Commit aa62204c authored by Lorenzo Stoakes's avatar Lorenzo Stoakes Committed by Andrew Morton
Browse files

mm: avoid unnecessary use of is_swap_pmd() 

PMD 'non-swap' swap entries are currently used for PMD-level migration
entries and device private entries.

To add to the confusion in this terminology we use is_swap_pmd() in an
inconsistent way similar to how is_swap_pte() was being used - sometimes
adopting the convention that !pmd_none(), !pmd_present() implies PMD 'swap'
entry, sometimes not.

This patch handles the low-hanging fruit of cases where we can simply
substitute other predicates for is_swap_pmd().

No functional change intended.

Link: https://lkml.kernel.org/r/8a1704b36a009c18032d5bea4cb68e71448fbbe5.1762812360.git.lorenzo.stoakes@oracle.com


Signed-off-by: default avatarLorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: default avatarVlastimil Babka <vbabka@suse.cz>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Janosch Frank <frankja@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Xu <weixugc@google.com>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent de4d6c94

fs/proc/task_mmu.c

+12 −3
Original line number Diff line number Diff line
@@ -1059,10 +1059,12 @@ static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr, 
	bool present = false;

	struct folio *folio;



	if (pmd_none(*pmd))

		return;

	if (pmd_present(*pmd)) {

		page = vm_normal_page_pmd(vma, addr, *pmd);

		present = true;

	} else if (unlikely(thp_migration_supported() && is_swap_pmd(*pmd))) {

	} else if (unlikely(thp_migration_supported())) {

		swp_entry_t entry = pmd_to_swp_entry(*pmd);



		if (is_pfn_swap_entry(entry))
@@ -2000,6 +2002,9 @@ static int pagemap_pmd_range_thp(pmd_t *pmdp, unsigned long addr, 
	if (vma->vm_flags & VM_SOFTDIRTY)

		flags |= PM_SOFT_DIRTY;



	if (pmd_none(pmd))

		goto populate_pagemap;



	if (pmd_present(pmd)) {

		page = pmd_page(pmd);
@@ -2010,7 +2015,7 @@ static int pagemap_pmd_range_thp(pmd_t *pmdp, unsigned long addr, 
			flags |= PM_UFFD_WP;

		if (pm->show_pfn)

			frame = pmd_pfn(pmd) + idx;

	} else if (thp_migration_supported() && is_swap_pmd(pmd)) {

	} else if (thp_migration_supported()) {

		swp_entry_t entry = pmd_to_swp_entry(pmd);

		unsigned long offset;
@@ -2037,6 +2042,7 @@ static int pagemap_pmd_range_thp(pmd_t *pmdp, unsigned long addr, 
			flags |= PM_FILE;

	}



populate_pagemap:

	for (; addr != end; addr += PAGE_SIZE, idx++) {

		u64 cur_flags = flags;

		pagemap_entry_t pme;
@@ -2399,6 +2405,9 @@ static unsigned long pagemap_thp_category(struct pagemap_scan_private *p, 
{

	unsigned long categories = PAGE_IS_HUGE;



	if (pmd_none(pmd))

		return categories;



	if (pmd_present(pmd)) {

		struct page *page;
@@ -2416,7 +2425,7 @@ static unsigned long pagemap_thp_category(struct pagemap_scan_private *p, 
			categories |= PAGE_IS_PFNZERO;

		if (pmd_soft_dirty(pmd))

			categories |= PAGE_IS_SOFT_DIRTY;

	} else if (is_swap_pmd(pmd)) {

	} else {

		swp_entry_t swp;



		categories |= PAGE_IS_SWAPPED;

include/linux/swapops.h

+14 −2
Original line number Diff line number Diff line
@@ -509,7 +509,13 @@ static inline pmd_t swp_entry_to_pmd(swp_entry_t entry) 


static inline int is_pmd_migration_entry(pmd_t pmd)

