Messages in this thread | | | Date | Tue, 31 Jul 2012 13:43:37 -0300 | From | Herton Ronaldo Krzesinski <> | Subject | Re: [ 28/41] mm: compaction: introduce sync-light migration for use by compaction |
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On Mon, Jul 30, 2012 at 10:31:27AM -0700, Greg Kroah-Hartman wrote: > From: Greg KH <gregkh@linuxfoundation.org> > > 3.0-stable review patch. If anyone has any objections, please let me know. > > ------------------ > > From: Mel Gorman <mgorman@suse.de> > > commit a6bc32b899223a877f595ef9ddc1e89ead5072b8 upstream.
We need also to pick recent fix dc32f63453f56d07a1073a697dcd843dd3098c09 after applying this one.
> > Stable note: Not tracked in Buzilla. This was part of a series that > reduced interactivity stalls experienced when THP was enabled. > These stalls were particularly noticable when copying data > to a USB stick but the experiences for users varied a lot. > > 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@redhat.com: This patch is heavily based on Andrea's work] > [akpm@linux-foundation.org: fix fs/nfs/write.c build] > [akpm@linux-foundation.org: fix fs/btrfs/disk-io.c build] > Signed-off-by: Mel Gorman <mgorman@suse.de> > Reviewed-by: Rik van Riel <riel@redhat.com> > Cc: Andrea Arcangeli <aarcange@redhat.com> > Cc: Minchan Kim <minchan.kim@gmail.com> > Cc: Dave Jones <davej@redhat.com> > Cc: Jan Kara <jack@suse.cz> > Cc: Andy Isaacson <adi@hexapodia.org> > Cc: Nai Xia <nai.xia@gmail.com> > Cc: Johannes Weiner <jweiner@redhat.com> > Signed-off-by: Andrew Morton <akpm@linux-foundation.org> > Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> > Signed-off-by: Mel Gorman <mgorman@suse.de> > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > > --- > fs/btrfs/disk-io.c | 5 +-- > fs/hugetlbfs/inode.c | 2 - > fs/nfs/internal.h | 2 - > fs/nfs/write.c | 4 +- > 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, 76 insertions(+), 52 deletions(-) > > --- a/fs/btrfs/disk-io.c > +++ b/fs/btrfs/disk-io.c > @@ -801,7 +801,8 @@ 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 mode) > { > /* > * we can't safely write a btree page from here, > @@ -816,7 +817,7 @@ static int btree_migratepage(struct addr > if (page_has_private(page) && > !try_to_release_page(page, GFP_KERNEL)) > return -EAGAIN; > - return migrate_page(mapping, newpage, page, sync); > + return migrate_page(mapping, newpage, page, mode); > } > #endif > > --- a/fs/hugetlbfs/inode.c > +++ b/fs/hugetlbfs/inode.c > @@ -569,7 +569,7 @@ 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; > > --- a/fs/nfs/internal.h > +++ b/fs/nfs/internal.h > @@ -315,7 +315,7 @@ 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 > --- a/fs/nfs/write.c > +++ b/fs/nfs/write.c > @@ -1662,7 +1662,7 @@ 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 mode) > { > /* > * If PagePrivate is set, then the page is currently associated with > @@ -1677,7 +1677,7 @@ int nfs_migrate_page(struct address_spac > > nfs_fscache_release_page(page, GFP_KERNEL); > > - return migrate_page(mapping, newpage, page, sync); > + return migrate_page(mapping, newpage, page, mode); > } > #endif > > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -523,6 +523,7 @@ enum positive_aop_returns { > struct page; > struct address_space; > struct writeback_control; > +enum migrate_mode; > > struct iov_iter { > const struct iovec *iov; > @@ -612,7 +613,7 @@ 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); > @@ -2481,7 +2482,8 @@ 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 > --- a/include/linux/migrate.h > +++ b/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 mode); > extern int migrate_huge_pages(struct list_head *l, new_page_t x, > unsigned long private, bool offlining, > - bool sync); > + enum migrate_mode mode); > > 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 mode) { 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 mode) { return -ENOSYS; } > > static inline int migrate_prep(void) { return -ENOSYS; } > static inline int migrate_prep_local(void) { return -ENOSYS; } > --- a/mm/compaction.c > +++ b/mm/compaction.c > @@ -577,7 +577,7 @@ 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; > > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -1464,7 +1464,7 @@ 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", > --- a/mm/memory_hotplug.c > +++ b/mm/memory_hotplug.c > @@ -747,7 +747,7 @@ 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); > } > --- a/mm/mempolicy.c > +++ b/mm/mempolicy.c > @@ -926,7 +926,7 @@ 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); > } > --- a/mm/migrate.c > +++ b/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; > @@ -478,13 +480,14 @@ 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; > @@ -501,17 +504,17 @@ 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; > @@ -521,8 +524,8 @@ 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)); > @@ -599,10 +602,11 @@ 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); > } > @@ -615,7 +619,7 @@ 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); > } > > /* > @@ -630,7 +634,7 @@ 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; > @@ -651,7 +655,7 @@ 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 > @@ -660,9 +664,9 @@ 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; > @@ -677,7 +681,7 @@ 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; > @@ -686,7 +690,7 @@ 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; > > /* > @@ -732,10 +736,12 @@ 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; > } > @@ -806,7 +812,7 @@ 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); > @@ -829,7 +835,8 @@ 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; > @@ -847,7 +854,7 @@ 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) { > /* > @@ -895,7 +902,8 @@ 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; > @@ -908,7 +916,7 @@ 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); > } > @@ -919,7 +927,7 @@ 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); > @@ -962,7 +970,7 @@ 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; > @@ -983,7 +991,7 @@ 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: > @@ -1013,7 +1021,7 @@ 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; > @@ -1030,7 +1038,7 @@ 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: > @@ -1159,7 +1167,7 @@ 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); > } > > > -- > To unsubscribe from this list: send the line "unsubscribe stable" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >
-- []'s Herton
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