The patch titled
Subject: mm: compaction: introduce sync-light migration for use by compaction
has been added to the -mm tree. Its filename is
mm-compaction-introduce-sync-light-migration-for-use-by-compaction.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
From: Mel Gorman <mgorman@xxxxxxx>
Subject: mm: compaction: introduce sync-light migration for use by compaction
This patch adds a lightweight sync migrate operation MIGRATE_SYNC_LIGHT
mode that avoids writing back pages to backing storage. Async compaction
maps to MIGRATE_ASYNC while sync compaction maps to MIGRATE_SYNC_LIGHT.
For other migrate_pages users such as memory hotplug, MIGRATE_SYNC is
used.
This avoids sync compaction stalling for an excessive length of time,
particularly when copying files to a USB stick where there might be a
large number of dirty pages backed by a filesystem that does not support
->writepages.
[aarcange@xxxxxxxxxx: This patch is heavily based on Andrea's work]
Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
Reviewed-by: Rik van Riel<riel@xxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Minchan Kim <minchan.kim@xxxxxxxxx>
Cc: Dave Jones <davej@xxxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Andy Isaacson <adi@xxxxxxxxxxxxx>
Cc: Nai Xia <nai.xia@xxxxxxxxx>
Cc: Johannes Weiner <jweiner@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/btrfs/disk-io.c | 3 -
fs/hugetlbfs/inode.c | 2
fs/nfs/internal.h | 2
fs/nfs/write.c | 2
include/linux/fs.h | 6 +-
include/linux/migrate.h | 23 ++++++++---
mm/compaction.c | 2
mm/memory-failure.c | 2
mm/memory_hotplug.c | 2
mm/mempolicy.c | 2
mm/migrate.c | 78 ++++++++++++++++++++------------------
11 files changed, 74 insertions(+), 50 deletions(-)
diff -puN fs/btrfs/disk-io.c~mm-compaction-introduce-sync-light-migration-for-use-by-compaction fs/btrfs/disk-io.c
--- a/fs/btrfs/disk-io.c~mm-compaction-introduce-sync-light-migration-for-use-by-compaction
+++ a/fs/btrfs/disk-io.c
@@ -872,7 +872,8 @@ static int btree_submit_bio_hook(struct
#ifdef CONFIG_MIGRATION
static int btree_migratepage(struct address_space *mapping,
- struct page *newpage, struct page *page, bool sync)
+ struct page *newpage, struct page *page,
+ enum migrate_mode sync)
{
/*
* we can't safely write a btree page from here,
diff -puN fs/hugetlbfs/inode.c~mm-compaction-introduce-sync-light-migration-for-use-by-compaction fs/hugetlbfs/inode.c
--- a/fs/hugetlbfs/inode.c~mm-compaction-introduce-sync-light-migration-for-use-by-compaction
+++ a/fs/hugetlbfs/inode.c
@@ -577,7 +577,7 @@ static int hugetlbfs_set_page_dirty(stru
static int hugetlbfs_migrate_page(struct address_space *mapping,
struct page *newpage, struct page *page,
- bool sync)
+ enum migrate_mode mode)
{
int rc;
diff -puN fs/nfs/internal.h~mm-compaction-introduce-sync-light-migration-for-use-by-compaction fs/nfs/internal.h
--- a/fs/nfs/internal.h~mm-compaction-introduce-sync-light-migration-for-use-by-compaction
+++ a/fs/nfs/internal.h
@@ -330,7 +330,7 @@ void nfs_commit_release_pages(struct nfs
#ifdef CONFIG_MIGRATION
extern int nfs_migrate_page(struct address_space *,
- struct page *, struct page *, bool);
+ struct page *, struct page *, enum migrate_mode);
#else
#define nfs_migrate_page NULL
#endif
diff -puN fs/nfs/write.c~mm-compaction-introduce-sync-light-migration-for-use-by-compaction fs/nfs/write.c
--- a/fs/nfs/write.c~mm-compaction-introduce-sync-light-migration-for-use-by-compaction
+++ a/fs/nfs/write.c
@@ -1711,7 +1711,7 @@ out_error:
#ifdef CONFIG_MIGRATION
int nfs_migrate_page(struct address_space *mapping, struct page *newpage,
- struct page *page, bool sync)
+ struct page *page, enum migrate_mode sync)
{
/*
* If PagePrivate is set, then the page is currently associated with
diff -puN include/linux/fs.h~mm-compaction-introduce-sync-light-migration-for-use-by-compaction include/linux/fs.h
--- a/include/linux/fs.h~mm-compaction-introduce-sync-light-migration-for-use-by-compaction
+++ a/include/linux/fs.h
@@ -525,6 +525,7 @@ enum positive_aop_returns {
struct page;
struct address_space;
struct writeback_control;
+enum migrate_mode;
struct iov_iter {
const struct iovec *iov;
@@ -614,7 +615,7 @@ struct address_space_operations {
* is false, it must not block.
