diff options
| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2016-01-16 01:54:40 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-01-16 02:56:32 +0100 |
| commit | 49071d436b51b58aeaf7abcd1877f38ca0146e31 (patch) | |
| tree | 2adf8f687cc81072646412a97c07d2abc077182a /mm | |
| parent | mm: prepare page_referenced() and page_idle to new THP refcounting (diff) | |
| download | linux-49071d436b51b58aeaf7abcd1877f38ca0146e31.tar.xz linux-49071d436b51b58aeaf7abcd1877f38ca0146e31.zip | |
thp: add debugfs handle to split all huge pages
Writing 1 into 'split_huge_pages' will try to find and split all huge
pages in the system. This is useful for debuging.
[akpm@linux-foundation.org: fix printk text, per Vlastimil]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/huge_memory.c | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index ab544b145b52..a0b910a0c2cb 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -23,6 +23,7 @@ #include <linux/freezer.h> #include <linux/mman.h> #include <linux/pagemap.h> +#include <linux/debugfs.h> #include <linux/migrate.h> #include <linux/hashtable.h> #include <linux/userfaultfd_k.h> @@ -3350,3 +3351,61 @@ static struct shrinker deferred_split_shrinker = { .scan_objects = deferred_split_scan, .seeks = DEFAULT_SEEKS, }; + +#ifdef CONFIG_DEBUG_FS +static int split_huge_pages_set(void *data, u64 val) +{ + struct zone *zone; + struct page *page; + unsigned long pfn, max_zone_pfn; + unsigned long total = 0, split = 0; + + if (val != 1) + return -EINVAL; + + for_each_populated_zone(zone) { + max_zone_pfn = zone_end_pfn(zone); + for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { + if (!pfn_valid(pfn)) + continue; + + page = pfn_to_page(pfn); + if (!get_page_unless_zero(page)) + continue; + + if (zone != page_zone(page)) + goto next; + + if (!PageHead(page) || !PageAnon(page) || + PageHuge(page)) + goto next; + + total++; + lock_page(page); + if (!split_huge_page(page)) + split++; + unlock_page(page); +next: + put_page(page); + } + } + + pr_info("%lu of %lu THP split", split, total); + + return 0; +} +DEFINE_SIMPLE_ATTRIBUTE(split_huge_pages_fops, NULL, split_huge_pages_set, + "%llu\n"); + +static int __init split_huge_pages_debugfs(void) +{ + void *ret; + + ret = debugfs_create_file("split_huge_pages", 0644, NULL, NULL, + &split_huge_pages_fops); + if (!ret) + pr_warn("Failed to create split_huge_pages in debugfs"); + return 0; +} +late_initcall(split_huge_pages_debugfs); +#endif |