linux-kernel - [PATCH v9 10/14] khugepaged: allow khugepaged to check all anonymous mTHP orders

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 for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250714003207.113275-11-npache@redhat.com>
Date: Sun, 13 Jul 2025 18:32:03 -0600
From: Nico Pache <npache@...hat.com>
To: linux-mm@...ck.org,
	linux-doc@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-trace-kernel@...r.kernel.org
Cc: david@...hat.com,
	ziy@...dia.com,
	baolin.wang@...ux.alibaba.com,
	lorenzo.stoakes@...cle.com,
	Liam.Howlett@...cle.com,
	ryan.roberts@....com,
	dev.jain@....com,
	corbet@....net,
	rostedt@...dmis.org,
	mhiramat@...nel.org,
	mathieu.desnoyers@...icios.com,
	akpm@...ux-foundation.org,
	baohua@...nel.org,
	willy@...radead.org,
	peterx@...hat.com,
	wangkefeng.wang@...wei.com,
	usamaarif642@...il.com,
	sunnanyong@...wei.com,
	vishal.moola@...il.com,
	thomas.hellstrom@...ux.intel.com,
	yang@...amperecomputing.com,
	kirill.shutemov@...ux.intel.com,
	aarcange@...hat.com,
	raquini@...hat.com,
	anshuman.khandual@....com,
	catalin.marinas@....com,
	tiwai@...e.de,
	will@...nel.org,
	dave.hansen@...ux.intel.com,
	jack@...e.cz,
	cl@...two.org,
	jglisse@...gle.com,
	surenb@...gle.com,
	zokeefe@...gle.com,
	hannes@...xchg.org,
	rientjes@...gle.com,
	mhocko@...e.com,
	rdunlap@...radead.org,
	hughd@...gle.com
Subject: [PATCH v9 10/14] khugepaged: allow khugepaged to check all anonymous mTHP orders

From: Baolin Wang <baolin.wang@...ux.alibaba.com>

We have now allowed mTHP collapse, but thp_vma_allowable_order() still only
checks if the PMD-sized mTHP is allowed to collapse. This prevents scanning
and collapsing of 64K mTHP when only 64K mTHP is enabled. Thus, we should
modify the checks to allow all large orders of anonymous mTHP.

Signed-off-by: Baolin Wang <baolin.wang@...ux.alibaba.com>
Signed-off-by: Nico Pache <npache@...hat.com>
---
 mm/khugepaged.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 7a9c4edf0e23..3772dc0d78ea 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -491,8 +491,11 @@ void khugepaged_enter_vma(struct vm_area_struct *vma,
 {
 	if (!test_bit(MMF_VM_HUGEPAGE, &vma->vm_mm->flags) &&
 	    hugepage_pmd_enabled()) {
-		if (thp_vma_allowable_order(vma, vm_flags, TVA_ENFORCE_SYSFS,
-					    PMD_ORDER))
+		unsigned long orders = vma_is_anonymous(vma) ?
+					THP_ORDERS_ALL_ANON : BIT(PMD_ORDER);
+
+		if (thp_vma_allowable_orders(vma, vm_flags, TVA_ENFORCE_SYSFS,
+					    orders))
 			__khugepaged_enter(vma->vm_mm);
 	}
 }
@@ -2624,6 +2627,8 @@ static unsigned int collapse_scan_mm_slot(unsigned int pages, int *result,
 
 	vma_iter_init(&vmi, mm, khugepaged_scan.address);
 	for_each_vma(vmi, vma) {
+		unsigned long orders = vma_is_anonymous(vma) ?
+					THP_ORDERS_ALL_ANON : BIT(PMD_ORDER);
 		unsigned long hstart, hend;
 
 		cond_resched();
@@ -2631,8 +2636,8 @@ static unsigned int collapse_scan_mm_slot(unsigned int pages, int *result,
 			progress++;
 			break;
 		}
-		if (!thp_vma_allowable_order(vma, vma->vm_flags,
-					TVA_ENFORCE_SYSFS, PMD_ORDER)) {
+		if (!thp_vma_allowable_orders(vma, vma->vm_flags,
+			TVA_ENFORCE_SYSFS, orders)) {
 skip:
 			progress++;
 			continue;
-- 
2.50.0