[PATCH v3 0/2] mm/damon: Fix some small bugs

[PATCH v3 0/2] mm/damon: Fix some small bugs

[Xin Hao]

v3 -> V2
  -- Fix some formatting issues
  -- Modify the return value of 'damon_targets_empty' to bool type

V1 -> V2
  -- As SeongJae Park advised, put 'ctx->adaptive_targets
  check' into 'dbgfs_monitor_on_write()'

Xin Hao (2):
  mm/damon: Remove unnecessary variable initialization
  mm/damon/dbgfs: Add adaptive_targets list check before enable
    monitor_on

 include/linux/damon.h |  1 +
 mm/damon/core.c       |  5 +++++
 mm/damon/dbgfs.c      | 13 ++++++++++---
 mm/damon/vaddr.c      |  2 +-
 4 files changed, 17 insertions(+), 4 deletions(-)

--
2.31.0

[PATCH v3 1/2] mm/damon: Remove unnecessary variable initialization

[Xin Hao]

In 'damon_va_apply_three_regions', There is no
need to set variable 'i' as 0

Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
---
 mm/damon/vaddr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c
index b8ba44f69db6..90be463efff7 100644
--- a/mm/damon/vaddr.c
+++ b/mm/damon/vaddr.c
@@ -305,7 +305,7 @@ static void damon_va_apply_three_regions(struct damon_target *t,
 		struct damon_addr_range bregions[3])
 {
 	struct damon_region *r, *next;
-	unsigned int i = 0;
+	unsigned int i;
 
 	/* Remove regions which are not in the three big regions now */
 	damon_for_each_region_safe(r, next, t) {
-- 
2.31.0

Re: [PATCH v3 1/2] mm/damon: Remove unnecessary variable initialization

[SeongJae Park]

On Wed, 20 Oct 2021 09:42:32 +0800 Xin Hao <xhao@linux.alibaba.com> wrote:

> In 'damon_va_apply_three_regions', There is no
> need to set variable 'i' as 0
> 
> Signed-off-by: Xin Hao <xhao@linux.alibaba.com>

I gave you my 'Reviewed-by:' for the last version of this patch, but seems you
missed putting it here.  So, I'm giving it here again ;)

Reviewed-by: SeongJae Park <sj@kernel.org>


Thanks,
SJ

> ---
>  mm/damon/vaddr.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c
> index b8ba44f69db6..90be463efff7 100644
> --- a/mm/damon/vaddr.c
> +++ b/mm/damon/vaddr.c
> @@ -305,7 +305,7 @@ static void damon_va_apply_three_regions(struct damon_target *t,
>  		struct damon_addr_range bregions[3])
>  {
>  	struct damon_region *r, *next;
> -	unsigned int i = 0;
> +	unsigned int i;
>  
>  	/* Remove regions which are not in the three big regions now */
>  	damon_for_each_region_safe(r, next, t) {
> -- 
> 2.31.0

[PATCH v3 2/2] mm/damon/dbgfs: Add adaptive_targets list check before enable monitor_on

[Xin Hao]

When the ctx->adaptive_targets list is empty,
I did some test on monitor_on interface like this.

    # echo > /sys/kernel/debug/damon/target_ids

Though the ctx->adaptive_targets list is empty, but the
kthread_run still be called, and the kdamond.x thread still
be created, this is meaningless.

So there adds a judgment in 'dbgfs_monitor_on_write',
if the ctx->adaptive_targets list is empty, return -EINVAL.

Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
---
 include/linux/damon.h |  1 +
 mm/damon/core.c       |  5 +++++
 mm/damon/dbgfs.c      | 13 ++++++++++---
 3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/include/linux/damon.h b/include/linux/damon.h
index 715dadd21f7c..4fce5f1f6dad 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -316,6 +316,7 @@ void damon_destroy_scheme(struct damos *s);

 struct damon_target *damon_new_target(unsigned long id);
 void damon_add_target(struct damon_ctx *ctx, struct damon_target *t);
+bool damon_targets_empty(struct damon_ctx *ctx);
 void damon_free_target(struct damon_target *t);
 void damon_destroy_target(struct damon_target *t);
 unsigned int damon_nr_regions(struct damon_target *t);
diff --git a/mm/damon/core.c b/mm/damon/core.c
index 2f6785737902..c3a1374dbe0b 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -156,6 +156,11 @@ void damon_add_target(struct damon_ctx *ctx, struct damon_target *t)
 	list_add_tail(&t->list, &ctx->adaptive_targets);
 }

+bool damon_targets_empty(struct damon_ctx *ctx)
+{
+	return list_empty(&ctx->adaptive_targets);
+}
+
 static void damon_del_target(struct damon_target *t)
 {
 	list_del(&t->list);
diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c
index 38188347d8ab..9dee29f7d103 100644
--- a/mm/damon/dbgfs.c
+++ b/mm/damon/dbgfs.c
@@ -865,12 +865,19 @@ static ssize_t dbgfs_monitor_on_write(struct file *file,
 		return -EINVAL;
 	}

-	if (!strncmp(kbuf, "on", count))
+	if (!strncmp(kbuf, "on", count)) {
+		int i;
+
+		for (i = 0; i < dbgfs_nr_ctxs; i++) {
+			if (damon_targets_empty(dbgfs_ctxs[i]))
+				return -EINVAL;
+		}
 		err = damon_start(dbgfs_ctxs, dbgfs_nr_ctxs);
-	else if (!strncmp(kbuf, "off", count))
+	} else if (!strncmp(kbuf, "off", count)) {
 		err = damon_stop(dbgfs_ctxs, dbgfs_nr_ctxs);
-	else
+	} else {
 		err = -EINVAL;
+	}

 	if (err)
 		ret = err;
--
2.31.0

Re: [PATCH v3 2/2] mm/damon/dbgfs: Add adaptive_targets list check before enable monitor_on

[SeongJae Park]

On Wed, 20 Oct 2021 09:42:33 +0800 Xin Hao <xhao@linux.alibaba.com> wrote:

> When the ctx->adaptive_targets list is empty,
> I did some test on monitor_on interface like this.
> 
>     # echo > /sys/kernel/debug/damon/target_ids

Thanks for the change, but you missed writing 'on' to 'monitor_on' in the above
example.

> 
> Though the ctx->adaptive_targets list is empty, but the
> kthread_run still be called, and the kdamond.x thread still
> be created, this is meaningless.
> 
> So there adds a judgment in 'dbgfs_monitor_on_write',
> if the ctx->adaptive_targets list is empty, return -EINVAL.
> 
> Signed-off-by: Xin Hao <xhao@linux.alibaba.com>

Other parts looks good to me.  However, seems this commit conflicts with a
patch[1] which already merged in -mm tree.  Could you please rebase this on it?
FYI, all DAMON patches that merged in -mm tree are also applied on DAMON
development tree.  So, you could get the patch applied tree by:

    $ git remote add sj git://git.kernel.org/pub/scm/linux/kernel/git/sj/linux.git
    $ git fetch sj
    $ git checkout 0fa378d04b12