*/
int (*migratepage) (struct address_space *,
- struct page *, struct page *, bool);
+ struct page *, struct page *, enum migrate_mode);
int (*launder_page) (struct page *);
int (*is_partially_uptodate) (struct page *, read_descriptor_t *,
unsigned long);
@@ -2582,7 +2583,8 @@ extern int generic_check_addressable(uns
#ifdef CONFIG_MIGRATION
extern int buffer_migrate_page(struct address_space *,
- struct page *, struct page *, bool);
+ struct page *, struct page *,
+ enum migrate_mode);
#else
#define buffer_migrate_page NULL
#endif
diff -puN include/linux/migrate.h~mm-compaction-introduce-sync-light-migration-for-use-by-compaction include/linux/migrate.h
--- a/include/linux/migrate.h~mm-compaction-introduce-sync-light-migration-for-use-by-compaction
+++ a/include/linux/migrate.h
@@ -6,18 +6,31 @@
typedef struct page *new_page_t(struct page *, unsigned long private, int **);
+/*
+ * MIGRATE_ASYNC means never block
+ * MIGRATE_SYNC_LIGHT in the current implementation means to allow blocking
+ * on most operations but not ->writepage as the potential stall time
+ * is too significant
+ * MIGRATE_SYNC will block when migrating pages
+ */
+enum migrate_mode {
+ MIGRATE_ASYNC,
+ MIGRATE_SYNC_LIGHT,
+ MIGRATE_SYNC,
+};
+
#ifdef CONFIG_MIGRATION
#define PAGE_MIGRATION 1
extern void putback_lru_pages(struct list_head *l);
extern int migrate_page(struct address_space *,
- struct page *, struct page *, bool);
+ struct page *, struct page *, enum migrate_mode);
extern int migrate_pages(struct list_head *l, new_page_t x,
unsigned long private, bool offlining,
- bool sync);
+ enum migrate_mode sync);
extern int migrate_huge_pages(struct list_head *l, new_page_t x,
unsigned long private, bool offlining,
- bool sync);
+ enum migrate_mode sync);
extern int fail_migrate_page(struct address_space *,
struct page *, struct page *);
@@ -36,10 +49,10 @@ extern int migrate_huge_page_move_mappin
static inline void putback_lru_pages(struct list_head *l) {}
static inline int migrate_pages(struct list_head *l, new_page_t x,
unsigned long private, bool offlining,
- bool sync) { return -ENOSYS; }
+ enum migrate_mode sync) { return -ENOSYS; }
static inline int migrate_huge_pages(struct list_head *l, new_page_t x,
unsigned long private, bool offlining,
- bool sync) { return -ENOSYS; }
+ enum migrate_mode sync) { return -ENOSYS; }
static inline int migrate_prep(void) { return -ENOSYS; }
static inline int migrate_prep_local(void) { return -ENOSYS; }
diff -puN mm/compaction.c~mm-compaction-introduce-sync-light-migration-for-use-by-compaction mm/compaction.c
--- a/mm/compaction.c~mm-compaction-introduce-sync-light-migration-for-use-by-compaction
+++ a/mm/compaction.c
@@ -557,7 +557,7 @@ static int compact_zone(struct zone *zon
nr_migrate = cc->nr_migratepages;
err = migrate_pages(&cc->migratepages, compaction_alloc,
(unsigned long)cc, false,
- cc->sync);
