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-rw-r--r--mm/rmap.c57
1 files changed, 33 insertions, 24 deletions
diff --git a/mm/rmap.c b/mm/rmap.c
index 08c56aaf72eb..b0fc27e77d6d 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -168,7 +168,7 @@ static void anon_vma_chain_link(struct vm_area_struct *vma,
*
* Anon-vma allocations are very subtle, because we may have
* optimistically looked up an anon_vma in page_lock_anon_vma_read()
- * and that may actually touch the spinlock even in the newly
+ * and that may actually touch the rwsem even in the newly
* allocated vma (it depends on RCU to make sure that the
* anon_vma isn't actually destroyed).
*
@@ -359,7 +359,7 @@ int anon_vma_fork(struct vm_area_struct *vma, struct vm_area_struct *pvma)
goto out_error_free_anon_vma;
/*
- * The root anon_vma's spinlock is the lock actually used when we
+ * The root anon_vma's rwsem is the lock actually used when we
* lock any of the anon_vmas in this anon_vma tree.
*/
anon_vma->root = pvma->anon_vma->root;
@@ -413,8 +413,15 @@ void unlink_anon_vmas(struct vm_area_struct *vma)
list_del(&avc->same_vma);
anon_vma_chain_free(avc);
}
- if (vma->anon_vma)
+ if (vma->anon_vma) {
vma->anon_vma->degree--;
+
+ /*
+ * vma would still be needed after unlink, and anon_vma will be prepared
+ * when handle fault.
+ */
+ vma->anon_vma = NULL;
+ }
unlock_anon_vma_root(root);
/*
@@ -455,8 +462,8 @@ void __init anon_vma_init(void)
* Getting a lock on a stable anon_vma from a page off the LRU is tricky!
*
* Since there is no serialization what so ever against page_remove_rmap()
- * the best this function can do is return a locked anon_vma that might
- * have been relevant to this page.
+ * the best this function can do is return a refcount increased anon_vma
+ * that might have been relevant to this page.
*
* The page might have been remapped to a different anon_vma or the anon_vma
* returned may already be freed (and even reused).
@@ -1079,8 +1086,7 @@ static void __page_check_anon_rmap(struct page *page,
* be set up correctly at this point.
*
* We have exclusion against page_add_anon_rmap because the caller
- * always holds the page locked, except if called from page_dup_rmap,
- * in which case the page is already known to be setup.
+ * always holds the page locked.
*
* We have exclusion against page_add_new_anon_rmap because those pages
* are initially only visible via the pagetables, and the pte is locked
@@ -1144,7 +1150,7 @@ void do_page_add_anon_rmap(struct page *page,
* disabled.
*/
if (compound)
- __inc_lruvec_page_state(page, NR_ANON_THPS);
+ __mod_lruvec_page_state(page, NR_ANON_THPS, nr);
__mod_lruvec_page_state(page, NR_ANON_MAPPED, nr);
}
@@ -1186,7 +1192,7 @@ void page_add_new_anon_rmap(struct page *page,
if (hpage_pincount_available(page))
atomic_set(compound_pincount_ptr(page), 0);
- __inc_lruvec_page_state(page, NR_ANON_THPS);
+ __mod_lruvec_page_state(page, NR_ANON_THPS, nr);
} else {
/* Anon THP always mapped first with PMD */
VM_BUG_ON_PAGE(PageTransCompound(page), page);
@@ -1211,16 +1217,20 @@ void page_add_file_rmap(struct page *page, bool compound)
VM_BUG_ON_PAGE(compound && !PageTransHuge(page), page);
lock_page_memcg(page);
if (compound && PageTransHuge(page)) {
- for (i = 0, nr = 0; i < thp_nr_pages(page); i++) {
+ int nr_pages = thp_nr_pages(page);
+
+ for (i = 0, nr = 0; i < nr_pages; i++) {
if (atomic_inc_and_test(&page[i]._mapcount))
nr++;
}
if (!atomic_inc_and_test(compound_mapcount_ptr(page)))
goto out;
if (PageSwapBacked(page))
- __inc_node_page_state(page, NR_SHMEM_PMDMAPPED);
+ __mod_lruvec_page_state(page, NR_SHMEM_PMDMAPPED,
+ nr_pages);
else
- __inc_node_page_state(page, NR_FILE_PMDMAPPED);
+ __mod_lruvec_page_state(page, NR_FILE_PMDMAPPED,
+ nr_pages);
} else {
if (PageTransCompound(page) && page_mapping(page)) {
VM_WARN_ON_ONCE(!PageLocked(page));
@@ -1252,16 +1262,20 @@ static void page_remove_file_rmap(struct page *page, bool compound)
/* page still mapped by someone else? */
if (compound && PageTransHuge(page)) {
- for (i = 0, nr = 0; i < thp_nr_pages(page); i++) {
+ int nr_pages = thp_nr_pages(page);
+
+ for (i = 0, nr = 0; i < nr_pages; i++) {
if (atomic_add_negative(-1, &page[i]._mapcount))
nr++;
}
if (!atomic_add_negative(-1, compound_mapcount_ptr(page)))
return;
if (PageSwapBacked(page))
- __dec_node_page_state(page, NR_SHMEM_PMDMAPPED);
+ __mod_lruvec_page_state(page, NR_SHMEM_PMDMAPPED,
+ -nr_pages);
else
- __dec_node_page_state(page, NR_FILE_PMDMAPPED);
+ __mod_lruvec_page_state(page, NR_FILE_PMDMAPPED,
+ -nr_pages);
} else {
if (!atomic_add_negative(-1, &page->_mapcount))
return;
@@ -1292,7 +1306,7 @@ static void page_remove_anon_compound_rmap(struct page *page)
if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
return;
- __dec_lruvec_page_state(page, NR_ANON_THPS);
+ __mod_lruvec_page_state(page, NR_ANON_THPS, -thp_nr_pages(page));
if (TestClearPageDoubleMap(page)) {
/*
@@ -1722,9 +1736,9 @@ static bool invalid_migration_vma(struct vm_area_struct *vma, void *arg)
return vma_is_temporary_stack(vma);
}
-static int page_mapcount_is_zero(struct page *page)
+static int page_not_mapped(struct page *page)
{
- return !total_mapcount(page);
+ return !page_mapped(page);
}
/**
@@ -1742,7 +1756,7 @@ bool try_to_unmap(struct page *page, enum ttu_flags flags)
struct rmap_walk_control rwc = {
.rmap_one = try_to_unmap_one,
.arg = (void *)flags,
- .done = page_mapcount_is_zero,
+ .done = page_not_mapped,
.anon_lock = page_lock_anon_vma_read,
};
@@ -1766,11 +1780,6 @@ bool try_to_unmap(struct page *page, enum ttu_flags flags)
return !page_mapcount(page) ? true : false;
}
-static int page_not_mapped(struct page *page)
-{
- return !page_mapped(page);
-};
-
/**
* try_to_munlock - try to munlock a page
* @page: the page to be munlocked
generated by cgit v1.2.3 (git 2.25.1) at 2024-09-17 16:26:00 +0000