Linux-Fsdevel Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Waiman Long <longman@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Michal Hocko <mhocko@kernel.org>,
	Vladimir Davydov <vdavydov.dev@gmail.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Alexey Dobriyan <adobriyan@gmail.com>,
	Ingo Molnar <mingo@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Juri Lelli <juri.lelli@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>
Cc: linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, cgroups@vger.kernel.org,
	linux-mm@kvack.org, Waiman Long <longman@redhat.com>
Subject: [RFC PATCH 7/8] memcg: Enable logging of memory control mitigation action
Date: Mon, 17 Aug 2020 10:08:30 -0400	[thread overview]
Message-ID: <20200817140831.30260-8-longman@redhat.com> (raw)
In-Reply-To: <20200817140831.30260-1-longman@redhat.com>

Some of the migitation actions of PR_SET_MEMCONTROL give no visible
signal that some actions are being done inside the kernel. To make it
more visble, a new PR_MEMFLAG_LOG flag is added to enable the logging
of the migitation action done in the kernel ring buffer.

The logging is done once when the mitigation action starts through the
setting of an internal PR_MEMFLAG_LOGGED flag. This flag will be cleared
when it is detected that the memory limit no longer exceeds memory.high.

Signed-off-by: Waiman Long <longman@redhat.com>
---
 include/uapi/linux/prctl.h |  1 +
 mm/memcontrol.c            | 34 +++++++++++++++++++++++++++++++++-
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h
index 7ba40e10737d..faa7a51fc52a 100644
--- a/include/uapi/linux/prctl.h
+++ b/include/uapi/linux/prctl.h
@@ -266,6 +266,7 @@ struct prctl_mm_map {
 /* Flags for PR_SET_MEMCONTROL */
 # define PR_MEMFLAG_SIGCONT		(1UL <<  0) /* Continuous signal delivery */
 # define PR_MEMFLAG_DIRECT		(1UL <<  1) /* Direct memory limit */
+# define PR_MEMFLAG_LOG			(1UL <<  2) /* Log action done */
 # define PR_MEMFLAG_RSS_ANON		(1UL <<  8) /* Check anonymous pages */
 # define PR_MEMFLAG_RSS_FILE		(1UL <<  9) /* Check file pages */
 # define PR_MEMFLAG_RSS_SHMEM		(1UL << 10) /* Check shmem pages */
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index bddf3e659469..5bda2dd755fc 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2640,6 +2640,7 @@ get_rss_counter(struct mm_struct *mm, int mm_bit, u16 flags, int rss_bit)
  * Return true if an action has been taken or further check is not needed,
  * false otherwise.
  */
+#define PR_MEMFLAG_LOGGED	(1UL << 7)	/* A log message printed */
 static bool __mem_cgroup_over_high_action(struct mem_cgroup *memcg, u8 action,
 					  u16 flags)
 {
@@ -2714,6 +2715,32 @@ static bool __mem_cgroup_over_high_action(struct mem_cgroup *memcg, u8 action,
 		break;
 	}
 
+	if ((flags & (PR_MEMFLAG_LOG|PR_MEMFLAG_LOGGED)) == PR_MEMFLAG_LOG) {
+		char name[80];
+		static const char * const acts[] = {
+			[PR_MEMACT_ENOMEM]   = "Action: return ENOMEM on some syscalls",
+			[PR_MEMACT_SLOWDOWN] = "Action: slow down process",
+			[PR_MEMACT_SIGNAL]   = "Action: send signal",
+			[PR_MEMACT_KILL]     = "Action: kill the process",
+		};
+
+		name[0] = '\0';
+		if (memcg)
+			cgroup_name(memcg->css.cgroup, name, sizeof(name));
+		else
+			strcpy(name, "N/A");
+
+		/*
+		 * Use printk_deferred() to minimize delay in the memory
+		 * allocation path.
+		 */
+		printk_deferred(KERN_INFO
+			"Cgroup: %s, Comm: %s, Pid: %d, Mem: %ld pages, %s\n",
+			name, current->comm, current->pid, mem, acts[action]);
+		WRITE_ONCE(current->memcg_over_high_flags,
+			   flags | PR_MEMFLAG_LOGGED);
+	}
+
 out:
 	mmput(mm);
 	/*
@@ -2740,8 +2767,13 @@ static inline bool mem_cgroup_over_high_action(struct mem_cgroup *memcg,
 
