RMID are allocated for each monitor or control group directory, because
each of these needs its own RMID. For control groups,
rdtgroup_mkdir_ctrl_mon() later goes on to allocate the CLOSID.
MPAM's equivalent of RMID are not an independent number, so can't be
allocated until the closid is known. An RMID allocation for one CLOSID
may fail, whereas another may succeed depending on how many monitor
groups a control group has.
The RMID allocation needs to move to be after the CLOSID has been
allocated.
Move the RMID allocation out of mkdir_rdt_prepare() to occur in its caller,
after the mkdir_rdt_prepare() call. This allows the RMID allocator to
know the CLOSID.
Tested-by: Shaopeng Tan <[email protected]>
Signed-off-by: James Morse <[email protected]>
---
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 29 +++++++++++++++++++-------
1 file changed, 22 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 841294ad6263..c67083a8a5f5 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -2892,6 +2892,12 @@ static int mkdir_rdt_prepare_rmid_alloc(struct rdtgroup *rdtgrp)
return 0;
}
+static void mkdir_rdt_prepare_rmid_free(struct rdtgroup *rgrp)
+{
+ if (rdt_mon_capable)
+ free_rmid(rgrp->closid, rgrp->mon.rmid);
+}
+
static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
const char *name, umode_t mode,
enum rdt_group_type rtype, struct rdtgroup **r)
@@ -2957,10 +2963,6 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
goto out_destroy;
}
- ret = mkdir_rdt_prepare_rmid_alloc(rdtgrp);
- if (ret)
- goto out_destroy;
-
kernfs_activate(kn);
/*
@@ -2981,7 +2983,6 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
static void mkdir_rdt_prepare_clean(struct rdtgroup *rgrp)
{
kernfs_remove(rgrp->kn);
- free_rmid(rgrp->closid, rgrp->mon.rmid);
rdtgroup_remove(rgrp);
}
@@ -3003,12 +3004,19 @@ static int rdtgroup_mkdir_mon(struct kernfs_node *parent_kn,
prgrp = rdtgrp->mon.parent;
rdtgrp->closid = prgrp->closid;
+ ret = mkdir_rdt_prepare_rmid_alloc(rdtgrp);
+ if (ret) {
+ mkdir_rdt_prepare_clean(rdtgrp);
+ goto out_unlock;
+ }
+
/*
* Add the rdtgrp to the list of rdtgrps the parent
* ctrl_mon group has to track.
*/
list_add_tail(&rdtgrp->mon.crdtgrp_list, &prgrp->mon.crdtgrp_list);
+out_unlock:
rdtgroup_kn_unlock(parent_kn);
return ret;
}
@@ -3039,10 +3047,15 @@ static int rdtgroup_mkdir_ctrl_mon(struct kernfs_node *parent_kn,
ret = 0;
rdtgrp->closid = closid;
- ret = rdtgroup_init_alloc(rdtgrp);
- if (ret < 0)
+
+ ret = mkdir_rdt_prepare_rmid_alloc(rdtgrp);
+ if (ret)
goto out_id_free;
+ ret = rdtgroup_init_alloc(rdtgrp);
+ if (ret < 0)
+ goto out_rmid_free;
+
list_add(&rdtgrp->rdtgroup_list, &rdt_all_groups);
if (rdt_mon_capable) {
@@ -3061,6 +3074,8 @@ static int rdtgroup_mkdir_ctrl_mon(struct kernfs_node *parent_kn,
out_del_list:
list_del(&rdtgrp->rdtgroup_list);
+out_rmid_free:
+ mkdir_rdt_prepare_rmid_free(rdtgrp);
out_id_free:
closid_free(closid);
out_common_fail:
--
2.30.2
Hi, James,
> RMID are allocated for each monitor or control group directory, because each
> of these needs its own RMID. For control groups,
> rdtgroup_mkdir_ctrl_mon() later goes on to allocate the CLOSID.
>
> MPAM's equivalent of RMID are not an independent number, so can't be
s/are/is/?
