From 786dee864804f8e851cf0f258df2ccbb4ee03d80 Mon Sep 17 00:00:00 2001
From: Liam Mark <lmark@codeaurora.org>
Date: Wed, 30 Jun 2021 18:52:43 -0700
Subject: [PATCH] mm/memory_hotplug: rate limit page migration warnings
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@linaro.org
Signed-off-by: Liam Mark <lmark@codeaurora.org>
Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
mm/memory_hotplug.c | 16 +++++++++++-----
1 file changed, 11 insertions(+), 5 deletions(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 492560b619998..1a9568d90ea76 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1406,6 +1406,8 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_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))
@@ -1452,8 +1454,10 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_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);
}
@@ -1482,9 +1486,11 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_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);
}
--
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