[PATCH v3 0/2] docs/ksm: fix advisor documentation and comment

[PATCH v3 0/2] docs/ksm: fix advisor documentation and comment

[Jinjiang Tu]

This series fixes two problems left in the KSM advisor documentation
and code comment:
 - Patch 1 fixes two typos in sysfs knob names ("adivsor_max_cpu" and
   "adivsor_max_pages_to_scan") in ksm.rst that don't match the actual
  knob names.
 - Patch 2 fixes the description of advisor_min_pages_to_scan: it is
   described as the lower limit of pages_to_scan, but is actually only
   used as it's initial value, and the runtime pages_to_scan can drop
   below advisor_min_pages_to_scan.

Changes since v2:
 * update cover letter
 * update commit message for patch2

Changes since v1:
 * remove fix tags for both patches
 * update commit message and comment for patch2
 * collect Acked-by for patch1

Jinjiang Tu (2):
  docs: ksm: fix typos in sysfs knob names
  mm/ksm: fix advisor_min_pages_to_scan description

 Documentation/admin-guide/mm/ksm.rst | 8 ++++----
 mm/ksm.c                             | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

-- 
2.43.0

[PATCH v3 1/2] docs: ksm: fix typos in sysfs knob names

[Jinjiang Tu]

The sysfs knob names in mm/ksm.c are "advisor_max_cpu" and
"advisor_max_pages_to_scan", but the ksm.rst documentation spelled
both as "adivsor_*", fix the two typos.

Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com>
---
 Documentation/admin-guide/mm/ksm.rst | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Documentation/admin-guide/mm/ksm.rst b/Documentation/admin-guide/mm/ksm.rst
index ad8e7a41f3b5..c9f533b10f6f 100644
--- a/Documentation/admin-guide/mm/ksm.rst
+++ b/Documentation/admin-guide/mm/ksm.rst
@@ -174,7 +174,7 @@ advisor_mode
         The section about ``advisor`` explains in detail how the scan time
         advisor works.
 
-adivsor_max_cpu
+advisor_max_cpu
         specifies the upper limit of the cpu percent usage of the ksmd
         background thread. The default is 70.
 
@@ -186,7 +186,7 @@ advisor_min_pages_to_scan
         specifies the lower limit of the ``pages_to_scan`` parameter of the
         scan time advisor. The default is 500.
 
-adivsor_max_pages_to_scan
+advisor_max_pages_to_scan
         specifies the upper limit of the ``pages_to_scan`` parameter of the
         scan time advisor. The default is 30000.
 
-- 
2.43.0

[PATCH v3 2/2] mm/ksm: fix advisor_min_pages_to_scan description

[Jinjiang Tu]

Both Documentation/admin-guide/mm/ksm.rst and the comment next to the
variable definition in mm/ksm.c describe advisor_min_pages_to_scan as a
lower limit of the pages_to_scan parameter, but that is not how the
scan-time advisor actually uses it. commit 4e5fa4f5eff6 ("mm/ksm: add ksm
advisor") only uses it to initialize ksm_thread_pages_to_scan when the
scan-time advisor is enabled.

ksm_thread_pages_to_scan is adjusted by scan_time_advisor() after a full
scan finishes. ksm_thread_pages_to_scan could be increased or decreased
depend on the real scan time is longer or shorter than the target scan
time. The min value of ksm_thread_pages_to_scan is only limited by
KSM_ADVISOR_MIN_CPU, so ksm_thread_pages_to_scan could be smaller than
ksm_advisor_min_pages_to_scan.

The semantics of advisor_min_pages_to_scan was updated in the v2 patchset
[1], but the documentation wasn't updated.

Update the documentation and comment to match the semantics of
advisor_min_pages_to_scan.