+ cc->sync ? MIGRATE_SYNC_LIGHT : MIGRATE_ASYNC);
update_nr_listpages(cc);
nr_remaining = cc->nr_migratepages;
diff -puN mm/memory-failure.c~mm-compaction-introduce-sync-light-migration-for-use-by-compaction mm/memory-failure.c
--- a/mm/memory-failure.c~mm-compaction-introduce-sync-light-migration-for-use-by-compaction
+++ a/mm/memory-failure.c
@@ -1557,7 +1557,7 @@ int soft_offline_page(struct page *page,
page_is_file_cache(page));
list_add(&page->lru, &pagelist);
ret = migrate_pages(&pagelist, new_page, MPOL_MF_MOVE_ALL,
- 0, true);
+ 0, MIGRATE_SYNC);
if (ret) {
putback_lru_pages(&pagelist);
pr_info("soft offline: %#lx: migration failed %d, type %lx\n",
diff -puN mm/memory_hotplug.c~mm-compaction-introduce-sync-light-migration-for-use-by-compaction mm/memory_hotplug.c
--- a/mm/memory_hotplug.c~mm-compaction-introduce-sync-light-migration-for-use-by-compaction
+++ a/mm/memory_hotplug.c
@@ -809,7 +809,7 @@ do_migrate_range(unsigned long start_pfn
}
/* this function returns # of failed pages */
ret = migrate_pages(&source, hotremove_migrate_alloc, 0,
- true, true);
+ true, MIGRATE_SYNC);
if (ret)
putback_lru_pages(&source);
}
diff -puN mm/mempolicy.c~mm-compaction-introduce-sync-light-migration-for-use-by-compaction mm/mempolicy.c
--- a/mm/mempolicy.c~mm-compaction-introduce-sync-light-migration-for-use-by-compaction
+++ a/mm/mempolicy.c
@@ -933,7 +933,7 @@ static int migrate_to_node(struct mm_str
if (!list_empty(&pagelist)) {
err = migrate_pages(&pagelist, new_node_page, dest,
- false, true);
+ false, MIGRATE_SYNC);
if (err)
putback_lru_pages(&pagelist);
}
diff -puN mm/migrate.c~mm-compaction-introduce-sync-light-migration-for-use-by-compaction mm/migrate.c
--- a/mm/migrate.c~mm-compaction-introduce-sync-light-migration-for-use-by-compaction
+++ a/mm/migrate.c
@@ -222,12 +222,13 @@ out:
#ifdef CONFIG_BLOCK
/* Returns true if all buffers are successfully locked */
-static bool buffer_migrate_lock_buffers(struct buffer_head *head, bool sync)
+static bool buffer_migrate_lock_buffers(struct buffer_head *head,
+ enum migrate_mode mode)
{
struct buffer_head *bh = head;
/* Simple case, sync compaction */
- if (sync) {
+ if (mode != MIGRATE_ASYNC) {
do {
get_bh(bh);
lock_buffer(bh);
@@ -263,7 +264,7 @@ static bool buffer_migrate_lock_buffers(
}
#else
static inline bool buffer_migrate_lock_buffers(struct buffer_head *head,
- bool sync)
+ enum migrate_mode mode)
{
return true;
}
@@ -279,7 +280,7 @@ static inline bool buffer_migrate_lock_b
*/
static int migrate_page_move_mapping(struct address_space *mapping,
struct page *newpage, struct page *page,
- struct buffer_head *head, bool sync)
+ struct buffer_head *head, enum migrate_mode mode)
{
int expected_count;
void **pslot;
@@ -315,7 +316,8 @@ static int migrate_page_move_mapping(str
* the mapping back due to an elevated page count, we would have to
* block waiting on other references to be dropped.
