mm/rmap: use rmap_walk() in try_to_munlock()
Now, we have an infrastructure in rmap_walk() to handle difference from
variants of rmap traversing functions.
So, just use it in try_to_munlock().
In this patch, I change following things.
1. remove some variants of rmap traversing functions.
cf> try_to_unmap_ksm, try_to_unmap_anon, try_to_unmap_file
2. mechanical change to use rmap_walk() in try_to_munlock().
3. copy and paste comments.
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Hillf Danton <dhillf@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/rmap.c b/mm/rmap.c
index b3263cb..c73e0c6 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1177,9 +1177,6 @@
}
/*
- * Subfunctions of try_to_unmap: try_to_unmap_one called
- * repeatedly from try_to_unmap_ksm, try_to_unmap_anon or try_to_unmap_file.
- *
* @arg: enum ttu_flags will be passed to this argument
*/
int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
@@ -1521,107 +1518,6 @@
return is_vma_temporary_stack(vma);
}
-/**
- * try_to_unmap_anon - unmap or unlock anonymous page using the object-based
- * rmap method
- * @page: the page to unmap/unlock
- * @flags: action and flags
- *
- * Find all the mappings of a page using the mapping pointer and the vma chains
- * contained in the anon_vma struct it points to.
- *
- * This function is only called from try_to_unmap/try_to_munlock for
- * anonymous pages.
- * When called from try_to_munlock(), the mmap_sem of the mm containing the vma
- * where the page was found will be held for write. So, we won't recheck
- * vm_flags for that VMA. That should be OK, because that vma shouldn't be
- * 'LOCKED.
- */
-static int try_to_unmap_anon(struct page *page, enum ttu_flags flags)
-{
- struct anon_vma *anon_vma;
- pgoff_t pgoff;
- struct anon_vma_chain *avc;
- int ret = SWAP_AGAIN;
-
- anon_vma = page_lock_anon_vma_read(page);
- if (!anon_vma)
- return ret;
-
- pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
- anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) {
- struct vm_area_struct *vma = avc->vma;
- unsigned long address;
-
- /*
- * During exec, a temporary VMA is setup and later moved.
- * The VMA is moved under the anon_vma lock but not the
- * page tables leading to a race where migration cannot
- * find the migration ptes. Rather than increasing the
- * locking requirements of exec(), migration skips
- * temporary VMAs until after exec() completes.
- */
- if (IS_ENABLED(CONFIG_MIGRATION) && (flags & TTU_MIGRATION) &&
- is_vma_temporary_stack(vma))
- continue;
-
- address = vma_address(page, vma);
- ret = try_to_unmap_one(page, vma, address, (void *)flags);
- if (ret != SWAP_AGAIN || !page_mapped(page))
- break;
- }
-
- page_unlock_anon_vma_read(anon_vma);
- return ret;
-}
-
-/**
- * try_to_unmap_file - unmap/unlock file page using the object-based rmap method
- * @page: the page to unmap/unlock
- * @flags: action and flags
- *
- * Find all the mappings of a page using the mapping pointer and the vma chains
- * contained in the address_space struct it points to.
- *
- * This function is only called from try_to_unmap/try_to_munlock for
- * object-based pages.
- * When called from try_to_munlock(), the mmap_sem of the mm containing the vma
- * where the page was found will be held for write. So, we won't recheck
- * vm_flags for that VMA. That should be OK, because that vma shouldn't be
- * 'LOCKED.
- */
-static int try_to_unmap_file(struct page *page, enum ttu_flags flags)
-{
- struct address_space *mapping = page->mapping;
- pgoff_t pgoff = page->index << compound_order(page);
- struct vm_area_struct *vma;
- int ret = SWAP_AGAIN;
-
- mutex_lock(&mapping->i_mmap_mutex);
- vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
- unsigned long address = vma_address(page, vma);
- ret = try_to_unmap_one(page, vma, address, (void *)flags);
- if (ret != SWAP_AGAIN || !page_mapped(page))
- goto out;
- }
-
- if (list_empty(&mapping->i_mmap_nonlinear))
- goto out;
-
- /*
- * We don't bother to try to find the munlocked page in nonlinears.
- * It's costly. Instead, later, page reclaim logic may call
- * try_to_unmap(TTU_MUNLOCK) and recover PG_mlocked lazily.
- */
- if (TTU_ACTION(flags) == TTU_MUNLOCK)
- goto out;
-
- ret = try_to_unmap_nonlinear(page, mapping, vma);
-out:
- mutex_unlock(&mapping->i_mmap_mutex);
- return ret;
-}
-
static int page_not_mapped(struct page *page)
{
return !page_mapped(page);
@@ -1689,14 +1585,25 @@
*/
int try_to_munlock(struct page *page)
{
+ int ret;
+ struct rmap_walk_control rwc = {
+ .rmap_one = try_to_unmap_one,
+ .arg = (void *)TTU_MUNLOCK,
+ .done = page_not_mapped,
+ /*
+ * We don't bother to try to find the munlocked page in
+ * nonlinears. It's costly. Instead, later, page reclaim logic
+ * may call try_to_unmap() and recover PG_mlocked lazily.
+ */
+ .file_nonlinear = NULL,
+ .anon_lock = page_lock_anon_vma_read,
+
+ };
+
VM_BUG_ON(!PageLocked(page) || PageLRU(page));
- if (unlikely(PageKsm(page)))
- return try_to_unmap_ksm(page, TTU_MUNLOCK);
- else if (PageAnon(page))
- return try_to_unmap_anon(page, TTU_MUNLOCK);
- else
- return try_to_unmap_file(page, TTU_MUNLOCK);
+ ret = rmap_walk(page, &rwc);
+ return ret;
}
void __put_anon_vma(struct anon_vma *anon_vma)
@@ -1732,8 +1639,18 @@
}
/*
- * rmap_walk() and its helpers rmap_walk_anon() and rmap_walk_file():
- * Called by migrate.c to remove migration ptes, but might be used more later.
+ * rmap_walk_anon - do something to anonymous page using the object-based
+ * rmap method
+ * @page: the page to be handled
+ * @rwc: control variable according to each walk type
+ *
+ * Find all the mappings of a page using the mapping pointer and the vma chains
+ * contained in the anon_vma struct it points to.
+ *
+ * When called from try_to_munlock(), the mmap_sem of the mm containing the vma
+ * where the page was found will be held for write. So, we won't recheck
+ * vm_flags for that VMA. That should be OK, because that vma shouldn't be
+ * LOCKED.
*/
static int rmap_walk_anon(struct page *page, struct rmap_walk_control *rwc)
{
@@ -1763,6 +1680,19 @@
return ret;
}
+/*
+ * rmap_walk_file - do something to file page using the object-based rmap method
+ * @page: the page to be handled
+ * @rwc: control variable according to each walk type
+ *
+ * Find all the mappings of a page using the mapping pointer and the vma chains
+ * contained in the address_space struct it points to.
+ *
+ * When called from try_to_munlock(), the mmap_sem of the mm containing the vma
+ * where the page was found will be held for write. So, we won't recheck
+ * vm_flags for that VMA. That should be OK, because that vma shouldn't be
+ * LOCKED.
+ */
static int rmap_walk_file(struct page *page, struct rmap_walk_control *rwc)
{
struct address_space *mapping = page->mapping;