From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932697AbbIVGYk (ORCPT ); Tue, 22 Sep 2015 02:24:40 -0400 Received: from mail-wi0-f172.google.com ([209.85.212.172]:36554 "EHLO mail-wi0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756147AbbIVGYU (ORCPT ); Tue, 22 Sep 2015 02:24:20 -0400 From: Ingo Molnar To: linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: Andy Lutomirski , Andrew Morton , Denys Vlasenko , Brian Gerst , Peter Zijlstra , Borislav Petkov , "H. Peter Anvin" , Linus Torvalds , Oleg Nesterov , Waiman Long , Thomas Gleixner Subject: [PATCH 08/11] x86/mm/pat/32: Remove pgd_list use from the PAT code Date: Tue, 22 Sep 2015 08:23:38 +0200 Message-Id: <1442903021-3893-9-git-send-email-mingo@kernel.org> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1442903021-3893-1-git-send-email-mingo@kernel.org> References: <1442903021-3893-1-git-send-email-mingo@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The 32-bit x86 PAT code uses __set_pmd_pte() to update pmds. This uses pgd_list currently, but we don't need the global list as we can walk the task list under RCU. (This code already holds the pgd_lock.) Cc: Andrew Morton Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Rik van Riel Cc: Thomas Gleixner Cc: Waiman Long Cc: linux-mm@kvack.org Signed-off-by: Ingo Molnar --- arch/x86/mm/pageattr.c | 25 ++++++++++++++++++++++--- 1 file changed, 22 insertions(+), 3 deletions(-) diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index b784ed7c9a7e..bc7533801014 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include @@ -438,18 +439,36 @@ static void __set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte) set_pte_atomic(kpte, pte); #ifdef CONFIG_X86_32 if (!SHARED_KERNEL_PMD) { - struct page *page; + struct task_struct *g; - list_for_each_entry(page, &pgd_list, lru) { + rcu_read_lock(); /* Task list walk */ + + for_each_process(g) { + struct task_struct *p; + struct mm_struct *mm; + spinlock_t *pgt_lock; pgd_t *pgd; pud_t *pud; pmd_t *pmd; - pgd = (pgd_t *)page_address(page) + pgd_index(address); + p = find_lock_task_mm(g); + if (!p) + continue; + + mm = p->mm; + pgt_lock = &mm->page_table_lock; + spin_lock(pgt_lock); + + pgd = mm->pgd + pgd_index(address); pud = pud_offset(pgd, address); pmd = pmd_offset(pud, address); set_pte_atomic((pte_t *)pmd, pte); + + spin_unlock(pgt_lock); + + task_unlock(p); } + rcu_read_unlock(); } #endif } -- 2.1.4