From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751640AbeAWK4e (ORCPT ); Tue, 23 Jan 2018 05:56:34 -0500 Received: from forwardcorp1g.cmail.yandex.net ([87.250.241.190]:59434 "EHLO forwardcorp1g.cmail.yandex.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751457AbeAWKzd (ORCPT ); Tue, 23 Jan 2018 05:55:33 -0500 Authentication-Results: smtpcorp1o.mail.yandex.net; dkim=pass header.i=@yandex-team.ru Subject: [PATCH 3/4] kernel/fork: switch vmapped stack callation to __vmalloc_area() From: Konstantin Khlebnikov To: Dave Hansen , linux-kernel@vger.kernel.org, Christoph Hellwig , linux-mm@kvack.org, Andy Lutomirski , Andrew Morton Date: Tue, 23 Jan 2018 13:55:29 +0300 Message-ID: <151670492913.658225.2758351129158778856.stgit@buzz> In-Reply-To: <151670492223.658225.4605377710524021456.stgit@buzz> References: <151670492223.658225.4605377710524021456.stgit@buzz> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This gives as pointer vm_struct without calling find_vm_area(). And fix comment about that task holds cache of vm area: this cache used for retrieving actual stack pages, freeing is done by vfree_deferred(). Signed-off-by: Konstantin Khlebnikov --- kernel/fork.c | 37 +++++++++++++++---------------------- 1 file changed, 15 insertions(+), 22 deletions(-) diff --git a/kernel/fork.c b/kernel/fork.c index 2295fc69717f..457c9151f3c8 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -204,39 +204,32 @@ static int free_vm_stack_cache(unsigned int cpu) static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node) { #ifdef CONFIG_VMAP_STACK - void *stack; + struct vm_struct *stack; int i; for (i = 0; i < NR_CACHED_STACKS; i++) { - struct vm_struct *s; - - s = this_cpu_xchg(cached_stacks[i], NULL); - - if (!s) + stack = this_cpu_xchg(cached_stacks[i], NULL); + if (!stack) continue; #ifdef CONFIG_DEBUG_KMEMLEAK /* Clear stale pointers from reused stack. */ - memset(s->addr, 0, THREAD_SIZE); + memset(stack->addr, 0, THREAD_SIZE); #endif - tsk->stack_vm_area = s; - return s->addr; + tsk->stack_vm_area = stack; + return stack->addr; } - stack = __vmalloc_node_range(THREAD_SIZE, THREAD_ALIGN, - VMALLOC_START, VMALLOC_END, - THREADINFO_GFP, - PAGE_KERNEL, - 0, node, __builtin_return_address(0)); + stack = __vmalloc_area(THREAD_SIZE, THREAD_ALIGN, + VMALLOC_START, VMALLOC_END, + THREADINFO_GFP, PAGE_KERNEL, + 0, node, __builtin_return_address(0)); + if (unlikely(!stack)) + return NULL; - /* - * We can't call find_vm_area() in interrupt context, and - * free_thread_stack() can be called in interrupt context, - * so cache the vm_struct. - */ - if (stack) - tsk->stack_vm_area = find_vm_area(stack); - return stack; + /* Cache the vm_struct for stack to page conversions. */ + tsk->stack_vm_area = stack; + return stack->addr; #else struct page *page = alloc_pages_node(node, THREADINFO_GFP, THREAD_SIZE_ORDER);