[v9] x86/resctrl: Miscellaneous resctrl features

[PATCH v9 5/9] x86/resctrl: Unwind the errors inside rdt_enable_ctx()

Posted by Babu Moger 2 years, 3 months ago

rdt_enable_ctx() enables the features provided during resctrl mount.

Additions to rdt_enable_ctx() are required to also modify error paths
of rdt_enable_ctx() callers to ensure correct unwinding if errors
are encountered after calling rdt_enable_ctx(). This is error prone.

Introduce rdt_disable_ctx() to refactor the error unwinding of
rdt_enable_ctx() to simplify future additions. This also simplifies
cleanup in rdt_kill_sb().

Remove cdp_disable_all() as it is not used anymore after the refactor.

Suggested-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Babu Moger <babu.moger@amd.com>
---
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 55 ++++++++++++++++----------
 1 file changed, 34 insertions(+), 21 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 35945b4bf196..34cb512be1de 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -2290,14 +2290,6 @@ int resctrl_arch_set_cdp_enabled(enum resctrl_res_level l, bool enable)
 	return 0;
 }
 
-static void cdp_disable_all(void)
-{
-	if (resctrl_arch_get_cdp_enabled(RDT_RESOURCE_L3))
-		resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L3, false);
-	if (resctrl_arch_get_cdp_enabled(RDT_RESOURCE_L2))
-		resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L2, false);
-}
-
 /*
  * We don't allow rdtgroup directories to be created anywhere
  * except the root directory. Thus when looking for the rdtgroup
@@ -2377,19 +2369,44 @@ static int mkdir_mondata_all(struct kernfs_node *parent_kn,
 			     struct rdtgroup *prgrp,
 			     struct kernfs_node **mon_data_kn);
 
+static void rdt_disable_ctx(void)
+{
+	resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L3, false);
+
+	resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L2, false);
+
+	set_mba_sc(false);
+}
+
 static int rdt_enable_ctx(struct rdt_fs_context *ctx)
 {
 	int ret = 0;
 
-	if (ctx->enable_cdpl2)
+	if (ctx->enable_cdpl2) {
 		ret = resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L2, true);
+		if (ret)
+			goto out_done;
+	}
 
-	if (!ret && ctx->enable_cdpl3)
+	if (ctx->enable_cdpl3) {
 		ret = resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L3, true);
+		if (ret)
+			goto out_cdpl2;
+	}
 
-	if (!ret && ctx->enable_mba_mbps)
+	if (ctx->enable_mba_mbps) {
 		ret = set_mba_sc(true);
+		if (ret)
+			goto out_cdpl3;
+	}
 
+	return 0;
+
+out_cdpl3:
+	resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L3, false);
+out_cdpl2:
+	resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L2, false);
+out_done:
 	return ret;
 }
 
@@ -2497,13 +2514,13 @@ static int rdt_get_tree(struct fs_context *fc)
 	}
 
 	ret = rdt_enable_ctx(ctx);
-	if (ret < 0)
-		goto out_cdp;
+	if (ret)
+		goto out;
 
 	ret = schemata_list_create();
 	if (ret) {
 		schemata_list_destroy();
-		goto out_mba;
+		goto out_ctx;
 	}
 
 	closid_init();
@@ -2562,11 +2579,8 @@ static int rdt_get_tree(struct fs_context *fc)
 	kernfs_remove(kn_info);
 out_schemata_free:
 	schemata_list_destroy();
-out_mba:
-	if (ctx->enable_mba_mbps)
-		set_mba_sc(false);
-out_cdp:
-	cdp_disable_all();
+out_ctx:
+	rdt_disable_ctx();
 out:
 	rdt_last_cmd_clear();
 	mutex_unlock(&rdtgroup_mutex);
@@ -2798,12 +2812,11 @@ static void rdt_kill_sb(struct super_block *sb)
 	cpus_read_lock();
 	mutex_lock(&rdtgroup_mutex);
 
-	set_mba_sc(false);
+	rdt_disable_ctx();
 
 	/*Put everything back to default values. */
 	for_each_alloc_capable_rdt_resource(r)
 		reset_all_ctrls(r);
-	cdp_disable_all();
 	rmdir_all_sub();
 	rdt_pseudo_lock_release();
 	rdtgroup_default.mode = RDT_MODE_SHAREABLE;
-- 
2.34.1

Re: [PATCH v9 5/9] x86/resctrl: Unwind the errors inside rdt_enable_ctx()

Posted by Reinette Chatre 2 years, 3 months ago

Hi Babu,

On 9/7/2023 4:51 PM, Babu Moger wrote:
> rdt_enable_ctx() enables the features provided during resctrl mount.
> 
> Additions to rdt_enable_ctx() are required to also modify error paths
> of rdt_enable_ctx() callers to ensure correct unwinding if errors
> are encountered after calling rdt_enable_ctx(). This is error prone.
> 
> Introduce rdt_disable_ctx() to refactor the error unwinding of
> rdt_enable_ctx() to simplify future additions. This also simplifies
> cleanup in rdt_kill_sb().
> 
> Remove cdp_disable_all() as it is not used anymore after the refactor.
> 
> Suggested-by: Reinette Chatre <reinette.chatre@intel.com>
> Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
> Signed-off-by: Babu Moger <babu.moger@amd.com>
> ---

This is one of the patches that received a change that was not
mentioned in cover letter nor in a patch specific list of changes.

