From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754168AbbG2TW6 (ORCPT ); Wed, 29 Jul 2015 15:22:58 -0400 Received: from casper.infradead.org ([85.118.1.10]:51185 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753434AbbG2TVQ (ORCPT ); Wed, 29 Jul 2015 15:21:16 -0400 Message-Id: <20150729191700.165016972@infradead.org> User-Agent: quilt/0.61-1 Date: Wed, 29 Jul 2015 21:08:54 +0200 From: Peter Zijlstra To: mingo@kernel.org, linux-kernel@vger.kernel.org Cc: will.deacon@arm.com, linux@arm.linux.org.uk, ralf@linux-mips.org, egtvedt@samfundet.no, michael@amarulasolutions.com, cmetcalf@ezchip.com, peterz@infradead.org Subject: [RFC][PATCH 6/7] Remove finish_arch_switch References: <20150729190848.678796654@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline; filename=chris_metcalf-finish_arch_switch.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Chris Metcalf Move the simulator bits into switch_to() and use finish_arch_post_lock_switch() for the homecache migration bits. Signed-off-by: Peter Zijlstra (Intel) --- arch/tile/include/asm/switch_to.h | 10 +++------- arch/tile/kernel/process.c | 17 +++++++++++++++-- 2 files changed, 18 insertions(+), 9 deletions(-) --- a/arch/tile/include/asm/switch_to.h +++ b/arch/tile/include/asm/switch_to.h @@ -53,15 +53,11 @@ extern unsigned long get_switch_to_pc(vo * Kernel threads can check to see if they need to migrate their * stack whenever they return from a context switch; for user * threads, we defer until they are returning to user-space. + * We defer homecache migration until the runqueue lock is released. */ -#define finish_arch_switch(prev) do { \ - if (unlikely((prev)->state == TASK_DEAD)) \ - __insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_EXIT | \ - ((prev)->pid << _SIM_CONTROL_OPERATOR_BITS)); \ - __insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_SWITCH | \ - (current->pid << _SIM_CONTROL_OPERATOR_BITS)); \ +#define finish_arch_post_lock_switch() do { \ if (current->mm == NULL && !kstack_hash && \ - current_thread_info()->homecache_cpu != smp_processor_id()) \ + current_thread_info()->homecache_cpu != raw_smp_processor_id()) \ homecache_migrate_kthread(); \ } while (0) --- a/arch/tile/kernel/process.c +++ b/arch/tile/kernel/process.c @@ -448,11 +448,24 @@ struct task_struct *__sched _switch_to(s /* * Switch kernel SP, PC, and callee-saved registers. + * Pass the value to use for SYSTEM_SAVE_K_0 when we reset our sp. + * Once we return from this function we will have changed stacks + * and be running with current == next. + */ + __switch_to(prev, next, next_current_ksp0(next)); + + /* Notify the simulator of task switch and task exit. */ + if (unlikely(prev->state == TASK_DEAD)) + __insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_EXIT | + (prev->pid << _SIM_CONTROL_OPERATOR_BITS)); + __insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_SWITCH | + (next->pid << _SIM_CONTROL_OPERATOR_BITS)); + + /* * In the context of the new task, return the old task pointer * (i.e. the task that actually called __switch_to). - * Pass the value to use for SYSTEM_SAVE_K_0 when we reset our sp. */ - return __switch_to(prev, next, next_current_ksp0(next)); + return prev; } /*