroup.subtree_control", "+pids")) ksft_exit_skip("Failed to set pids controller\n"); + proc_status = proc_mount_contains("pids_miglimit"); + if (proc_status < 0) + ksft_exit_skip("Failed to query cgroup mount option\n"); + has_miglimit = proc_status; + for (i = 0; i < ARRAY_SIZE(tests); i++) { switch (tests[i].fn(root)) { case KSFT_PASS: