Messages in this thread Patch in this message | | | Date | Tue, 10 Jan 2006 14:41:40 -0800 (PST) | From | Christoph Lameter <> | Subject | [PATCH 5/5] Direct Migration V9: Avoid writeback / page_migrate() method |
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Migrate a page with buffers without requiring writeback
This introduces a new address space operation migratepage() that may be used by a filesystem to implement its own version of page migration.
A version is provided that migrates buffers attached to pages. Some filesystems (ext2, ext3, xfs) are modified to utilize this feature.
The swapper address space operation are modified so that a regular migrate_page() will occur for anonymous pages without writeback (migrate_pages forces every anonymous page to have a swap entry).
V7->V8: - Export more functions in order for loadable filesystems to be able to define their own migration function.
V2->V3: - export functions for filesystems that are modules and for modules that perform migration by calling migrate_pages(). - Fix macro name clash. Fix build on UP and systems without CONFIG_MIGRATION
V1->V2: - Fix CONFIG_MIGRATION handling
Signed-off-by: Mike Kravetz <kravetz@us.ibm.com> Signed-off-by: Christoph Lameter <clameter@sgi.com>
Index: linux-2.6.15/include/linux/fs.h =================================================================== --- linux-2.6.15.orig/include/linux/fs.h 2006-01-10 09:43:04.000000000 -0800 +++ linux-2.6.15/include/linux/fs.h 2006-01-10 14:31:54.000000000 -0800 @@ -369,6 +369,8 @@ struct address_space_operations { loff_t offset, unsigned long nr_segs); struct page* (*get_xip_page)(struct address_space *, sector_t, int); + /* migrate the contents of a page to the specified target */ + int (*migratepage) (struct page *, struct page *); }; struct backing_dev_info; @@ -1713,6 +1715,12 @@ extern void simple_release_fs(struct vfs extern ssize_t simple_read_from_buffer(void __user *, size_t, loff_t *, const void *, size_t); +#ifdef CONFIG_MIGRATION +extern int buffer_migrate_page(struct page *, struct page *); +#else +#define buffer_migrate_page NULL +#endif + extern int inode_change_ok(struct inode *, struct iattr *); extern int __must_check inode_setattr(struct inode *, struct iattr *); Index: linux-2.6.15/mm/swap_state.c =================================================================== --- linux-2.6.15.orig/mm/swap_state.c 2006-01-10 09:43:04.000000000 -0800 +++ linux-2.6.15/mm/swap_state.c 2006-01-10 14:31:54.000000000 -0800 @@ -27,6 +27,7 @@ static struct address_space_operations s .writepage = swap_writepage, .sync_page = block_sync_page, .set_page_dirty = __set_page_dirty_nobuffers, + .migratepage = migrate_page, }; static struct backing_dev_info swap_backing_dev_info = { Index: linux-2.6.15/fs/xfs/linux-2.6/xfs_aops.c =================================================================== --- linux-2.6.15.orig/fs/xfs/linux-2.6/xfs_aops.c 2006-01-02 19:21:10.000000000 -0800 +++ linux-2.6.15/fs/xfs/linux-2.6/xfs_aops.c 2006-01-10 14:31:54.000000000 -0800 @@ -1347,4 +1347,5 @@ struct address_space_operations linvfs_a .commit_write = generic_commit_write, .bmap = linvfs_bmap, .direct_IO = linvfs_direct_IO, + .migratepage = buffer_migrate_page, }; Index: linux-2.6.15/fs/buffer.c =================================================================== --- linux-2.6.15.orig/fs/buffer.c 2006-01-10 09:43:04.000000000 -0800 +++ linux-2.6.15/fs/buffer.c 2006-01-10 14:31:54.000000000 -0800 @@ -3049,6 +3049,71 @@ asmlinkage long sys_bdflush(int func, lo } /* + * Migration function for pages with buffers. This function can only be used + * if the underlying filesystem guarantees that no other references to "page" + * exist. + */ +#ifdef CONFIG_MIGRATION +int buffer_migrate_page(struct page *newpage, struct page *page) +{ + struct address_space *mapping = page->mapping; + struct buffer_head *bh, *head; + + if (!mapping) + return -EAGAIN; + + if (!page_has_buffers(page)) + return migrate_page(newpage, page); + + head = page_buffers(page); + + if (migrate_page_remove_references(newpage, page, 3)) + return -EAGAIN; + + spin_lock(&mapping->private_lock); + + bh = head; + do { + get_bh(bh); + lock_buffer(bh); + bh = bh->b_this_page; + + } while (bh != head); + + ClearPagePrivate(page); + set_page_private(newpage, page_private(page)); + set_page_private(page, 0); + put_page(page); + get_page(newpage); + + bh = head; + do { + set_bh_page(bh, newpage, bh_offset(bh)); + bh = bh->b_this_page; + + } while (bh != head); + + SetPagePrivate(newpage); + spin_unlock(&mapping->private_lock); + + migrate_page_copy(newpage, page); + + spin_lock(&mapping->private_lock); + bh = head; + do { + unlock_buffer(bh); + put_bh(bh); + bh = bh->b_this_page; + + } while (bh != head); + spin_unlock(&mapping->private_lock); + + return 0; +} +EXPORT_SYMBOL(buffer_migrate_page); +#endif + +/* * Buffer-head allocation */ static kmem_cache_t *bh_cachep; Index: linux-2.6.15/fs/ext3/inode.c =================================================================== --- linux-2.6.15.orig/fs/ext3/inode.c 2006-01-02 19:21:10.000000000 -0800 +++ linux-2.6.15/fs/ext3/inode.c 2006-01-10 14:31:54.000000000 -0800 @@ -1559,6 +1559,7 @@ static struct address_space_operations e .invalidatepage = ext3_invalidatepage, .releasepage = ext3_releasepage, .direct_IO = ext3_direct_IO, + .migratepage = buffer_migrate_page, }; static struct address_space_operations ext3_writeback_aops = { @@ -1572,6 +1573,7 @@ static struct address_space_operations e .invalidatepage = ext3_invalidatepage, .releasepage = ext3_releasepage, .direct_IO = ext3_direct_IO, + .migratepage = buffer_migrate_page, }; static struct address_space_operations ext3_journalled_aops = { Index: linux-2.6.15/fs/ext2/inode.c =================================================================== --- linux-2.6.15.orig/fs/ext2/inode.c 2006-01-02 19:21:10.000000000 -0800 +++ linux-2.6.15/fs/ext2/inode.c 2006-01-10 14:31:54.000000000 -0800 @@ -706,6 +706,7 @@ struct address_space_operations ext2_aop .bmap = ext2_bmap, .direct_IO = ext2_direct_IO, .writepages = ext2_writepages, + .migratepage = buffer_migrate_page, }; struct address_space_operations ext2_aops_xip = { @@ -723,6 +724,7 @@ struct address_space_operations ext2_nob .bmap = ext2_bmap, .direct_IO = ext2_direct_IO, .writepages = ext2_writepages, + .migratepage = buffer_migrate_page, }; /* Index: linux-2.6.15/fs/xfs/linux-2.6/xfs_buf.c =================================================================== --- linux-2.6.15.orig/fs/xfs/linux-2.6/xfs_buf.c 2006-01-02 19:21:10.000000000 -0800 +++ linux-2.6.15/fs/xfs/linux-2.6/xfs_buf.c 2006-01-10 14:31:54.000000000 -0800 @@ -1568,6 +1568,7 @@ xfs_mapping_buftarg( struct address_space *mapping; static struct address_space_operations mapping_aops = { .sync_page = block_sync_page, + .migratepage = fail_migrate_page, }; inode = new_inode(bdev->bd_inode->i_sb); Index: linux-2.6.15/mm/vmscan.c =================================================================== --- linux-2.6.15.orig/mm/vmscan.c 2006-01-10 14:31:45.000000000 -0800 +++ linux-2.6.15/mm/vmscan.c 2006-01-10 14:31:54.000000000 -0800 @@ -604,6 +604,15 @@ int putback_lru_pages(struct list_head * } /* + * Non migratable page + */ +int fail_migrate_page(struct page *newpage, struct page *page) +{ + return -EIO; +} +EXPORT_SYMBOL(fail_migrate_page); + +/* * swapout a single page * page is locked upon entry, unlocked on exit */ @@ -648,6 +657,8 @@ unlock_retry: retry: return -EAGAIN; } +EXPORT_SYMBOL(swap_page); + /* * Page migration was first developed in the context of the memory hotplug * project. The main authors of the migration code are: @@ -748,6 +759,7 @@ int migrate_page_remove_references(struc return 0; } +EXPORT_SYMBOL(migrate_page_remove_references); /* * Copy the page to its new location @@ -787,6 +799,7 @@ void migrate_page_copy(struct page *newp if (PageWriteback(newpage)) end_page_writeback(newpage); } +EXPORT_SYMBOL(migrate_page_copy); /* * Common logic to directly migrate a single page suitable for @@ -814,6 +827,7 @@ int migrate_page(struct page *newpage, s remove_from_swap(newpage); return 0; } +EXPORT_SYMBOL(migrate_page); /* * migrate_pages @@ -913,6 +927,11 @@ redo: if (!mapping) goto unlock_both; + if (mapping->a_ops->migratepage) { + rc = mapping->a_ops->migratepage(newpage, page); + goto unlock_both; + } + /* * Trigger writeout if page is dirty */ @@ -982,6 +1001,7 @@ next: return nr_failed + retry; } +EXPORT_SYMBOL(migrate_pages); static void lru_add_drain_per_cpu(void *dummy) { @@ -1024,6 +1044,7 @@ redo: } return rc; } +EXPORT_SYMBOL(isolate_lru_page); #endif /* Index: linux-2.6.15/include/linux/swap.h =================================================================== --- linux-2.6.15.orig/include/linux/swap.h 2006-01-10 14:31:45.000000000 -0800 +++ linux-2.6.15/include/linux/swap.h 2006-01-10 14:31:54.000000000 -0800 @@ -183,6 +183,11 @@ extern int migrate_page_remove_reference extern void migrate_page_copy(struct page *, struct page *); extern int migrate_pages(struct list_head *l, struct list_head *t, struct list_head *moved, struct list_head *failed); +extern int fail_migrate_page(struct page *, struct page *); +#else +/* Possible settings for the migrate_page() method in address_operations */ +#define migrate_page NULL +#define fail_migrate_page NULL #endif #ifdef CONFIG_MMU Index: linux-2.6.15/mm/rmap.c =================================================================== --- linux-2.6.15.orig/mm/rmap.c 2006-01-10 14:31:45.000000000 -0800 +++ linux-2.6.15/mm/rmap.c 2006-01-10 14:31:54.000000000 -0800 @@ -232,6 +232,7 @@ void remove_from_swap(struct page *page) delete_from_swap_cache(page); } +EXPORT_SYMBOL(remove_from_swap); #endif /* - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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