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mm: Convert page-writeback to XArray

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Includes moving mapping_tagged() to fs.h as a static inline, and
changing it to return bool.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
This commit is contained in:
Matthew Wilcox 2017-11-22 11:41:23 -05:00
parent 8fa8e538e4
commit ff9c745b81
2 changed files with 37 additions and 54 deletions
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19
include/linux/fs.h
View File

@ -483,15 +483,18 @@ struct block_device {
struct mutex bd_fsfreeze_mutex;
} __randomize_layout;
/*
* Radix-tree tags, for tagging dirty and writeback pages within the pagecache
* radix trees
*/
#define PAGECACHE_TAG_DIRTY 0
#define PAGECACHE_TAG_WRITEBACK 1
#define PAGECACHE_TAG_TOWRITE 2
/* XArray tags, for tagging dirty and writeback pages in the pagecache. */
#define PAGECACHE_TAG_DIRTY XA_MARK_0
#define PAGECACHE_TAG_WRITEBACK XA_MARK_1
#define PAGECACHE_TAG_TOWRITE XA_MARK_2
int mapping_tagged(struct address_space *mapping, int tag);
/*
* Returns true if any of the pages in the mapping are marked with the tag.
*/
static inline bool mapping_tagged(struct address_space *mapping, xa_mark_t tag)
{
return xa_marked(&mapping->i_pages, tag);
}
static inline void i_mmap_lock_write(struct address_space *mapping)
{

