mm:add KPF_ZERO_PAGE flag for /proc/kpageflags

[mirror_ubuntu-focal-kernel.git] / fs / proc / page.c

diff --git a/fs/proc/page.c b/fs/proc/page.c
index 1e3187da1fedbb76fedd9252a8969c159d7c15a2..7eee2d8b97d9786b7c05ca1078d477c4db6af5e1 100644 (file)
--- a/fs/proc/page.c
+++ b/fs/proc/page.c
@@ -5,6 +5,7 @@
 #include <linux/ksm.h>
 #include <linux/mm.h>
 #include <linux/mmzone.h>
+#include <linux/huge_mm.h>
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
 #include <linux/hugetlb.h>
@@ -121,9 +122,18 @@ u64 stable_page_flags(struct page *page)
         * just checks PG_head/PG_tail, so we need to check PageLRU/PageAnon
         * to make sure a given page is a thp, not a non-huge compound page.
         */
-       else if (PageTransCompound(page) && (PageLRU(compound_head(page)) ||
-                                            PageAnon(compound_head(page))))
-               u |= 1 << KPF_THP;
+       else if (PageTransCompound(page)) {
+               struct page *head = compound_head(page);
+
+               if (PageLRU(head) || PageAnon(head))
+                       u |= 1 << KPF_THP;
+               else if (is_huge_zero_page(head)) {
+                       u |= 1 << KPF_ZERO_PAGE;
+                       u |= 1 << KPF_THP;
+               }
+       } else if (is_zero_pfn(page_to_pfn(page)))
+               u |= 1 << KPF_ZERO_PAGE;
+
 
        /*
         * Caveats on high order pages: page->_count will only be set