From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752190AbbCZCg6 (ORCPT ); Wed, 25 Mar 2015 22:36:58 -0400 Received: from cn.fujitsu.com ([59.151.112.132]:43974 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751342AbbCZCgv (ORCPT ); Wed, 25 Mar 2015 22:36:51 -0400 X-IronPort-AV: E=Sophos;i="5.04,848,1406563200"; d="scan'208";a="89352324" From: Gu Zheng To: CC: , , , , , , Subject: [PATCH 1/2] x86/cpu hotplug: make apicid <--> cpuid mapping persistent Date: Thu, 26 Mar 2015 10:17:54 +0800 Message-ID: <1427336275-32066-2-git-send-email-guz.fnst@cn.fujitsu.com> X-Mailer: git-send-email 1.7.7 In-Reply-To: <1427336275-32066-1-git-send-email-guz.fnst@cn.fujitsu.com> References: <1427336275-32066-1-git-send-email-guz.fnst@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.167.226.100] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Previously, we build the apicid <--> cpuid mapping when the cpu is present, but the relationship will be changed if the cpu/node hotplug happenned, because we always choose the first free cpuid for the hot added cpu (whether it is new-add or re-add), so this the cpuid <--> node mapping changed if node hot plug occurred, and it causes the wq sub-system allocation failture: == SLUB: Unable to allocate memory on node 2 (gfp=0x80d0) cache: kmalloc-192, object size: 192, buffer size: 192, default order: 1, min order: 0 node 0: slabs: 6172, objs: 259224, free: 245741 node 1: slabs: 3261, objs: 136962, free: 127656 == So here we build the persistent [lapic id] <--> cpuid mapping when the cpu first present, and never change it. Suggested-by: KAMEZAWA Hiroyuki Signed-off-by: Gu Zheng --- arch/x86/kernel/apic/apic.c | 31 ++++++++++++++++++++++++++++++- 1 files changed, 30 insertions(+), 1 deletions(-) diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index ad3639a..d539ebc 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -2038,6 +2038,30 @@ void disconnect_bsp_APIC(int virt_wire_setup) apic_write(APIC_LVT1, value); } +/* + * Logic cpu number(cpuid) to local APIC id persistent mappings. + * Do not clear the mapping even if cpu hot removed. + * */ +static int apicid_to_x86_cpu[MAX_LOCAL_APIC] = { + [0 ... MAX_LOCAL_APIC - 1] = -1, +}; + +/* + * Internal cpu id bits, set the bit once cpu present, and never clear it. + * */ +static cpumask_t cpuid_mask = CPU_MASK_NONE; + +static int get_cpuid(int apicid) +{ + int cpuid; + + cpuid = apicid_to_x86_cpu[apicid]; + if (cpuid == -1) + cpuid = cpumask_next_zero(-1, &cpuid_mask); + + return cpuid; +} + int generic_processor_info(int apicid, int version) { int cpu, max = nr_cpu_ids; @@ -2115,7 +2139,10 @@ int generic_processor_info(int apicid, int version) */ cpu = 0; } else - cpu = cpumask_next_zero(-1, cpu_present_mask); + cpu = get_cpuid(apicid); + + /* Store the mapping */ + apicid_to_x86_cpu[apicid] = cpu; /* * Validate version @@ -2144,6 +2171,8 @@ int generic_processor_info(int apicid, int version) early_per_cpu(x86_cpu_to_logical_apicid, cpu) = apic->x86_32_early_logical_apicid(cpu); #endif + /* Mark this cpu id as uesed (already mapping a local apic id) */ + cpumask_set_cpu(cpu, &cpuid_mask); set_cpu_possible(cpu, true); set_cpu_present(cpu, true); -- 1.7.7