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author | Matthew Wilcox (Oracle) <willy@infradead.org> | 2022-01-28 16:03:42 -0500 |
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committer | Matthew Wilcox (Oracle) <willy@infradead.org> | 2022-03-21 13:01:35 -0400 |
commit | 0d2514859ceda3cc42386f819d3131f782fd69d5 (patch) | |
tree | 18d77fbd567157cd1f1d024162401852cfee48de /mm/rmap.c | |
parent | 4b8554c527f3cfa183f6c06d231a9387873205a0 (diff) | |
download | lwn-0d2514859ceda3cc42386f819d3131f782fd69d5.tar.gz lwn-0d2514859ceda3cc42386f819d3131f782fd69d5.zip |
mm/rmap: Convert make_device_exclusive_range() to use folios
Move the PageTail check earlier so we can avoid even taking the folio
lock on tail pages. Otherwise, this is a straightforward use of
folios throughout.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Diffstat (limited to 'mm/rmap.c')
-rw-r--r-- | mm/rmap.c | 58 |
1 files changed, 31 insertions, 27 deletions
diff --git a/mm/rmap.c b/mm/rmap.c index 8497da29193c..c74de8af7eec 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1990,8 +1990,9 @@ struct make_exclusive_args { static bool page_make_device_exclusive_one(struct page *page, struct vm_area_struct *vma, unsigned long address, void *priv) { + struct folio *folio = page_folio(page); struct mm_struct *mm = vma->vm_mm; - DEFINE_PAGE_VMA_WALK(pvmw, page, vma, address, 0); + DEFINE_FOLIO_VMA_WALK(pvmw, folio, vma, address, 0); struct make_exclusive_args *args = priv; pte_t pteval; struct page *subpage; @@ -2002,12 +2003,13 @@ static bool page_make_device_exclusive_one(struct page *page, mmu_notifier_range_init_owner(&range, MMU_NOTIFY_EXCLUSIVE, 0, vma, vma->vm_mm, address, min(vma->vm_end, - address + page_size(page)), args->owner); + address + folio_size(folio)), + args->owner); mmu_notifier_invalidate_range_start(&range); while (page_vma_mapped_walk(&pvmw)) { /* Unexpected PMD-mapped THP? */ - VM_BUG_ON_PAGE(!pvmw.pte, page); + VM_BUG_ON_FOLIO(!pvmw.pte, folio); if (!pte_present(*pvmw.pte)) { ret = false; @@ -2015,16 +2017,17 @@ static bool page_make_device_exclusive_one(struct page *page, break; } - subpage = page - page_to_pfn(page) + pte_pfn(*pvmw.pte); + subpage = folio_page(folio, + pte_pfn(*pvmw.pte) - folio_pfn(folio)); address = pvmw.address; /* Nuke the page table entry. */ flush_cache_page(vma, address, pte_pfn(*pvmw.pte)); pteval = ptep_clear_flush(vma, address, pvmw.pte); - /* Move the dirty bit to the page. Now the pte is gone. */ + /* Set the dirty flag on the folio now the pte is gone. */ if (pte_dirty(pteval)) - set_page_dirty(page); + folio_mark_dirty(folio); /* * Check that our target page is still mapped at the expected @@ -2066,21 +2069,22 @@ static bool page_make_device_exclusive_one(struct page *page, } /** - * page_make_device_exclusive - mark the page exclusively owned by a device - * @page: the page to replace page table entries for - * @mm: the mm_struct where the page is expected to be mapped - * @address: address where the page is expected to be mapped + * folio_make_device_exclusive - Mark the folio exclusively owned by a device. + * @folio: The folio to replace page table entries for. + * @mm: The mm_struct where the folio is expected to be mapped. + * @address: Address where the folio is expected to be mapped. * @owner: passed to MMU_NOTIFY_EXCLUSIVE range notifier callbacks * - * Tries to remove all the page table entries which are mapping this page and - * replace them with special device exclusive swap entries to grant a device - * exclusive access to the page. Caller must hold the page lock. + * Tries to remove all the page table entries which are mapping this + * folio and replace them with special device exclusive swap entries to + * grant a device exclusive access to the folio. * - * Returns false if the page is still mapped, or if it could not be unmapped + * Context: Caller must hold the folio lock. + * Return: false if the page is still mapped, or if it could not be unmapped * from the expected address. Otherwise returns true (success). */ -static bool page_make_device_exclusive(struct page *page, struct mm_struct *mm, - unsigned long address, void *owner) +static bool folio_make_device_exclusive(struct folio *folio, + struct mm_struct *mm, unsigned long address, void *owner) { struct make_exclusive_args args = { .mm = mm, @@ -2096,16 +2100,15 @@ static bool page_make_device_exclusive(struct page *page, struct mm_struct *mm, }; /* - * Restrict to anonymous pages for now to avoid potential writeback - * issues. Also tail pages shouldn't be passed to rmap_walk so skip - * those. + * Restrict to anonymous folios for now to avoid potential writeback + * issues. */ - if (!PageAnon(page) || PageTail(page)) + if (!folio_test_anon(folio)) return false; - rmap_walk(page, &rwc); + rmap_walk(&folio->page, &rwc); - return args.valid && !page_mapcount(page); + return args.valid && !folio_mapcount(folio); } /** @@ -2143,15 +2146,16 @@ int make_device_exclusive_range(struct mm_struct *mm, unsigned long start, return npages; for (i = 0; i < npages; i++, start += PAGE_SIZE) { - if (!trylock_page(pages[i])) { - put_page(pages[i]); + struct folio *folio = page_folio(pages[i]); + if (PageTail(pages[i]) || !folio_trylock(folio)) { + folio_put(folio); pages[i] = NULL; continue; } - if (!page_make_device_exclusive(pages[i], mm, start, owner)) { - unlock_page(pages[i]); - put_page(pages[i]); + if (!folio_make_device_exclusive(folio, mm, start, owner)) { + folio_unlock(folio); + folio_put(folio); pages[i] = NULL; } } |