[v3,03/19] x86/resctrl: Create helper for RMID allocation and mondata dir creation
Commit Message
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.
To make a subsequent change that does this easier to read, move the RMID
allocation and mondata dir creation to a helper.
Tested-by: Shaopeng Tan <tan.shaopeng@fujitsu.com>
Signed-off-by: James Morse <james.morse@arm.com>
---
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 42 +++++++++++++++++---------
1 file changed, 27 insertions(+), 15 deletions(-)
Comments
On Mon, 20 Mar 2023, 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
> 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.
>
> To make a subsequent change that does this easier to read, move the RMID
> allocation and mondata dir creation to a helper.
>
> Tested-by: Shaopeng Tan <tan.shaopeng@fujitsu.com>
> Signed-off-by: James Morse <james.morse@arm.com>
> ---
> arch/x86/kernel/cpu/resctrl/rdtgroup.c | 42 +++++++++++++++++---------
> 1 file changed, 27 insertions(+), 15 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> index 6ecaf34a4e32..b785beb0db26 100644
> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> @@ -3135,6 +3135,30 @@ static int rdtgroup_init_alloc(struct rdtgroup *rdtgrp)
> return 0;
> }
>
> +static int mkdir_rdt_prepare_rmid_alloc(struct rdtgroup *rdtgrp)
> +{
> + int ret;
> +
> + if (!rdt_mon_capable)
> + return 0;
> +
> + ret = alloc_rmid();
> + if (ret < 0) {
> + rdt_last_cmd_puts("Out of RMIDs\n");
> + return ret;
> + }
> + rdtgrp->mon.rmid = ret;
> +
> + ret = mkdir_mondata_all(rdtgrp->kn, rdtgrp, &rdtgrp->mon.mon_data_kn);
> + if (ret) {
> + rdt_last_cmd_puts("kernfs subdir error\n");
> + free_rmid(rdtgrp->closid, rdtgrp->mon.rmid);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
> const char *name, umode_t mode,
> enum rdt_group_type rtype, struct rdtgroup **r)
> @@ -3200,20 +3224,10 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
> goto out_destroy;
> }
>
> - if (rdt_mon_capable) {
> - ret = alloc_rmid();
> - if (ret < 0) {
> - rdt_last_cmd_puts("Out of RMIDs\n");
> - goto out_destroy;
> - }
> - rdtgrp->mon.rmid = ret;
> + ret = mkdir_rdt_prepare_rmid_alloc(rdtgrp);
> + if (ret)
> + goto out_destroy;
>
> - ret = mkdir_mondata_all(kn, rdtgrp, &rdtgrp->mon.mon_data_kn);
> - if (ret) {
> - rdt_last_cmd_puts("kernfs subdir error\n");
> - goto out_idfree;
> - }
> - }
> kernfs_activate(kn);
>
> /*
> @@ -3221,8 +3235,6 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
> */
> return 0;
>
> -out_idfree:
> - free_rmid(rdtgrp->closid, rdtgrp->mon.rmid);
> out_destroy:
> kernfs_put(rdtgrp->kn);
> kernfs_remove(rdtgrp->kn);
>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Hi James,
On 3/20/2023 10:26 AM, James Morse wrote:
> RMID are allocated for each monitor or control group directory, because
control groups do not always get an RMID, only if they are capable of
monitoring. How about "RMID are allocated for each monitor group and
control group that is also capable of monitoring". Please feel free to
improve.
Reinette
@@ -3135,6 +3135,30 @@ static int rdtgroup_init_alloc(struct rdtgroup *rdtgrp)
return 0;
}
+static int mkdir_rdt_prepare_rmid_alloc(struct rdtgroup *rdtgrp)
+{
+ int ret;
+
+ if (!rdt_mon_capable)
+ return 0;
+
+ ret = alloc_rmid();
+ if (ret < 0) {
+ rdt_last_cmd_puts("Out of RMIDs\n");
+ return ret;
+ }
+ rdtgrp->mon.rmid = ret;
+
+ ret = mkdir_mondata_all(rdtgrp->kn, rdtgrp, &rdtgrp->mon.mon_data_kn);
+ if (ret) {
+ rdt_last_cmd_puts("kernfs subdir error\n");
+ free_rmid(rdtgrp->closid, rdtgrp->mon.rmid);
+ return ret;
+ }
+
+ return 0;
+}
+
static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
const char *name, umode_t mode,
enum rdt_group_type rtype, struct rdtgroup **r)
@@ -3200,20 +3224,10 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
goto out_destroy;
}
- if (rdt_mon_capable) {
- ret = alloc_rmid();
- if (ret < 0) {
- rdt_last_cmd_puts("Out of RMIDs\n");
- goto out_destroy;
- }
- rdtgrp->mon.rmid = ret;
+ ret = mkdir_rdt_prepare_rmid_alloc(rdtgrp);
+ if (ret)
+ goto out_destroy;
- ret = mkdir_mondata_all(kn, rdtgrp, &rdtgrp->mon.mon_data_kn);
- if (ret) {
- rdt_last_cmd_puts("kernfs subdir error\n");
- goto out_idfree;
- }
- }
kernfs_activate(kn);
/*
@@ -3221,8 +3235,6 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
*/
return 0;
-out_idfree:
- free_rmid(rdtgrp->closid, rdtgrp->mon.rmid);
out_destroy:
kernfs_put(rdtgrp->kn);
kernfs_remove(rdtgrp->kn);