72
mm/page-writeback.c
View File

@ -2097,34 +2097,25 @@ void __init page_writeback_init(void)
* dirty pages in the file (thus it is important for this function to be quick
* so that it can tag pages faster than a dirtying process can create them).
*/
/*
* We tag pages in batches of WRITEBACK_TAG_BATCH to reduce the i_pages lock
* latency.
*/
void tag_pages_for_writeback(struct address_space *mapping,
pgoff_t start, pgoff_t end)
{
#define WRITEBACK_TAG_BATCH 4096
unsigned long tagged = 0;
struct radix_tree_iter iter;
void **slot;
XA_STATE(xas, &mapping->i_pages, start);
unsigned int tagged = 0;
void *page;
xa_lock_irq(&mapping->i_pages);
radix_tree_for_each_tagged(slot, &mapping->i_pages, &iter, start,
PAGECACHE_TAG_DIRTY) {
if (iter.index > end)
break;
radix_tree_iter_tag_set(&mapping->i_pages, &iter,
PAGECACHE_TAG_TOWRITE);
tagged++;
if ((tagged % WRITEBACK_TAG_BATCH) != 0)
xas_lock_irq(&xas);
xas_for_each_marked(&xas, page, end, PAGECACHE_TAG_DIRTY) {
xas_set_mark(&xas, PAGECACHE_TAG_TOWRITE);
if (++tagged % XA_CHECK_SCHED)
continue;
slot = radix_tree_iter_resume(slot, &iter);
xa_unlock_irq(&mapping->i_pages);
xas_pause(&xas);
xas_unlock_irq(&xas);
cond_resched();
xa_lock_irq(&mapping->i_pages);
xas_lock_irq(&xas);
}
xa_unlock_irq(&mapping->i_pages);
xas_unlock_irq(&xas);
}
EXPORT_SYMBOL(tag_pages_for_writeback);
@ -2164,7 +2155,7 @@ int write_cache_pages(struct address_space *mapping,
pgoff_t done_index;
int cycled;
int range_whole = 0;
int tag;
xa_mark_t tag;
pagevec_init(&pvec);
if (wbc->range_cyclic) {
@ -2445,7 +2436,7 @@ void account_page_cleaned(struct page *page, struct address_space *mapping,
/*
* For address_spaces which do not use buffers. Just tag the page as dirty in
* its radix tree.
* the xarray.
*
* This is also used when a single buffer is being dirtied: we want to set the
* page dirty in that case, but not all the buffers. This is a "bottom-up"
@ -2471,7 +2462,7 @@ int __set_page_dirty_nobuffers(struct page *page)
BUG_ON(page_mapping(page) != mapping);
WARN_ON_ONCE(!PagePrivate(page) && !PageUptodate(page));
account_page_dirtied(page, mapping);
radix_tree_tag_set(&mapping->i_pages, page_index(page),
__xa_set_mark(&mapping->i_pages, page_index(page),
PAGECACHE_TAG_DIRTY);
xa_unlock_irqrestore(&mapping->i_pages, flags);
unlock_page_memcg(page);
@ -2634,13 +2625,13 @@ EXPORT_SYMBOL(__cancel_dirty_page);
* Returns true if the page was previously dirty.
*
* This is for preparing to put the page under writeout. We leave the page
* tagged as dirty in the radix tree so that a concurrent write-for-sync
* tagged as dirty in the xarray so that a concurrent write-for-sync
* can discover it via a PAGECACHE_TAG_DIRTY walk. The ->writepage
* implementation will run either set_page_writeback() or set_page_dirty(),
* at which stage we bring the page's dirty flag and radix-tree dirty tag
* at which stage we bring the page's dirty flag and xarray dirty tag
* back into sync.
*
* This incoherency between the page's dirty flag and radix-tree tag is
* This incoherency between the page's dirty flag and xarray tag is
* unfortunate, but it only exists while the page is locked.
*/
int clear_page_dirty_for_io(struct page *page)
@ -2721,7 +2712,7 @@ int test_clear_page_writeback(struct page *page)
xa_lock_irqsave(&mapping->i_pages, flags);
ret = TestClearPageWriteback(page);
if (ret) {
radix_tree_tag_clear(&mapping->i_pages, page_index(page),
__xa_clear_mark(&mapping->i_pages, page_index(page),
PAGECACHE_TAG_WRITEBACK);
if (bdi_cap_account_writeback(bdi)) {
struct bdi_writeback *wb = inode_to_wb(inode);
@ -2761,11 +2752,13 @@ int __test_set_page_writeback(struct page *page, bool keep_write)
lock_page_memcg(page);
if (mapping && mapping_use_writeback_tags(mapping)) {
XA_STATE(xas, &mapping->i_pages, page_index(page));
struct inode *inode = mapping->host;
struct backing_dev_info *bdi = inode_to_bdi(inode);
unsigned long flags;
xa_lock_irqsave(&mapping->i_pages, flags);
xas_lock_irqsave(&xas, flags);
xas_load(&xas);
ret = TestSetPageWriteback(page);
if (!ret) {
bool on_wblist;
@ -2773,8 +2766,7 @@ int __test_set_page_writeback(struct page *page, bool keep_write)
on_wblist = mapping_tagged(mapping,
PAGECACHE_TAG_WRITEBACK);
radix_tree_tag_set(&mapping->i_pages, page_index(page),
PAGECACHE_TAG_WRITEBACK);
xas_set_mark(&xas, PAGECACHE_TAG_WRITEBACK);
if (bdi_cap_account_writeback(bdi))
inc_wb_stat(inode_to_wb(inode), WB_WRITEBACK);
@ -2787,12 +2779,10 @@ int __test_set_page_writeback(struct page *page, bool keep_write)
sb_mark_inode_writeback(mapping->host);
}
if (!PageDirty(page))
radix_tree_tag_clear(&mapping->i_pages, page_index(page),
PAGECACHE_TAG_DIRTY);
xas_clear_mark(&xas, PAGECACHE_TAG_DIRTY);
if (!keep_write)
radix_tree_tag_clear(&mapping->i_pages, page_index(page),
PAGECACHE_TAG_TOWRITE);
xa_unlock_irqrestore(&mapping->i_pages, flags);
xas_clear_mark(&xas, PAGECACHE_TAG_TOWRITE);
xas_unlock_irqrestore(&xas, flags);
} else {
ret = TestSetPageWriteback(page);
}
@ -2806,16 +2796,6 @@ int __test_set_page_writeback(struct page *page, bool keep_write)
}
EXPORT_SYMBOL(__test_set_page_writeback);
/*
* Return true if any of the pages in the mapping are marked with the
* passed tag.
*/
int mapping_tagged(struct address_space *mapping, int tag)
{
return radix_tree_tagged(&mapping->i_pages, tag);
}
EXPORT_SYMBOL(mapping_tagged);
/**
* wait_for_stable_page() - wait for writeback to finish, if necessary.
* @page: The page to wait on.