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Date: Fri, 4 Feb 2022 19:58:26 +0000
From: "Matthew Wilcox (Oracle)" <willy@...radead.org>
To: linux-mm@...ck.org
Cc: "Matthew Wilcox (Oracle)" <willy@...radead.org>,
linux-kernel@...r.kernel.org
Subject: [PATCH 49/75] mm/mlock: Turn munlock_vma_page() into munlock_vma_folio()
Add back munlock_vma_page() as a wrapper function. Saves a few calls
to compound_head() and an assertion that the page is not a tail page.
Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>
---
mm/folio-compat.c | 5 +++
mm/internal.h | 3 +-
mm/mlock.c | 86 +++++++++++++++++++++++------------------------
3 files changed, 50 insertions(+), 44 deletions(-)
diff --git a/mm/folio-compat.c b/mm/folio-compat.c
index 90f03187a5e3..3804fd8c1f20 100644
--- a/mm/folio-compat.c
+++ b/mm/folio-compat.c
@@ -176,6 +176,11 @@ void mlock_vma_page(struct page *page)
mlock_vma_folio(page_folio(page));
}
+unsigned long munlock_vma_page(struct page *page)
+{
+ return munlock_vma_folio(page_folio(page));
+}
+
void page_mlock(struct page *page)
{
folio_mlock(page_folio(page));
diff --git a/mm/internal.h b/mm/internal.h
index 18b024aa7e59..66645972cbd7 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -413,7 +413,8 @@ static inline void munlock_vma_pages_all(struct vm_area_struct *vma)
*/
void mlock_vma_page(struct page *page);
void mlock_vma_folio(struct folio *folio);
-extern unsigned int munlock_vma_page(struct page *page);
+unsigned long munlock_vma_page(struct page *page);
+unsigned long munlock_vma_folio(struct folio *folio);
extern int mlock_future_check(struct mm_struct *mm, unsigned long flags,
unsigned long len);
diff --git a/mm/mlock.c b/mm/mlock.c
index d998fd5c84bf..f188038ef48e 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -115,82 +115,81 @@ void mlock_vma_folio(struct folio *folio)
/*
* Finish munlock after successful page isolation
*
- * Page must be locked. This is a wrapper for page_mlock()
- * and putback_lru_page() with munlock accounting.
+ * Folio must be locked. This is a wrapper for folio_mlock()
+ * and folio_putback_lru() with munlock accounting.
*/
-static void __munlock_isolated_page(struct page *page)
+static void __munlock_isolated_folio(struct folio *folio)
{
/*
* Optimization: if the page was mapped just once, that's our mapping
* and we don't need to check all the other vmas.
*/
- if (page_mapcount(page) > 1)
- page_mlock(page);
+ /* XXX: should be folio_mapcount(), surely? */
+ if (page_mapcount(&folio->page) > 1)
+ folio_mlock(folio);
/* Did try_to_unlock() succeed or punt? */
- if (!PageMlocked(page))
- count_vm_events(UNEVICTABLE_PGMUNLOCKED, thp_nr_pages(page));
+ if (!folio_test_mlocked(folio))
+ count_vm_events(UNEVICTABLE_PGMUNLOCKED, folio_nr_pages(folio));
- putback_lru_page(page);
+ folio_putback_lru(folio);
}
/*
- * Accounting for page isolation fail during munlock
+ * Accounting for folio isolation fail during munlock
*
- * Performs accounting when page isolation fails in munlock. There is nothing
- * else to do because it means some other task has already removed the page
- * from the LRU. putback_lru_page() will take care of removing the page from
+ * Performs accounting when folio isolation fails in munlock. There is nothing
+ * else to do because it means some other task has already removed the folio
+ * from the LRU. folio_putback_lru() will take care of removing the folio from
* the unevictable list, if necessary. vmscan [folio_referenced()] will move
- * the page back to the unevictable list if some other vma has it mlocked.
+ * the folio back to the unevictable list if some other vma has it mlocked.
