The patch titled
Subject: mm: convert do_swap_page()'s swapcache variable to a folio
has been added to the -mm mm-unstable branch. Its filename is
mm-convert-do_swap_pages-swapcache-variable-to-a-folio.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-convert-do_swap_pages-swapcache-variable-to-a-folio.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: mm: convert do_swap_page()'s swapcache variable to a folio
Date: Fri, 2 Sep 2022 20:46:11 +0100
The 'swapcache' variable is used to track whether the page is from the
swapcache or not. It can do this equally well by being the folio of the
page rather than the page itself, and this saves a number of calls to
compound_head().
Link: https://lkml.kernel.org/r/20220902194653.1739778-16-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory.c | 31 +++++++++++++++----------------
1 file changed, 15 insertions(+), 16 deletions(-)
--- a/mm/memory.c~mm-convert-do_swap_pages-swapcache-variable-to-a-folio
+++ a/mm/memory.c
@@ -3726,8 +3726,8 @@ static vm_fault_t handle_pte_marker(stru
vm_fault_t do_swap_page(struct vm_fault *vmf)
{
struct vm_area_struct *vma = vmf->vma;
- struct folio *folio;
- struct page *page = NULL, *swapcache;
+ struct folio *swapcache, *folio = NULL;
+ struct page *page;
struct swap_info_struct *si = NULL;
rmap_t rmap_flags = RMAP_NONE;
bool exclusive = false;
@@ -3770,11 +3770,11 @@ vm_fault_t do_swap_page(struct vm_fault
goto out;
page = lookup_swap_cache(entry, vma, vmf->address);
- swapcache = page;
if (page)
folio = page_folio(page);
+ swapcache = folio;
- if (!page) {
+ if (!folio) {
if (data_race(si->flags & SWP_SYNCHRONOUS_IO) &&
__swap_count(entry) == 1) {
/* skip swapcache */
@@ -3807,12 +3807,12 @@ vm_fault_t do_swap_page(struct vm_fault
} else {
page = swapin_readahead(entry, GFP_HIGHUSER_MOVABLE,
vmf);
- swapcache = page;
if (page)
folio = page_folio(page);
+ swapcache = folio;
}
- if (!page) {
+ if (!folio) {
/*
* Back out if somebody else faulted in this pte
* while we released the pte lock.
@@ -3864,7 +3864,6 @@ vm_fault_t do_swap_page(struct vm_fault
page = ksm_might_need_to_copy(page, vma, vmf->address);
if (unlikely(!page)) {
ret = VM_FAULT_OOM;
- page = swapcache;
goto out_page;
}
folio = page_folio(page);
@@ -3875,7 +3874,7 @@ vm_fault_t do_swap_page(struct vm_fault
* owner. Try removing the extra reference from the local LRU
* pagevecs if required.
*/
- if ((vmf->flags & FAULT_FLAG_WRITE) && page == swapcache &&
+ if ((vmf->flags & FAULT_FLAG_WRITE) && folio == swapcache &&
!folio_test_ksm(folio) && !folio_test_lru(folio))
lru_add_drain();
}
@@ -3916,7 +3915,7 @@ vm_fault_t do_swap_page(struct vm_fault
* without __HAVE_ARCH_PTE_SWP_EXCLUSIVE.
*/
exclusive = pte_swp_exclusive(vmf->orig_pte);
- if (page != swapcache) {
+ if (folio != swapcache) {
/*
* We have a fresh page that is not exposed to the
* swapcache -> certainly exclusive.
@@ -3984,7 +3983,7 @@ vm_fault_t do_swap_page(struct vm_fault
vmf->orig_pte = pte;
/* ksm created a completely new copy */
- if (unlikely(page != swapcache && swapcache)) {
+ if (unlikely(folio != swapcache && swapcache)) {
page_add_new_anon_rmap(page, vma, vmf->address);
folio_add_lru_vma(folio, vma);
} else {
@@ -3997,7 +3996,7 @@ vm_fault_t do_swap_page(struct vm_fault
arch_do_swap_page(vma->vm_mm, vma, vmf->address, pte, vmf->orig_pte);
folio_unlock(folio);
- if (page != swapcache && swapcache) {
+ if (folio != swapcache && swapcache) {
/*
* Hold the lock to avoid the swap entry to be reused
* until we take the PT lock for the pte_same() check
@@ -4006,8 +4005,8 @@ vm_fault_t do_swap_page(struct vm_fault
* so that the swap count won't change under a
* parallel locked swapcache.
