From patchwork Mon Mar 16 11:33:15 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Hao X-Patchwork-Id: 450507 X-Patchwork-Delegate: michael@ellerman.id.au Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id D497F1400DD for ; Mon, 16 Mar 2015 22:36:44 +1100 (AEDT) Authentication-Results: ozlabs.org; dkim=fail reason="verification failed; unprotected key" header.d=gmail.com header.i=@gmail.com header.b=IOuOl318; dkim-adsp=none (unprotected policy); dkim-atps=neutral Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id A60A71A0C7F for ; Mon, 16 Mar 2015 22:36:44 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dkim=fail reason="verification failed; unprotected key" header.d=gmail.com header.i=@gmail.com header.b=IOuOl318; dkim-adsp=none (unprotected policy); dkim-atps=neutral X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Received: from mail-yk0-x22c.google.com (mail-yk0-x22c.google.com [IPv6:2607:f8b0:4002:c07::22c]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id EB8DE1A06F5 for ; Mon, 16 Mar 2015 22:33:40 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dkim=pass reason="2048-bit key; unprotected key" header.d=gmail.com header.i=@gmail.com header.b=IOuOl318; dkim-adsp=pass; dkim-atps=neutral Received: by ykcn8 with SMTP id n8so16287259ykc.3 for ; Mon, 16 Mar 2015 04:33:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=7by45RC3+IBrDwgohW3q+3v2r4Rg4Tm3kHQ+rRRyfHw=; b=IOuOl318Y4NgR4rFthOwMjvWkfS3+59KaP8K0urUzH9tLr4jKuReEz9o5/1OYjP6sB 4tEYsoVqS5wr1rfJv+QANT+1Z/yZ36MYRbce27GN2dClYVO5rP6KF21tksLfTtKacoid JpbTlxqHOHGDHx3Vhth5TPKzyoElApBnfBfuDIPOObWq5H3IggoODc3dFhZ4qHkN/ENo 1W1qDAcj2ZjImkk8BBW7LJ9JtudgQLBfnqf/3S8LbGUUYpT/l2dOLiz2CV8OqaK4J6i2 oZtA34cQKuOk96iHPcfcFz3vJy4vYBNwPwtMMO/IHtSm+D++99j4YRDAWhwopiJyLoZD CrIg== X-Received: by 10.170.208.147 with SMTP id z141mr67191840yke.106.1426505618973; Mon, 16 Mar 2015 04:33:38 -0700 (PDT) Received: from pek-khao-d1.corp.ad.wrs.com ([106.120.101.38]) by mx.google.com with ESMTPSA id n47sm8931614yha.55.2015.03.16.04.33.35 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 16 Mar 2015 04:33:38 -0700 (PDT) From: Kevin Hao To: linuxppc-dev@lists.ozlabs.org Subject: [PATCH 1/3] powerpc: introduce PPC_HAS_LOCK_OWNER Date: Mon, 16 Mar 2015 19:33:15 +0800 Message-Id: <1426505597-1042-2-git-send-email-haokexin@gmail.com> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1426505597-1042-1-git-send-email-haokexin@gmail.com> References: <1426505597-1042-1-git-send-email-haokexin@gmail.com> Cc: Paul Mackerras X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" On a system with shared processors (a physical processor is multiplexed between several virtual processors), we encode the lock owner into the lock token in order to avoid unnecessarily spinning on a lock if the lock holder isn't currently scheduled on a physical processor. In the current kernel, we unconditionally encode the lock owner into the lock token for all the ppc64 platforms no matter it is a shared processor or not. This introduces a new kernel option to distinguish the platforms which need