Commit 8ee53820edfd ("thp: mmu_notifier_test_young") introduced mmu_notifier_test_young(), but we should pass the address need to test. In xxx_scan_pmd(), the actual iteration address is "_address" not "address". We seem to misuse the variable on the very beginning.
Change it to the right one.
Fixes: 8ee53820edfd ("thp: mmu_notifier_test_young") Signed-off-by: Wei Yang richard.weiyang@gmail.com Cc: David Hildenbrand david@redhat.com Cc: Lorenzo Stoakes lorenzo.stoakes@oracle.com Cc: Zi Yan ziy@nvidia.com Cc: Baolin Wang baolin.wang@linux.alibaba.com Cc: Liam R. Howlett Liam.Howlett@oracle.com Cc: Nico Pache npache@redhat.com Cc: Ryan Roberts ryan.roberts@arm.com Cc: Dev Jain dev.jain@arm.com Cc: Barry Song baohua@kernel.org CC: stable@vger.kernel.org
--- The original commit 8ee53820edfd is at 2011. Then the code is moved to khugepaged.c in commit b46e756f5e470 ("thp: extract khugepaged from mm/huge_memory.c") in 2022. --- mm/khugepaged.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 24e18a7f8a93..b000942250d1 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1418,7 +1418,7 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm, if (cc->is_khugepaged && (pte_young(pteval) || folio_test_young(folio) || folio_test_referenced(folio) || mmu_notifier_test_young(vma->vm_mm, - address))) + _address))) referenced++; } if (!writable) {
On 22/08/25 12:03 pm, Wei Yang wrote:
Commit 8ee53820edfd ("thp: mmu_notifier_test_young") introduced mmu_notifier_test_young(), but we should pass the address need to test. In xxx_scan_pmd(), the actual iteration address is "_address" not "address". We seem to misuse the variable on the very beginning.
Change it to the right one.
Fixes: 8ee53820edfd ("thp: mmu_notifier_test_young") Signed-off-by: Wei Yang richard.weiyang@gmail.com Cc: David Hildenbrand david@redhat.com Cc: Lorenzo Stoakes lorenzo.stoakes@oracle.com Cc: Zi Yan ziy@nvidia.com Cc: Baolin Wang baolin.wang@linux.alibaba.com Cc: Liam R. Howlett Liam.Howlett@oracle.com Cc: Nico Pache npache@redhat.com Cc: Ryan Roberts ryan.roberts@arm.com Cc: Dev Jain dev.jain@arm.com Cc: Barry Song baohua@kernel.org CC: stable@vger.kernel.org
The original commit 8ee53820edfd is at 2011. Then the code is moved to khugepaged.c in commit b46e756f5e470 ("thp: extract khugepaged from mm/huge_memory.c") in 2022.
mm/khugepaged.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 24e18a7f8a93..b000942250d1 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1418,7 +1418,7 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm, if (cc->is_khugepaged && (pte_young(pteval) || folio_test_young(folio) || folio_test_referenced(folio) || mmu_notifier_test_young(vma->vm_mm,
address)))
_address))) referenced++; } if (!writable) {
Wow, I have gone through this code so many times and never noticed this.
Reviewed-by: Dev Jain dev.jain@arm.com
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On Fri, Aug 22, 2025 at 01:04:51PM +0530, Dev Jain wrote:
On 22/08/25 12:03 pm, Wei Yang wrote:
Commit 8ee53820edfd ("thp: mmu_notifier_test_young") introduced mmu_notifier_test_young(), but we should pass the address need to test. In xxx_scan_pmd(), the actual iteration address is "_address" not "address". We seem to misuse the variable on the very beginning.
Change it to the right one.
Fixes: 8ee53820edfd ("thp: mmu_notifier_test_young") Signed-off-by: Wei Yang richard.weiyang@gmail.com Cc: David Hildenbrand david@redhat.com Cc: Lorenzo Stoakes lorenzo.stoakes@oracle.com Cc: Zi Yan ziy@nvidia.com Cc: Baolin Wang baolin.wang@linux.alibaba.com Cc: Liam R. Howlett Liam.Howlett@oracle.com Cc: Nico Pache npache@redhat.com Cc: Ryan Roberts ryan.roberts@arm.com Cc: Dev Jain dev.jain@arm.com Cc: Barry Song baohua@kernel.org CC: stable@vger.kernel.org
The original commit 8ee53820edfd is at 2011. Then the code is moved to khugepaged.c in commit b46e756f5e470 ("thp: extract khugepaged from mm/huge_memory.c") in 2022.
mm/khugepaged.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 24e18a7f8a93..b000942250d1 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1418,7 +1418,7 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm, if (cc->is_khugepaged && (pte_young(pteval) || folio_test_young(folio) || folio_test_referenced(folio) || mmu_notifier_test_young(vma->vm_mm,
address)))
_address))) referenced++; } if (!writable) {Wow, I have gone through this code so many times and never noticed this.
