mm: Enhance per process reclaim to consider shared pages
Some pages could be shared by several processes. (ex, libc)
In case of that, it's too bad to reclaim them from the beginnig.
This patch causes VM to keep them on memory until last task
try to reclaim them so shared pages will be reclaimed only if
all of task has gone swapping out.
This feature doesn't handle non-linear mapping on ramfs because
it's very time-consuming and doesn't make sure of reclaiming and
not common.
Change-Id: I7e5f34f2e947f5db6d405867fe2ad34863ca40f7
Signed-off-by: Sangseok Lee <sangseok.lee@lge.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Patch-mainline: linux-mm @ 9 May 2013 16:21:27
[vinmenon@codeaurora.org: trivial merge conflict fixes + changes
to make the patch work with 4.9 kernel]
Signed-off-by: Vinayak Menon <vinmenon@codeaurora.org>
diff --git a/mm/rmap.c b/mm/rmap.c
index cd37c1c..dfb19f0 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1616,9 +1616,12 @@
* try_to_unmap - try to remove all page table mappings to a page
* @page: the page to get unmapped
* @flags: action and flags
+ * @vma : target vma for reclaim
*
* Tries to remove all the page table entries which are mapping this
* page, used in the pageout path. Caller must hold the page lock.
+ * If @vma is not NULL, this function try to remove @page from only @vma
+ * without peeking all mapped vma for @page.
* Return values are:
*
* SWAP_SUCCESS - we succeeded in removing all mappings
@@ -1626,7 +1629,8 @@
* SWAP_FAIL - the page is unswappable
* SWAP_MLOCK - page is mlocked.
*/
-int try_to_unmap(struct page *page, enum ttu_flags flags)
+int try_to_unmap(struct page *page, enum ttu_flags flags,
+ struct vm_area_struct *vma)
{
int ret;
struct rmap_private rp = {
@@ -1639,6 +1643,7 @@
.arg = &rp,
.done = page_mapcount_is_zero,
.anon_lock = page_lock_anon_vma_read,
+ .target_vma = vma,
};
/*
@@ -1698,6 +1703,7 @@
.arg = &rp,
.done = page_not_mapped,
.anon_lock = page_lock_anon_vma_read,
+ .target_vma = NULL,
};
@@ -1760,6 +1766,11 @@
struct anon_vma_chain *avc;
int ret = SWAP_AGAIN;
+ if (rwc->target_vma) {
+ unsigned long address = vma_address(page, rwc->target_vma);
+ return rwc->rmap_one(page, rwc->target_vma, address, rwc->arg);
+ }
+
if (locked) {
anon_vma = page_anon_vma(page);
/* anon_vma disappear under us? */
@@ -1767,6 +1778,7 @@
} else {
anon_vma = rmap_walk_anon_lock(page, rwc);
}
+
if (!anon_vma)
return ret;
@@ -1811,6 +1823,7 @@
struct address_space *mapping = page_mapping(page);
pgoff_t pgoff;
struct vm_area_struct *vma;
+ unsigned long address;
int ret = SWAP_AGAIN;
/*
@@ -1827,6 +1840,13 @@
pgoff = page_to_pgoff(page);
if (!locked)
i_mmap_lock_read(mapping);
+
+ if (rwc->target_vma) {
+ address = vma_address(page, rwc->target_vma);
+ ret = rwc->rmap_one(page, rwc->target_vma, address, rwc->arg);
+ goto done;
+ }
+
vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
unsigned long address = vma_address(page, vma);