From ca827d55ebaa24de9fca36ee24e42d6fc5119ee3 Mon Sep 17 00:00:00 2001 From: Khalid Aziz Date: Wed, 21 Feb 2018 10:15:44 -0700 Subject: mm, swap: Add infrastructure for saving page metadata on swap If a processor supports special metadata for a page, for example ADI version tags on SPARC M7, this metadata must be saved when the page is swapped out. The same metadata must be restored when the page is swapped back in. This patch adds two new architecture specific functions - arch_do_swap_page() to be called when a page is swapped in, and arch_unmap_one() to be called when a page is being unmapped for swap out. These architecture hooks allow page metadata to be saved if the architecture supports it. Signed-off-by: Khalid Aziz Cc: Khalid Aziz Acked-by: Jerome Marchand Reviewed-by: Anthony Yznaga Acked-by: Andrew Morton Signed-off-by: David S. Miller --- mm/rmap.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'mm/rmap.c') diff --git a/mm/rmap.c b/mm/rmap.c index 47db27f8049e..144c66e688a9 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1497,6 +1497,14 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma, (flags & (TTU_MIGRATION|TTU_SPLIT_FREEZE))) { swp_entry_t entry; pte_t swp_pte; + + if (arch_unmap_one(mm, vma, address, pteval) < 0) { + set_pte_at(mm, address, pvmw.pte, pteval); + ret = false; + page_vma_mapped_walk_done(&pvmw); + break; + } + /* * Store the pfn of the page in a special migration * pte. do_swap_page() will wait until the migration @@ -1556,6 +1564,12 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma, page_vma_mapped_walk_done(&pvmw); break; } + if (arch_unmap_one(mm, vma, address, pteval) < 0) { + set_pte_at(mm, address, pvmw.pte, pteval); + ret = false; + page_vma_mapped_walk_done(&pvmw); + break; + } if (list_empty(&mm->mmlist)) { spin_lock(&mmlist_lock); if (list_empty(&mm->mmlist)) -- cgit v1.2.1