Hi James,
On 10/4/24 11:03 AM, James Morse wrote:
> 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.
>
> Co-developed-by: Dave Martin <Dave.Martin@arm.com>
> Signed-off-by: Dave Martin <Dave.Martin@arm.com>
> Signed-off-by: James Morse <james.morse@arm.com>
> Tested-by: Carl Worth <carl@os.amperecomputing.com> # arm64
> Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
> Reviewed-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
> ---
> Changes since v1:
> * Rename the for_each_capable_rdt_resource() introduced in the new
> function resctrl_arch_reset_resources(), back to
> for_each_alloc_capable_rdt_resource() as it was in the original code.
>
> The change looked unintentional; and presumably a resource that does
> not support resource allocation doesn't have any properties to
> reset...
> ---
> 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 52f2326e2b1e..5622943f6354 100644
> --- a/arch/x86/include/asm/resctrl.h
> +++ b/arch/x86/include/asm/resctrl.h
> @@ -16,6 +16,8 @@
> */
> #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 61c8add103fe..a15198f90b29 100644
> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> @@ -2883,6 +2883,14 @@ static int reset_all_ctrls(struct rdt_resource *r)
> return 0;
> }
>
> +void resctrl_arch_reset_resources(void)
> +{
> + struct rdt_resource *r;
> +
> + for_each_alloc_capable_rdt_resource(r)
> + reset_all_ctrls(r);
> +}
Wouldn't this require all archs to have a duplicate helper as above with
only the resctrl_all_ctrls() actually being arch specific?
What if it is instead:
resctrl_reset_alloc_resources() or reset_alloc_resources() or ...
{
struct rdt_resource *r;
for_each_alloc_capable_rdt_resource(r)
resctrl_arch_reset_all_ctrls(r);
}
With above archs only need to implement the actual reset code.
> +
> /*
> * Move tasks from one to the other group. If @from is NULL, then all tasks
> * in the systems are moved unconditionally (used for teardown).
> @@ -2992,16 +3000,14 @@ 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)
> - 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;
Reinette