[PATCH v13 066/137] mm/writeback: Add __folio_end_writeback()

Matthew Wilcox (Oracle)
2021-07-12T03:43:37Z

test_clear_page_writeback() is actually an mm-internal function, although
it's named as if it's a pagecache function. Move it to mm/internal.h,
rename it to __folio_end_writeback() and change the return type to bool.

The conversion from page to folio is mostly about accounting the number
of pages being written back, although it does eliminate a couple of
calls to compound_head().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
include/linux/page-flags.h | 1 -
mm/filemap.c | 2 +-
mm/internal.h | 1 +
mm/page-writeback.c | 29 +++++++++++++++--------------
4 files changed, 17 insertions(+), 16 deletions(-)

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index fb914468b302..fb5219ab9eee 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -655,7 +655,6 @@ static __always_inline void SetPageUptodate(struct page *page)

CLEARPAGEFLAG(Uptodate, uptodate, PF_NO_TAIL)

-int test_clear_page_writeback(struct page *page);
int __test_set_page_writeback(struct page *page, bool keep_write);

#define test_set_page_writeback(page) \
diff --git a/mm/filemap.c b/mm/filemap.c
index cc21da4157f1..b04c91ad294c 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1535,7 +1535,7 @@ void folio_end_writeback(struct folio *folio)
* reused before the folio_wake().
*/
folio_get(folio);
- if (!test_clear_page_writeback(&folio->page))
+ if (!__folio_end_writeback(folio))
BUG();

smp_mb__after_atomic();
diff --git a/mm/internal.h b/mm/internal.h
index fa31a7f0ed79..08e8a28994d1 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -43,6 +43,7 @@ static inline void *folio_raw_mapping(struct folio *folio)

vm_fault_t do_swap_page(struct vm_fault *vmf);
void folio_rotate_reclaimable(struct folio *folio);
+bool __folio_end_writeback(struct folio *folio);

void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
unsigned long floor, unsigned long ceiling);
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 1056ff779bfe..c173fc831d3a 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -583,7 +583,7 @@ static void wb_domain_writeout_add(struct wb_domain *dom,

/*
* Increment @wb's writeout completion count and the global writeout
- * completion count. Called from test_clear_page_writeback().
+ * completion count. Called from __folio_end_writeback().
*/
static inline void __wb_writeout_add(struct bdi_writeback *wb, long nr)
{
@@ -2731,27 +2731,28 @@ int clear_page_dirty_for_io(struct page *page)
}
EXPORT_SYMBOL(clear_page_dirty_for_io);

-int test_clear_page_writeback(struct page *page)
+bool __folio_end_writeback(struct folio *folio)
{
- struct address_space *mapping = page_mapping(page);
- int ret;
+ long nr = folio_nr_pages(folio);
+ struct address_space *mapping = folio_mapping(folio);
+ bool ret;

- lock_page_memcg(page);
+ folio_memcg_lock(folio);
if (mapping && mapping_use_writeback_tags(mapping)) {
struct inode *inode = mapping->host;
struct backing_dev_info *bdi = inode_to_bdi(inode);
unsigned long flags;

xa_lock_irqsave(&mapping->i_pages, flags);
- ret = TestClearPageWriteback(page);
+ ret = folio_test_clear_writeback_flag(folio);
if (ret) {
- __xa_clear_mark(&mapping->i_pages, page_index(page),
+ __xa_clear_mark(&mapping->i_pages, folio_index(folio),
PAGECACHE_TAG_WRITEBACK);
if (bdi->capabilities & BDI_CAP_WRITEBACK_ACCT) {
struct bdi_writeback *wb = inode_to_wb(inode);

- dec_wb_stat(wb, WB_WRITEBACK);
- __wb_writeout_add(wb, 1);
+ wb_stat_mod(wb, WB_WRITEBACK, -nr);
+ __wb_writeout_add(wb, nr);
}
}

@@ -2761,14 +2762,14 @@ int test_clear_page_writeback(struct page *page)

xa_unlock_irqrestore(&mapping->i_pages, flags);
} else {
- ret = TestClearPageWriteback(page);
+ ret = folio_test_clear_writeback_flag(folio);
}
if (ret) {
- dec_lruvec_page_state(page, NR_WRITEBACK);
- dec_zone_page_state(page, NR_ZONE_WRITE_PENDING);
- inc_node_page_state(page, NR_WRITTEN);
+ 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);
}
- unlock_page_memcg(page);
+ folio_memcg_unlock(folio);
return ret;
}

--
2.30.2