The patch titled
Subject: migrate: convert migrate_pages() to use folios
has been added to the -mm mm-unstable branch. Its filename is
migrate-convert-migrate_pages-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-migrate_pages-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: Huang Ying <ying.huang@xxxxxxxxx>
Subject: migrate: convert migrate_pages() to use folios
Date: Wed, 9 Nov 2022 09:23:48 +0800
Quite straightforward, the page functions are converted to corresponding
folio functions. Same for comments.
THP specific code are converted to be large folio.
Link: https://lkml.kernel.org/r/20221109012348.93849-3-ying.huang@xxxxxxxxx
Signed-off-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
Reviewed-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Tested-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Cc: Zi Yan <ziy@xxxxxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/migrate.c | 210 ++++++++++++++++++++++++++-----------------------
1 file changed, 112 insertions(+), 98 deletions(-)
--- a/mm/migrate.c~migrate-convert-migrate_pages-to-use-folios
+++ a/mm/migrate.c
@@ -1373,231 +1373,245 @@ out:
return rc;
}
-static inline int try_split_thp(struct page *page, struct list_head *split_pages)
+static inline int try_split_folio(struct folio *folio, struct list_head *split_folios)
{
int rc;
- lock_page(page);
- rc = split_huge_page_to_list(page, split_pages);
- unlock_page(page);
+ folio_lock(folio);
+ rc = split_folio_to_list(folio, split_folios);
+ folio_unlock(folio);
if (!rc)
- list_move_tail(&page->lru, split_pages);
+ list_move_tail(&folio->lru, split_folios);
return rc;
}
/*
- * migrate_pages - migrate the pages specified in a list, to the free pages
+ * migrate_pages - migrate the folios specified in a list, to the free folios
* supplied as the target for the page migration
*
- * @from: The list of pages to be migrated.
- * @get_new_page: The function used to allocate free pages to be used
- * as the target of the page migration.
- * @put_new_page: The function used to free target pages if migration
+ * @from: The list of folios to be migrated.
+ * @get_new_page: The function used to allocate free folios to be used
+ * as the target of the folio migration.
+ * @put_new_page: The function used to free target folios if migration
* fails, or NULL if no special handling is necessary.
* @private: Private data to be passed on to get_new_page()
* @mode: The migration mode that specifies the constraints for
- * page migration, if any.
- * @reason: The reason for page migration.
- * @ret_succeeded: Set to the number of normal pages migrated successfully if
+ * folio migration, if any.
+ * @reason: The reason for folio migration.
+ * @ret_succeeded: Set to the number of folios migrated successfully if
* the caller passes a non-NULL pointer.
*
- * The function returns after 10 attempts or if no pages are movable any more
- * because the list has become empty or no retryable pages exist any more.
- * It is caller's responsibility to call putback_movable_pages() to return pages
+ * The function returns after 10 attempts or if no folios are movable any more
+ * because the list has become empty or no retryable folios exist any more.
+ * It is caller's responsibility to call putback_movable_pages() to return folios
* to the LRU or free list only if ret != 0.
*
- * Returns the number of {normal page, THP, hugetlb} that were not migrated, or
- * an error code. The number of THP splits will be considered as the number of
- * non-migrated THP, no matter how many subpages of the THP are migrated successfully.
+ * Returns the number of {normal folio, large folio, hugetlb} that were not
+ * migrated, or an error code. The number of large folio splits will be
+ * considered as the number of non-migrated large folio, no matter how many
+ * split folios of the large folio are migrated successfully.
*/
int migrate_pages(struct list_head *from, new_page_t get_new_page,
free_page_t put_new_page, unsigned long private,
enum migrate_mode mode, int reason, unsigned int *ret_succeeded)
{
int retry = 1;
+ int large_retry = 1;
int thp_retry = 1;
int nr_failed = 0;
int nr_failed_pages = 0;
int nr_retry_pages = 0;
int nr_succeeded = 0;
int nr_thp_succeeded = 0;
+ int nr_large_failed = 0;
int nr_thp_failed = 0;
int nr_thp_split = 0;
int pass = 0;
+ bool is_large = false;
bool is_thp = false;
- struct page *page;
- struct page *page2;
- int rc, nr_subpages;
- LIST_HEAD(ret_pages);
- LIST_HEAD(thp_split_pages);
+ struct folio *folio, *folio2;
+ int rc, nr_pages;
+ LIST_HEAD(ret_folios);
+ LIST_HEAD(split_folios);
bool nosplit = (reason == MR_NUMA_MISPLACED);
- bool no_subpage_counting = false;
+ bool no_split_folio_counting = false;
trace_mm_migrate_pages_start(mode, reason);
-thp_subpage_migration:
- for (pass = 0; pass < 10 && (retry || thp_retry); pass++) {
+split_folio_migration:
+ for (pass = 0; pass < 10 && (retry || large_retry); pass++) {
retry = 0;
+ large_retry = 0;
thp_retry = 0;
nr_retry_pages = 0;
- list_for_each_entry_safe(page, page2, from, lru) {
+ list_for_each_entry_safe(folio, folio2, from, lru) {
/*
- * THP statistics is based on the source huge page.