{

	return is_swap_pmd(pmd) && is_migration_entry(pmd_to_swp_entry(pmd));

	swp_entry_t entry;



	if (pmd_present(pmd))

		return 0;



	entry = pmd_to_swp_entry(pmd);

	return is_migration_entry(entry);

}

#else  /* CONFIG_ARCH_ENABLE_THP_MIGRATION */

static inline int set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
@@ -557,7 +563,13 @@ static inline int is_pmd_migration_entry(pmd_t pmd) 
 */

static inline int is_pmd_device_private_entry(pmd_t pmd)

{

	return is_swap_pmd(pmd) && is_device_private_entry(pmd_to_swp_entry(pmd));

	swp_entry_t entry;



	if (pmd_present(pmd))

		return 0;



	entry = pmd_to_swp_entry(pmd);

	return is_device_private_entry(entry);

}



#else /* CONFIG_ZONE_DEVICE && CONFIG_ARCH_ENABLE_THP_MIGRATION */

mm/huge_memory.c

+3 −1
Original line number Diff line number Diff line
@@ -2354,9 +2354,11 @@ static pmd_t move_soft_dirty_pmd(pmd_t pmd) 


static pmd_t clear_uffd_wp_pmd(pmd_t pmd)

{

	if (pmd_none(pmd))

		return pmd;

	if (pmd_present(pmd))

		pmd = pmd_clear_uffd_wp(pmd);

	else if (is_swap_pmd(pmd))

	else

		pmd = pmd_swp_clear_uffd_wp(pmd);



	return pmd;

mm/memory.c

+28 −22
Original line number Diff line number Diff line
@@ -1376,6 +1376,7 @@ copy_pmd_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 
		next = pmd_addr_end(addr, end);

		if (is_swap_pmd(*src_pmd) || pmd_trans_huge(*src_pmd)) {

			int err;



			VM_BUG_ON_VMA(next-addr != HPAGE_PMD_SIZE, src_vma);

			err = copy_huge_pmd(dst_mm, src_mm, dst_pmd, src_pmd,

					    addr, dst_vma, src_vma);
@@ -6340,12 +6341,17 @@ static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma, 
	if (pmd_none(*vmf.pmd) &&

	    thp_vma_allowable_order(vma, vm_flags, TVA_PAGEFAULT, PMD_ORDER)) {

		ret = create_huge_pmd(&vmf);

		if (!(ret & VM_FAULT_FALLBACK))

		if (ret & VM_FAULT_FALLBACK)

			goto fallback;

		else

			return ret;

	} else {

	}



	vmf.orig_pmd = pmdp_get_lockless(vmf.pmd);

	if (pmd_none(vmf.orig_pmd))

		goto fallback;



		if (unlikely(is_swap_pmd(vmf.orig_pmd))) {

	if (unlikely(!pmd_present(vmf.orig_pmd))) {

		if (is_pmd_device_private_entry(vmf.orig_pmd))

			return do_huge_pmd_device_private(&vmf);
@@ -6367,8 +6373,8 @@ static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma, 
			return 0;

		}

	}

	}



fallback:

	return handle_pte_fault(&vmf);

}

mm/page_table_check.c

+8 −4
Original line number Diff line number Diff line
@@ -215,10 +215,14 @@ EXPORT_SYMBOL(__page_table_check_ptes_set); 


static inline void page_table_check_pmd_flags(pmd_t pmd)

{

	if (pmd_present(pmd) && pmd_uffd_wp(pmd))

	if (pmd_present(pmd)) {

		if (pmd_uffd_wp(pmd))

			WARN_ON_ONCE(pmd_write(pmd));

	else if (is_swap_pmd(pmd) && pmd_swp_uffd_wp(pmd))

		WARN_ON_ONCE(swap_cached_writable(pmd_to_swp_entry(pmd)));

	} else if (pmd_swp_uffd_wp(pmd)) {

		swp_entry_t entry = pmd_to_swp_entry(pmd);



		WARN_ON_ONCE(swap_cached_writable(entry));

	}

}



void __page_table_check_pmds_set(struct mm_struct *mm, pmd_t *pmdp, pmd_t pmd,