[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <bda4c7e6-a819-dfa4-7f1d-f9e3f6adbd23@arm.com>
Date: Tue, 28 Mar 2023 14:14:51 +0200
From: Pierre Gondois <pierre.gondois@....com>
To: Yicong Yang <yangyicong@...wei.com>, gregkh@...uxfoundation.org,
rafael@...nel.org, sudeep.holla@....com, palmer@...osinc.com,
linux-kernel@...r.kernel.org
Cc: prime.zeng@...ilicon.com, linuxarm@...wei.com,
yangyicong@...ilicon.com
Subject: Re: [PATCH v2] cacheinfo: Fix LLC is not exported through sysfs
Hello Yicong,
Thanks for the new version,
Reviewed-by: Pierre Gondois <pierre.gondois@....com>
On 3/28/23 13:49, Yicong Yang wrote:
> From: Yicong Yang <yangyicong@...ilicon.com>
>
> After entering 6.3-rc1 the LLC cacheinfo is not exported on our ACPI
> based arm64 server. This is because the LLC cacheinfo is partly reset
> when secondary CPUs boot up. On arm64 the primary cpu will allocate
> and setup cacheinfo:
> init_cpu_topology()
> for_each_possible_cpu()
> fetch_cache_info() // Allocate cacheinfo and init levels
> detect_cache_attributes()
> cache_shared_cpu_map_setup()
> if (!last_level_cache_is_valid()) // not valid, setup LLC
> cache_setup_properties() // setup LLC
>
> On secondary CPU boot up:
> detect_cache_attributes()
> populate_cache_leaves()
> get_cache_type() // Get cache type from clidr_el1,
> // for LLC type=CACHE_TYPE_NOCACHE
> cache_shared_cpu_map_setup()
> if (!last_level_cache_is_valid()) // Valid and won't go to this branch,
> // leave LLC's type=CACHE_TYPE_NOCACHE
>
> The last_level_cache_is_valid() use cacheinfo->{attributes, fw_token} to
> test it's valid or not, but populate_cache_leaves() will only reset
> LLC's type, so we won't try to re-setup LLC's type and leave it
> CACHE_TYPE_NOCACHE and won't export it through sysfs.
>
> This patch tries to fix this by not re-populating the cache leaves if
> the LLC is valid.
>
> Fixes: 5944ce092b97 ("arch_topology: Build cacheinfo from primary CPU")
> Signed-off-by: Yicong Yang <yangyicong@...ilicon.com>
> ---
> Change since v1:
> - Get rid of the goto label, per Pierre
> Link: https://lore.kernel.org/all/20230323122528.16691-1-yangyicong@huawei.com/
>
> drivers/base/cacheinfo.c | 16 +++++++++++-----
> 1 file changed, 11 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
> index f6573c335f4c..f3903d002819 100644
> --- a/drivers/base/cacheinfo.c
> +++ b/drivers/base/cacheinfo.c
> @@ -474,12 +474,18 @@ int detect_cache_attributes(unsigned int cpu)
>
> populate_leaves:
> /*
> - * populate_cache_leaves() may completely setup the cache leaves and
> - * shared_cpu_map or it may leave it partially setup.
> + * If LLC is valid the cache leaves were already populated so just go to
> + * update the cpu map.
> */
> - ret = populate_cache_leaves(cpu);
> - if (ret)
> - goto free_ci;
> + if (!last_level_cache_is_valid(cpu)) {
> + /*
> + * populate_cache_leaves() may completely setup the cache leaves and
> + * shared_cpu_map or it may leave it partially setup.
> + */
> + ret = populate_cache_leaves(cpu);
> + if (ret)
> + goto free_ci;
> + }
>
> /*
> * For systems using DT for cache hierarchy, fw_token
Powered by blists - more mailing lists