Commit 3bd786f7 authored by Yin Fengwei's avatar Yin Fengwei Committed by Andrew Morton
Browse files

mm: convert do_set_pte() to set_pte_range() 

set_pte_range() allows to setup page table entries for a specific
range.  It takes advantage of batched rmap update for large folio.
It now takes care of calling update_mmu_cache_range().

Link: https://lkml.kernel.org/r/20230802151406.3735276-37-willy@infradead.org


Signed-off-by: default avatarYin Fengwei <fengwei.yin@intel.com>
Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 86f35f69

Documentation/filesystems/locking.rst

+1 −1
Original line number Diff line number Diff line
@@ -661,7 +661,7 @@ locked. The VM will unlock the page. 
Filesystem should find and map pages associated with offsets from "start_pgoff"

till "end_pgoff". ->map_pages() is called with the RCU lock held and must

not block.  If it's not possible to reach a page without blocking,

filesystem should skip it. Filesystem should use do_set_pte() to setup

filesystem should skip it. Filesystem should use set_pte_range() to setup

page table entry. Pointer to entry associated with the page is passed in

"pte" field in vm_fault structure. Pointers to entries for other offsets

should be calculated relative to "pte".

include/linux/mm.h

+2 −1
Original line number Diff line number Diff line
@@ -1322,7 +1322,8 @@ static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma) 
}



vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page);

void do_set_pte(struct vm_fault *vmf, struct page *page, unsigned long addr);

void set_pte_range(struct vm_fault *vmf, struct folio *folio,

		struct page *page, unsigned int nr, unsigned long addr);



vm_fault_t finish_fault(struct vm_fault *vmf);

vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf);

mm/filemap.c

+1 −2
Original line number Diff line number Diff line
@@ -3501,8 +3501,7 @@ static vm_fault_t filemap_map_folio_range(struct vm_fault *vmf, 
			ret = VM_FAULT_NOPAGE;



		ref_count++;

		do_set_pte(vmf, page, addr);

		update_mmu_cache(vma, addr, vmf->pte);

		set_pte_range(vmf, folio, page, 1, addr);

	} while (vmf->pte++, page++, addr += PAGE_SIZE, ++count < nr_pages);



	/* Restore the vmf->pte */

mm/memory.c

+24 −13
Original line number Diff line number Diff line
@@ -4330,15 +4330,24 @@ vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page) 
}

#endif



void do_set_pte(struct vm_fault *vmf, struct page *page, unsigned long addr)

/**

 * set_pte_range - Set a range of PTEs to point to pages in a folio.

 * @vmf: Fault decription.

 * @folio: The folio that contains @page.

 * @page: The first page to create a PTE for.

 * @nr: The number of PTEs to create.

 * @addr: The first address to create a PTE for.

 */

void set_pte_range(struct vm_fault *vmf, struct folio *folio,

		struct page *page, unsigned int nr, unsigned long addr)

{

	struct vm_area_struct *vma = vmf->vma;

	bool uffd_wp = vmf_orig_pte_uffd_wp(vmf);

	bool write = vmf->flags & FAULT_FLAG_WRITE;

	bool prefault = vmf->address != addr;

	bool prefault = in_range(vmf->address, addr, nr * PAGE_SIZE);

	pte_t entry;



	flush_icache_page(vma, page);

	flush_icache_pages(vma, page, nr);

	entry = mk_pte(page, vma->vm_page_prot);



	if (prefault && arch_wants_old_prefaulted_pte())
@@ -4352,14 +4361,18 @@ void do_set_pte(struct vm_fault *vmf, struct page *page, unsigned long addr) 
		entry = pte_mkuffd_wp(entry);

	/* copy-on-write page */

	if (write && !(vma->vm_flags & VM_SHARED)) {

		inc_mm_counter(vma->vm_mm, MM_ANONPAGES);

		page_add_new_anon_rmap(page, vma, addr);

		lru_cache_add_inactive_or_unevictable(page, vma);

		add_mm_counter(vma->vm_mm, MM_ANONPAGES, nr);

		VM_BUG_ON_FOLIO(nr != 1, folio);

		folio_add_new_anon_rmap(folio, vma, addr);

		folio_add_lru_vma(folio, vma);

	} else {

		inc_mm_counter(vma->vm_mm, mm_counter_file(page));

		page_add_file_rmap(page, vma, false);

		add_mm_counter(vma->vm_mm, mm_counter_file(page), nr);

		folio_add_file_rmap_range(folio, page, nr, vma, false);

	}

	set_pte_at(vma->vm_mm, addr, vmf->pte, entry);

	set_ptes(vma->vm_mm, addr, vmf->pte, entry, nr);



	/* no need to invalidate: a not-present page won't be cached */

	update_mmu_cache_range(vmf, vma, addr, vmf->pte, nr);

}



static bool vmf_pte_changed(struct vm_fault *vmf)
@@ -4427,11 +4440,9 @@ vm_fault_t finish_fault(struct vm_fault *vmf) 


	/* Re-check under ptl */

	if (likely(!vmf_pte_changed(vmf))) {

		do_set_pte(vmf, page, vmf->address);



		/* no need to invalidate: a not-present page won't be cached */

		update_mmu_cache(vma, vmf->address, vmf->pte);

		struct folio *folio = page_folio(page);



		set_pte_range(vmf, folio, page, 1, vmf->address);

		ret = 0;

	} else {

		update_mmu_tlb(vma, vmf->address, vmf->pte);