[PATCHv3, RFC 12/34] thp, mm: rewrite delete_from_page_cache() to support huge pages

From: Kirill A. Shutemov
Date: Fri Apr 05 2013 - 08:06:29 EST


From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>

As with add_to_page_cache_locked() we handle HPAGE_CACHE_NR pages a
time.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
mm/filemap.c | 28 ++++++++++++++++++++++------
1 file changed, 22 insertions(+), 6 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index ce1ded8..56a81e3 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -115,6 +115,7 @@
void __delete_from_page_cache(struct page *page)
{
struct address_space *mapping = page->mapping;
+ int nr;

trace_mm_filemap_delete_from_page_cache(page);
/*
@@ -127,13 +128,28 @@ void __delete_from_page_cache(struct page *page)
else
cleancache_invalidate_page(mapping, page);

- radix_tree_delete(&mapping->page_tree, page->index);
+ if (PageTransHuge(page)) {
+ int i;
+
+ radix_tree_delete(&mapping->page_tree, page->index);
+ for (i = 1; i < HPAGE_CACHE_NR; i++) {
+ radix_tree_delete(&mapping->page_tree, page->index + i);
+ page[i].mapping = NULL;
+ page_cache_release(page + i);
+ }
+ __dec_zone_page_state(page, NR_FILE_TRANSPARENT_HUGEPAGES);
+ nr = HPAGE_CACHE_NR;
+ } else {
+ radix_tree_delete(&mapping->page_tree, page->index);
+ __dec_zone_page_state(page, NR_FILE_PAGES);
+ nr = 1;
+ }
+
page->mapping = NULL;
/* Leave page->index set: truncation lookup relies upon it */
- mapping->nrpages--;
- __dec_zone_page_state(page, NR_FILE_PAGES);
+ mapping->nrpages -= nr;
if (PageSwapBacked(page))
- __dec_zone_page_state(page, NR_SHMEM);
+ __mod_zone_page_state(page_zone(page), NR_SHMEM, -nr);
BUG_ON(page_mapped(page));

/*
@@ -144,8 +160,8 @@ void __delete_from_page_cache(struct page *page)
* having removed the page entirely.
*/
if (PageDirty(page) && mapping_cap_account_dirty(mapping)) {
- dec_zone_page_state(page, NR_FILE_DIRTY);
- dec_bdi_stat(mapping->backing_dev_info, BDI_RECLAIMABLE);
+ mod_zone_page_state(page_zone(page), NR_FILE_DIRTY, -nr);
+ add_bdi_stat(mapping->backing_dev_info, BDI_RECLAIMABLE, -nr);
}
}

--
1.7.10.4

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