Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752637AbaF0FF3 (ORCPT ); Fri, 27 Jun 2014 01:05:29 -0400 Received: from 174.37.253.146-static.reverse.softlayer.com ([174.37.253.146]:34053 "EHLO primary.scalemp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752019AbaF0FF2 (ORCPT ); Fri, 27 Jun 2014 01:05:28 -0400 Message-ID: <53ACFB90.7030608@scalemp.com> Date: Fri, 27 Jun 2014 08:05:20 +0300 From: Oren Twaig User-Agent: Mozilla/5.0 (X11; Linux i686; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 MIME-Version: 1.0 To: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , David Rientjes , Yoshihiro YUNOMAE , Paul Gortmaker , Jan Kiszka , Andi Kleen , HATAYAMA Daisuke , Richard Weinberger CC: x86@kernel.org, linux-kernel@vger.kernel.org, Shai Fultheim Subject: Re: [PATCH] x86, vsmp: Remove is_vsmp_box() from apic_is_clustered_box() References: <53A7BC92.3080307@scalemp.com> In-Reply-To: <53A7BC92.3080307@scalemp.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - primary.scalemp.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - scalemp.com X-Get-Message-Sender-Via: primary.scalemp.com: authenticated_id: oren+scalemp.com/only user confirmed/virtual account not confirmed X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ping On 06/23/2014 08:35 AM, Oren Twaig wrote: > Remove invalid code which caused TSC to be declared as "unstable" on vSMP > Foundation box even if it was stable and let the kernel decide for itself. > > When a vSMP Foundation box is detected, the function apic_cluster_num() counts > the number of APIC clusters found. If more than one found, a multi board > configuration is assumed, and TSC marked as unstable. This behavior is > incorrect as vSMP Foundation may use processors from single node only, attached > to memory of other nodes - and such node may have more than one APIC cluster > (typically any recent intel box has more than single APIC_CLUSTERID(x)). > > To fix this, we simply remove the code which detects a vSMP Foundation box and > affects apic_is_clusted_box() return value. This can be done because later the > kernel checks by itself if the TSC is stable using the > check_tsc_sync_[source|target]() functions and marks TSC as unstable if needed. > > Signed-off-by: Oren Twaig > Acked-by: Shai Fultheim > --- > arch/x86/include/asm/apic.h | 8 ------ > arch/x86/kernel/apic/apic.c | 60 +------------------------------------------ > 2 files changed, 1 insertion(+), 67 deletions(-) > > diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h > index 19b0eba..c100694 100644 > --- a/arch/x86/include/asm/apic.h > +++ b/arch/x86/include/asm/apic.h > @@ -85,14 +85,6 @@ static inline bool apic_from_smp_config(void) > #include > #endif > > -#ifdef CONFIG_X86_64 > -extern int is_vsmp_box(void); > -#else > -static inline int is_vsmp_box(void) > -{ > - return 0; > -} > -#endif > extern int setup_profiling_timer(unsigned int); > > static inline void native_apic_mem_write(u32 reg, u32 v) > diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c > index ad28db7..2b85bb9 100644 > --- a/arch/x86/kernel/apic/apic.c > +++ b/arch/x86/kernel/apic/apic.c > @@ -2451,51 +2451,6 @@ static void apic_pm_activate(void) { } > > #ifdef CONFIG_X86_64 > > -static int apic_cluster_num(void) > -{ > - int i, clusters, zeros; > - unsigned id; > - u16 *bios_cpu_apicid; > - DECLARE_BITMAP(clustermap, NUM_APIC_CLUSTERS); > - > - bios_cpu_apicid = early_per_cpu_ptr(x86_bios_cpu_apicid); > - bitmap_zero(clustermap, NUM_APIC_CLUSTERS); > - > - for (i = 0; i < nr_cpu_ids; i++) { > - /* are we being called early in kernel startup? */ > - if (bios_cpu_apicid) { > - id = bios_cpu_apicid[i]; > - } else if (i < nr_cpu_ids) { > - if (cpu_present(i)) > - id = per_cpu(x86_bios_cpu_apicid, i); > - else > - continue; > - } else > - break; > - > - if (id != BAD_APICID) > - __set_bit(APIC_CLUSTERID(id), clustermap); > - } > - > - /* Problem: Partially populated chassis may not have CPUs in some of > - * the APIC clusters they have been allocated. Only present CPUs have > - * x86_bios_cpu_apicid entries, thus causing zeroes in the bitmap. > - * Since clusters are allocated sequentially, count zeros only if > - * they are bounded by ones. > - */ > - clusters = 0; > - zeros = 0; > - for (i = 0; i < NUM_APIC_CLUSTERS; i++) { > - if (test_bit(i, clustermap)) { > - clusters += 1 + zeros; > - zeros = 0; > - } else > - ++zeros; > - } > - > - return clusters; > -} > - > static int multi_checked; > static int multi; > > @@ -2540,20 +2495,7 @@ static void dmi_check_multi(void) > int apic_is_clustered_box(void) > { > dmi_check_multi(); > - if (multi) > - return 1; > - > - if (!is_vsmp_box()) > - return 0; > - > - /* > - * ScaleMP vSMPowered boxes have one cluster per board and TSCs are > - * not guaranteed to be synced between boards > - */ > - if (apic_cluster_num() > 1) > - return 1; > - > - return 0; > + return multi; > } > #endif > > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/