Commit 2580d554 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

mm: use folio_xor_flags_has_waiters() in folio_end_writeback() 

Match how folio_unlock() works by combining the test for PG_waiters with
the clearing of PG_writeback.  This should have a small performance win,
and removes the last user of folio_wake().

Link: https://lkml.kernel.org/r/20231004165317.1061855-18-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 7d0795d0

mm/filemap.c

+3 −12
Original line number Diff line number Diff line
@@ -1175,13 +1175,6 @@ static void folio_wake_bit(struct folio *folio, int bit_nr) 
	spin_unlock_irqrestore(&q->lock, flags);

}



static void folio_wake(struct folio *folio, int bit)

{

	if (!folio_test_waiters(folio))

		return;

	folio_wake_bit(folio, bit);

}



/*

 * A choice of three behaviors for folio_wait_bit_common():

 */
@@ -1618,13 +1611,11 @@ void folio_end_writeback(struct folio *folio) 
	 * Writeback does not hold a folio reference of its own, relying

	 * on truncation to wait for the clearing of PG_writeback.

	 * But here we must make sure that the folio is not freed and

	 * reused before the folio_wake().

	 * reused before the folio_wake_bit().

	 */

	folio_get(folio);

	__folio_end_writeback(folio);



	smp_mb__after_atomic();

	folio_wake(folio, PG_writeback);

	if (__folio_end_writeback(folio))

		folio_wake_bit(folio, PG_writeback);

	acct_reclaim_writeback(folio);

	folio_put(folio);

}

mm/internal.h

+1 −1
Original line number Diff line number Diff line
@@ -105,7 +105,7 @@ static inline void wake_throttle_isolated(pg_data_t *pgdat) 


vm_fault_t do_swap_page(struct vm_fault *vmf);

void folio_rotate_reclaimable(struct folio *folio);

void __folio_end_writeback(struct folio *folio);

bool __folio_end_writeback(struct folio *folio);

void deactivate_file_folio(struct folio *folio);

void folio_activate(struct folio *folio);

mm/page-writeback.c

+6 −3
Original line number Diff line number Diff line
@@ -2940,10 +2940,11 @@ static void wb_inode_writeback_end(struct bdi_writeback *wb) 
	spin_unlock_irqrestore(&wb->work_lock, flags);

}



void __folio_end_writeback(struct folio *folio)

bool __folio_end_writeback(struct folio *folio)

{

	long nr = folio_nr_pages(folio);

	struct address_space *mapping = folio_mapping(folio);

	bool ret;



	folio_memcg_lock(folio);

	if (mapping && mapping_use_writeback_tags(mapping)) {
@@ -2952,7 +2953,7 @@ void __folio_end_writeback(struct folio *folio) 
		unsigned long flags;



		xa_lock_irqsave(&mapping->i_pages, flags);

		folio_test_clear_writeback(folio);

		ret = folio_xor_flags_has_waiters(folio, 1 << PG_writeback);

		__xa_clear_mark(&mapping->i_pages, folio_index(folio),

					PAGECACHE_TAG_WRITEBACK);

		if (bdi->capabilities & BDI_CAP_WRITEBACK_ACCT) {
@@ -2970,13 +2971,15 @@ void __folio_end_writeback(struct folio *folio) 


		xa_unlock_irqrestore(&mapping->i_pages, flags);

	} else {

		folio_test_clear_writeback(folio);

		ret = folio_xor_flags_has_waiters(folio, 1 << PG_writeback);

	}



	lruvec_stat_mod_folio(folio, NR_WRITEBACK, -nr);

	zone_stat_mod_folio(folio, NR_ZONE_WRITE_PENDING, -nr);

	node_stat_mod_folio(folio, NR_WRITTEN, nr);

	folio_memcg_unlock(folio);



	return ret;

}



bool __folio_start_writeback(struct folio *folio, bool keep_write)