*/
- if (!sync && head && !buffer_migrate_lock_buffers(head, sync)) {
+ if (mode == MIGRATE_ASYNC && head &&
+ !buffer_migrate_lock_buffers(head, mode)) {
page_unfreeze_refs(page, expected_count);
spin_unlock_irq(&mapping->tree_lock);
return -EAGAIN;
@@ -476,13 +478,14 @@ EXPORT_SYMBOL(fail_migrate_page);
* Pages are locked upon entry and exit.
*/
int migrate_page(struct address_space *mapping,
- struct page *newpage, struct page *page, bool sync)
+ struct page *newpage, struct page *page,
+ enum migrate_mode mode)
{
int rc;
BUG_ON(PageWriteback(page)); /* Writeback must be complete */
- rc = migrate_page_move_mapping(mapping, newpage, page, NULL, sync);
+ rc = migrate_page_move_mapping(mapping, newpage, page, NULL, mode);
if (rc)
return rc;
@@ -499,17 +502,17 @@ EXPORT_SYMBOL(migrate_page);
* exist.
*/
int buffer_migrate_page(struct address_space *mapping,
- struct page *newpage, struct page *page, bool sync)
+ struct page *newpage, struct page *page, enum migrate_mode mode)
{
struct buffer_head *bh, *head;
int rc;
if (!page_has_buffers(page))
- return migrate_page(mapping, newpage, page, sync);
+ return migrate_page(mapping, newpage, page, mode);
head = page_buffers(page);
- rc = migrate_page_move_mapping(mapping, newpage, page, head, sync);
+ rc = migrate_page_move_mapping(mapping, newpage, page, head, mode);
if (rc)
return rc;
@@ -519,8 +522,8 @@ int buffer_migrate_page(struct address_s
* with an IRQ-safe spinlock held. In the sync case, the buffers
* need to be locked now
*/
- if (sync)
- BUG_ON(!buffer_migrate_lock_buffers(head, sync));
+ if (mode != MIGRATE_ASYNC)
+ BUG_ON(!buffer_migrate_lock_buffers(head, mode));
ClearPagePrivate(page);
set_page_private(newpage, page_private(page));
@@ -597,10 +600,11 @@ static int writeout(struct address_space
* Default handling if a filesystem does not provide a migration function.
*/
static int fallback_migrate_page(struct address_space *mapping,
- struct page *newpage, struct page *page, bool sync)
+ struct page *newpage, struct page *page, enum migrate_mode mode)
{
if (PageDirty(page)) {
- if (!sync)
+ /* Only writeback pages in full synchronous migration */
+ if (mode != MIGRATE_SYNC)
return -EBUSY;
return writeout(mapping, page);
}
@@ -613,7 +617,7 @@ static int fallback_migrate_page(struct
!try_to_release_page(page, GFP_KERNEL))
return -EAGAIN;
- return migrate_page(mapping, newpage, page, sync);
+ return migrate_page(mapping, newpage, page, mode);
}
/*
@@ -628,7 +632,7 @@ static int fallback_migrate_page(struct
* == 0 - success
*/
static int move_to_new_page(struct page *newpage, struct page *page,
- int remap_swapcache, bool sync)
+ int remap_swapcache, enum migrate_mode mode)
{
struct address_space *mapping;
int rc;
@@ -649,7 +653,7 @@ static int move_to_new_page(struct page
mapping = page_mapping(page);
if (!mapping)
- rc = migrate_page(mapping, newpage, page, sync);
+ rc = migrate_page(mapping, newpage, page, mode);
else if (mapping->a_ops->migratepage)
/*
* Most pages have a mapping and most filesystems provide a
@@ -658,9 +662,9 @@ static int move_to_new_page(struct page
* is the most common path for page migration.
