Commit 25ff8b15 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle)
Browse files

mm/writeback: Add folio_account_redirty() 



Account the number of pages in the folio that we're redirtying.
Turn account_page_dirty() into a wrapper around it.  Also turn
the comment on folio_account_redirty() into kernel-doc and
edit it slightly so it makes sense to its potential callers.

Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDavid Howells <dhowells@redhat.com>
Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
parent 9350f20a

include/linux/writeback.h

+5 −1
Original line number Original line Diff line number Diff line
@@ -394,7 +394,11 @@ void tag_pages_for_writeback(struct address_space *mapping, 
			     pgoff_t start, pgoff_t end);

			     pgoff_t start, pgoff_t end);





bool filemap_dirty_folio(struct address_space *mapping, struct folio *folio);

bool filemap_dirty_folio(struct address_space *mapping, struct folio *folio);

void account_page_redirty(struct page *page);

void folio_account_redirty(struct folio *folio);

static inline void account_page_redirty(struct page *page)

{

	folio_account_redirty(page_folio(page));

}





void sb_mark_inode_writeback(struct inode *inode);

void sb_mark_inode_writeback(struct inode *inode);

void sb_clear_inode_writeback(struct inode *inode);

void sb_clear_inode_writeback(struct inode *inode);

mm/page-writeback.c

+19 −13
Original line number Original line Diff line number Diff line
@@ -1084,7 +1084,7 @@ static void wb_update_write_bandwidth(struct bdi_writeback *wb, 
	 * write_bandwidth = ---------------------------------------------------

	 * write_bandwidth = ---------------------------------------------------

	 *                                          period

	 *                                          period

	 *

	 *

	 * @written may have decreased due to account_page_redirty().

	 * @written may have decreased due to folio_account_redirty().

	 * Avoid underflowing @bw calculation.

	 * Avoid underflowing @bw calculation.

	 */

	 */

	bw = written - min(written, wb->written_stamp);

	bw = written - min(written, wb->written_stamp);
@@ -2544,30 +2544,36 @@ bool filemap_dirty_folio(struct address_space *mapping, struct folio *folio) 
}

}

EXPORT_SYMBOL(filemap_dirty_folio);

EXPORT_SYMBOL(filemap_dirty_folio);





/*

/**

 * Call this whenever redirtying a page, to de-account the dirty counters

 * folio_account_redirty - Manually account for redirtying a page.

 * (NR_DIRTIED, WB_DIRTIED, tsk->nr_dirtied), so that they match the written

 * @folio: The folio which is being redirtied.

 * counters (NR_WRITTEN, WB_WRITTEN) in long term. The mismatches will lead to

 *

 * systematic errors in balanced_dirty_ratelimit and the dirty pages position

 * Most filesystems should call folio_redirty_for_writepage() instead

 * control.

 * of this fuction.  If your filesystem is doing writeback outside the

 * context of a writeback_control(), it can call this when redirtying

 * a folio, to de-account the dirty counters (NR_DIRTIED, WB_DIRTIED,

 * tsk->nr_dirtied), so that they match the written counters (NR_WRITTEN,

 * WB_WRITTEN) in long term. The mismatches will lead to systematic errors

 * in balanced_dirty_ratelimit and the dirty pages position control.

 */

 */

void account_page_redirty(struct page *page)

void folio_account_redirty(struct folio *folio)

{

{

	struct address_space *mapping = page->mapping;

	struct address_space *mapping = folio->mapping;





	if (mapping && mapping_can_writeback(mapping)) {

	if (mapping && mapping_can_writeback(mapping)) {

		struct inode *inode = mapping->host;

		struct inode *inode = mapping->host;

		struct bdi_writeback *wb;

		struct bdi_writeback *wb;

		struct wb_lock_cookie cookie = {};

		struct wb_lock_cookie cookie = {};

		long nr = folio_nr_pages(folio);





		wb = unlocked_inode_to_wb_begin(inode, &cookie);

		wb = unlocked_inode_to_wb_begin(inode, &cookie);

		current->nr_dirtied--;

		current->nr_dirtied -= nr;

		dec_node_page_state(page, NR_DIRTIED);

		node_stat_mod_folio(folio, NR_DIRTIED, -nr);

		dec_wb_stat(wb, WB_DIRTIED);

		wb_stat_mod(wb, WB_DIRTIED, -nr);

		unlocked_inode_to_wb_end(inode, &cookie);

		unlocked_inode_to_wb_end(inode, &cookie);

	}

	}

}

}

EXPORT_SYMBOL(account_page_redirty);

EXPORT_SYMBOL(folio_account_redirty);





/*

/*

 * When a writepage implementation decides that it doesn't want to write this

 * When a writepage implementation decides that it doesn't want to write this