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-next>] [day] [month] [year] [list]
Message-ID: <20240815083102.653820-1-link@vivo.com>
Date: Thu, 15 Aug 2024 16:31:01 +0800
From: Huan Yang <link@...o.com>
To: usamaarif642@...il.com,
	yuzhao@...gle.com,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Cc: opensource.kernel@...o.com,
	Huan Yang <link@...o.com>
Subject: [PATCH] mm: move the easily assessable conditions forward

Current try_to_map_unused_to_zeropage try to use shared zero page to
save some memory of sub page.

If forbids zeropage, no need to do anything rather than attempting to
assess wthether to use it afterwards.

Signed-off-by: Huan Yang <link@...o.com>
---
 mm/migrate.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/mm/migrate.c b/mm/migrate.c
index 6e32098ac2dc..d71cc4ff190f 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -192,6 +192,9 @@ static bool try_to_map_unused_to_zeropage(struct page_vma_mapped_walk *pvmw,
 	VM_BUG_ON_PAGE(!PageLocked(page), page);
 	VM_BUG_ON_PAGE(pte_present(*pvmw->pte), page);
 
+	if (mm_forbids_zeropage(pvmw->vma->vm_mm))
+		return false;
+
 	if (PageMlocked(page) || (pvmw->vma->vm_flags & VM_LOCKED))
 		return false;
 
@@ -204,7 +207,7 @@ static bool try_to_map_unused_to_zeropage(struct page_vma_mapped_walk *pvmw,
 	contains_data = memchr_inv(addr, 0, PAGE_SIZE);
 	kunmap_local(addr);
 
-	if (contains_data || mm_forbids_zeropage(pvmw->vma->vm_mm))
+	if (contains_data)
 		return false;
 
 	newpte = pte_mkspecial(pfn_pte(my_zero_pfn(pvmw->address),

base-commit: edd1ec2e3a9f5de7fb267a3af73e4f00e7e052b7
-- 
2.45.2


Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