Having a list of changes within each patch in this area is
helpful in reviews.

>  arch/x86/kernel/cpu/resctrl/rdtgroup.c | 55 ++++++++++++++++----------
>  1 file changed, 34 insertions(+), 21 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> index 35945b4bf196..34cb512be1de 100644
> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> @@ -2290,14 +2290,6 @@ int resctrl_arch_set_cdp_enabled(enum resctrl_res_level l, bool enable)
>  	return 0;
>  }
>  
> -static void cdp_disable_all(void)
> -{
> -	if (resctrl_arch_get_cdp_enabled(RDT_RESOURCE_L3))
> -		resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L3, false);
> -	if (resctrl_arch_get_cdp_enabled(RDT_RESOURCE_L2))
> -		resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L2, false);
> -}
> -
>  /*
>   * We don't allow rdtgroup directories to be created anywhere
>   * except the root directory. Thus when looking for the rdtgroup
> @@ -2377,19 +2369,44 @@ static int mkdir_mondata_all(struct kernfs_node *parent_kn,
>  			     struct rdtgroup *prgrp,
>  			     struct kernfs_node **mon_data_kn);
>  
> +static void rdt_disable_ctx(void)
> +{
> +	resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L3, false);
> +
> +	resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L2, false);
> +
> +	set_mba_sc(false);
> +}

Could you please remove the empty line following each call?

With the above change you can add:

Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>

Reinette

Re: [PATCH v9 5/9] x86/resctrl: Unwind the errors inside rdt_enable_ctx()

Posted by Moger, Babu 2 years, 3 months ago

Hi Reinette,

On 9/11/23 17:58, Reinette Chatre wrote:
> Hi Babu,
> 
> On 9/7/2023 4:51 PM, Babu Moger wrote:
>> rdt_enable_ctx() enables the features provided during resctrl mount.
>>
>> Additions to rdt_enable_ctx() are required to also modify error paths
>> of rdt_enable_ctx() callers to ensure correct unwinding if errors
>> are encountered after calling rdt_enable_ctx(). This is error prone.
>>
>> Introduce rdt_disable_ctx() to refactor the error unwinding of
>> rdt_enable_ctx() to simplify future additions. This also simplifies
>> cleanup in rdt_kill_sb().
>>
>> Remove cdp_disable_all() as it is not used anymore after the refactor.
>>
>> Suggested-by: Reinette Chatre <reinette.chatre@intel.com>
>> Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
>> Signed-off-by: Babu Moger <babu.moger@amd.com>
>> ---
> 
> This is one of the patches that received a change that was not
> mentioned in cover letter nor in a patch specific list of changes.

Yes. My bad.

> 
> Having a list of changes within each patch in this area is
> helpful in reviews.
> 
>>  arch/x86/kernel/cpu/resctrl/rdtgroup.c | 55 ++++++++++++++++----------
>>  1 file changed, 34 insertions(+), 21 deletions(-)
>>
>> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> index 35945b4bf196..34cb512be1de 100644
>> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> @@ -2290,14 +2290,6 @@ int resctrl_arch_set_cdp_enabled(enum resctrl_res_level l, bool enable)
>>  	return 0;
>>  }
>>  
>> -static void cdp_disable_all(void)
>> -{
>> -	if (resctrl_arch_get_cdp_enabled(RDT_RESOURCE_L3))
>> -		resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L3, false);
>> -	if (resctrl_arch_get_cdp_enabled(RDT_RESOURCE_L2))
>> -		resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L2, false);
>> -}
>> -
>>  /*
>>   * We don't allow rdtgroup directories to be created anywhere
>>   * except the root directory. Thus when looking for the rdtgroup
>> @@ -2377,19 +2369,44 @@ static int mkdir_mondata_all(struct kernfs_node *parent_kn,
>>  			     struct rdtgroup *prgrp,
>>  			     struct kernfs_node **mon_data_kn);
>>  
>> +static void rdt_disable_ctx(void)
>> +{
>> +	resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L3, false);
>> +
>> +	resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L2, false);
>> +
>> +	set_mba_sc(false);
>> +}
> 
> Could you please remove the empty line following each call?

Sure.

> 
> With the above change you can add:
> 
> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
-- 
Thanks
Babu Moger