Re: [RFC PATCH v2 1/4] mm/damon: Generic context creation for modules

[Gutierrez Asier <gutierrez.asier@huawei-partners.com>]

On 3/11/2026 3:57 AM, SeongJae Park wrote:
> On Tue, 10 Mar 2026 16:24:17 +0000 <gutierrez.asier@huawei-partners.com> wrote:
> 
>> From: Asier Gutierrez <gutierrez.asier@huawei-partners.com>
>>
>> It is more elegant to have a generic version of new context creation
>> which receives the mode as a parameter.
>>
>> Signed-off-by: Asier Gutierrez <gutierrez.asier@huawei-partners.com>
>> Co-developed-by: Anatoly Stepanov <stepanov.anatoly@huawei.com>
>> ---
>>  mm/damon/lru_sort.c       | 5 +++--
>>  mm/damon/modules-common.c | 6 +++---
>>  mm/damon/modules-common.h | 4 ++--
>>  mm/damon/reclaim.c        | 5 +++--
>>  4 files changed, 11 insertions(+), 9 deletions(-)
>>
>> diff --git a/mm/damon/lru_sort.c b/mm/damon/lru_sort.c
>> index 7bc5c0b2aea3..143ee0b21da6 100644
>> --- a/mm/damon/lru_sort.c
>> +++ b/mm/damon/lru_sort.c
>> @@ -287,7 +287,8 @@ static int damon_lru_sort_apply_parameters(void)
>>  	unsigned int hot_thres, cold_thres;
>>  	int err;
>>  
>> -	err = damon_modules_new_paddr_ctx_target(&param_ctx, &param_target);
>> +	err = damon_modules_new_ctx_target(&param_ctx, &param_target,
>> +				DAMON_OPS_PADDR);
> 
> I like the name of the function is becoming shorter.  But I'm not happy with
> the fact the resulting calling code becomes longer.
> 
> I understand you are doing this extension because you want a version of the
> function for vaddr.  What about introducing another dedicated function, say,
> damon_modules_new_vaddr_ctx_target() ?
> 
> And you can avoid duplicates between damon_modules_new_{p,v}addr_ctx_target()
> by implementing internal function, say, damon_modules_new_ctx_target() that
> receives the damon_ops_id.  And damon_modules_new_{P,v}addr_ctx_target() will
> just wrappers of damon_modules_new_ctx_target().

Sure, I will do it.

Since this is some generic code not related to the module I am working on,
maybe I can move this to a different patch set that we can upstream. What do
you think?

> 
>>  	if (err)
>>  		return err;
>>  
>> @@ -479,7 +480,7 @@ static int __init damon_lru_sort_init(void)
>>  		err = -ENOMEM;
>>  		goto out;
>>  	}
>> -	err = damon_modules_new_paddr_ctx_target(&ctx, &target);
>> +	err = damon_modules_new_ctx_target(&ctx, &target, DAMON_OPS_PADDR);
> 
> Ditto.
> 
>>  	if (err)
>>  		goto out;
>>  
>> diff --git a/mm/damon/modules-common.c b/mm/damon/modules-common.c
>> index 86d58f8c4f63..ae50b2fa3a86 100644
>> --- a/mm/damon/modules-common.c
>> +++ b/mm/damon/modules-common.c
>> @@ -14,8 +14,8 @@
>>   * @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)
>> +int damon_modules_new_ctx_target(struct damon_ctx **ctxp,
>> +		struct damon_target **targetp, enum damon_ops_id mode)
> 
> Nit.  I'd suggest 'ops_id' as the parameter name, instead of 'mode'.
> 
>>  {
>>  	struct damon_ctx *ctx;
>>  	struct damon_target *target;
>> @@ -24,7 +24,7 @@ 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, mode)) {
>>  		damon_destroy_ctx(ctx);
>>  		return -EINVAL;
>>  	}
>> diff --git a/mm/damon/modules-common.h b/mm/damon/modules-common.h
>> index f103ad556368..379b49c6a617 100644
>> --- a/mm/damon/modules-common.h
>> +++ b/mm/damon/modules-common.h
>> @@ -45,5 +45,5 @@
>>  	module_param_named(nr_##qt_exceed_name, stat.qt_exceeds, ulong,	\
>>  			0400);
>>  
>> -int damon_modules_new_paddr_ctx_target(struct damon_ctx **ctxp,
>> -		struct damon_target **targetp);
>> +int damon_modules_new_ctx_target(struct damon_ctx **ctxp,
>> +		struct damon_target **targetp, enum damon_ops_id mode);
>> diff --git a/mm/damon/reclaim.c b/mm/damon/reclaim.c
>> index 43d76f5bed44..24786a58683a 100644
>> --- a/mm/damon/reclaim.c
>> +++ b/mm/damon/reclaim.c
>> @@ -197,7 +197,8 @@ static int damon_reclaim_apply_parameters(void)
>>  	struct damos_filter *filter;
>>  	int err;
>>  
>> -	err = damon_modules_new_paddr_ctx_target(&param_ctx, &param_target);
>> +	err = damon_modules_new_ctx_target(&param_ctx, &param_target,
>> +				DAMON_OPS_PADDR);
>>  	if (err)
>>  		return err;
>>  
>> @@ -381,7 +382,7 @@ static int __init damon_reclaim_init(void)
>>  		err = -ENOMEM;
>>  		goto out;
>>  	}
>> -	err = damon_modules_new_paddr_ctx_target(&ctx, &target);
>> +	err = damon_modules_new_ctx_target(&ctx, &target, DAMON_OPS_PADDR);
>>  	if (err)
>>  		goto out;
>>  
>> -- 
>> 2.43.0
> 
> 
> Thanks,
> SJ
> 

-- 
Asier Gutierrez
Huawei