[1] https://lore.kernel.org/linux-mm/20211014073014.35754-1-sj@kernel.org/


Thanks,
SJ

> ---
>  include/linux/damon.h |  1 +
>  mm/damon/core.c       |  5 +++++
>  mm/damon/dbgfs.c      | 13 ++++++++++---
>  3 files changed, 16 insertions(+), 3 deletions(-)
> 
> diff --git a/include/linux/damon.h b/include/linux/damon.h
> index 715dadd21f7c..4fce5f1f6dad 100644
> --- a/include/linux/damon.h
> +++ b/include/linux/damon.h
> @@ -316,6 +316,7 @@ void damon_destroy_scheme(struct damos *s);
> 
>  struct damon_target *damon_new_target(unsigned long id);
>  void damon_add_target(struct damon_ctx *ctx, struct damon_target *t);
> +bool damon_targets_empty(struct damon_ctx *ctx);
>  void damon_free_target(struct damon_target *t);
>  void damon_destroy_target(struct damon_target *t);
>  unsigned int damon_nr_regions(struct damon_target *t);
> diff --git a/mm/damon/core.c b/mm/damon/core.c
> index 2f6785737902..c3a1374dbe0b 100644
> --- a/mm/damon/core.c
> +++ b/mm/damon/core.c
> @@ -156,6 +156,11 @@ void damon_add_target(struct damon_ctx *ctx, struct damon_target *t)
>  	list_add_tail(&t->list, &ctx->adaptive_targets);
>  }
> 
> +bool damon_targets_empty(struct damon_ctx *ctx)
> +{
> +	return list_empty(&ctx->adaptive_targets);
> +}
> +
>  static void damon_del_target(struct damon_target *t)
>  {
>  	list_del(&t->list);
> diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c
> index 38188347d8ab..9dee29f7d103 100644
> --- a/mm/damon/dbgfs.c
> +++ b/mm/damon/dbgfs.c
> @@ -865,12 +865,19 @@ static ssize_t dbgfs_monitor_on_write(struct file *file,
>  		return -EINVAL;
>  	}
> 
> -	if (!strncmp(kbuf, "on", count))
> +	if (!strncmp(kbuf, "on", count)) {
> +		int i;
> +
> +		for (i = 0; i < dbgfs_nr_ctxs; i++) {
> +			if (damon_targets_empty(dbgfs_ctxs[i]))
> +				return -EINVAL;
> +		}
>  		err = damon_start(dbgfs_ctxs, dbgfs_nr_ctxs);
> -	else if (!strncmp(kbuf, "off", count))
> +	} else if (!strncmp(kbuf, "off", count)) {
>  		err = damon_stop(dbgfs_ctxs, dbgfs_nr_ctxs);
> -	else
> +	} else {
>  		err = -EINVAL;
> +	}
> 
>  	if (err)
>  		ret = err;
> --
> 2.31.0

Re: [PATCH v3 2/2] mm/damon/dbgfs: Add adaptive_targets list check before enable monitor_on

[SeongJae Park]

On Wed, 20 Oct 2021 07:21:21 +0000 SeongJae Park <sj@kernel.org> wrote:

