This is a note to let you know that I've just added the patch titled
mm/memory_hotplug: rate limit page migration warnings
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-memory_hotplug-rate-limit-page-migration-warnings.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 786dee864804f8e851cf0f258df2ccbb4ee03d80 Mon Sep 17 00:00:00 2001
From: Liam Mark <lmark@xxxxxxxxxxxxxx>
Date: Wed, 30 Jun 2021 18:52:43 -0700
Subject: mm/memory_hotplug: rate limit page migration warnings
From: Liam Mark <lmark@xxxxxxxxxxxxxx>
commit 786dee864804f8e851cf0f258df2ccbb4ee03d80 upstream.
When offlining memory the system can attempt to migrate a lot of pages, if
there are problems with migration this can flood the logs. Printing all
the data hogs the CPU and cause some RT threads to run for a long time,
which may have some bad consequences.
Rate limit the page migration warnings in order to avoid this.
Link: https://lkml.kernel.org/r/20210505140542.24935-1-georgi.djakov@xxxxxxxxxx
Signed-off-by: Liam Mark <lmark@xxxxxxxxxxxxxx>
Signed-off-by: Georgi Djakov <georgi.djakov@xxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: <pjy@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/memory_hotplug.c | 16 +++++++++++-----
1 file changed, 11 insertions(+), 5 deletions(-)
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1279,6 +1279,8 @@ do_migrate_range(unsigned long start_pfn
struct page *page, *head;
int ret = 0;
LIST_HEAD(source);
+ static DEFINE_RATELIMIT_STATE(migrate_rs, DEFAULT_RATELIMIT_INTERVAL,
+ DEFAULT_RATELIMIT_BURST);
for (pfn = start_pfn; pfn < end_pfn; pfn++) {
if (!pfn_valid(pfn))
@@ -1325,8 +1327,10 @@ do_migrate_range(unsigned long start_pfn
page_is_file_lru(page));
} else {
- pr_warn("failed to isolate pfn %lx\n", pfn);
- dump_page(page, "isolation failed");
+ if (__ratelimit(&migrate_rs)) {
+ pr_warn("failed to isolate pfn %lx\n", pfn);
+ dump_page(page, "isolation failed");
+ }
}
put_page(page);
}
@@ -1355,9 +1359,11 @@ do_migrate_range(unsigned long start_pfn
(unsigned long)&mtc, MIGRATE_SYNC, MR_MEMORY_HOTPLUG);
if (ret) {
list_for_each_entry(page, &source, lru) {
- pr_warn("migrating pfn %lx failed ret:%d ",
- page_to_pfn(page), ret);
- dump_page(page, "migration failure");
+ if (__ratelimit(&migrate_rs)) {
+ pr_warn("migrating pfn %lx failed ret:%d\n",
+ page_to_pfn(page), ret);
+ dump_page(page, "migration failure");
+ }
}
putback_movable_pages(&source);
}
Patches currently in stable-queue which might be from lmark@xxxxxxxxxxxxxx are
queue-5.10/mm-memory_hotplug-rate-limit-page-migration-warnings.patch
