Commit 786dee86 authored by Liam Mark's avatar Liam Mark Committed by Linus Torvalds
Browse files

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: default avatarLiam Mark <lmark@codeaurora.org>
Signed-off-by: default avatarGeorgi Djakov <georgi.djakov@linaro.org>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e5bfac53

mm/memory_hotplug.c

+11 −5
Original line number Diff line number Diff line
@@ -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))
@@ -1452,9 +1454,11 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) 
						    page_is_file_lru(page));



		} else {

			if (__ratelimit(&migrate_rs)) {

				pr_warn("failed to isolate pfn %lx\n", pfn);

				dump_page(page, "isolation failed");

			}

		}

		put_page(page);

	}

	if (!list_empty(&source)) {
@@ -1482,10 +1486,12 @@ 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 ",

				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);

		}

	}