Commit 30472509 authored by Johannes Weiner's avatar Johannes Weiner Committed by Linus Torvalds
Browse files

mm: remove irqsave/restore locking from contexts with irqs enabled 

The page cache deletion paths all have interrupts enabled, so no need to
use irqsafe/irqrestore locking variants.

They used to have irqs disabled by the memcg lock added in commit
c4843a75 ("memcg: add per cgroup dirty page accounting"), but that has
since been replaced by memcg taking the page lock instead, commit
0a31bc97 ("mm: memcontrol: rewrite uncharge AP").

Link: https://lkml.kernel.org/r/20210614211904.14420-1-hannes@cmpxchg.org


Signed-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 20792ebf

mm/filemap.c

+6 −9
Original line number Diff line number Diff line
@@ -258,12 +258,11 @@ static void page_cache_free_page(struct address_space *mapping, 
void delete_from_page_cache(struct page *page)

{

	struct address_space *mapping = page_mapping(page);

	unsigned long flags;



	BUG_ON(!PageLocked(page));

	xa_lock_irqsave(&mapping->i_pages, flags);

	xa_lock_irq(&mapping->i_pages);

	__delete_from_page_cache(page, NULL);

	xa_unlock_irqrestore(&mapping->i_pages, flags);

	xa_unlock_irq(&mapping->i_pages);



	page_cache_free_page(mapping, page);

}
@@ -335,19 +334,18 @@ void delete_from_page_cache_batch(struct address_space *mapping, 
				  struct pagevec *pvec)

{

	int i;

	unsigned long flags;



	if (!pagevec_count(pvec))

		return;



	xa_lock_irqsave(&mapping->i_pages, flags);

	xa_lock_irq(&mapping->i_pages);

	for (i = 0; i < pagevec_count(pvec); i++) {

		trace_mm_filemap_delete_from_page_cache(pvec->pages[i]);



		unaccount_page_cache_page(mapping, pvec->pages[i]);

	}

	page_cache_delete_batch(mapping, pvec);

	xa_unlock_irqrestore(&mapping->i_pages, flags);

	xa_unlock_irq(&mapping->i_pages);



	for (i = 0; i < pagevec_count(pvec); i++)

		page_cache_free_page(mapping, pvec->pages[i]);
@@ -821,7 +819,6 @@ void replace_page_cache_page(struct page *old, struct page *new) 
	void (*freepage)(struct page *) = mapping->a_ops->freepage;

	pgoff_t offset = old->index;

	XA_STATE(xas, &mapping->i_pages, offset);

	unsigned long flags;



	VM_BUG_ON_PAGE(!PageLocked(old), old);

	VM_BUG_ON_PAGE(!PageLocked(new), new);
@@ -833,7 +830,7 @@ void replace_page_cache_page(struct page *old, struct page *new) 


	mem_cgroup_migrate(old, new);



	xas_lock_irqsave(&xas, flags);

	xas_lock_irq(&xas);

	xas_store(&xas, new);



	old->mapping = NULL;
@@ -846,7 +843,7 @@ void replace_page_cache_page(struct page *old, struct page *new) 
		__dec_lruvec_page_state(old, NR_SHMEM);

	if (PageSwapBacked(new))

		__inc_lruvec_page_state(new, NR_SHMEM);

	xas_unlock_irqrestore(&xas, flags);

	xas_unlock_irq(&xas);

	if (freepage)

		freepage(old);

	put_page(old);

mm/truncate.c

+3 −5
Original line number Diff line number Diff line
@@ -560,21 +560,19 @@ void invalidate_mapping_pagevec(struct address_space *mapping, 
static int

invalidate_complete_page2(struct address_space *mapping, struct page *page)

{

	unsigned long flags;



	if (page->mapping != mapping)

		return 0;



	if (page_has_private(page) && !try_to_release_page(page, GFP_KERNEL))

		return 0;



	xa_lock_irqsave(&mapping->i_pages, flags);

	xa_lock_irq(&mapping->i_pages);

	if (PageDirty(page))

		goto failed;



	BUG_ON(page_has_private(page));

	__delete_from_page_cache(page, NULL);

	xa_unlock_irqrestore(&mapping->i_pages, flags);

	xa_unlock_irq(&mapping->i_pages);



	if (mapping->a_ops->freepage)

		mapping->a_ops->freepage(page);
@@ -582,7 +580,7 @@ invalidate_complete_page2(struct address_space *mapping, struct page *page) 
	put_page(page);	/* pagecache ref */

	return 1;

failed:

	xa_unlock_irqrestore(&mapping->i_pages, flags);

	xa_unlock_irq(&mapping->i_pages);

	return 0;

}

mm/vmscan.c

+4 −5
Original line number Diff line number Diff line
@@ -1052,14 +1052,13 @@ static pageout_t pageout(struct page *page, struct address_space *mapping) 
static int __remove_mapping(struct address_space *mapping, struct page *page,

			    bool reclaimed, struct mem_cgroup *target_memcg)

{

	unsigned long flags;

	int refcount;

	void *shadow = NULL;



	BUG_ON(!PageLocked(page));

	BUG_ON(mapping != page_mapping(page));



	xa_lock_irqsave(&mapping->i_pages, flags);

	xa_lock_irq(&mapping->i_pages);

	/*

	 * The non racy check for a busy page.

	 *
@@ -1100,7 +1099,7 @@ static int __remove_mapping(struct address_space *mapping, struct page *page, 
		if (reclaimed && !mapping_exiting(mapping))

			shadow = workingset_eviction(page, target_memcg);

		__delete_from_swap_cache(page, swap, shadow);

		xa_unlock_irqrestore(&mapping->i_pages, flags);

		xa_unlock_irq(&mapping->i_pages);

		put_swap_page(page, swap);

	} else {

		void (*freepage)(struct page *);
@@ -1126,7 +1125,7 @@ static int __remove_mapping(struct address_space *mapping, struct page *page, 
		    !mapping_exiting(mapping) && !dax_mapping(mapping))

			shadow = workingset_eviction(page, target_memcg);

		__delete_from_page_cache(page, shadow);

		xa_unlock_irqrestore(&mapping->i_pages, flags);

		xa_unlock_irq(&mapping->i_pages);



		if (freepage != NULL)

			freepage(page);
@@ -1135,7 +1134,7 @@ static int __remove_mapping(struct address_space *mapping, struct page *page, 
	return 1;



cannot_free:

	xa_unlock_irqrestore(&mapping->i_pages, flags);

	xa_unlock_irq(&mapping->i_pages);

	return 0;

}