Commit 1486fb50 authored by Kefeng Wang's avatar Kefeng Wang Committed by Andrew Morton
Browse files

mm: ksm: use more folio api in ksm_might_need_to_copy() 

Patch series "mm: cleanup and use more folio in page fault", v3.

Rename page_copy_prealloc() to folio_prealloc(), which is used by more
functions, also do more folio conversion in page fault.


This patch (of 5):

Since ksm only support normal page, no swapout/in for ksm large folio too,
add large folio check in ksm_might_need_to_copy(), also convert
page->index to folio->index as page->index is going away.

Then convert ksm_might_need_to_copy() to use more folio api to save nine
compound_head() calls, short 'address' to reduce max-line-length.

Link: https://lkml.kernel.org/r/20231118023232.1409103-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20231118023232.1409103-2-wangkefeng.wang@huawei.com


Signed-off-by: default avatarKefeng Wang <wangkefeng.wang@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 6140edee

include/linux/ksm.h

+2 −2
Original line number Diff line number Diff line
@@ -77,7 +77,7 @@ static inline void ksm_exit(struct mm_struct *mm) 
 * but what if the vma was unmerged while the page was swapped out?

 */

struct page *ksm_might_need_to_copy(struct page *page,

			struct vm_area_struct *vma, unsigned long address);

			struct vm_area_struct *vma, unsigned long addr);



void rmap_walk_ksm(struct folio *folio, struct rmap_walk_control *rwc);

void folio_migrate_ksm(struct folio *newfolio, struct folio *folio);
@@ -130,7 +130,7 @@ static inline int ksm_madvise(struct vm_area_struct *vma, unsigned long start, 
}



static inline struct page *ksm_might_need_to_copy(struct page *page,

			struct vm_area_struct *vma, unsigned long address)

			struct vm_area_struct *vma, unsigned long addr)

{

	return page;

}

mm/ksm.c

+21 −18
Original line number Diff line number Diff line
@@ -2876,48 +2876,51 @@ void __ksm_exit(struct mm_struct *mm) 
}



struct page *ksm_might_need_to_copy(struct page *page,

			struct vm_area_struct *vma, unsigned long address)

			struct vm_area_struct *vma, unsigned long addr)

{

	struct folio *folio = page_folio(page);

	struct anon_vma *anon_vma = folio_anon_vma(folio);

	struct page *new_page;

	struct folio *new_folio;



	if (PageKsm(page)) {

		if (page_stable_node(page) &&

	if (folio_test_large(folio))

		return page;



	if (folio_test_ksm(folio)) {

		if (folio_stable_node(folio) &&

		    !(ksm_run & KSM_RUN_UNMERGE))

			return page;	/* no need to copy it */

	} else if (!anon_vma) {

		return page;		/* no need to copy it */

	} else if (page->index == linear_page_index(vma, address) &&

	} else if (folio->index == linear_page_index(vma, addr) &&

			anon_vma->root == vma->anon_vma->root) {

		return page;		/* still no need to copy it */

	}

	if (PageHWPoison(page))

		return ERR_PTR(-EHWPOISON);

	if (!PageUptodate(page))

	if (!folio_test_uptodate(folio))

		return page;		/* let do_swap_page report the error */



	new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);

	if (new_page &&

	    mem_cgroup_charge(page_folio(new_page), vma->vm_mm, GFP_KERNEL)) {

		put_page(new_page);

		new_page = NULL;

	new_folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, vma, addr, false);

	if (new_folio &&

	    mem_cgroup_charge(new_folio, vma->vm_mm, GFP_KERNEL)) {

		folio_put(new_folio);

		new_folio = NULL;

	}

	if (new_page) {

		if (copy_mc_user_highpage(new_page, page, address, vma)) {

			put_page(new_page);

	if (new_folio) {

		if (copy_mc_user_highpage(&new_folio->page, page, addr, vma)) {

			folio_put(new_folio);

			memory_failure_queue(page_to_pfn(page), 0);

			return ERR_PTR(-EHWPOISON);

		}

		SetPageDirty(new_page);

		__SetPageUptodate(new_page);

		__SetPageLocked(new_page);

		folio_set_dirty(new_folio);

		__folio_mark_uptodate(new_folio);

		__folio_set_locked(new_folio);

#ifdef CONFIG_SWAP

		count_vm_event(KSM_SWPIN_COPY);

#endif

	}



	return new_page;

	return new_folio ? &new_folio->page : NULL;

}



void rmap_walk_ksm(struct folio *folio, struct rmap_walk_control *rwc)