> On Wed, 20 Oct 2021 09:42:33 +0800 Xin Hao <xhao@linux.alibaba.com> wrote:
> 
> > When the ctx->adaptive_targets list is empty,
> > I did some test on monitor_on interface like this.
> > 
> >     # echo > /sys/kernel/debug/damon/target_ids
> 
> Thanks for the change, but you missed writing 'on' to 'monitor_on' in the above
> example.
> 
> > 
> > Though the ctx->adaptive_targets list is empty, but the
> > kthread_run still be called, and the kdamond.x thread still
> > be created, this is meaningless.
> > 
> > So there adds a judgment in 'dbgfs_monitor_on_write',
> > if the ctx->adaptive_targets list is empty, return -EINVAL.
> > 
> > Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
> 
> Other parts looks good to me.  However, seems this commit conflicts with a
> patch[1] which already merged in -mm tree.  Could you please rebase this on it?
> FYI, all DAMON patches that merged in -mm tree are also applied on DAMON
> development tree.  So, you could get the patch applied tree by:
> 
>     $ git remote add sj git://git.kernel.org/pub/scm/linux/kernel/git/sj/linux.git
>     $ git fetch sj
>     $ git checkout 0fa378d04b12
> 
> [1] https://lore.kernel.org/linux-mm/20211014073014.35754-1-sj@kernel.org/
> 
> 
> Thanks,
> SJ
> 
> > ---
> >  include/linux/damon.h |  1 +
> >  mm/damon/core.c       |  5 +++++
> >  mm/damon/dbgfs.c      | 13 ++++++++++---
> >  3 files changed, 16 insertions(+), 3 deletions(-)
> > 
> > diff --git a/include/linux/damon.h b/include/linux/damon.h
> > index 715dadd21f7c..4fce5f1f6dad 100644
> > --- a/include/linux/damon.h
> > +++ b/include/linux/damon.h
> > @@ -316,6 +316,7 @@ void damon_destroy_scheme(struct damos *s);
> > 
> >  struct damon_target *damon_new_target(unsigned long id);
> >  void damon_add_target(struct damon_ctx *ctx, struct damon_target *t);
> > +bool damon_targets_empty(struct damon_ctx *ctx);
> >  void damon_free_target(struct damon_target *t);
> >  void damon_destroy_target(struct damon_target *t);
> >  unsigned int damon_nr_regions(struct damon_target *t);
> > diff --git a/mm/damon/core.c b/mm/damon/core.c
> > index 2f6785737902..c3a1374dbe0b 100644
> > --- a/mm/damon/core.c
> > +++ b/mm/damon/core.c
> > @@ -156,6 +156,11 @@ void damon_add_target(struct damon_ctx *ctx, struct damon_target *t)
> >  	list_add_tail(&t->list, &ctx->adaptive_targets);
> >  }
> > 
> > +bool damon_targets_empty(struct damon_ctx *ctx)
> > +{
> > +	return list_empty(&ctx->adaptive_targets);
> > +}
> > +
> >  static void damon_del_target(struct damon_target *t)
> >  {
> >  	list_del(&t->list);
> > diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c
> > index 38188347d8ab..9dee29f7d103 100644
> > --- a/mm/damon/dbgfs.c
> > +++ b/mm/damon/dbgfs.c
> > @@ -865,12 +865,19 @@ static ssize_t dbgfs_monitor_on_write(struct file *file,
> >  		return -EINVAL;
> >  	}
> > 
> > -	if (!strncmp(kbuf, "on", count))
> > +	if (!strncmp(kbuf, "on", count)) {
> > +		int i;
> > +
> > +		for (i = 0; i < dbgfs_nr_ctxs; i++) {
> > +			if (damon_targets_empty(dbgfs_ctxs[i]))
> > +				return -EINVAL;

Oops, I forgot that you should 'kfree(kbuf)' before returning here.  Please do
that.


Thanks,
SJ

> > +		}
> >  		err = damon_start(dbgfs_ctxs, dbgfs_nr_ctxs);
> > -	else if (!strncmp(kbuf, "off", count))
> > +	} else if (!strncmp(kbuf, "off", count)) {
> >  		err = damon_stop(dbgfs_ctxs, dbgfs_nr_ctxs);
> > -	else
> > +	} else {
> >  		err = -EINVAL;
> > +	}
> > 
> >  	if (err)
> >  		ret = err;
> > --
> > 2.31.0
> 
> 

Re: [PATCH v3 2/2] mm/damon/dbgfs: Add adaptive_targets list check before enable monitor_on

[Xin Hao]

