+ mm-update-mark_victim-tracepoints-fields.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm: update mark_victim tracepoints fields
has been added to the -mm mm-unstable branch.  Its filename is
     mm-update-mark_victim-tracepoints-fields.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-update-mark_victim-tracepoints-fields.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Carlos Galo <carlosgalo@google.com>
Subject: mm: update mark_victim tracepoints fields
Date: Thu, 11 Jan 2024 21:05:30 +0000

The current implementation of the mark_victim tracepoint provides only the
process ID (pid) of the victim process.  This limitation poses challenges
for userspace tools that need additional information about the OOM victim.
The association between pid and the additional data may be lost after the
kill, making it difficult for userspace to correlate the OOM event with
the specific process.

In order to mitigate this limitation, add the following fields:

- UID
   In Android each installed application has a unique UID. Including
   the `uid` assists in correlating OOM events with specific apps.

- Process Name (comm)
   Enables identification of the affected process.

- OOM Score
   Allows userspace to get additional insights of the relative kill
   priority of the OOM victim.

Link: https://lkml.kernel.org/r/20240111210539.636607-1-carlosgalo@google.com
Signed-off-by: Carlos Galo <carlosgalo@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/trace/events/oom.h |   19 +++++++++++++++----
 mm/oom_kill.c              |    6 +++++-
 2 files changed, 20 insertions(+), 5 deletions(-)

--- a/include/trace/events/oom.h~mm-update-mark_victim-tracepoints-fields
+++ a/include/trace/events/oom.h
@@ -72,19 +72,30 @@ TRACE_EVENT(reclaim_retry_zone,
 );
 
 TRACE_EVENT(mark_victim,
-	TP_PROTO(int pid),
+	TP_PROTO(struct task_struct *task, uid_t uid),
 
-	TP_ARGS(pid),
+	TP_ARGS(task, uid),
 
 	TP_STRUCT__entry(
 		__field(int, pid)
+		__field(uid_t, uid)
+		__string(comm, task->comm)
+		__field(short, oom_score_adj)
 	),
 
 	TP_fast_assign(
-		__entry->pid = pid;
+		__entry->pid = task->pid;
+		__entry->uid = uid;
+		__assign_str(comm, task->comm);
+		__entry->oom_score_adj = task->signal->oom_score_adj;
 	),
 
-	TP_printk("pid=%d", __entry->pid)
+	TP_printk("pid=%d uid=%u comm=%s oom_score_adj=%hd",
+		__entry->pid,
+		__entry->uid,
+		__get_str(comm),
+		__entry->oom_score_adj
+	)
 );
 
 TRACE_EVENT(wake_reaper,
--- a/mm/oom_kill.c~mm-update-mark_victim-tracepoints-fields
+++ a/mm/oom_kill.c
@@ -44,6 +44,7 @@
 #include <linux/kthread.h>
 #include <linux/init.h>
 #include <linux/mmu_notifier.h>
+#include <linux/cred.h>
 
 #include <asm/tlb.h>
 #include "internal.h"
@@ -754,6 +755,7 @@ static inline void queue_oom_reaper(stru
  */
 static void mark_oom_victim(struct task_struct *tsk)
 {
+	const struct cred *cred;
 	struct mm_struct *mm = tsk->mm;
 
 	WARN_ON(oom_killer_disabled);
@@ -773,7 +775,9 @@ static void mark_oom_victim(struct task_
 	 */
 	__thaw_task(tsk);
 	atomic_inc(&oom_victims);
-	trace_mark_victim(tsk->pid);
+	cred = get_task_cred(tsk);
+	trace_mark_victim(tsk, cred->uid.val);
+	put_cred(cred);
 }
 
 /**
_

Patches currently in -mm which might be from carlosgalo@google.com are

mm-update-mark_victim-tracepoints-fields.patch