From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BA59010FC for ; Wed, 7 Jun 2023 20:28:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3B301C4339B; Wed, 7 Jun 2023 20:28:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1686169713; bh=ovzPYdzv2Xe23sZa7j8VZLK5I64txN8XhI6S3Wp1Nf8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gAOSS0NIsI7kW24ggHe75CX8r9Z9VFvP3KdEiOwQp19703w9saNOwUi53aGHnTqwC H9oN1+1CGoWEkG46zAHEhtg9jkoAPxkpKJkgosJZzjjsxOeEQ3rlkbmjsACha6DdAd gJyNO1L3Tm5nB8/48JMb6ZDDo0prmv+8/Yos7DUI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, K Prateek Nayak , Yicong Yang , Sudeep Holla , Sasha Levin Subject: [PATCH 6.3 185/286] drivers: base: cacheinfo: Update cpu_map_populated during CPU Hotplug Date: Wed, 7 Jun 2023 22:14:44 +0200 Message-ID: <20230607200929.317634621@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230607200922.978677727@linuxfoundation.org> References: <20230607200922.978677727@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: K Prateek Nayak [ Upstream commit c26fabe73330d983c7ce822c6b6ec0879b4da61f ] Until commit 5c2712387d48 ("cacheinfo: Fix LLC is not exported through sysfs"), cacheinfo called populate_cache_leaves() for CPU coming online which let the arch specific functions handle (at least on x86) populating the shared_cpu_map. However, with the changes in the aforementioned commit, populate_cache_leaves() is not called when a CPU comes online as a result of hotplug since last_level_cache_is_valid() returns true as the cacheinfo data is not discarded. The CPU coming online is not present in shared_cpu_map, however, it will not be added since the cpu_cacheinfo->cpu_map_populated flag is set (it is set in populate_cache_leaves() when cacheinfo is first populated for x86) This can lead to inconsistencies in the shared_cpu_map when an offlined CPU comes online again. Example below depicts the inconsistency in the shared_cpu_list in cacheinfo when CPU8 is offlined and onlined again on a 3rd Generation EPYC processor: # for i in /sys/devices/system/cpu/cpu8/cache/index*/shared_cpu_list; do echo -n "$i: "; cat $i; done /sys/devices/system/cpu/cpu8/cache/index0/shared_cpu_list: 8,136 /sys/devices/system/cpu/cpu8/cache/index1/shared_cpu_list: 8,136 /sys/devices/system/cpu/cpu8/cache/index2/shared_cpu_list: 8,136 /sys/devices/system/cpu/cpu8/cache/index3/shared_cpu_list: 8-15,136-143 # echo 0 > /sys/devices/system/cpu/cpu8/online # echo 1 > /sys/devices/system/cpu/cpu8/online # for i in /sys/devices/system/cpu/cpu8/cache/index*/shared_cpu_list; do echo -n "$i: "; cat $i; done /sys/devices/system/cpu/cpu8/cache/index0/shared_cpu_list: 8 /sys/devices/system/cpu/cpu8/cache/index1/shared_cpu_list: 8 /sys/devices/system/cpu/cpu8/cache/index2/shared_cpu_list: 8 /sys/devices/system/cpu/cpu8/cache/index3/shared_cpu_list: 8 # cat /sys/devices/system/cpu/cpu136/cache/index0/shared_cpu_list 136 # cat /sys/devices/system/cpu/cpu136/cache/index3/shared_cpu_list 9-15,136-143 Clear the flag when the CPU is removed from shared_cpu_map when cache_shared_cpu_map_remove() is called during CPU hotplug. This will allow cache_shared_cpu_map_setup() to add the CPU coming back online in the shared_cpu_map. Set the flag again when the shared_cpu_map is setup. Following are results of performing the same test as described above with the changes: # for i in /sys/devices/system/cpu/cpu8/cache/index*/shared_cpu_list; do echo -n "$i: "; cat $i; done /sys/devices/system/cpu/cpu8/cache/index0/shared_cpu_list: 8,136 /sys/devices/system/cpu/cpu8/cache/index1/shared_cpu_list: 8,136 /sys/devices/system/cpu/cpu8/cache/index2/shared_cpu_list: 8,136 /sys/devices/system/cpu/cpu8/cache/index3/shared_cpu_list: 8-15,136-143 # echo 0 > /sys/devices/system/cpu/cpu8/online # echo 1 > /sys/devices/system/cpu/cpu8/online # for i in /sys/devices/system/cpu/cpu8/cache/index*/shared_cpu_list; do echo -n "$i: "; cat $i; done /sys/devices/system/cpu/cpu8/cache/index0/shared_cpu_list: 8,136 /sys/devices/system/cpu/cpu8/cache/index1/shared_cpu_list: 8,136 /sys/devices/system/cpu/cpu8/cache/index2/shared_cpu_list: 8,136 /sys/devices/system/cpu/cpu8/cache/index3/shared_cpu_list: 8-15,136-143 # cat /sys/devices/system/cpu/cpu136/cache/index0/shared_cpu_list 8,136 # cat /sys/devices/system/cpu/cpu136/cache/index3/shared_cpu_list 8-15,136-143 Fixes: 5c2712387d48 ("cacheinfo: Fix LLC is not exported through sysfs") Signed-off-by: K Prateek Nayak Reviewed-by: Yicong Yang Reviewed-by: Sudeep Holla Link: https://lore.kernel.org/r/20230508084115.1157-3-kprateek.nayak@amd.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/base/cacheinfo.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c index 6351db6ecb57f..0fc8fbe7b361d 100644 --- a/drivers/base/cacheinfo.c +++ b/drivers/base/cacheinfo.c @@ -402,11 +402,14 @@ static int cache_shared_cpu_map_setup(unsigned int cpu) coherency_max_size = this_leaf->coherency_line_size; } + /* shared_cpu_map is now populated for the cpu */ + this_cpu_ci->cpu_map_populated = true; return 0; } static void cache_shared_cpu_map_remove(unsigned int cpu) { + struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu); struct cacheinfo *this_leaf, *sib_leaf; unsigned int sibling, index, sib_index; @@ -439,6 +442,9 @@ static void cache_shared_cpu_map_remove(unsigned int cpu) } } } + + /* cpu is no longer populated in the shared map */ + this_cpu_ci->cpu_map_populated = false; } static void free_cache_attributes(unsigned int cpu) -- 2.39.2