From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9A437105F7AE for ; Fri, 13 Mar 2026 14:48:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=i3iVJCrQuiE/fT0n3ZNi75PrcATjrN/i4euH/oVenuM=; b=X9BZzq1hCS4NH5xVm00QVLWVus WM8Nl+TwZcO7wJR7ubDOBbPs8cu1FYF/HlSz+MhJ3oLh8Y2lMJX2sidnOdGXM4iCQl2Km7TQJcnnn ohzJ9Q32OvMXKeTirkvpK8GEsG5X6n3QBIs3MCenA6sCYj3krVmT5Ht0uRSU/VWf2EAa7j29VxPGl D9vI8XHOUcmE4LpgYbBYP569G/l4BCbPdS9IJPi80ayjeFKcHjcjKyyaygdR7Of8Coarx8kOqyEEy LZXXEnlGnriJDIeG9WRZ8BIYp8UGvi1cRHhoQAwfO28DZSASX8Qf/2U90o2eMvxIfLpx51KUubvfz haeiDG/w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1w13oo-00000000SLi-2ROB; Fri, 13 Mar 2026 14:48:50 +0000 Received: from desiato.infradead.org ([2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1w13ol-00000000SGs-1yPs for linux-arm-kernel@bombadil.infradead.org; Fri, 13 Mar 2026 14:48:47 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Transfer-Encoding:MIME-Version :References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=i3iVJCrQuiE/fT0n3ZNi75PrcATjrN/i4euH/oVenuM=; b=JXIXX2aEiaWTWjNz14toilzDMV l6j/hYsy2LIlZ23yV5w6zOpurxgy8EuNXNDfzFyPhxWUbZoqBnEOKQzt9BYkvF3TN9G5Z70tQxMnB twjp4SRWeLta28iAPlN3XsFXv+Xxj+aS76fxQyWY25tMWzZVBF8Y22kY0x864X0xebycMOwvaAUYm 6X1fk3by/6N3pzyY4gapl5X+q4mB6wZOAN3GA0mbFp7v+8YTDu8W2EB5eOx2NRi5iYx263f12LT3K RfB8wy11XvjkTllwPvuOMjRfgr+EJ8olW3xS5F72pngVuOKnd9NLBpY+gJ85cQ3przkV9Jr2+1bb2 bhIUbGrw==; Received: from foss.arm.com ([217.140.110.172]) by desiato.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1w13oh-00000003a9q-2fQI for linux-arm-kernel@lists.infradead.org; Fri, 13 Mar 2026 14:48:45 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 9BD872454; Fri, 13 Mar 2026 07:48:36 -0700 (PDT) Received: from e134344.cambridge.arm.com (e134344.arm.com [10.1.196.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id CFFA43F7BD; Fri, 13 Mar 2026 07:48:38 -0700 (PDT) From: Ben Horgan To: ben.horgan@arm.com Cc: amitsinght@marvell.com, baisheng.gao@unisoc.com, baolin.wang@linux.alibaba.com, carl@os.amperecomputing.com, dave.martin@arm.com, david@kernel.org, dfustini@baylibre.com, fenghuay@nvidia.com, gshan@redhat.com, james.morse@arm.com, jonathan.cameron@huawei.com, kobak@nvidia.com, lcherian@marvell.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, peternewman@google.com, punit.agrawal@oss.qualcomm.com, quic_jiles@quicinc.com, reinette.chatre@intel.com, rohit.mathew@arm.com, scott@os.amperecomputing.com, sdonthineni@nvidia.com, tan.shaopeng@fujitsu.com, xhao@linux.alibaba.com, catalin.marinas@arm.com, will@kernel.org, corbet@lwn.net, maz@kernel.org, oupton@kernel.org, joey.gouly@arm.com, suzuki.poulose@arm.com, kvmarm@lists.linux.dev, zengheng4@huawei.com, linux-doc@vger.kernel.org, Shaopeng Tan Subject: [PATCH v6 31/40] arm_mpam: resctrl: Update the rmid reallocation limit Date: Fri, 13 Mar 2026 14:46:08 +0000 Message-ID: <20260313144617.3420416-32-ben.horgan@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260313144617.3420416-1-ben.horgan@arm.com> References: <20260313144617.3420416-1-ben.horgan@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260313_144844_110497_DE5E851F X-CRM114-Status: GOOD ( 14.28 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: James Morse resctrl's limbo code needs to be told when the data left in a cache is small enough for the partid+pmg value to be re-allocated. x86 uses the cache size divided by the number of rmid users the cache may have. Do the same, but for the smallest cache, and with the number of partid-and-pmg users. Tested-by: Gavin Shan Tested-by: Shaopeng Tan Tested-by: Peter Newman Tested-by: Zeng Heng Tested-by: Punit Agrawal Reviewed-by: Zeng Heng Reviewed-by: Shaopeng Tan Reviewed-by: Jonathan Cameron Signed-off-by: James Morse Signed-off-by: Ben Horgan --- Changes since v2: Move waiting for cache info into it's own patch Changes since v3: Move check class is csu higher (just kept to document intent) continue -> break to squash update rmid limits use raw_smp_processor_id() --- drivers/resctrl/mpam_resctrl.c | 39 ++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) diff --git a/drivers/resctrl/mpam_resctrl.c b/drivers/resctrl/mpam_resctrl.c index 4f6a53d1bd4f..3979808f7253 100644 --- a/drivers/resctrl/mpam_resctrl.c +++ b/drivers/resctrl/mpam_resctrl.c @@ -438,6 +438,42 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain_hdr *hdr, closid, rmid, val); } +/* + * The rmid realloc threshold should be for the smallest cache exposed to + * resctrl. + */ +static int update_rmid_limits(struct mpam_class *class) +{ + u32 num_unique_pmg = resctrl_arch_system_num_rmid_idx(); + struct mpam_props *cprops = &class->props; + struct cacheinfo *ci; + + lockdep_assert_cpus_held(); + + if (!mpam_has_feature(mpam_feat_msmon_csu, cprops)) + return 0; + + /* + * Assume cache levels are the same size for all CPUs... + * The check just requires any online CPU and it can't go offline as we + * hold the cpu lock. + */ + ci = get_cpu_cacheinfo_level(raw_smp_processor_id(), class->level); + if (!ci || ci->size == 0) { + pr_debug("Could not read cache size for class %u\n", + class->level); + return -EINVAL; + } + + if (!resctrl_rmid_realloc_limit || + ci->size < resctrl_rmid_realloc_limit) { + resctrl_rmid_realloc_limit = ci->size; + resctrl_rmid_realloc_threshold = ci->size / num_unique_pmg; + } + + return 0; +} + static bool cache_has_usable_cpor(struct mpam_class *class) { struct mpam_props *cprops = &class->props; @@ -856,6 +892,9 @@ static void mpam_resctrl_pick_counters(void) /* CSU counters only make sense on a cache. */ switch (class->type) { case MPAM_CLASS_CACHE: + if (update_rmid_limits(class)) + break; + counter_update_class(QOS_L3_OCCUP_EVENT_ID, class); break; default: -- 2.43.0