The patch titled
Subject: migrate: convert __unmap_and_move() to use folios
has been added to the -mm mm-unstable branch. Its filename is
migrate-convert-__unmap_and_move-to-use-folios.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/migrate-convert-__unmap_and_move-to-use-folios.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: migrate: convert __unmap_and_move() to use folios
Date: Fri, 2 Sep 2022 20:46:46 +0100
Removes a lot of calls to compound_head(). Also remove a VM_BUG_ON that
can never trigger as the PageAnon bit is the bottom bit of page->mapping.
Link: https://lkml.kernel.org/r/20220902194653.1739778-51-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/migrate.c | 75 ++++++++++++++++++++++++-------------------------
1 file changed, 37 insertions(+), 38 deletions(-)
--- a/mm/migrate.c~migrate-convert-__unmap_and_move-to-use-folios
+++ a/mm/migrate.c
@@ -993,17 +993,15 @@ out:
return rc;
}
-static int __unmap_and_move(struct page *page, struct page *newpage,
+static int __unmap_and_move(struct folio *src, struct folio *dst,
int force, enum migrate_mode mode)
{
- struct folio *folio = page_folio(page);
- struct folio *dst = page_folio(newpage);
int rc = -EAGAIN;
bool page_was_mapped = false;
struct anon_vma *anon_vma = NULL;
- bool is_lru = !__PageMovable(page);
+ bool is_lru = !__PageMovable(&src->page);
- if (!trylock_page(page)) {
+ if (!folio_trylock(src)) {
if (!force || mode == MIGRATE_ASYNC)
goto out;
@@ -1023,10 +1021,10 @@ static int __unmap_and_move(struct page
if (current->flags & PF_MEMALLOC)
goto out;
- lock_page(page);
+ folio_lock(src);
}
- if (PageWriteback(page)) {
+ if (folio_test_writeback(src)) {
/*
* Only in the case of a full synchronous migration is it
* necessary to wait for PageWriteback. In the async case,
@@ -1043,12 +1041,12 @@ static int __unmap_and_move(struct page
}
if (!force)
goto out_unlock;
- wait_on_page_writeback(page);
+ folio_wait_writeback(src);
}
/*
- * By try_to_migrate(), page->mapcount goes down to 0 here. In this case,
- * we cannot notice that anon_vma is freed while we migrates a page.
+ * By try_to_migrate(), src->mapcount goes down to 0 here. In this case,
+ * we cannot notice that anon_vma is freed while we migrate a page.
* This get_anon_vma() delays freeing anon_vma pointer until the end
* of migration. File cache pages are no problem because of page_lock()
* File Caches may use write_page() or lock_page() in migration, then,
@@ -1060,22 +1058,22 @@ static int __unmap_and_move(struct page
* because that implies that the anon page is no longer mapped
* (and cannot be remapped so long as we hold the page lock).
*/
- if (PageAnon(page) && !PageKsm(page))
- anon_vma = page_get_anon_vma(page);
+ if (folio_test_anon(src) && !folio_test_ksm(src))
+ anon_vma = page_get_anon_vma(&src->page);
/*
* Block others from accessing the new page when we get around to
* establishing additional references. We are usually the only one
- * holding a reference to newpage at this point. We used to have a BUG
- * here if trylock_page(newpage) fails, but would like to allow for
- * cases where there might be a race with the previous use of newpage.
+ * holding a reference to dst at this point. We used to have a BUG
+ * here if folio_trylock(dst) fails, but would like to allow for
+ * cases where there might be a race with the previous use of dst.
* This is much like races on refcount of oldpage: just don't BUG().
*/
- if (unlikely(!trylock_page(newpage)))
+ if (unlikely(!folio_trylock(dst)))
goto out_unlock;
if (unlikely(!is_lru)) {
- rc = move_to_new_folio(dst, folio, mode);
+ rc = move_to_new_folio(dst, src, mode);
goto out_unlock_both;
}
@@ -1083,7 +1081,7 @@ static int __unmap_and_move(struct page
* Corner case handling:
* 1. When a new swap-cache page is read into, it is added to the LRU
* and treated as swapcache but it has no rmap yet.