> allocated until the closid is known. An RMID allocation for one CLOSID may fail,
s/closid/CLOSID/
> whereas another may succeed depending on how many monitor groups a
> control group has.
>
> The RMID allocation needs to move to be after the CLOSID has been allocated.
>
> Move the RMID allocation out of mkdir_rdt_prepare() to occur in its caller, after
> the mkdir_rdt_prepare() call. This allows the RMID allocator to know the CLOSID.
>
> Tested-by: Shaopeng Tan <[email protected]>
> Signed-off-by: James Morse <[email protected]>
> ---
> arch/x86/kernel/cpu/resctrl/rdtgroup.c | 29 +++++++++++++++++++-------
> 1 file changed, 22 insertions(+), 7 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> index 841294ad6263..c67083a8a5f5 100644
> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> @@ -2892,6 +2892,12 @@ static int mkdir_rdt_prepare_rmid_alloc(struct
> rdtgroup *rdtgrp)
> return 0;
> }
>
> +static void mkdir_rdt_prepare_rmid_free(struct rdtgroup *rgrp) {
> + if (rdt_mon_capable)
> + free_rmid(rgrp->closid, rgrp->mon.rmid); }
> +
> static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
> const char *name, umode_t mode,
> enum rdt_group_type rtype, struct rdtgroup **r)
> @@ -2957,10 +2963,6 @@ static int mkdir_rdt_prepare(struct kernfs_node
> *parent_kn,
> goto out_destroy;
> }
>
> - ret = mkdir_rdt_prepare_rmid_alloc(rdtgrp);
> - if (ret)
> - goto out_destroy;
> -
> kernfs_activate(kn);
>
> /*
> @@ -2981,7 +2983,6 @@ static int mkdir_rdt_prepare(struct kernfs_node
> *parent_kn, static void mkdir_rdt_prepare_clean(struct rdtgroup *rgrp) {
> kernfs_remove(rgrp->kn);
> - free_rmid(rgrp->closid, rgrp->mon.rmid);
> rdtgroup_remove(rgrp);
> }
>
> @@ -3003,12 +3004,19 @@ static int rdtgroup_mkdir_mon(struct kernfs_node
> *parent_kn,
> prgrp = rdtgrp->mon.parent;
> rdtgrp->closid = prgrp->closid;
>
> + ret = mkdir_rdt_prepare_rmid_alloc(rdtgrp);
> + if (ret) {
> + mkdir_rdt_prepare_clean(rdtgrp);
> + goto out_unlock;
> + }
> +
> /*
> * Add the rdtgrp to the list of rdtgrps the parent
> * ctrl_mon group has to track.
> */
> list_add_tail(&rdtgrp->mon.crdtgrp_list, &prgrp->mon.crdtgrp_list);
>
> +out_unlock:
> rdtgroup_kn_unlock(parent_kn);
> return ret;
> }
> @@ -3039,10 +3047,15 @@ static int rdtgroup_mkdir_ctrl_mon(struct
> kernfs_node *parent_kn,
> ret = 0;
>
> rdtgrp->closid = closid;
> - ret = rdtgroup_init_alloc(rdtgrp);
> - if (ret < 0)
> +
> + ret = mkdir_rdt_prepare_rmid_alloc(rdtgrp);
> + if (ret)
> goto out_id_free;
>
> + ret = rdtgroup_init_alloc(rdtgrp);
> + if (ret < 0)
> + goto out_rmid_free;
> +
> list_add(&rdtgrp->rdtgroup_list, &rdt_all_groups);
>
> if (rdt_mon_capable) {
> @@ -3061,6 +3074,8 @@ static int rdtgroup_mkdir_ctrl_mon(struct
> kernfs_node *parent_kn,
>
> out_del_list:
> list_del(&rdtgrp->rdtgroup_list);
> +out_rmid_free:
> + mkdir_rdt_prepare_rmid_free(rdtgrp);
> out_id_free:
> closid_free(closid);
> out_common_fail:
> --
> 2.30.2
Thanks.
