RE: [PATCH v1 09/31] x86/resctrl: Add a resctrl helper to reset all the resources

Shaopeng Tan (Fujitsu)
2024-04-03T07:54:03Z

Hello James,

> On umount(), resctrl resets each resource back to its default configuration. It
> only ever does this for all resources in one go.
>
> reset_all_ctrls() is architecture specific as it works with struct
> rdt_hw_resource.
>
> Add an architecture helper to reset all resources.
>
> Signed-off-by: James Morse <james.morse@arm.com>
> ---
> arch/x86/include/asm/resctrl.h | 2 ++
> arch/x86/kernel/cpu/resctrl/rdtgroup.c | 16 +++++++++++-----
> 2 files changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/arch/x86/include/asm/resctrl.h b/arch/x86/include/asm/resctrl.h
> index f61382258743..5f6a5375bb4a 100644
> --- a/arch/x86/include/asm/resctrl.h
> +++ b/arch/x86/include/asm/resctrl.h
> @@ -15,6 +15,8 @@
> */
> #define X86_RESCTRL_EMPTY_CLOSID ((u32)~0)
>
> +void resctrl_arch_reset_resources(void);
> +
> /**
> * struct resctrl_pqr_state - State cache for the PQR MSR
> * @cur_rmid: The cached Resource Monitoring ID
> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> index 1a49c9918f8d..13c24cb18d76 100644
> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> @@ -2859,6 +2859,14 @@ static int reset_all_ctrls(struct rdt_resource *r)
> return 0;
> }
>
> +void resctrl_arch_reset_resources(void)
> +{
> + struct rdt_resource *r;
> +
> + for_each_capable_rdt_resource(r)
Could you explain why not "for_each_alloc_capable_rdt_resource(r)"?

> + reset_all_ctrls(r);
> +}
> +
> /*
> * Move tasks from one to the other group. If @from is NULL, then all tasks
> * in the systems are moved unconditionally (used for teardown).
> @@ -2968,16 +2976,14 @@ static void rmdir_all_sub(void)
>
> static void rdt_kill_sb(struct super_block *sb) {
> - struct rdt_resource *r;
> -
> cpus_read_lock();
> mutex_lock(&rdtgroup_mutex);
>
> rdt_disable_ctx();
>
> - /*Put everything back to default values. */
> - for_each_alloc_capable_rdt_resource(r)
This was "for_each_alloc_capable_rdt_resource(r)".

Best regards,
Shaopeng TAN

> - reset_all_ctrls(r);
> + /* Put everything back to default values. */
> + resctrl_arch_reset_resources();
> +
> rmdir_all_sub();
> rdt_pseudo_lock_release();
> rdtgroup_default.mode = RDT_MODE_SHAREABLE;
> --
> 2.39.2