Yeah, also I am surprised when noticing it.
On 22/08/25 12:03 pm, Wei Yang wrote:
Commit 8ee53820edfd ("thp: mmu_notifier_test_young") introduced mmu_notifier_test_young(), but we should pass the address need to test. In xxx_scan_pmd(), the actual iteration address is "_address" not "address". We seem to misuse the variable on the very beginning.
Change it to the right one.
Fixes: 8ee53820edfd ("thp: mmu_notifier_test_young") Signed-off-by: Wei Yang richard.weiyang@gmail.com Cc: David Hildenbrand david@redhat.com Cc: Lorenzo Stoakes lorenzo.stoakes@oracle.com Cc: Zi Yan ziy@nvidia.com Cc: Baolin Wang baolin.wang@linux.alibaba.com Cc: Liam R. Howlett Liam.Howlett@oracle.com Cc: Nico Pache npache@redhat.com Cc: Ryan Roberts ryan.roberts@arm.com Cc: Dev Jain dev.jain@arm.com Cc: Barry Song baohua@kernel.org CC: stable@vger.kernel.org
I hope you must have rebased since your previous patch got pulled, and the difference of time between these two events is less than 1.5 hours :)
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On Fri, Aug 22, 2025 at 01:08:57PM +0530, Dev Jain wrote:
IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.
Now deleted.
On Fri, Aug 22, 2025 at 01:08:57PM +0530, Dev Jain wrote:
On 22/08/25 12:03 pm, Wei Yang wrote:
Commit 8ee53820edfd ("thp: mmu_notifier_test_young") introduced mmu_notifier_test_young(), but we should pass the address need to test. In xxx_scan_pmd(), the actual iteration address is "_address" not "address". We seem to misuse the variable on the very beginning.
Change it to the right one.
Fixes: 8ee53820edfd ("thp: mmu_notifier_test_young") Signed-off-by: Wei Yang richard.weiyang@gmail.com Cc: David Hildenbrand david@redhat.com Cc: Lorenzo Stoakes lorenzo.stoakes@oracle.com Cc: Zi Yan ziy@nvidia.com Cc: Baolin Wang baolin.wang@linux.alibaba.com Cc: Liam R. Howlett Liam.Howlett@oracle.com Cc: Nico Pache npache@redhat.com Cc: Ryan Roberts ryan.roberts@arm.com Cc: Dev Jain dev.jain@arm.com Cc: Barry Song baohua@kernel.org CC: stable@vger.kernel.org
I hope you must have rebased since your previous patch got pulled, and the difference of time between these two events is less than 1.5 hours :)
Thanks
I took a look at the latest mm-new, this one applies.
On 22 Aug 2025, at 2:33, Wei Yang wrote:
Commit 8ee53820edfd ("thp: mmu_notifier_test_young") introduced mmu_notifier_test_young(), but we should pass the address need to test. In xxx_scan_pmd(), the actual iteration address is "_address" not "address". We seem to misuse the variable on the very beginning.
Change it to the right one.
Fixes: 8ee53820edfd ("thp: mmu_notifier_test_young") Signed-off-by: Wei Yang richard.weiyang@gmail.com Cc: David Hildenbrand david@redhat.com Cc: Lorenzo Stoakes lorenzo.stoakes@oracle.com Cc: Zi Yan ziy@nvidia.com Cc: Baolin Wang baolin.wang@linux.alibaba.com Cc: Liam R. Howlett Liam.Howlett@oracle.com Cc: Nico Pache npache@redhat.com Cc: Ryan Roberts ryan.roberts@arm.com Cc: Dev Jain dev.jain@arm.com Cc: Barry Song baohua@kernel.org CC: stable@vger.kernel.org
The original commit 8ee53820edfd is at 2011. Then the code is moved to khugepaged.c in commit b46e756f5e470 ("thp: extract khugepaged from mm/huge_memory.c") in 2022.
mm/khugepaged.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 24e18a7f8a93..b000942250d1 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1418,7 +1418,7 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm, if (cc->is_khugepaged && (pte_young(pteval) || folio_test_young(folio) || folio_test_referenced(folio) || mmu_notifier_test_young(vma->vm_mm,
address)))
_address))) referenced++;-- 2.34.1
LGTM. Reviewed-by: Zi Yan ziy@nvidia.com
-- Best Regards, Yan, Zi
On 22.08.25 08:33, Wei Yang wrote:
Commit 8ee53820edfd ("thp: mmu_notifier_test_young") introduced mmu_notifier_test_young(), but we should pass the address need to test.
