The patch titled
Subject: mm, page_owner: track and print last migrate reason
has been added to the -mm tree. Its filename is
mm-page_owner-track-and-print-last-migrate-reason.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-page_owner-track-and-print-last-migrate-reason.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-page_owner-track-and-print-last-migrate-reason.patch
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------------------------------------------------------
From: Vlastimil Babka <vbabka@xxxxxxx>
Subject: mm, page_owner: track and print last migrate reason
During migration, page_owner info is now copied with the rest of the page,
so the stacktrace leading to free page allocation during migration is
overwritten. For debugging purposes, it might be however useful to know
that the page has been migrated since its initial allocation. This might
happen many times during the lifetime for different reasons and fully
tracking this, especially with stacktraces would incur extra memory costs.
As a compromise, store and print the migrate_reason of the last migration
that occured to the page. This is enough to distinguish compaction, numa
balancing etc.
Example page_owner entry after the patch:
Page allocated via order 0, mask 0x24280ca
PFN 669757 type Reclaimable Block 1308 type Reclaimable Flags UDLA
[<ffffffff81164e8a>] __alloc_pages_nodemask+0x15a/0xa30
[<ffffffff811ad435>] alloc_pages_vma+0xb5/0x250
[<ffffffff8118ba54>] handle_mm_fault+0x1304/0x1820
[<ffffffff81051213>] __do_page_fault+0x183/0x3f0
[<ffffffff810514a2>] do_page_fault+0x22/0x30
[<ffffffff81573ba8>] page_fault+0x28/0x30
[<ffffffffffffffff>] 0xffffffffffffffff
Page has been migrated, last migrate reason: compaction
Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Sasha Levin <sasha.levin@xxxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/migrate.h | 6 +++++-
include/linux/page_ext.h | 1 +
include/linux/page_owner.h | 9 +++++++++
mm/migrate.c | 20 +++++++++++++++++---
mm/page_owner.c | 17 +++++++++++++++++
5 files changed, 49 insertions(+), 4 deletions(-)
diff -puN include/linux/migrate.h~mm-page_owner-track-and-print-last-migrate-reason include/linux/migrate.h
--- a/include/linux/migrate.h~mm-page_owner-track-and-print-last-migrate-reason
+++ a/include/linux/migrate.h
@@ -23,9 +23,13 @@ enum migrate_reason {
MR_SYSCALL, /* also applies to cpusets */
MR_MEMPOLICY_MBIND,
MR_NUMA_MISPLACED,
- MR_CMA
+ MR_CMA,
+ MR_TYPES
};
+/* In mm/migrate.c; also keep sync with include/trace/events/migrate.h */
+extern char * migrate_reason_names[MR_TYPES];
+
#ifdef CONFIG_MIGRATION
extern void putback_movable_pages(struct list_head *l);
diff -puN include/linux/page_ext.h~mm-page_owner-track-and-print-last-migrate-reason include/linux/page_ext.h
--- a/include/linux/page_ext.h~mm-page_owner-track-and-print-last-migrate-reason
+++ a/include/linux/page_ext.h
@@ -45,6 +45,7 @@ struct page_ext {
unsigned int order;
gfp_t gfp_mask;
unsigned int nr_entries;
+ int last_migrate_reason;
unsigned long trace_entries[8];
#endif
};
diff -puN include/linux/page_owner.h~mm-page_owner-track-and-print-last-migrate-reason include/linux/page_owner.h
--- a/include/linux/page_owner.h~mm-page_owner-track-and-print-last-migrate-reason
+++ a/include/linux/page_owner.h
@@ -12,6 +12,7 @@ extern void __set_page_owner(struct page
unsigned int order, gfp_t gfp_mask);
extern gfp_t __get_page_owner_gfp(struct page *page);
extern void __copy_page_owner(struct page *oldpage, struct page *newpage);
+extern void __set_page_owner_migrate_reason(struct page *page, int reason);
static inline void reset_page_owner(struct page *page, unsigned int order)
{
@@ -38,6 +39,11 @@ static inline void copy_page_owner(struc
if (static_branch_unlikely(&page_owner_inited))
__copy_page_owner(oldpage, newpage);
}
+static inline void set_page_owner_migrate_reason(struct page *page, int reason)
+{
+ if (static_branch_unlikely(&page_owner_inited))
+ __set_page_owner_migrate_reason(page, reason);
+}
#else
static inline void reset_page_owner(struct page *page, unsigned int order)
{
@@ -53,5 +59,8 @@ static inline gfp_t get_page_owner_gfp(s
static inline void copy_page_owner(struct page *oldpage, struct page *newpage)
{
}
+static inline void set_page_owner_migrate_reason(struct page *page, int reason)