Link: https://lore.kernel.org/linux-mm/20231028000945.2428830-2-shr@devkernel.io/ [1]
Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com>
---
 Documentation/admin-guide/mm/ksm.rst | 4 ++--
 mm/ksm.c                             | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/Documentation/admin-guide/mm/ksm.rst b/Documentation/admin-guide/mm/ksm.rst
index c9f533b10f6f..c329ca747b8c 100644
--- a/Documentation/admin-guide/mm/ksm.rst
+++ b/Documentation/admin-guide/mm/ksm.rst
@@ -183,8 +183,8 @@ advisor_target_scan_time
         pages. The default value is 200 seconds.
 
 advisor_min_pages_to_scan
-        specifies the lower limit of the ``pages_to_scan`` parameter of the
-        scan time advisor. The default is 500.
+        specifies the initial value of the ``pages_to_scan`` parameter of
+        the scan time advisor. The default is 500.
 
 advisor_max_pages_to_scan
         specifies the upper limit of the ``pages_to_scan`` parameter of the
diff --git a/mm/ksm.c b/mm/ksm.c
index 7d5b76478f0b..4a6cf8cf5d60 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -342,7 +342,7 @@ static enum ksm_advisor_type ksm_advisor;
  * Only called through the sysfs control interface:
  */
 
-/* At least scan this many pages per batch. */
+/* Initial number of pages to scan per batch. */
 static unsigned long ksm_advisor_min_pages_to_scan = 500;
 
 static void set_advisor_defaults(void)
-- 
2.43.0

Re: [PATCH v3 2/2] mm/ksm: fix advisor_min_pages_to_scan description

[David Hildenbrand (Arm)]

On 8/24/26 08:10, Jinjiang Tu wrote:
> Both Documentation/admin-guide/mm/ksm.rst and the comment next to the
> variable definition in mm/ksm.c describe advisor_min_pages_to_scan as a
> lower limit of the pages_to_scan parameter, but that is not how the
> scan-time advisor actually uses it. commit 4e5fa4f5eff6 ("mm/ksm: add ksm
> advisor") only uses it to initialize ksm_thread_pages_to_scan when the
> scan-time advisor is enabled.
> 
> ksm_thread_pages_to_scan is adjusted by scan_time_advisor() after a full
> scan finishes. ksm_thread_pages_to_scan could be increased or decreased
> depend on the real scan time is longer or shorter than the target scan
> time. The min value of ksm_thread_pages_to_scan is only limited by
> KSM_ADVISOR_MIN_CPU, so ksm_thread_pages_to_scan could be smaller than
> ksm_advisor_min_pages_to_scan.
> 
> The semantics of advisor_min_pages_to_scan was updated in the v2 patchset
> [1], but the documentation wasn't updated.
> 
> Update the documentation and comment to match the semantics of
> advisor_min_pages_to_scan.
> 
> Link: https://lore.kernel.org/linux-mm/20231028000945.2428830-2-shr@devkernel.io/ [1]
> Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com>
> ---

Acked-by: David Hildenbrand (Arm) <david@kernel.org>

-- 
Cheers,

David

Re: [PATCH v3 2/2] mm/ksm: fix advisor_min_pages_to_scan description

[Lorenzo Stoakes (ARM)]

On Mon, Aug 24, 2026 at 02:10:10PM +0800, Jinjiang Tu wrote:
> Both Documentation/admin-guide/mm/ksm.rst and the comment next to the
> variable definition in mm/ksm.c describe advisor_min_pages_to_scan as a
> lower limit of the pages_to_scan parameter, but that is not how the
> scan-time advisor actually uses it. commit 4e5fa4f5eff6 ("mm/ksm: add ksm
> advisor") only uses it to initialize ksm_thread_pages_to_scan when the
> scan-time advisor is enabled.
>
> ksm_thread_pages_to_scan is adjusted by scan_time_advisor() after a full
> scan finishes. ksm_thread_pages_to_scan could be increased or decreased
> depend on the real scan time is longer or shorter than the target scan
> time. The min value of ksm_thread_pages_to_scan is only limited by
> KSM_ADVISOR_MIN_CPU, so ksm_thread_pages_to_scan could be smaller than
> ksm_advisor_min_pages_to_scan.
>
> The semantics of advisor_min_pages_to_scan was updated in the v2 patchset
> [1], but the documentation wasn't updated.
>
> Update the documentation and comment to match the semantics of
> advisor_min_pages_to_scan.
>
> Link: https://lore.kernel.org/linux-mm/20231028000945.2428830-2-shr@devkernel.io/ [1]
> Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com>

