Commit 64c8902e authored by Huang Ying's avatar Huang Ying Committed by Andrew Morton

migrate_pages: split unmap_and_move() to _unmap() and _move()

This is a preparation patch to batch the folio unmapping and moving.

In this patch, unmap_and_move() is split to migrate_folio_unmap() and
migrate_folio_move().  So, we can batch _unmap() and _move() in different
loops later.  To pass some information between unmap and move, the
original unused dst->mapping and dst->private are used.

Link: https://lkml.kernel.org/r/20230213123444.155149-5-ying.huang@intel.comSigned-off-by: default avatar"Huang, Ying" <ying.huang@intel.com>
Reviewed-by: default avatarBaolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: default avatarXin Hao <xhao@linux.alibaba.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Bharata B Rao <bharata@amd.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 42012e04
...@@ -18,6 +18,7 @@ struct migration_target_control; ...@@ -18,6 +18,7 @@ struct migration_target_control;
* - zero on page migration success; * - zero on page migration success;
*/ */
#define MIGRATEPAGE_SUCCESS 0 #define MIGRATEPAGE_SUCCESS 0
#define MIGRATEPAGE_UNMAP 1
/** /**
* struct movable_operations - Driver page migration * struct movable_operations - Driver page migration
......
...@@ -1027,11 +1027,53 @@ static int move_to_new_folio(struct folio *dst, struct folio *src, ...@@ -1027,11 +1027,53 @@ static int move_to_new_folio(struct folio *dst, struct folio *src,
return rc; return rc;
} }
static int __unmap_and_move(struct folio *src, struct folio *dst, /*
* To record some information during migration, we use some unused
* fields (mapping and private) of struct folio of the newly allocated
* destination folio. This is safe because nobody is using them
* except us.
*/
static void __migrate_folio_record(struct folio *dst,
unsigned long page_was_mapped,
struct anon_vma *anon_vma)
{
dst->mapping = (void *)anon_vma;
dst->private = (void *)page_was_mapped;
}
static void __migrate_folio_extract(struct folio *dst,
int *page_was_mappedp,
struct anon_vma **anon_vmap)
{
*anon_vmap = (void *)dst->mapping;
*page_was_mappedp = (unsigned long)dst->private;
dst->mapping = NULL;
dst->private = NULL;
}
/* Cleanup src folio upon migration success */
static void migrate_folio_done(struct folio *src,
enum migrate_reason reason)
{
/*
* Compaction can migrate also non-LRU pages which are
* not accounted to NR_ISOLATED_*. They can be recognized
* as __PageMovable
*/
if (likely(!__folio_test_movable(src)))
mod_node_page_state(folio_pgdat(src), NR_ISOLATED_ANON +
folio_is_file_lru(src), -folio_nr_pages(src));
if (reason != MR_MEMORY_FAILURE)
/* We release the page in page_handle_poison. */
folio_put(src);
}
static int __migrate_folio_unmap(struct folio *src, struct folio *dst,
int force, enum migrate_mode mode) int force, enum migrate_mode mode)
{ {
int rc = -EAGAIN; int rc = -EAGAIN;
bool page_was_mapped = false; int page_was_mapped = 0;
struct anon_vma *anon_vma = NULL; struct anon_vma *anon_vma = NULL;
bool is_lru = !__PageMovable(&src->page); bool is_lru = !__PageMovable(&src->page);
...@@ -1107,8 +1149,8 @@ static int __unmap_and_move(struct folio *src, struct folio *dst, ...@@ -1107,8 +1149,8 @@ static int __unmap_and_move(struct folio *src, struct folio *dst,
goto out_unlock; goto out_unlock;
if (unlikely(!is_lru)) { if (unlikely(!is_lru)) {
rc = move_to_new_folio(dst, src, mode); __migrate_folio_record(dst, page_was_mapped, anon_vma);
goto out_unlock_both; return MIGRATEPAGE_UNMAP;
} }
/* /*
...@@ -1133,11 +1175,42 @@ static int __unmap_and_move(struct folio *src, struct folio *dst, ...@@ -1133,11 +1175,42 @@ static int __unmap_and_move(struct folio *src, struct folio *dst,
VM_BUG_ON_FOLIO(folio_test_anon(src) && VM_BUG_ON_FOLIO(folio_test_anon(src) &&