On 2021/10/20 下午4:12, SeongJae Park wrote:
> On Wed, 20 Oct 2021 07:21:21 +0000 SeongJae Park <sj@kernel.org> wrote:
>
>> On Wed, 20 Oct 2021 09:42:33 +0800 Xin Hao <xhao@linux.alibaba.com> wrote:
>>
>>> When the ctx->adaptive_targets list is empty,
>>> I did some test on monitor_on interface like this.
>>>
>>>      # echo > /sys/kernel/debug/damon/target_ids
>> Thanks for the change, but you missed writing 'on' to 'monitor_on' in the above
>> example.
Sorry.
>>
>>> Though the ctx->adaptive_targets list is empty, but the
>>> kthread_run still be called, and the kdamond.x thread still
>>> be created, this is meaningless.
>>>
>>> So there adds a judgment in 'dbgfs_monitor_on_write',
>>> if the ctx->adaptive_targets list is empty, return -EINVAL.
>>>
>>> Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
>> Other parts looks good to me.  However, seems this commit conflicts with a
>> patch[1] which already merged in -mm tree.  Could you please rebase this on it?
>> FYI, all DAMON patches that merged in -mm tree are also applied on DAMON
>> development tree.  So, you could get the patch applied tree by:
>>
>>      $ git remote add sj git://git.kernel.org/pub/scm/linux/kernel/git/sj/linux.git
>>      $ git fetch sj
>>      $ git checkout 0fa378d04b12
>>
>> [1] https://lore.kernel.org/linux-mm/20211014073014.35754-1-sj@kernel.org/
Ok, i will correct it.
>>
>>
>> Thanks,
>> SJ
>>
>>> ---
>>>   include/linux/damon.h |  1 +
>>>   mm/damon/core.c       |  5 +++++
>>>   mm/damon/dbgfs.c      | 13 ++++++++++---
>>>   3 files changed, 16 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/include/linux/damon.h b/include/linux/damon.h
>>> index 715dadd21f7c..4fce5f1f6dad 100644
>>> --- a/include/linux/damon.h
>>> +++ b/include/linux/damon.h
>>> @@ -316,6 +316,7 @@ void damon_destroy_scheme(struct damos *s);
>>>
>>>   struct damon_target *damon_new_target(unsigned long id);
>>>   void damon_add_target(struct damon_ctx *ctx, struct damon_target *t);
>>> +bool damon_targets_empty(struct damon_ctx *ctx);
>>>   void damon_free_target(struct damon_target *t);
>>>   void damon_destroy_target(struct damon_target *t);
>>>   unsigned int damon_nr_regions(struct damon_target *t);
>>> diff --git a/mm/damon/core.c b/mm/damon/core.c
>>> index 2f6785737902..c3a1374dbe0b 100644
>>> --- a/mm/damon/core.c
>>> +++ b/mm/damon/core.c
>>> @@ -156,6 +156,11 @@ void damon_add_target(struct damon_ctx *ctx, struct damon_target *t)
>>>   	list_add_tail(&t->list, &ctx->adaptive_targets);
>>>   }
>>>
>>> +bool damon_targets_empty(struct damon_ctx *ctx)
>>> +{
>>> +	return list_empty(&ctx->adaptive_targets);
>>> +}
>>> +
>>>   static void damon_del_target(struct damon_target *t)
>>>   {
>>>   	list_del(&t->list);
>>> diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c
>>> index 38188347d8ab..9dee29f7d103 100644
>>> --- a/mm/damon/dbgfs.c
>>> +++ b/mm/damon/dbgfs.c
>>> @@ -865,12 +865,19 @@ static ssize_t dbgfs_monitor_on_write(struct file *file,
>>>   		return -EINVAL;
>>>   	}
>>>
>>> -	if (!strncmp(kbuf, "on", count))
>>> +	if (!strncmp(kbuf, "on", count)) {
>>> +		int i;
>>> +
>>> +		for (i = 0; i < dbgfs_nr_ctxs; i++) {
>>> +			if (damon_targets_empty(dbgfs_ctxs[i]))
>>> +				return -EINVAL;
> Oops, I forgot that you should 'kfree(kbuf)' before returning here.  Please do
> that.
Okay,  i will correct it, thank you.
>
> Thanks,
> SJ
>
>>> +		}
>>>   		err = damon_start(dbgfs_ctxs, dbgfs_nr_ctxs);
>>> -	else if (!strncmp(kbuf, "off", count))
>>> +	} else if (!strncmp(kbuf, "off", count)) {
>>>   		err = damon_stop(dbgfs_ctxs, dbgfs_nr_ctxs);
>>> -	else
>>> +	} else {
>>>   		err = -EINVAL;
>>> +	}
>>>
>>>   	if (err)
>>>   		ret = err;
>>> --
>>> 2.31.0
>>
-- 
Best Regards!
Xin Hao