*/
rc = mapping->a_ops->migratepage(mapping,
- newpage, page, sync);
+ newpage, page, mode);
else
- rc = fallback_migrate_page(mapping, newpage, page, sync);
+ rc = fallback_migrate_page(mapping, newpage, page, mode);
if (rc) {
newpage->mapping = NULL;
@@ -675,7 +679,7 @@ static int move_to_new_page(struct page
}
static int __unmap_and_move(struct page *page, struct page *newpage,
- int force, bool offlining, bool sync)
+ int force, bool offlining, enum migrate_mode mode)
{
int rc = -EAGAIN;
int remap_swapcache = 1;
@@ -684,7 +688,7 @@ static int __unmap_and_move(struct page
struct anon_vma *anon_vma = NULL;
if (!trylock_page(page)) {
- if (!force || !sync)
+ if (!force || mode == MIGRATE_ASYNC)
goto out;
/*
@@ -730,10 +734,12 @@ static int __unmap_and_move(struct page
if (PageWriteback(page)) {
/*
- * For !sync, there is no point retrying as the retry loop
- * is expected to be too short for PageWriteback to be cleared
+ * Only in the case of a full syncronous migration is it
+ * necessary to wait for PageWriteback. In the async case,
+ * the retry loop is too short and in the sync-light case,
+ * the overhead of stalling is too much
*/
- if (!sync) {
+ if (mode != MIGRATE_SYNC) {
rc = -EBUSY;
goto uncharge;
}
@@ -804,7 +810,7 @@ static int __unmap_and_move(struct page
skip_unmap:
if (!page_mapped(page))
- rc = move_to_new_page(newpage, page, remap_swapcache, sync);
+ rc = move_to_new_page(newpage, page, remap_swapcache, mode);
if (rc && remap_swapcache)
remove_migration_ptes(page, page);
@@ -827,7 +833,8 @@ out:
* to the newly allocated page in newpage.
*/
static int unmap_and_move(new_page_t get_new_page, unsigned long private,
- struct page *page, int force, bool offlining, bool sync)
+ struct page *page, int force, bool offlining,
+ enum migrate_mode mode)
{
int rc = 0;
int *result = NULL;
@@ -845,7 +852,7 @@ static int unmap_and_move(new_page_t get
if (unlikely(split_huge_page(page)))
goto out;
- rc = __unmap_and_move(page, newpage, force, offlining, sync);
+ rc = __unmap_and_move(page, newpage, force, offlining, mode);
out:
if (rc != -EAGAIN) {
/*
@@ -893,7 +900,8 @@ out:
*/
static int unmap_and_move_huge_page(new_page_t get_new_page,
unsigned long private, struct page *hpage,
- int force, bool offlining, bool sync)
+ int force, bool offlining,
+ enum migrate_mode mode)
{
int rc = 0;
int *result = NULL;
@@ -906,7 +914,7 @@ static int unmap_and_move_huge_page(new_
rc = -EAGAIN;
if (!trylock_page(hpage)) {
- if (!force || !sync)
+ if (!force || mode != MIGRATE_SYNC)
goto out;
lock_page(hpage);
}
@@ -917,7 +925,7 @@ static int unmap_and_move_huge_page(new_
try_to_unmap(hpage, TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS);
if (!page_mapped(hpage))
- rc = move_to_new_page(new_hpage, hpage, 1, sync);
+ rc = move_to_new_page(new_hpage, hpage, 1, mode);
if (rc)
remove_migration_ptes(hpage, hpage);
@@ -960,7 +968,7 @@ out:
*/
int migrate_pages(struct list_head *from,
new_page_t get_new_page, unsigned long private, bool offlining,
- bool sync)
+ enum migrate_mode mode)
{
int retry = 1;
int nr_failed = 0;
@@ -981,7 +989,7 @@ int migrate_pages(struct list_head *from