... "but we are passing the wrong address".
In xxx_scan_pmd(), the actual iteration address is "_address" not "address". We seem to misuse the variable on the very beginning.
Change it to the right one.
Fixes: 8ee53820edfd ("thp: mmu_notifier_test_young") Signed-off-by: Wei Yang richard.weiyang@gmail.com Cc: David Hildenbrand david@redhat.com Cc: Lorenzo Stoakes lorenzo.stoakes@oracle.com Cc: Zi Yan ziy@nvidia.com Cc: Baolin Wang baolin.wang@linux.alibaba.com Cc: Liam R. Howlett Liam.Howlett@oracle.com Cc: Nico Pache npache@redhat.com Cc: Ryan Roberts ryan.roberts@arm.com Cc: Dev Jain dev.jain@arm.com Cc: Barry Song baohua@kernel.org CC: stable@vger.kernel.org
The original commit 8ee53820edfd is at 2011. Then the code is moved to khugepaged.c in commit b46e756f5e470 ("thp: extract khugepaged from mm/huge_memory.c") in 2022.
mm/khugepaged.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 24e18a7f8a93..b000942250d1 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1418,7 +1418,7 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm, if (cc->is_khugepaged && (pte_young(pteval) || folio_test_young(folio) || folio_test_referenced(folio) || mmu_notifier_test_young(vma->vm_mm,
address)))
_address)))
Please just put that into a single line, that's a perfectly reasonable case to exceed 80 chars.
Acked-by: David Hildenbrand david@redhat.com
referenced++;} if (!writable) {
Maybe, just maybe, it's because of *horrible* variable naming.
Can someone please send a cleanup to rename address -> pmd_addr and _address -> pte_addr or sth like that?
pretty much any naming is better than this.
On Tue, Aug 26, 2025 at 10:53:45AM +0200, David Hildenbrand wrote:
On 22.08.25 08:33, Wei Yang wrote:
Commit 8ee53820edfd ("thp: mmu_notifier_test_young") introduced mmu_notifier_test_young(), but we should pass the address need to test.
... "but we are passing the wrong address".
In xxx_scan_pmd(), the actual iteration address is "_address" not "address". We seem to misuse the variable on the very beginning.
Change it to the right one.
Fixes: 8ee53820edfd ("thp: mmu_notifier_test_young") Signed-off-by: Wei Yang richard.weiyang@gmail.com Cc: David Hildenbrand david@redhat.com Cc: Lorenzo Stoakes lorenzo.stoakes@oracle.com Cc: Zi Yan ziy@nvidia.com Cc: Baolin Wang baolin.wang@linux.alibaba.com Cc: Liam R. Howlett Liam.Howlett@oracle.com Cc: Nico Pache npache@redhat.com Cc: Ryan Roberts ryan.roberts@arm.com Cc: Dev Jain dev.jain@arm.com Cc: Barry Song baohua@kernel.org CC: stable@vger.kernel.org
The original commit 8ee53820edfd is at 2011. Then the code is moved to khugepaged.c in commit b46e756f5e470 ("thp: extract khugepaged from mm/huge_memory.c") in 2022.
mm/khugepaged.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 24e18a7f8a93..b000942250d1 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1418,7 +1418,7 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm, if (cc->is_khugepaged && (pte_young(pteval) || folio_test_young(folio) || folio_test_referenced(folio) || mmu_notifier_test_young(vma->vm_mm,
address)))
_address)))Please just put that into a single line, that's a perfectly reasonable case to exceed 80 chars.
Acked-by: David Hildenbrand david@redhat.com
referenced++;} if (!writable) {
Maybe, just maybe, it's because of *horrible* variable naming.
Can someone please send a cleanup to rename address -> pmd_addr and _address -> pte_addr or sth like that?
YES THIS.
pretty much any naming is better than this.
I despise it, and I realyl underlined this on review in Nico's series because it's just beyond belief.
It's terrible. I mean maybe even I will do something about this, if my review load eases up at some point...