this hack. Signed-off-by: Kevin Hao --- arch/powerpc/Kconfig | 3 +++ arch/powerpc/include/asm/spinlock.h | 12 ++++++++---- arch/powerpc/lib/locks.c | 4 ++-- arch/powerpc/platforms/pseries/Kconfig | 1 + 4 files changed, 14 insertions(+), 6 deletions(-) diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 9b780e0d2c18..6949d6099d4c 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -303,6 +303,9 @@ config PGTABLE_LEVELS default 3 if PPC_64K_PAGES default 4 +config PPC_HAS_LOCK_OWNER + bool + source "init/Kconfig" source "kernel/Kconfig.freezer" diff --git a/arch/powerpc/include/asm/spinlock.h b/arch/powerpc/include/asm/spinlock.h index 4dbe072eecbe..38f40ea63a8c 100644 --- a/arch/powerpc/include/asm/spinlock.h +++ b/arch/powerpc/include/asm/spinlock.h @@ -30,7 +30,7 @@ #define smp_mb__after_unlock_lock() smp_mb() /* Full ordering for lock. */ -#ifdef CONFIG_PPC64 +#ifdef CONFIG_PPC_HAS_LOCK_OWNER /* use 0x800000yy when locked, where yy == CPU number */ #ifdef __BIG_ENDIAN__ #define LOCK_TOKEN (*(u32 *)(&get_paca()->lock_token)) @@ -109,7 +109,7 @@ static inline int arch_spin_trylock(arch_spinlock_t *lock) * value. */ -#if defined(CONFIG_PPC_SPLPAR) +#if defined(CONFIG_PPC_HAS_LOCK_OWNER) /* We only yield to the hypervisor if we are in shared processor mode */ #define SHARED_PROCESSOR (lppaca_shared_proc(local_paca->lppaca_ptr)) extern void __spin_yield(arch_spinlock_t *lock); @@ -164,7 +164,7 @@ static inline void arch_spin_unlock(arch_spinlock_t *lock) lock->slock = 0; } -#ifdef CONFIG_PPC64 +#ifdef CONFIG_PPC_HAS_LOCK_OWNER extern void arch_spin_unlock_wait(arch_spinlock_t *lock); #else #define arch_spin_unlock_wait(lock) \ @@ -187,9 +187,13 @@ extern void arch_spin_unlock_wait(arch_spinlock_t *lock); #ifdef CONFIG_PPC64 #define __DO_SIGN_EXTEND "extsw %0,%0\n" -#define WRLOCK_TOKEN LOCK_TOKEN /* it's negative */ #else #define __DO_SIGN_EXTEND +#endif + +#ifdef CONFIG_PPC_HAS_LOCK_OWNER +#define WRLOCK_TOKEN LOCK_TOKEN /* it's negative */ +#else #define WRLOCK_TOKEN (-1) #endif diff --git a/arch/powerpc/lib/locks.c b/arch/powerpc/lib/locks.c index 170a0346f756..66513b3e9b0e 100644 --- a/arch/powerpc/lib/locks.c +++ b/arch/powerpc/lib/locks.c @@ -19,7 +19,7 @@ #include /* waiting for a spinlock... */ -#if defined(CONFIG_PPC_SPLPAR) +#if defined(CONFIG_PPC_HAS_LOCK_OWNER) #include #include @@ -66,7 +66,6 @@ void __rw_yield(arch_rwlock_t *rw) plpar_hcall_norets(H_CONFER, get_hard_smp_processor_id(holder_cpu), yield_count); } -#endif void arch_spin_unlock_wait(arch_spinlock_t *lock) { @@ -83,3 +82,4 @@ void arch_spin_unlock_wait(arch_spinlock_t *lock) } EXPORT_SYMBOL(arch_spin_unlock_wait); +#endif diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig index a758a9c3bbba..5402fcc30c3e 100644 --- a/arch/powerpc/platforms/pseries/Kconfig +++ b/arch/powerpc/platforms/pseries/Kconfig @@ -27,6 +27,7 @@ config PPC_PSERIES config PPC_SPLPAR depends on PPC_PSERIES bool "Support for shared-processor logical partitions" + select PPC_HAS_LOCK_OWNER default n help Enabling this option will make the kernel run more efficiently