lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <8a2a87affac65f2ecdcea9917b5ae7a261689676.1724054125.git.baolin.wang@linux.alibaba.com>
Date: Mon, 19 Aug 2024 16:14:05 +0800
From: Baolin Wang <baolin.wang@...ux.alibaba.com>
To: akpm@...ux-foundation.org
Cc: hughd@...gle.com,
	willy@...radead.org,
	david@...hat.com,
	21cnbao@...il.com,
	ryan.roberts@....com,
	shy828301@...il.com,
	ziy@...dia.com,
	baolin.wang@...ux.alibaba.com,
	linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 4/5] mm: khugepaged: support shmem mTHP collapse

Shmem already supports the allocation of mTHP, but khugepaged does not yet
support collapsing mTHP folios. Now khugepaged is ready to support mTHP,
and this patch enables the collapse of shmem mTHP.

Signed-off-by: Baolin Wang <baolin.wang@...ux.alibaba.com>
---
 mm/khugepaged.c | 28 +++++++++++-----------------
 1 file changed, 11 insertions(+), 17 deletions(-)

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 91ee672db202..4b35239b5e46 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1847,7 +1847,7 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr,
 		}
 	} while (1);
 
-	for (index = start; index < end; index++) {
+	for (index = start; index < end;) {
 		xas_set(&xas, index);
 		folio = xas_load(&xas);
 
@@ -1866,6 +1866,7 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr,
 					}
 				}
 				nr_none++;
+				index++;
 				continue;
 			}
 
@@ -1947,12 +1948,10 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr,
 		 * we locked the first folio, then a THP might be there already.
 		 * This will be discovered on the first iteration.
 		 */
-		if (folio_test_large(folio)) {
-			result = folio_order(folio) == HPAGE_PMD_ORDER &&
-					folio->index == start
-					/* Maybe PMD-mapped */
-					? SCAN_PTE_MAPPED_HUGEPAGE
-					: SCAN_PAGE_COMPOUND;
+		if (folio_order(folio) == HPAGE_PMD_ORDER &&
+		    folio->index == start) {
+			/* Maybe PMD-mapped */
+			result = SCAN_PTE_MAPPED_HUGEPAGE;
 			goto out_unlock;
 		}
 
@@ -2013,6 +2012,7 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr,
 		 * Accumulate the folios that are being collapsed.
 		 */
 		list_add_tail(&folio->lru, &pagelist);
+		index += folio_nr_pages(folio);
 		continue;
 out_unlock:
 		folio_unlock(folio);
@@ -2265,16 +2265,10 @@ static int hpage_collapse_scan_file(struct mm_struct *mm, unsigned long addr,
 			continue;
 		}
 
-		/*
-		 * TODO: khugepaged should compact smaller compound pages
-		 * into a PMD sized page
-		 */
-		if (folio_test_large(folio)) {
-			result = folio_order(folio) == HPAGE_PMD_ORDER &&
-					folio->index == start
-					/* Maybe PMD-mapped */
-					? SCAN_PTE_MAPPED_HUGEPAGE
-					: SCAN_PAGE_COMPOUND;
+		if (folio_order(folio) == HPAGE_PMD_ORDER &&
+		    folio->index == start) {
+			/* Maybe PMD-mapped */
+			result = SCAN_PTE_MAPPED_HUGEPAGE;
 			/*
 			 * For SCAN_PTE_MAPPED_HUGEPAGE, further processing
 			 * by the caller won't touch the page cache, and so
-- 
2.39.3


Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