-- Cheers
David / dhildenb
Cheers, Lorenzo
On Tue, Aug 26, 2025 at 10:03:27AM +0100, Lorenzo Stoakes wrote: [...]
referenced++;} if (!writable) {
Maybe, just maybe, it's because of *horrible* variable naming.
Can someone please send a cleanup to rename address -> pmd_addr and _address -> pte_addr or sth like that?
YES THIS.
pretty much any naming is better than this.
I despise it, and I realyl underlined this on review in Nico's series because it's just beyond belief.
I see your comment to Nico's series.
It's terrible. I mean maybe even I will do something about this, if my review load eases up at some point...
If you are fine, I could help to do the renaming.
Cheers, Lorenzo
On Tue, Aug 26, 2025 at 10:53:45AM +0200, David Hildenbrand wrote:
On 22.08.25 08:33, Wei Yang wrote:
Commit 8ee53820edfd ("thp: mmu_notifier_test_young") introduced mmu_notifier_test_young(), but we should pass the address need to test.
... "but we are passing the wrong address".
In xxx_scan_pmd(), the actual iteration address is "_address" not "address". We seem to misuse the variable on the very beginning.
Change it to the right one.
Fixes: 8ee53820edfd ("thp: mmu_notifier_test_young") Signed-off-by: Wei Yang richard.weiyang@gmail.com Cc: David Hildenbrand david@redhat.com Cc: Lorenzo Stoakes lorenzo.stoakes@oracle.com Cc: Zi Yan ziy@nvidia.com Cc: Baolin Wang baolin.wang@linux.alibaba.com Cc: Liam R. Howlett Liam.Howlett@oracle.com Cc: Nico Pache npache@redhat.com Cc: Ryan Roberts ryan.roberts@arm.com Cc: Dev Jain dev.jain@arm.com Cc: Barry Song baohua@kernel.org CC: stable@vger.kernel.org
The original commit 8ee53820edfd is at 2011. Then the code is moved to khugepaged.c in commit b46e756f5e470 ("thp: extract khugepaged from mm/huge_memory.c") in 2022.
mm/khugepaged.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 24e18a7f8a93..b000942250d1 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1418,7 +1418,7 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm, if (cc->is_khugepaged && (pte_young(pteval) || folio_test_young(folio) || folio_test_referenced(folio) || mmu_notifier_test_young(vma->vm_mm,
address)))
_address)))Please just put that into a single line, that's a perfectly reasonable case to exceed 80 chars.
Acked-by: David Hildenbrand david@redhat.com
Thanks.
@Andrew
Would you mind adjust the changelog and put it into one line?
referenced++;} if (!writable) {
Maybe, just maybe, it's because of *horrible* variable naming.
Can someone please send a cleanup to rename address -> pmd_addr and _address -> pte_addr or sth like that?
pretty much any naming is better than this.
-- Cheers
David / dhildenb
On Fri, Aug 22, 2025 at 06:33:18AM +0000, Wei Yang wrote:
Commit 8ee53820edfd ("thp: mmu_notifier_test_young") introduced mmu_notifier_test_young(), but we should pass the address need to test. In xxx_scan_pmd(), the actual iteration address is "_address" not "address". We seem to misuse the variable on the very beginning.
Change it to the right one.
Fixes: 8ee53820edfd ("thp: mmu_notifier_test_young") Signed-off-by: Wei Yang richard.weiyang@gmail.com Cc: David Hildenbrand david@redhat.com Cc: Lorenzo Stoakes lorenzo.stoakes@oracle.com Cc: Zi Yan ziy@nvidia.com Cc: Baolin Wang baolin.wang@linux.alibaba.com Cc: Liam R. Howlett Liam.Howlett@oracle.com Cc: Nico Pache npache@redhat.com Cc: Ryan Roberts ryan.roberts@arm.com Cc: Dev Jain dev.jain@arm.com Cc: Barry Song baohua@kernel.org CC: stable@vger.kernel.org
Good spot. This code is beyond belief.
Reviewed-by: Lorenzo Stoakes lorenzo.stoakes@oracle.com
The original commit 8ee53820edfd is at 2011.
Oopsies!
Then the code is moved to khugepaged.c in commit b46e756f5e470 ("thp: extract khugepaged from mm/huge_memory.c") in 2022.
mm/khugepaged.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 24e18a7f8a93..b000942250d1 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1418,7 +1418,7 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm, if (cc->is_khugepaged && (pte_young(pteval) || folio_test_young(folio) || folio_test_referenced(folio) || mmu_notifier_test_young(vma->vm_mm,
address)))
_address))) referenced++;-- 2.34.1
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