- * Capture required information that might get lost
- * during migration.
+ * Large folio statistics is based on the source large
+ * folio. Capture required information that might get
+ * lost during migration.
*/
- is_thp = PageTransHuge(page) && !PageHuge(page);
- nr_subpages = compound_nr(page);
+ is_large = folio_test_large(folio) && !folio_test_hugetlb(folio);
+ is_thp = is_large && folio_test_pmd_mappable(folio);
+ nr_pages = folio_nr_pages(folio);
cond_resched();
- if (PageHuge(page))
+ if (folio_test_hugetlb(folio))
rc = unmap_and_move_huge_page(get_new_page,
- put_new_page, private, page,
- pass > 2, mode, reason,
- &ret_pages);
+ put_new_page, private,
+ &folio->page, pass > 2, mode,
+ reason,
+ &ret_folios);
else
rc = unmap_and_move(get_new_page, put_new_page,
- private, page_folio(page), pass > 2, mode,
- reason, &ret_pages);
+ private, folio, pass > 2, mode,
+ reason, &ret_folios);
/*
* The rules are:
- * Success: non hugetlb page will be freed, hugetlb
- * page will be put back
+ * Success: non hugetlb folio will be freed, hugetlb
+ * folio will be put back
* -EAGAIN: stay on the from list
* -ENOMEM: stay on the from list
* -ENOSYS: stay on the from list
- * Other errno: put on ret_pages list then splice to
+ * Other errno: put on ret_folios list then splice to
* from list
*/
switch(rc) {
/*
- * THP migration might be unsupported or the
- * allocation could've failed so we should
- * retry on the same page with the THP split
- * to base pages.
+ * Large folio migration might be unsupported or
+ * the allocation could've failed so we should retry
+ * on the same folio with the large folio split
+ * to normal folios.
*
- * Sub-pages are put in thp_split_pages, and
+ * Split folios are put in split_folios, and
* we will migrate them after the rest of the
* list is processed.
*/
case -ENOSYS:
- /* THP migration is unsupported */
- if (is_thp) {
- nr_thp_failed++;
- if (!try_split_thp(page, &thp_split_pages)) {
- nr_thp_split++;
+ /* Large folio migration is unsupported */
+ if (is_large) {
+ nr_large_failed++;
+ nr_thp_failed += is_thp;
+ if (!try_split_folio(folio, &split_folios)) {
+ nr_thp_split += is_thp;
break;
}
/* Hugetlb migration is unsupported */
- } else if (!no_subpage_counting) {
+ } else if (!no_split_folio_counting) {
nr_failed++;
}
- nr_failed_pages += nr_subpages;
- list_move_tail(&page->lru, &ret_pages);
+ nr_failed_pages += nr_pages;
+ list_move_tail(&folio->lru, &ret_folios);
break;
case -ENOMEM:
/*
* When memory is low, don't bother to try to migrate
- * other pages, just exit.
+ * other folios, just exit.
*/
- if (is_thp) {
- nr_thp_failed++;
- /* THP NUMA faulting doesn't split THP to retry. */
+ if (is_large) {
+ nr_large_failed++;
+ nr_thp_failed += is_thp;
+ /* Large folio NUMA faulting doesn't split to retry. */
if (!nosplit) {
- int ret = try_split_thp(page, &thp_split_pages);
+ int ret = try_split_folio(folio, &split_folios);
if (!ret) {
- nr_thp_split++;
+ nr_thp_split += is_thp;
break;
} else if (reason == MR_LONGTERM_PIN &&
ret == -EAGAIN) {
/*
- * Try again to split THP to mitigate
- * the failure of longterm pinning.