*/
-static void __munlock_isolation_failed(struct page *page)
+static void __munlock_isolation_failed(struct folio *folio)
{
- int nr_pages = thp_nr_pages(page);
+ long nr_pages = folio_nr_pages(folio);
- if (PageUnevictable(page))
+ if (folio_test_unevictable(folio))
__count_vm_events(UNEVICTABLE_PGSTRANDED, nr_pages);
else
__count_vm_events(UNEVICTABLE_PGMUNLOCKED, nr_pages);
}
/**
- * munlock_vma_page - munlock a vma page
- * @page: page to be unlocked, either a normal page or THP page head
+ * munlock_vma_folio() - munlock a vma folio.
+ * @folio: Folio to be unlocked.
*
- * returns the size of the page as a page mask (0 for normal page,
- * HPAGE_PMD_NR - 1 for THP head page)
- *
- * called from munlock()/munmap() path with page supposedly on the LRU.
- * When we munlock a page, because the vma where we found the page is being
+ * called from munlock()/munmap() path with folio supposedly on the LRU.
+ * When we munlock a folio, because the vma where we found the folio is being
* munlock()ed or munmap()ed, we want to check whether other vmas hold the
- * page locked so that we can leave it on the unevictable lru list and not
- * bother vmscan with it. However, to walk the page's rmap list in
- * page_mlock() we must isolate the page from the LRU. If some other
- * task has removed the page from the LRU, we won't be able to do that.
- * So we clear the PageMlocked as we might not get another chance. If we
- * can't isolate the page, we leave it for putback_lru_page() and vmscan
+ * folio locked so that we can leave it on the unevictable lru list and not
+ * bother vmscan with it. However, to walk the folio's rmap list in
+ * folio_mlock() we must isolate the folio from the LRU. If some other
+ * task has removed the folio from the LRU, we won't be able to do that.
+ * So we clear the folio mlocked flag as we might not get another chance. If
+ * we can't isolate the folio, we leave it for folio_putback_lru() and vmscan
* [folio_referenced()/try_to_unmap()] to deal with.
+ *
+ * Return: The size of the folio as a page mask (2^order - 1).
*/
-unsigned int munlock_vma_page(struct page *page)
+unsigned long munlock_vma_folio(struct folio *folio)
{
- int nr_pages;
+ long nr_pages;
- /* For page_mlock() and to serialize with page migration */
- BUG_ON(!PageLocked(page));
- VM_BUG_ON_PAGE(PageTail(page), page);
+ /* For folio_mlock() and to serialize with page migration */
+ BUG_ON(!folio_test_locked(folio));
- if (!TestClearPageMlocked(page)) {
- /* Potentially, PTE-mapped THP: do not skip the rest PTEs */
+ if (!folio_test_clear_mlocked(folio)) {
+ /* Potentially, PTE-mapped folio: do not skip the other PTEs */
return 0;
}
- nr_pages = thp_nr_pages(page);
- mod_zone_page_state(page_zone(page), NR_MLOCK, -nr_pages);
+ nr_pages = folio_nr_pages(folio);
+ zone_stat_mod_folio(folio, NR_MLOCK, -nr_pages);
- if (!isolate_lru_page(page))
- __munlock_isolated_page(page);
+ if (!folio_isolate_lru(folio))
+ __munlock_isolated_folio(folio);
else
- __munlock_isolation_failed(page);
+ __munlock_isolation_failed(folio);
return nr_pages - 1;
}
@@ -289,7 +288,7 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone)
del_page_from_lru_list(page, lruvec);
continue;
} else
- __munlock_isolation_failed(page);
+ __munlock_isolation_failed(folio);
} else {
delta_munlocked++;
}
@@ -318,6 +317,7 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone)
struct page *page = pvec->pages[i];
if (page) {
+ struct folio *folio = page_folio(page);
lock_page(page);
if (!__putback_lru_fast_prepare(page, &pvec_putback,
&pgrescued)) {
@@ -326,7 +326,7 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone)
* pin before unlock_page()
*/
get_page(page); /* for putback_lru_page() */
- __munlock_isolated_page(page);
+ __munlock_isolated_folio(folio);
unlock_page(page);
put_page(page); /* from follow_page_mask() */
}
--
2.34.1
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