LGTM so:

Reviewed-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>

> ---
>  Documentation/admin-guide/mm/ksm.rst | 4 ++--
>  mm/ksm.c                             | 2 +-
>  2 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/admin-guide/mm/ksm.rst b/Documentation/admin-guide/mm/ksm.rst
> index c9f533b10f6f..c329ca747b8c 100644
> --- a/Documentation/admin-guide/mm/ksm.rst
> +++ b/Documentation/admin-guide/mm/ksm.rst
> @@ -183,8 +183,8 @@ advisor_target_scan_time
>          pages. The default value is 200 seconds.
>
>  advisor_min_pages_to_scan
> -        specifies the lower limit of the ``pages_to_scan`` parameter of the
> -        scan time advisor. The default is 500.
> +        specifies the initial value of the ``pages_to_scan`` parameter of
> +        the scan time advisor. The default is 500.
>
>  advisor_max_pages_to_scan
>          specifies the upper limit of the ``pages_to_scan`` parameter of the
> diff --git a/mm/ksm.c b/mm/ksm.c
> index 7d5b76478f0b..4a6cf8cf5d60 100644
> --- a/mm/ksm.c
> +++ b/mm/ksm.c
> @@ -342,7 +342,7 @@ static enum ksm_advisor_type ksm_advisor;
>   * Only called through the sysfs control interface:
>   */
>
> -/* At least scan this many pages per batch. */
> +/* Initial number of pages to scan per batch. */
>  static unsigned long ksm_advisor_min_pages_to_scan = 500;
>
>  static void set_advisor_defaults(void)
> --
> 2.43.0
>

--
Cheers, Lorenzo

Re: [PATCH v3 1/2] docs: ksm: fix typos in sysfs knob names

[Randy Dunlap]

On 8/23/26 11:10 PM, Jinjiang Tu wrote:
> The sysfs knob names in mm/ksm.c are "advisor_max_cpu" and
> "advisor_max_pages_to_scan", but the ksm.rst documentation spelled
> both as "adivsor_*", fix the two typos.
> 
> Acked-by: David Hildenbrand (Arm) <david@kernel.org>
> Reviewed-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
> Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com>

Acked-by: Randy Dunlap <rdunlap@infradead.org>
Thanks.

> ---
>  Documentation/admin-guide/mm/ksm.rst | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/admin-guide/mm/ksm.rst b/Documentation/admin-guide/mm/ksm.rst
> index ad8e7a41f3b5..c9f533b10f6f 100644
> --- a/Documentation/admin-guide/mm/ksm.rst
> +++ b/Documentation/admin-guide/mm/ksm.rst
> @@ -174,7 +174,7 @@ advisor_mode
>          The section about ``advisor`` explains in detail how the scan time
>          advisor works.
>  
> -adivsor_max_cpu
> +advisor_max_cpu
>          specifies the upper limit of the cpu percent usage of the ksmd
>          background thread. The default is 70.
>  
> @@ -186,7 +186,7 @@ advisor_min_pages_to_scan
>          specifies the lower limit of the ``pages_to_scan`` parameter of the
>          scan time advisor. The default is 500.
>  
> -adivsor_max_pages_to_scan
> +advisor_max_pages_to_scan
>          specifies the upper limit of the ``pages_to_scan`` parameter of the
>          scan time advisor. The default is 30000.
>  

-- 
~Randy