f2fs: add customized migrate_page callback

This patch improves the migration of dirty pages and allows migrating atomic
written pages that F2FS uses in Page Cache. Instead of the fallback releasing
page path, it provides better performance for memory compaction, CMA and other
users of memory page migrating. For dirty pages, there is no need to write back
first when migrating. For an atomic written page before committing, we can
migrate the page and update the related 'inmem_pages' list at the same time.

Signed-off-by: Weichao Guo <guoweichao@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
[Jaegeuk Kim: fix some coding style]
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 591db95222d131c517c0e12e25d8910fc0017910..64e389285f54ee92ea1bb96e863c96c012e6e2d7 100644 (file)
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -388,6 +388,9 @@ const struct address_space_operations f2fs_meta_aops = {
        .set_page_dirty = f2fs_set_meta_page_dirty,
        .invalidatepage = f2fs_invalidate_page,
        .releasepage    = f2fs_release_page,
+#ifdef CONFIG_MIGRATION
+       .migratepage    = f2fs_migrate_page,
+#endif
 };
 
 static void __add_ino_entry(struct f2fs_sb_info *sbi, nid_t ino, int type)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 637b81d0f9f0ade57ed171f3e0da74d7979306d8..ed834cd0250204149a6bca18a255305908e422b6 100644 (file)
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1883,6 +1883,58 @@ static sector_t f2fs_bmap(struct address_space *mapping, sector_t block)
        return generic_block_bmap(mapping, block, get_data_block_bmap);
 }
 
+#ifdef CONFIG_MIGRATION
+#include <linux/migrate.h>
+
+int f2fs_migrate_page(struct address_space *mapping,
+               struct page *newpage, struct page *page, enum migrate_mode mode)
+{
+       int rc, extra_count;
+       struct f2fs_inode_info *fi = F2FS_I(mapping->host);
+       bool atomic_written = IS_ATOMIC_WRITTEN_PAGE(page);
+
+       BUG_ON(PageWriteback(page));
+
+       /* migrating an atomic written page is safe with the inmem_lock hold */
+       if (atomic_written && !mutex_trylock(&fi->inmem_lock))
+               return -EAGAIN;
+
+       /*
+        * A reference is expected if PagePrivate set when move mapping,
+        * however F2FS breaks this for maintaining dirty page counts when
+        * truncating pages. So here adjusting the 'extra_count' make it work.
+        */
+       extra_count = (atomic_written ? 1 : 0) - page_has_private(page);
+       rc = migrate_page_move_mapping(mapping, newpage,
+                               page, NULL, mode, extra_count);
+       if (rc != MIGRATEPAGE_SUCCESS) {
+               if (atomic_written)
+                       mutex_unlock(&fi->inmem_lock);
+               return rc;
+       }
+
+       if (atomic_written) {
+               struct inmem_pages *cur;
+               list_for_each_entry(cur, &fi->inmem_pages, list)
+                       if (cur->page == page) {
+                               cur->page = newpage;
+                               break;
+                       }
+               mutex_unlock(&fi->inmem_lock);
+               put_page(page);
+               get_page(newpage);
+       }
+
+       if (PagePrivate(page))
+               SetPagePrivate(newpage);
+       set_page_private(newpage, page_private(page));
+
+       migrate_page_copy(newpage, page);
+
+       return MIGRATEPAGE_SUCCESS;
+}
+#endif
+
 const struct address_space_operations f2fs_dblock_aops = {
        .readpage       = f2fs_read_data_page,
        .readpages      = f2fs_read_data_pages,
@@ -1895,4 +1947,7 @@ const struct address_space_operations f2fs_dblock_aops = {
        .releasepage    = f2fs_release_page,
        .direct_IO      = f2fs_direct_IO,
        .bmap           = f2fs_bmap,
+#ifdef CONFIG_MIGRATION
+       .migratepage    = f2fs_migrate_page,
+#endif
 };

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 2fb8c353ab4acd19bcd2e02661b42df881f0d3dc..0903191149619e9f4720334fd0c8214859a1b3af 100644 (file)
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -2152,6 +2152,10 @@ int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *, u64, u64);
 void f2fs_set_page_dirty_nobuffers(struct page *);
 void f2fs_invalidate_page(struct page *, unsigned int, unsigned int);
 int f2fs_release_page(struct page *, gfp_t);
+#ifdef CONFIG_MIGRATION
+int f2fs_migrate_page(struct address_space *, struct page *, struct page *,
+                               enum migrate_mode);
+#endif
 
 /*
  * gc.c

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 2322a8e817bf6c0e529e90398c712e6b925fe938..55c22a9c4f9e67553261959a3f2c7d014d891e4b 100644 (file)
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1670,6 +1670,9 @@ const struct address_space_operations f2fs_node_aops = {
        .set_page_dirty = f2fs_set_node_page_dirty,
        .invalidatepage = f2fs_invalidate_page,
        .releasepage    = f2fs_release_page,
+#ifdef CONFIG_MIGRATION
+       .migratepage    = f2fs_migrate_page,
+#endif
 };
 
 static struct free_nid *__lookup_free_nid_list(struct f2fs_nm_info *nm_i,