+ * Try again to split large folio to
+ * mitigate the failure of longterm pinning.
*/
- thp_retry++;
- nr_retry_pages += nr_subpages;
+ large_retry++;
+ thp_retry += is_thp;
+ nr_retry_pages += nr_pages;
break;
}
}
- } else if (!no_subpage_counting) {
+ } else if (!no_split_folio_counting) {
nr_failed++;
}
- nr_failed_pages += nr_subpages + nr_retry_pages;
+ nr_failed_pages += nr_pages + nr_retry_pages;
/*
- * There might be some subpages of fail-to-migrate THPs
- * left in thp_split_pages list. Move them back to migration
+ * There might be some split folios of fail-to-migrate large
+ * folios left in split_folios list. Move them back to migration
* list so that they could be put back to the right list by
- * the caller otherwise the page refcnt will be leaked.
+ * the caller otherwise the folio refcnt will be leaked.
*/
- list_splice_init(&thp_split_pages, from);
+ list_splice_init(&split_folios, from);
/* nr_failed isn't updated for not used */
+ nr_large_failed += large_retry;
nr_thp_failed += thp_retry;
goto out;
case -EAGAIN:
- if (is_thp)
- thp_retry++;
- else if (!no_subpage_counting)
+ if (is_large) {
+ large_retry++;
+ thp_retry += is_thp;
+ } else if (!no_split_folio_counting) {
retry++;
- nr_retry_pages += nr_subpages;
+ }
+ nr_retry_pages += nr_pages;
break;
case MIGRATEPAGE_SUCCESS:
- nr_succeeded += nr_subpages;
- if (is_thp)
- nr_thp_succeeded++;
+ nr_succeeded += nr_pages;
+ nr_thp_succeeded += is_thp;
break;
default:
/*
* Permanent failure (-EBUSY, etc.):
- * unlike -EAGAIN case, the failed page is
- * removed from migration page list and not
+ * unlike -EAGAIN case, the failed folio is
+ * removed from migration folio list and not
* retried in the next outer loop.
*/
- if (is_thp)
- nr_thp_failed++;
- else if (!no_subpage_counting)
+ if (is_large) {
+ nr_large_failed++;
+ nr_thp_failed += is_thp;
+ } else if (!no_split_folio_counting) {
nr_failed++;
+ }
- nr_failed_pages += nr_subpages;
+ nr_failed_pages += nr_pages;
break;
}
}
}
nr_failed += retry;
+ nr_large_failed += large_retry;
nr_thp_failed += thp_retry;
nr_failed_pages += nr_retry_pages;
/*
- * Try to migrate subpages of fail-to-migrate THPs, no nr_failed
- * counting in this round, since all subpages of a THP is counted
- * as 1 failure in the first round.
+ * Try to migrate split folios of fail-to-migrate large folios, no
+ * nr_failed counting in this round, since all split folios of a
+ * large folio is counted as 1 failure in the first round.
*/
- if (!list_empty(&thp_split_pages)) {
+ if (!list_empty(&split_folios)) {
/*
- * Move non-migrated pages (after 10 retries) to ret_pages
+ * Move non-migrated folios (after 10 retries) to ret_folios
* to avoid migrating them again.
*/
- list_splice_init(from, &ret_pages);
- list_splice_init(&thp_split_pages, from);
- no_subpage_counting = true;
+ list_splice_init(from, &ret_folios);
+ list_splice_init(&split_folios, from);
+ no_split_folio_counting = true;
retry = 1;
- goto thp_subpage_migration;
+ goto split_folio_migration;
}
- rc = nr_failed + nr_thp_failed;
+ rc = nr_failed + nr_large_failed;
out:
/*
- * Put the permanent failure page back to migration list, they
+ * Put the permanent failure folio back to migration list, they
* will be put back to the right list by the caller.
*/
- list_splice(&ret_pages, from);
+ list_splice(&ret_folios, from);
/*
- * Return 0 in case all subpages of fail-to-migrate THPs are
- * migrated successfully.
+ * Return 0 in case all split folios of fail-to-migrate large folios
+ * are migrated successfully.
*/
if (list_empty(from))
rc = 0;
_
Patches currently in -mm which might be from ying.huang@xxxxxxxxx are
migrate-convert-unmap_and_move-to-use-folios.patch
migrate-convert-migrate_pages-to-use-folios.patch
