On Wed, Jun 12, 2019 at 10:15 AM Nathan Lynch <nath...@linux.ibm.com> wrote:
>
> Allow external callers to force the cacheinfo code to release all its
> references to cache nodes, e.g. before processing device tree updates
> post-migration, and to rebuild the hierarchy afterward.
>
> CPU online/offline must be blocked by callers; enforce this.
>
> Fixes: 410bccf97881 ("powerpc/pseries: Partition migration in the kernel")
> Signed-off-by: Nathan Lynch <nath...@linux.ibm.com>
Reviewed-by: Gautham R. Shenoy <e...@linux.vnet.ibm.com>
> ---
> arch/powerpc/kernel/cacheinfo.c | 21 +++++++++++++++++++++
> arch/powerpc/kernel/cacheinfo.h | 4 ++++
> 2 files changed, 25 insertions(+)
>
> diff --git a/arch/powerpc/kernel/cacheinfo.c b/arch/powerpc/kernel/cacheinfo.c
> index 862e2890bd3d..42c559efe060 100644
> --- a/arch/powerpc/kernel/cacheinfo.c
> +++ b/arch/powerpc/kernel/cacheinfo.c
> @@ -896,4 +896,25 @@ void cacheinfo_cpu_offline(unsigned int cpu_id)
> if (cache)
> cache_cpu_clear(cache, cpu_id);
> }
> +
> +void cacheinfo_teardown(void)
> +{
> + unsigned int cpu;
> +
> + lockdep_assert_cpus_held();
> +
> + for_each_online_cpu(cpu)
> + cacheinfo_cpu_offline(cpu);
> +}
> +
> +void cacheinfo_rebuild(void)
> +{
> + unsigned int cpu;
> +
> + lockdep_assert_cpus_held();
> +
> + for_each_online_cpu(cpu)
> + cacheinfo_cpu_online(cpu);
> +}
> +
> #endif /* (CONFIG_PPC_PSERIES && CONFIG_SUSPEND) || CONFIG_HOTPLUG_CPU */
> diff --git a/arch/powerpc/kernel/cacheinfo.h b/arch/powerpc/kernel/cacheinfo.h
> index 955f5e999f1b..52bd3fc6642d 100644
> --- a/arch/powerpc/kernel/cacheinfo.h
> +++ b/arch/powerpc/kernel/cacheinfo.h
> @@ -6,4 +6,8 @@
> extern void cacheinfo_cpu_online(unsigned int cpu_id);
> extern void cacheinfo_cpu_offline(unsigned int cpu_id);
>
> +/* Allow migration/suspend to tear down and rebuild the hierarchy. */
> +extern void cacheinfo_teardown(void);
> +extern void cacheinfo_rebuild(void);
> +
> #endif /* _PPC_CACHEINFO_H */
> --
> 2.20.1
>
--
Thanks and Regards
gautham.
