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From: Hugh Dickins <hughd@google.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Roman Gushchin <guro@fb.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	 Michal Hocko <mhocko@kernel.org>,
	Vlastimil Babka <vbabka@suse.cz>,
	 linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: [PATCH 1/4] mm: restore node stat checking in /proc/sys/vm/stat_refresh
Date: Thu, 25 Feb 2021 15:10:09 -0800 (PST)	[thread overview]
Message-ID: <alpine.LSU.2.11.2102251502240.13363@eggly.anvils> (raw)

v4.7 52b6f46bc163 ("mm: /proc/sys/vm/stat_refresh to force vmstat update")
introduced vmstat_refresh(), with its vmstat underflow checking; then
v4.8 75ef71840539 ("mm, vmstat: add infrastructure for per-node vmstats")
split NR_VM_NODE_STAT_ITEMS out of NR_VM_ZONE_STAT_ITEMS without updating
vmstat_refresh(): so it has been missing out much of the vmstat underflow
checking ever since. Reinstate it. Thanks to Roman Gushchin <guro@fb.com>
for tangentially pointing this out.

Signed-off-by: Hugh Dickins <hughd@google.com>
---

 mm/vmstat.c |    8 ++++++++
 1 file changed, 8 insertions(+)

--- 5.12-rc/mm/vmstat.c	2021-02-24 12:03:55.000000000 -0800
+++ vmstat1/mm/vmstat.c	2021-02-25 11:50:36.000000000 -0800
@@ -1857,6 +1857,14 @@ int vmstat_refresh(struct ctl_table *tab
 		}
 	}
 #endif
+	for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
+		val = atomic_long_read(&vm_node_stat[i]);
+		if (val < 0) {
+			pr_warn("%s: %s %ld\n",
+				__func__, node_stat_name(i), val);
+			err = -EINVAL;
+		}
+	}
 	if (err)
 		return err;
 	if (write)


             reply	other threads:[~2021-02-25 23:10 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-25 23:10 Hugh Dickins [this message]
2021-02-25 23:12 ` [PATCH 2/4] mm: no more EINVAL from /proc/sys/vm/stat_refresh Hugh Dickins
2021-03-01  0:38   ` Roman Gushchin
2021-02-25 23:14 ` [PATCH 3/4] mm: /proc/sys/vm/stat_refresh skip checking known negative stats Hugh Dickins
2021-03-01  0:53   ` Roman Gushchin
2021-03-01 22:08     ` Hugh Dickins
2021-03-02  0:34       ` Roman Gushchin
2021-03-02  6:03         ` [PATCH v2 " Hugh Dickins
2021-03-04  2:25           ` Roman Gushchin
2021-02-25 23:15 ` [PATCH 4/4] mm: /proc//sys/vm/stat_refresh stop checking monotonic numa stats Hugh Dickins
2021-03-01  0:53   ` Roman Gushchin
2021-03-01  0:37 ` [PATCH 1/4] mm: restore node stat checking in /proc/sys/vm/stat_refresh Roman Gushchin

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