-Fenghua
Hi James,
On 1/13/2023 9:54 AM, James Morse wrote:
> RMID are allocated for each monitor or control group directory, because
> each of these needs its own RMID. For control groups,
> rdtgroup_mkdir_ctrl_mon() later goes on to allocate the CLOSID.
>
> MPAM's equivalent of RMID are not an independent number, so can't be
> allocated until the closid is known. An RMID allocation for one CLOSID
Could you please be consistent with CLOSID vs closid (also RMID vs rmid)?
When reading through the series and seeing the switch it is not clear if
text refers to same concept.
> may fail, whereas another may succeed depending on how many monitor
> groups a control group has.
>
> The RMID allocation needs to move to be after the CLOSID has been
> allocated.
>
> Move the RMID allocation out of mkdir_rdt_prepare() to occur in its caller,
> after the mkdir_rdt_prepare() call. This allows the RMID allocator to
> know the CLOSID.
>
> Tested-by: Shaopeng Tan <[email protected]>
> Signed-off-by: James Morse <[email protected]>
> ---
> arch/x86/kernel/cpu/resctrl/rdtgroup.c | 29 +++++++++++++++++++-------
> 1 file changed, 22 insertions(+), 7 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> index 841294ad6263..c67083a8a5f5 100644
> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> @@ -2892,6 +2892,12 @@ static int mkdir_rdt_prepare_rmid_alloc(struct rdtgroup *rdtgrp)
> return 0;
> }
>
> +static void mkdir_rdt_prepare_rmid_free(struct rdtgroup *rgrp)
> +{
> + if (rdt_mon_capable)
> + free_rmid(rgrp->closid, rgrp->mon.rmid);
> +}
> +
> static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
> const char *name, umode_t mode,
> enum rdt_group_type rtype, struct rdtgroup **r)
> @@ -2957,10 +2963,6 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
> goto out_destroy;
> }
>
> - ret = mkdir_rdt_prepare_rmid_alloc(rdtgrp);
> - if (ret)
> - goto out_destroy;
> -
> kernfs_activate(kn);
>
This moves the creation of the monitoring related files/directories to later, but leaves
the kernfs_activate() that activates the node and make it visible to user space. Should
this activation be moved?
Reinette
Hi Reinette,
On 02/02/2023 23:45, Reinette Chatre wrote:
> On 1/13/2023 9:54 AM, James Morse wrote:
>> RMID are allocated for each monitor or control group directory, because
>> each of these needs its own RMID. For control groups,
>> rdtgroup_mkdir_ctrl_mon() later goes on to allocate the CLOSID.
>>
>> MPAM's equivalent of RMID are not an independent number, so can't be
>> allocated until the closid is known. An RMID allocation for one CLOSID
> Could you please be consistent with CLOSID vs closid (also RMID vs rmid)?
> When reading through the series and seeing the switch it is not clear if
> text refers to same concept.
Yup, I'm trying, but there will be some that slip through.
>> may fail, whereas another may succeed depending on how many monitor
>> groups a control group has.
>>
>> The RMID allocation needs to move to be after the CLOSID has been
>> allocated.
>>
>> Move the RMID allocation out of mkdir_rdt_prepare() to occur in its caller,
>> after the mkdir_rdt_prepare() call. This allows the RMID allocator to
>> know the CLOSID.
>> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> index 841294ad6263..c67083a8a5f5 100644
>> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> @@ -2957,10 +2963,6 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
>> goto out_destroy;
>> }
>>
>> - ret = mkdir_rdt_prepare_rmid_alloc(rdtgrp);
>> - if (ret)
>> - goto out_destroy;
>> -
>> kernfs_activate(kn);
>>
>
> This moves the creation of the monitoring related files/directories to later, but leaves
> the kernfs_activate() that activates the node and make it visible to user space. Should
> this activation be moved?
I hadn't properly grasped what that was doing Yes, I've moved it to after the
mkdir_rdt_prepare_rmid_alloc() calls in the two callers.
Thanks,
James