Commit 89574945 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Matthew Wilcox (Oracle)
Browse files

mm: simplify freeing of devmap managed pages 

Make put_devmap_managed_page return if it took charge of the page
or not and remove the separate page_is_devmap_managed helper.

Link: https://lkml.kernel.org/r/20220210072828.2930359-6-hch@lst.de


Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarLogan Gunthorpe <logang@deltatee.com>
Reviewed-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Reviewed-by: default avatarChaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: default avatarDan Williams <dan.j.williams@intel.com>
Tested-by: default avatar"Sierra Guiza, Alejandro (Alex)" <alex.sierra@amd.com>

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Christian Knig <christian.koenig@amd.com>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Karol Herbst <kherbst@redhat.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: "Pan, Xinhui" <Xinhui.Pan@amd.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
parent 75e55d8a

include/linux/mm.h

+10 −24
Original line number Diff line number Diff line
@@ -1094,33 +1094,24 @@ static inline bool is_zone_movable_page(const struct page *page) 
#ifdef CONFIG_DEV_PAGEMAP_OPS

DECLARE_STATIC_KEY_FALSE(devmap_managed_key);



static inline bool page_is_devmap_managed(struct page *page)

bool __put_devmap_managed_page(struct page *page);

static inline bool put_devmap_managed_page(struct page *page)

{

	if (!static_branch_unlikely(&devmap_managed_key))

		return false;

	if (!is_zone_device_page(page))

		return false;

	switch (page->pgmap->type) {

	case MEMORY_DEVICE_PRIVATE:

	case MEMORY_DEVICE_FS_DAX:

		return true;

	default:

		break;

	}

	if (page->pgmap->type != MEMORY_DEVICE_PRIVATE &&

	    page->pgmap->type != MEMORY_DEVICE_FS_DAX)

		return false;

	return __put_devmap_managed_page(page);

}



void put_devmap_managed_page(struct page *page);



#else /* CONFIG_DEV_PAGEMAP_OPS */

static inline bool page_is_devmap_managed(struct page *page)

static inline bool put_devmap_managed_page(struct page *page)

{

	return false;

}



static inline void put_devmap_managed_page(struct page *page)

{

}

#endif /* CONFIG_DEV_PAGEMAP_OPS */



static inline bool is_device_private_page(const struct page *page)
@@ -1220,16 +1211,11 @@ static inline void put_page(struct page *page) 
	struct folio *folio = page_folio(page);



	/*

	 * For devmap managed pages we need to catch refcount transition from

	 * 2 to 1, when refcount reach one it means the page is free and we

	 * need to inform the device driver through callback. See

	 * include/linux/memremap.h and HMM for details.

	 * For some devmap managed pages we need to catch refcount transition

	 * from 2 to 1:

	 */

	if (page_is_devmap_managed(&folio->page)) {

		put_devmap_managed_page(&folio->page);

	if (put_devmap_managed_page(&folio->page))

		return;

	}



	folio_put(folio);

}

mm/memremap.c

+9 −11
Original line number Diff line number Diff line
@@ -502,24 +502,22 @@ void free_devmap_managed_page(struct page *page) 
	page->pgmap->ops->page_free(page);

}



void put_devmap_managed_page(struct page *page)

bool __put_devmap_managed_page(struct page *page)

{

	int count;



	if (WARN_ON_ONCE(!page_is_devmap_managed(page)))

		return;



	count = page_ref_dec_return(page);



	/*

	 * devmap page refcounts are 1-based, rather than 0-based: if

	 * refcount is 1, then the page is free and the refcount is

	 * stable because nobody holds a reference on the page.

	 */

	if (count == 1)

	switch (page_ref_dec_return(page)) {

	case 1:

		free_devmap_managed_page(page);

	else if (!count)

		break;

	case 0:

		__put_page(page);

		break;

	}

	return true;

}

EXPORT_SYMBOL(put_devmap_managed_page);

EXPORT_SYMBOL(__put_devmap_managed_page);

#endif /* CONFIG_DEV_PAGEMAP_OPS */

mm/swap.c

+1 −9
Original line number Diff line number Diff line
@@ -930,16 +930,8 @@ void release_pages(struct page **pages, int nr) 
				unlock_page_lruvec_irqrestore(lruvec, flags);

				lruvec = NULL;

			}

			/*

			 * ZONE_DEVICE pages that return 'false' from

			 * page_is_devmap_managed() do not require special

			 * processing, and instead, expect a call to

			 * put_page_testzero().

			 */

			if (page_is_devmap_managed(page)) {

				put_devmap_managed_page(page);

			if (put_devmap_managed_page(page))

				continue;

			}

			if (put_page_testzero(page))

				put_dev_pagemap(page->pgmap);

			continue;