+{
+}
#endif /* CONFIG_PAGE_OWNER */
#endif /* __LINUX_PAGE_OWNER_H */
diff -puN mm/migrate.c~mm-page_owner-track-and-print-last-migrate-reason mm/migrate.c
--- a/mm/migrate.c~mm-page_owner-track-and-print-last-migrate-reason
+++ a/mm/migrate.c
@@ -47,6 +47,16 @@
#include "internal.h"
+char *migrate_reason_names[MR_TYPES] = {
+ "compaction",
+ "memory_failure",
+ "memory_hotplug",
+ "syscall_or_cpuset",
+ "mempolicy_mbind",
+ "numa_misplaced",
+ "cma",
+};
+
/*
* migrate_prep() needs to be called before we start compiling a list of pages
* to be migrated using isolate_lru_page(). If scheduling work on other CPUs is
@@ -955,8 +965,10 @@ static ICE_noinline int unmap_and_move(n
}
rc = __unmap_and_move(page, newpage, force, mode);
- if (rc == MIGRATEPAGE_SUCCESS)
+ if (rc == MIGRATEPAGE_SUCCESS) {
put_new_page = NULL;
+ set_page_owner_migrate_reason(newpage, reason);
+ }
out:
if (rc != -EAGAIN) {
@@ -1021,7 +1033,7 @@ out:
static int unmap_and_move_huge_page(new_page_t get_new_page,
free_page_t put_new_page, unsigned long private,
struct page *hpage, int force,
- enum migrate_mode mode)
+ enum migrate_mode mode, int reason)
{
int rc = -EAGAIN;
int *result = NULL;
@@ -1079,6 +1091,7 @@ put_anon:
if (rc == MIGRATEPAGE_SUCCESS) {
hugetlb_cgroup_migrate(hpage, new_hpage);
put_new_page = NULL;
+ set_page_owner_migrate_reason(new_hpage, reason);
}
unlock_page(hpage);
@@ -1151,7 +1164,7 @@ int migrate_pages(struct list_head *from
if (PageHuge(page))
rc = unmap_and_move_huge_page(get_new_page,
put_new_page, private, page,
- pass > 2, mode);
+ pass > 2, mode, reason);
else
rc = unmap_and_move(get_new_page, put_new_page,
private, page, pass > 2, mode,
@@ -1842,6 +1855,7 @@ fail_putback:
set_page_memcg(new_page, page_memcg(page));
set_page_memcg(page, NULL);
page_remove_rmap(page, true);
+ set_page_owner_migrate_reason(new_page, MR_NUMA_MISPLACED);
spin_unlock(ptl);
mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
diff -puN mm/page_owner.c~mm-page_owner-track-and-print-last-migrate-reason mm/page_owner.c
--- a/mm/page_owner.c~mm-page_owner-track-and-print-last-migrate-reason
+++ a/mm/page_owner.c
@@ -6,6 +6,7 @@
#include <linux/stacktrace.h>
#include <linux/page_owner.h>
#include <linux/jump_label.h>
+#include <linux/migrate.h>
#include "internal.h"
static bool page_owner_disabled = true;
@@ -73,10 +74,18 @@ void __set_page_owner(struct page *page,
page_ext->order = order;
page_ext->gfp_mask = gfp_mask;
page_ext->nr_entries = trace.nr_entries;
+ page_ext->last_migrate_reason = -1;
__set_bit(PAGE_EXT_OWNER, &page_ext->flags);
}
+void __set_page_owner_migrate_reason(struct page *page, int reason)
+{
+ struct page_ext *page_ext = lookup_page_ext(page);
+
+ page_ext->last_migrate_reason = reason;
+}
+
gfp_t __get_page_owner_gfp(struct page *page)
{
struct page_ext *page_ext = lookup_page_ext(page);
@@ -161,6 +170,14 @@ print_page_owner(char __user *buf, size_
if (ret >= count)
goto err;
+ if (page_ext->last_migrate_reason != -1) {
+ ret += snprintf(kbuf + ret, count - ret,
+ "Page has been migrated, last migrate reason: %s\n",
+ migrate_reason_names[page_ext->last_migrate_reason]);
+ if (ret >= count)
+ goto err;
+ }
+
ret += snprintf(kbuf + ret, count - ret, "\n");
if (ret >= count)
goto err;
_
Patches currently in -mm which might be from vbabka@xxxxxxx are
mm-fix-swapped-movable-and-reclaimable-in-proc-pagetypeinfo.patch
mm-documentation-clarify-proc-pid-status-vmswap-limitations-for-shmem.patch
mm-proc-account-for-shmem-swap-in-proc-pid-smaps.patch
mm-proc-reduce-cost-of-proc-pid-smaps-for-shmem-mappings.patch
mm-proc-reduce-cost-of-proc-pid-smaps-for-unpopulated-shmem-mappings.patch
mm-debug-fix-wrongly-filtered-flags-in-dump_vma.patch
mm-page_owner-print-symbolic-migratetype-of-both-page-and-pageblock.patch
mm-page_owner-convert-page_owner_inited-to-static-key.patch
mm-page_owner-copy-page-owner-info-during-migration.patch
mm-page_owner-track-and-print-last-migrate-reason.patch
mm-debug-introduce-dump_gfpflag_names-for-symbolic-printing-of-gfp_flags.patch
mm-page_owner-dump-page-owner-info-from-dump_page.patch
mm-page_alloc-print-symbolic-gfp_flags-on-allocation-failure.patch
mm-oom-print-symbolic-gfp_flags-in-oom-warning.patch
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