[RFC PATCH v1 1/1] mm/damon: generalize ctx_target creation for damon_ops_id and add vaddr support

[RFC PATCH v1 1/1] mm/damon: generalize ctx_target creation for damon_ops_id and add vaddr support

[gutierrez.asier]

From: Asier Gutierrez <gutierrez.asier@huawei-partners.com>

This patch adds a new function damon_modules_new_vaddr_ctx_target.
Since ctx_target creation for vaddr and paddr is almost identical,
the logic is extracted to a new function,
damon_modules_new_ctx_target, and vaddr and paddr functions are left
just as interfaces.

This change was suggested earlier[1] and it is needed to allow
developers to create DAMON modules that use DAMON_OPS_PADDR targets.

[1]: https://lore.kernel.org/damon/20260311005759.90440-1-sj@kernel.org/

Signed-off-by: Asier Gutierrez <gutierrez.asier@huawei-partners.com>
Suggested-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/modules-common.c | 31 +++++++++++++++++++++++++++----
 mm/damon/modules-common.h |  3 +++
 2 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/mm/damon/modules-common.c b/mm/damon/modules-common.c
index 86d58f8c4f63..fe12d109c87b 100644
--- a/mm/damon/modules-common.c
+++ b/mm/damon/modules-common.c
@@ -10,12 +10,13 @@
 #include "modules-common.h"
 
 /*
- * Allocate, set, and return a DAMON context for the physical address space.
+ * Allocate, set, and return a DAMON context.
  * @ctxp:	Pointer to save the point to the newly created context
  * @targetp:	Pointer to save the point to the newly created target
+ * @id:	Set of operations, physical or virtual
  */
-int damon_modules_new_paddr_ctx_target(struct damon_ctx **ctxp,
-		struct damon_target **targetp)
+static int damon_modules_new_ctx_target(struct damon_ctx **ctxp,
+		struct damon_target **targetp, enum damon_ops_id id)
 {
 	struct damon_ctx *ctx;
 	struct damon_target *target;
@@ -24,7 +25,7 @@ int damon_modules_new_paddr_ctx_target(struct damon_ctx **ctxp,
 	if (!ctx)
 		return -ENOMEM;
 
-	if (damon_select_ops(ctx, DAMON_OPS_PADDR)) {
+	if (damon_select_ops(ctx, id)) {
 		damon_destroy_ctx(ctx);
 		return -EINVAL;
 	}
@@ -40,3 +41,25 @@ int damon_modules_new_paddr_ctx_target(struct damon_ctx **ctxp,
 	*targetp = target;
 	return 0;
 }
+
+/*
+ * Allocate, set, and return a DAMON context for the physical address space.
+ * @ctxp:	Pointer to save the point to the newly created context
+ * @targetp:	Pointer to save the point to the newly created target
+ */
+int damon_modules_new_paddr_ctx_target(struct damon_ctx **ctxp,
+		struct damon_target **targetp)
+{
+	return damon_modules_new_ctx_target(ctxp, targetp, DAMON_OPS_PADDR);
+}
+
+/*
+ * Allocate, set, and return a DAMON context for the virtual address space.
+ * @ctxp:	Pointer to save the point to the newly created context
+ * @targetp:	Pointer to save the point to the newly created target
+ */
+int damon_modules_new_vaddr_ctx_target(struct damon_ctx **ctxp,
+		struct damon_target **targetp)
+{
+	return damon_modules_new_ctx_target(ctxp, targetp, DAMON_OPS_VADDR);
+}
diff --git a/mm/damon/modules-common.h b/mm/damon/modules-common.h
index f103ad556368..324b9cb4957e 100644
--- a/mm/damon/modules-common.h
+++ b/mm/damon/modules-common.h
@@ -47,3 +47,6 @@
 
 int damon_modules_new_paddr_ctx_target(struct damon_ctx **ctxp,
 		struct damon_target **targetp);
+
+int damon_modules_new_vaddr_ctx_target(struct damon_ctx **ctxp,
+		struct damon_target **targetp);
-- 
2.43.0

Re: [RFC PATCH v1 1/1] mm/damon: generalize ctx_target creation for damon_ops_id and add vaddr support

[SeongJae Park]

On Mon, 13 Apr 2026 14:59:43 +0000 <gutierrez.asier@huawei-partners.com> wrote:

> From: Asier Gutierrez <gutierrez.asier@huawei-partners.com>
> 
> This patch adds a new function damon_modules_new_vaddr_ctx_target.
> Since ctx_target creation for vaddr and paddr is almost identical,
> the logic is extracted to a new function,
> damon_modules_new_ctx_target, and vaddr and paddr functions are left
> just as interfaces.
> 
> This change was suggested earlier[1] and it is needed to allow
> developers to create DAMON modules that use DAMON_OPS_PADDR targets.

You mean DAMON_OPS_VADDR?

And I agree this can be useful if we will make a DAMON module that runs for
virtual address spaces.  But we don't add new functions without their callers.
So this patch should be submitted only together with the caller of the
function.

> 
> [1]: https://lore.kernel.org/damon/20260311005759.90440-1-sj@kernel.org/


Thanks,
SJ

[...]

Re: [RFC PATCH v1 1/1] mm/damon: generalize ctx_target creation for damon_ops_id and add vaddr support

[Gutierrez Asier]

Hi SJ,

On 4/14/2026 3:47 AM, SeongJae Park wrote:
> On Mon, 13 Apr 2026 14:59:43 +0000 <gutierrez.asier@huawei-partners.com> wrote:
> 
>> From: Asier Gutierrez <gutierrez.asier@huawei-partners.com>
>>
>> This patch adds a new function damon_modules_new_vaddr_ctx_target.
>> Since ctx_target creation for vaddr and paddr is almost identical,
>> the logic is extracted to a new function,
>> damon_modules_new_ctx_target, and vaddr and paddr functions are left
>> just as interfaces.
>>
>> This change was suggested earlier[1] and it is needed to allow
>> developers to create DAMON modules that use DAMON_OPS_PADDR targets.
> 
> You mean DAMON_OPS_VADDR?

Right, I missed that.
 
> And I agree this can be useful if we will make a DAMON module that runs for
> virtual address spaces.  But we don't add new functions without their callers.
> So this patch should be submitted only together with the caller of the
> function.

Fair enough. I will carry on working on the module for hugepages autotuning,
which will use this function. I will resubmit this along with the caller.

>>
>> [1]: https://lore.kernel.org/damon/20260311005759.90440-1-sj@kernel.org/
> 
> 
> Thanks,
> SJ
> 
> [...]

-- 
Asier Gutierrez
Huawei