rc = unmap_and_move(get_new_page, private,
page, pass > 2, offlining,
- sync);
+ mode);
switch(rc) {
case -ENOMEM:
@@ -1011,7 +1019,7 @@ out:
int migrate_huge_pages(struct list_head *from,
new_page_t get_new_page, unsigned long private, bool offlining,
- bool sync)
+ enum migrate_mode mode)
{
int retry = 1;
int nr_failed = 0;
@@ -1028,7 +1036,7 @@ int migrate_huge_pages(struct list_head
rc = unmap_and_move_huge_page(get_new_page,
private, page, pass > 2, offlining,
- sync);
+ mode);
switch(rc) {
case -ENOMEM:
@@ -1157,7 +1165,7 @@ set_status:
err = 0;
if (!list_empty(&pagelist)) {
err = migrate_pages(&pagelist, new_page_node,
- (unsigned long)pm, 0, true);
+ (unsigned long)pm, 0, MIGRATE_SYNC);
if (err)
putback_lru_pages(&pagelist);
}
_
Subject: Subject: mm: compaction: introduce sync-light migration for use by compaction
Patches currently in -mm which might be from mgorman@xxxxxxx are
linux-next.patch
mm-page-writebackc-make-determine_dirtyable_memory-static-again.patch
mm-reduce-the-amount-of-work-done-when-updating-min_free_kbytes.patch
mm-reduce-the-amount-of-work-done-when-updating-min_free_kbytes-checkpatch-fixes.patch
mm-avoid-livelock-on-__gfp_fs-allocations-v2.patch
mm-more-intensive-memory-corruption-debug.patch
mm-more-intensive-memory-corruption-debug-fix.patch
pm-hibernate-do-not-count-debug-pages-as-savable.patch
slub-min-order-when-debug_guardpage_minorder-0.patch
mm-debug-test-for-online-nid-when-allocating-on-single-node.patch
mm-exclude-reserved-pages-from-dirtyable-memory.patch
mm-exclude-reserved-pages-from-dirtyable-memory-fix.patch
mm-try-to-distribute-dirty-pages-fairly-across-zones.patch
mm-filemap-pass-__gfp_write-from-grab_cache_page_write_begin.patch
btrfs-pass-__gfp_write-for-buffered-write-page-allocations.patch
mm-compaction-push-isolate-search-base-of-compact-control-one-pfn-ahead.patch
mm-fix-off-by-two-in-__zone_watermark_ok.patch
mremap-enforce-rmap-src-dst-vma-ordering-in-case-of-vma_merge-succeeding-in-copy_vma.patch
mremap-enforce-rmap-src-dst-vma-ordering-in-case-of-vma_merge-succeeding-in-copy_vma-update.patch
mm-do-not-stall-in-synchronous-compaction-for-thp-allocations.patch
revert-mm-do-not-stall-in-synchronous-compaction-for-thp-allocations.patch
mm-compaction-allow-compaction-to-isolate-dirty-pages.patch
mm-compaction-use-synchronous-compaction-for-proc-sys-vm-compact_memory.patch
mm-vmscan-check-if-we-isolated-a-compound-page-during-lumpy-scan.patch
mm-vmscan-do-not-oom-if-aborting-reclaim-to-start-compaction.patch
mm-compaction-determine-if-dirty-pages-can-be-migrated-without-blocking-within-migratepage.patch
mm-compaction-make-isolate_lru_page-filter-aware-again.patch
mm-page-allocator-do-not-call-direct-reclaim-for-thp-allocations-while-compaction-is-deferred.patch
mm-compaction-introduce-sync-light-migration-for-use-by-compaction.patch
mm-vmscan-when-reclaiming-for-compaction-ensure-there-are-sufficient-free-pages-available.patch
mm-vmscan-check-if-reclaim-should-really-abort-even-if-compaction_ready-is-true-for-one-zone.patch
mm-isolate-pages-for-immediate-reclaim-on-their-own-lru.patch
--
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