 	if (flags & PR_MEMFLAG_DIRECT)
 		memcg = NULL;	/* Direct per-task memory limit checking */
-	else if (!mem_high)
+	else if (!mem_high) {
+		/* Clear the PR_MEMFLAG_LOGGED flag, if set */
+		if (flags & PR_MEMFLAG_LOGGED)
+			WRITE_ONCE(current->memcg_over_high_flags,
+				   flags & ~PR_MEMFLAG_LOGGED);
 		return false;
+	}
 
 	return __mem_cgroup_over_high_action(memcg, action, flags);
 }
-- 
2.18.1


  parent reply	other threads:[~2020-08-17 14:11 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-17 14:08 [RFC PATCH 0/8] memcg: Enable fine-grained per process memory control Waiman Long
2020-08-17 14:08 ` [RFC PATCH 1/8] memcg: Enable fine-grained control of over memory.high action Waiman Long
2020-08-17 14:30   ` Chris Down
2020-08-17 15:38     ` Waiman Long
2020-08-17 16:11       ` Chris Down
2020-08-17 16:44   ` Shakeel Butt
2020-08-17 16:56     ` Chris Down
2020-08-18 19:12       ` Waiman Long
2020-08-18 19:14     ` Waiman Long
2020-08-17 14:08 ` [RFC PATCH 2/8] memcg, mm: Return ENOMEM or delay if memcg_over_limit Waiman Long
2020-08-17 14:08 ` [RFC PATCH 3/8] memcg: Allow the use of task RSS memory as over-high action trigger Waiman Long
2020-08-17 14:08 ` [RFC PATCH 4/8] fs/proc: Support a new procfs memctl file Waiman Long
2020-08-17 14:08 ` [RFC PATCH 5/8] memcg: Allow direct per-task memory limit checking Waiman Long
2020-08-17 14:08 ` [RFC PATCH 6/8] memcg: Introduce additional memory control slowdown if needed Waiman Long
2020-08-17 14:08 ` Waiman Long [this message]
2020-08-17 14:08 ` [RFC PATCH 8/8] memcg: Add over-high action prctl() documentation Waiman Long
2020-08-17 15:26 ` [RFC PATCH 0/8] memcg: Enable fine-grained per process memory control Michal Hocko
2020-08-17 15:55   ` Waiman Long
2020-08-17 19:26     ` Michal Hocko
2020-08-18 19:20       ` Waiman Long
2020-08-18  9:14 ` peterz
2020-08-18  9:26   ` Michal Hocko
2020-08-18  9:59     ` peterz
2020-08-18 10:05       ` Michal Hocko
2020-08-18 10:18         ` peterz
2020-08-18 10:30           ` Michal Hocko
2020-08-18 10:36             ` peterz
2020-08-18 13:49           ` Johannes Weiner
2020-08-21 19:37             ` Peter Zijlstra
2020-08-24 16:58               ` Johannes Weiner
2020-09-07 11:47                 ` Chris Down
2020-09-09 11:53                 ` Michal Hocko
2020-08-18 10:17       ` Chris Down
2020-08-18 10:26         ` peterz
2020-08-18 10:35           ` Chris Down
2020-08-23  2:49         ` Waiman Long
2020-08-18  9:27   ` Chris Down
2020-08-18 10:04     ` peterz
2020-08-18 12:55       ` Matthew Wilcox
2020-08-20  6:11         ` Dave Chinner
2020-08-18 19:30     ` Waiman Long
2020-08-18 19:27   ` Waiman Long

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200817140831.30260-8-longman@redhat.com \
    --to=longman@redhat.com \
    --cc=adobriyan@gmail.com \
    --cc=akpm@linux-foundation.org \
    --cc=cgroups@vger.kernel.org \
    --cc=corbet@lwn.net \
    --cc=hannes@cmpxchg.org \
    --cc=juri.lelli@redhat.com \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mhocko@kernel.org \
    --cc=mingo@kernel.org \
    --cc=peterz@infradead.org \
    --cc=vdavydov.dev@gmail.com \
    --cc=vincent.guittot@linaro.org \
    --subject='Re: [RFC PATCH 7/8] memcg: Enable logging of memory control mitigation action' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).