*/
- unlock_page(swapcache);
- put_page(swapcache);
+ folio_unlock(swapcache);
+ folio_put(swapcache);
}
if (vmf->flags & FAULT_FLAG_WRITE) {
@@ -4031,9 +4030,9 @@ out_page:
folio_unlock(folio);
out_release:
folio_put(folio);
- if (page != swapcache && swapcache) {
- unlock_page(swapcache);
- put_page(swapcache);
+ if (folio != swapcache && swapcache) {
+ folio_unlock(swapcache);
+ folio_put(swapcache);
}
if (si)
put_swap_device(si);
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
tools-fix-compilation-after-gfp_typesh-split.patch
mm-fix-vm_bug_on-in-__delete_from_swap_cache.patch
vmscan-check-folio_test_private-not-folio_get_private.patch
support-highmem-pages-in-vmap_pages_range_noflush.patch
mm-add-vma-iterator.patch
mmap-use-the-vma-iterator-in-count_vma_pages_range.patch
proc-remove-vma-rbtree-use-from-nommu.patch
arm64-remove-mmap-linked-list-from-vdso.patch
parisc-remove-mmap-linked-list-from-cache-handling.patch
powerpc-remove-mmap-linked-list-walks.patch
s390-remove-vma-linked-list-walks.patch
x86-remove-vma-linked-list-walks.patch
xtensa-remove-vma-linked-list-walks.patch
cxl-remove-vma-linked-list-walk.patch
optee-remove-vma-linked-list-walk.patch
um-remove-vma-linked-list-walk.patch
coredump-remove-vma-linked-list-walk.patch
exec-use-vma-iterator-instead-of-linked-list.patch
fs-proc-task_mmu-stop-using-linked-list-and-highest_vm_end.patch
acct-use-vma-iterator-instead-of-linked-list.patch
perf-use-vma-iterator.patch
sched-use-maple-tree-iterator-to-walk-vmas.patch
fork-use-vma-iterator.patch
mm-khugepaged-stop-using-vma-linked-list.patch
mm-ksm-use-vma-iterators-instead-of-vma-linked-list.patch
mm-mlock-use-vma-iterator-and-maple-state-instead-of-vma-linked-list.patch
mm-pagewalk-use-vma_find-instead-of-vma-linked-list.patch
i915-use-the-vma-iterator.patch
nommu-remove-uses-of-vma-linked-list.patch
mm-vmscan-fix-a-lot-of-comments.patch
mm-add-the-first-tail-page-to-struct-folio.patch
mm-reimplement-folio_order-and-folio_nr_pages.patch
mm-add-split_folio.patch
mm-add-folio_add_lru_vma.patch
shmem-convert-shmem_writepage-to-use-a-folio-throughout.patch
shmem-convert-shmem_delete_from_page_cache-to-take-a-folio.patch
shmem-convert-shmem_replace_page-to-use-folios-throughout.patch
mm-swapfile-remove-page_swapcount.patch
mm-swapfile-convert-try_to_free_swap-to-folio_free_swap.patch
mm-swap-convert-__read_swap_cache_async-to-use-a-folio.patch
mm-swap-convert-add_to_swap_cache-to-take-a-folio.patch
mm-swap-convert-put_swap_page-to-put_swap_folio.patch
mm-convert-do_swap_page-to-use-a-folio.patch
mm-convert-do_swap_pages-swapcache-variable-to-a-folio.patch
memcg-convert-mem_cgroup_swapin_charge_page-to-mem_cgroup_swapin_charge_folio.patch
shmem-convert-shmem_mfill_atomic_pte-to-use-a-folio.patch
shmem-convert-shmem_replace_page-to-shmem_replace_folio.patch
swap-add-swap_cache_get_folio.patch
shmem-eliminate-struct-page-from-shmem_swapin_folio.patch
shmem-convert-shmem_getpage_gfp-to-shmem_get_folio_gfp.patch
shmem-convert-shmem_fault-to-use-shmem_get_folio_gfp.patch
shmem-convert-shmem_read_mapping_page_gfp-to-use-shmem_get_folio_gfp.patch
shmem-add-shmem_get_folio.patch
shmem-convert-shmem_get_partial_folio-to-use-shmem_get_folio.patch
shmem-convert-shmem_write_begin-to-use-shmem_get_folio.patch
shmem-convert-shmem_file_read_iter-to-use-shmem_get_folio.patch
shmem-convert-shmem_fallocate-to-use-a-folio.patch
shmem-convert-shmem_symlink-to-use-a-folio.patch
shmem-convert-shmem_get_link-to-use-a-folio.patch
khugepaged-call-shmem_get_folio.patch
userfaultfd-convert-mcontinue_atomic_pte-to-use-a-folio.patch
shmem-remove-shmem_getpage.patch
swapfile-convert-try_to_unuse-to-use-a-folio.patch
swapfile-convert-__try_to_reclaim_swap-to-use-a-folio.patch
swapfile-convert-unuse_pte_range-to-use-a-folio.patch
mm-convert-do_swap_page-to-use-swap_cache_get_folio.patch
mm-remove-lookup_swap_cache.patch
swap_state-convert-free_swap_cache-to-use-a-folio.patch
swap-convert-swap_writepage-to-use-a-folio.patch
mm-convert-do_wp_page-to-use-a-folio.patch
huge_memory-convert-do_huge_pmd_wp_page-to-use-a-folio.patch
madvise-convert-madvise_free_pte_range-to-use-a-folio.patch
uprobes-use-folios-more-widely-in-__replace_page.patch
ksm-use-a-folio-in-replace_page.patch
mm-convert-do_swap_page-to-use-folio_free_swap.patch
memcg-convert-mem_cgroup_swap_full-to-take-a-folio.patch
mm-remove-try_to_free_swap.patch
rmap-convert-page_move_anon_rmap-to-use-a-folio.patch
migrate-convert-__unmap_and_move-to-use-folios.patch
migrate-convert-unmap_and_move_huge_page-to-use-folios.patch
huge_memory-convert-split_huge_page_to_list-to-use-a-folio.patch
huge_memory-convert-unmap_page-to-unmap_folio.patch
mm-convert-page_get_anon_vma-to-folio_get_anon_vma.patch
rmap-remove-page_unlock_anon_vma_read.patch
uprobes-use-new_folio-in-__replace_page.patch
mm-convert-lock_page_or_retry-to-folio_lock_or_retry.patch