!folio_test_ksm(src) && !anon_vma, src); !folio_test_ksm(src) && !anon_vma, src);
try_to_migrate(src, 0); try_to_migrate(src, 0);
page_was_mapped = true; page_was_mapped = 1;
} }
if (!folio_mapped(src)) if (!folio_mapped(src)) {
rc = move_to_new_folio(dst, src, mode); __migrate_folio_record(dst, page_was_mapped, anon_vma);
return MIGRATEPAGE_UNMAP;
}
if (page_was_mapped)
remove_migration_ptes(src, src, false);
out_unlock_both:
folio_unlock(dst);
out_unlock:
/* Drop an anon_vma reference if we took one */
if (anon_vma)
put_anon_vma(anon_vma);
folio_unlock(src);
out:
return rc;
}
static int __migrate_folio_move(struct folio *src, struct folio *dst,
enum migrate_mode mode)
{
int rc;
int page_was_mapped = 0;
struct anon_vma *anon_vma = NULL;
bool is_lru = !__PageMovable(&src->page);
__migrate_folio_extract(dst, &page_was_mapped, &anon_vma);
rc = move_to_new_folio(dst, src, mode);
if (unlikely(!is_lru))
goto out_unlock_both;
/* /*
* When successful, push dst to LRU immediately: so that if it * When successful, push dst to LRU immediately: so that if it
...@@ -1160,12 +1233,10 @@ static int __unmap_and_move(struct folio *src, struct folio *dst, ...@@ -1160,12 +1233,10 @@ static int __unmap_and_move(struct folio *src, struct folio *dst,
out_unlock_both: out_unlock_both:
folio_unlock(dst); folio_unlock(dst);
out_unlock:
/* Drop an anon_vma reference if we took one */ /* Drop an anon_vma reference if we took one */
if (anon_vma) if (anon_vma)
put_anon_vma(anon_vma); put_anon_vma(anon_vma);
folio_unlock(src); folio_unlock(src);
out:
/* /*
* If migration is successful, decrease refcount of dst, * If migration is successful, decrease refcount of dst,
* which will not free the page because new page owner increased * which will not free the page because new page owner increased
...@@ -1177,19 +1248,15 @@ static int __unmap_and_move(struct folio *src, struct folio *dst, ...@@ -1177,19 +1248,15 @@ static int __unmap_and_move(struct folio *src, struct folio *dst,
return rc; return rc;
} }
/* /* Obtain the lock on page, remove all ptes. */
* Obtain the lock on folio, remove all ptes and migrate the folio static int migrate_folio_unmap(new_page_t get_new_page, free_page_t put_new_page,
* to the newly allocated folio in dst. unsigned long private, struct folio *src,
*/ struct folio **dstp, int force,
static int unmap_and_move(new_page_t get_new_page, enum migrate_mode mode, enum migrate_reason reason,
free_page_t put_new_page, struct list_head *ret)
unsigned long private, struct folio *src,
int force, enum migrate_mode mode,
enum migrate_reason reason,
struct list_head *ret)
{ {
struct folio *dst; struct folio *dst;
int rc = MIGRATEPAGE_SUCCESS; int rc = MIGRATEPAGE_UNMAP;
struct page *newpage = NULL; struct page *newpage = NULL;
if (!thp_migration_supported() && folio_test_transhuge(src)) if (!thp_migration_supported() && folio_test_transhuge(src))
...@@ -1200,20 +1267,49 @@ static int unmap_and_move(new_page_t get_new_page, ...@@ -1200,20 +1267,49 @@ static int unmap_and_move(new_page_t get_new_page,
folio_clear_active(src); folio_clear_active(src);
folio_clear_unevictable(src); folio_clear_unevictable(src);
/* free_pages_prepare() will clear PG_isolated. */ /* free_pages_prepare() will clear PG_isolated. */
goto out; list_del(&src->lru);
migrate_folio_done(src, reason);
return MIGRATEPAGE_SUCCESS;
} }
newpage = get_new_page(&src->page, private); newpage = get_new_page(&src->page, private);
if (!newpage) if (!newpage)
return -ENOMEM; return -ENOMEM;
dst = page_folio(newpage); dst = page_folio(newpage);
*dstp = dst;
dst->private = NULL; dst->private = NULL;
rc = __unmap_and_move(src, dst, force, mode); rc = __migrate_folio_unmap(src, dst, force, mode);
if (rc == MIGRATEPAGE_UNMAP)
return rc;
/*
* A folio that has not been unmapped will be restored to
* right list unless we want to retry.
