Merge: mm: fix the inaccurate memory statistics issue for users

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-10/-/merge_requests/1198

JIRA: https://issues.redhat.com/browse/RHEL-101961

This MR fixes an accounting issue with the 64K kernel on large systems where VmRSS, RssAnon and RssFile from /proc/self/status may be reported as zeroes for certain applications.

Signed-off-by: Luiz Capitulino <luizcap@redhat.com>

Approved-by: Waiman Long <longman@redhat.com>
Approved-by: Rafael Aquini <raquini@redhat.com>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>

Merged-by: CKI GitLab Kmaint Pipeline Bot <26919896-cki-kmaint-pipeline-bot@users.noreply.gitlab.com>

Author: CKI KWF Bot

fs/proc/task_mmu.c

@@ -36,9 +36,9 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
 	unsigned long text, lib, swap, anon, file, shmem;
 	unsigned long hiwater_vm, total_vm, hiwater_rss, total_rss;
 
-	anon = get_mm_counter(mm, MM_ANONPAGES);
-	file = get_mm_counter(mm, MM_FILEPAGES);
-	shmem = get_mm_counter(mm, MM_SHMEMPAGES);
+	anon = get_mm_counter_sum(mm, MM_ANONPAGES);
+	file = get_mm_counter_sum(mm, MM_FILEPAGES);
+	shmem = get_mm_counter_sum(mm, MM_SHMEMPAGES);
 
 	/*
 	 * Note: to minimize their overhead, mm maintains hiwater_vm and
@@ -59,7 +59,7 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
 	text = min(text, mm->exec_vm << PAGE_SHIFT);
 	lib = (mm->exec_vm << PAGE_SHIFT) - text;
 
-	swap = get_mm_counter(mm, MM_SWAPENTS);
+	swap = get_mm_counter_sum(mm, MM_SWAPENTS);
 	SEQ_PUT_DEC("VmPeak:\t", hiwater_vm);
 	SEQ_PUT_DEC(" kB\nVmSize:\t", total_vm);
 	SEQ_PUT_DEC(" kB\nVmLck:\t", mm->locked_vm);
@@ -92,12 +92,12 @@ unsigned long task_statm(struct mm_struct *mm,
 			 unsigned long *shared, unsigned long *text,
 			 unsigned long *data, unsigned long *resident)
 {
-	*shared = get_mm_counter(mm, MM_FILEPAGES) +
-			get_mm_counter(mm, MM_SHMEMPAGES);
+	*shared = get_mm_counter_sum(mm, MM_FILEPAGES) +
+			get_mm_counter_sum(mm, MM_SHMEMPAGES);
 	*text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK))
 								>> PAGE_SHIFT;
 	*data = mm->data_vm + mm->stack_vm;
-	*resident = *shared + get_mm_counter(mm, MM_ANONPAGES);
+	*resident = *shared + get_mm_counter_sum(mm, MM_ANONPAGES);
 	return mm->total_vm;
 }
 

include/linux/mm.h

@@ -2669,6 +2669,11 @@ static inline unsigned long get_mm_counter(struct mm_struct *mm, int member)
 	return percpu_counter_read_positive(&mm->rss_stat[member]);
 }
 
+static inline unsigned long get_mm_counter_sum(struct mm_struct *mm, int member)
+{
+	return percpu_counter_sum_positive(&mm->rss_stat[member]);
+}
+
 void mm_trace_rss_stat(struct mm_struct *mm, int member);
 
 static inline void add_mm_counter(struct mm_struct *mm, int member, long value)