- * Calling try_to_unmap() against a page->mapping==NULL page will
+ * Calling try_to_unmap() against a src->mapping==NULL page will
* trigger a BUG. So handle it here.
* 2. An orphaned page (see truncate_cleanup_page) might have
* fs-private metadata. The page can be picked up due to memory
@@ -1091,57 +1089,56 @@ static int __unmap_and_move(struct page
* invisible to the vm, so the page can not be migrated. So try to
* free the metadata, so the page can be freed.
*/
- if (!page->mapping) {
- VM_BUG_ON_PAGE(PageAnon(page), page);
- if (page_has_private(page)) {
- try_to_free_buffers(folio);
+ if (!src->mapping) {
+ if (folio_test_private(src)) {
+ try_to_free_buffers(src);
goto out_unlock_both;
}
- } else if (page_mapped(page)) {
+ } else if (folio_mapped(src)) {
/* Establish migration ptes */
- VM_BUG_ON_PAGE(PageAnon(page) && !PageKsm(page) && !anon_vma,
- page);
- try_to_migrate(folio, 0);
+ VM_BUG_ON_FOLIO(folio_test_anon(src) &&
+ !folio_test_ksm(src) && !anon_vma, src);
+ try_to_migrate(src, 0);
page_was_mapped = true;
}
- if (!page_mapped(page))
- rc = move_to_new_folio(dst, folio, mode);
+ if (!folio_mapped(src))
+ rc = move_to_new_folio(dst, src, mode);
/*
- * When successful, push newpage to LRU immediately: so that if it
+ * When successful, push dst to LRU immediately: so that if it
* turns out to be an mlocked page, remove_migration_ptes() will
- * automatically build up the correct newpage->mlock_count for it.
+ * automatically build up the correct dst->mlock_count for it.
*
* We would like to do something similar for the old page, when
* unsuccessful, and other cases when a page has been temporarily
* isolated from the unevictable LRU: but this case is the easiest.
*/
if (rc == MIGRATEPAGE_SUCCESS) {
- lru_cache_add(newpage);
+ folio_add_lru(dst);
if (page_was_mapped)
lru_add_drain();
}
if (page_was_mapped)
- remove_migration_ptes(folio,
- rc == MIGRATEPAGE_SUCCESS ? dst : folio, false);
+ remove_migration_ptes(src,
+ rc == MIGRATEPAGE_SUCCESS ? dst : src, false);
out_unlock_both:
- unlock_page(newpage);
+ folio_unlock(dst);
out_unlock:
/* Drop an anon_vma reference if we took one */
if (anon_vma)
put_anon_vma(anon_vma);
- unlock_page(page);
+ folio_unlock(src);
out:
/*
- * If migration is successful, decrease refcount of the newpage,
+ * If migration is successful, decrease refcount of dst,
* which will not free the page because new page owner increased
* refcounter.
*/
if (rc == MIGRATEPAGE_SUCCESS)
- put_page(newpage);
+ folio_put(dst);
return rc;
}
@@ -1157,6 +1154,7 @@ static int unmap_and_move(new_page_t get
enum migrate_reason reason,
struct list_head *ret)
{
+ struct folio *dst, *src = page_folio(page);
int rc = MIGRATEPAGE_SUCCESS;
struct page *newpage = NULL;
@@ -1174,9 +1172,10 @@ static int unmap_and_move(new_page_t get
newpage = get_new_page(page, private);
if (!newpage)
return -ENOMEM;
+ dst = page_folio(newpage);
newpage->private = 0;
- rc = __unmap_and_move(page, newpage, force, mode);
+ rc = __unmap_and_move(src, dst, force, mode);
if (rc == MIGRATEPAGE_SUCCESS)
set_page_owner_migrate_reason(newpage, reason);
_
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