*/
if (rc != -EAGAIN)
list_move_tail(&src->lru, ret);
if (put_new_page)
put_new_page(&dst->page, private);
else
folio_put(dst);
return rc;
}
/* Migrate the folio to the newly allocated folio in dst. */
static int migrate_folio_move(free_page_t put_new_page, unsigned long private,
struct folio *src, struct folio *dst,
enum migrate_mode mode, enum migrate_reason reason,
struct list_head *ret)
{
int rc;
rc = __migrate_folio_move(src, dst, mode);
if (rc == MIGRATEPAGE_SUCCESS) if (rc == MIGRATEPAGE_SUCCESS)
set_page_owner_migrate_reason(&dst->page, reason); set_page_owner_migrate_reason(&dst->page, reason);
out:
if (rc != -EAGAIN) { if (rc != -EAGAIN) {
/* /*
* A folio that has been migrated has all references * A folio that has been migrated has all references
...@@ -1229,20 +1325,7 @@ static int unmap_and_move(new_page_t get_new_page, ...@@ -1229,20 +1325,7 @@ static int unmap_and_move(new_page_t get_new_page,
* we want to retry. * we want to retry.
*/ */
if (rc == MIGRATEPAGE_SUCCESS) { if (rc == MIGRATEPAGE_SUCCESS) {
/* migrate_folio_done(src, reason);
* Compaction can migrate also non-LRU folios which are
* not accounted to NR_ISOLATED_*. They can be recognized
* as __folio_test_movable
*/
if (likely(!__folio_test_movable(src)))
mod_node_page_state(folio_pgdat(src), NR_ISOLATED_ANON +
folio_is_file_lru(src), -folio_nr_pages(src));
if (reason != MR_MEMORY_FAILURE)
/*
* We release the folio in page_handle_poison.
*/
folio_put(src);
} else { } else {
if (rc != -EAGAIN) if (rc != -EAGAIN)
list_add_tail(&src->lru, ret); list_add_tail(&src->lru, ret);
...@@ -1534,7 +1617,7 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, ...@@ -1534,7 +1617,7 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page,
int pass = 0; int pass = 0;
bool is_large = false; bool is_large = false;
bool is_thp = false; bool is_thp = false;
struct folio *folio, *folio2; struct folio *folio, *folio2, *dst = NULL;
int rc, nr_pages; int rc, nr_pages;
LIST_HEAD(split_folios); LIST_HEAD(split_folios);
bool nosplit = (reason == MR_NUMA_MISPLACED); bool nosplit = (reason == MR_NUMA_MISPLACED);
...@@ -1561,9 +1644,13 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, ...@@ -1561,9 +1644,13 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page,
cond_resched(); cond_resched();
rc = unmap_and_move(get_new_page, put_new_page, rc = migrate_folio_unmap(get_new_page, put_new_page, private,
private, folio, pass > 2, mode, folio, &dst, pass > 2, mode,
reason, ret_folios); reason, ret_folios);
if (rc == MIGRATEPAGE_UNMAP)
rc = migrate_folio_move(put_new_page, private,
folio, dst, mode,
reason, ret_folios);
/* /*
* The rules are: * The rules are:
* Success: folio will be freed * Success: folio will be freed
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment