From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752313AbdK0Kw2 (ORCPT ); Mon, 27 Nov 2017 05:52:28 -0500 Received: from mail-wr0-f196.google.com ([209.85.128.196]:43181 "EHLO mail-wr0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752625AbdK0KwH (ORCPT ); Mon, 27 Nov 2017 05:52:07 -0500 X-Google-Smtp-Source: AGs4zMZJES5CcEGoGfMPUBtT1s0cEsKCzd6RftburDEyxKb3iwNqAAra1JHbgHoJ0R9GG+w8h0Sayw== From: Ingo Molnar To: linux-kernel@vger.kernel.org Cc: Dave Hansen , Andy Lutomirski , Thomas Gleixner , "H . Peter Anvin" , Peter Zijlstra , Borislav Petkov , Linus Torvalds Subject: [PATCH 24/24] x86/mm/kaiser: Use the other page_table_lock pattern Date: Mon, 27 Nov 2017 11:49:23 +0100 Message-Id: <20171127104923.14378-25-mingo@kernel.org> X-Mailer: git-send-email 2.14.1 In-Reply-To: <20171127104923.14378-1-mingo@kernel.org> References: <20171127104923.14378-1-mingo@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Peter Zijlstra Use the other page_table_lock pattern; this removes the free from under the lock, reducing worst case hold times and makes it a leaf lock. Signed-off-by: Peter Zijlstra (Intel) Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Dave Hansen Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20171127085906.uth5hldrtbbqsnkr@hirez.programming.kicks-ass.net Signed-off-by: Ingo Molnar --- arch/x86/mm/kaiser.c | 24 +++++++++++++++--------- 1 file changed, 15 insertions(+), 9 deletions(-) diff --git a/arch/x86/mm/kaiser.c b/arch/x86/mm/kaiser.c index 0282169ede18..0ff502fa655b 100644 --- a/arch/x86/mm/kaiser.c +++ b/arch/x86/mm/kaiser.c @@ -196,11 +196,13 @@ static pte_t *kaiser_shadow_pagetable_walk(unsigned long address, return NULL; spin_lock(&shadow_table_allocation_lock); - if (p4d_none(*p4d)) + if (p4d_none(*p4d)) { set_p4d(p4d, __p4d(_KERNPG_TABLE | __pa(new_pud_page))); - else - free_page(new_pud_page); + new_pud_page = 0; + } spin_unlock(&shadow_table_allocation_lock); + if (new_pud_page) + free_page(new_pud_page); } pud = pud_offset(p4d, address); @@ -215,11 +217,13 @@ static pte_t *kaiser_shadow_pagetable_walk(unsigned long address, return NULL; spin_lock(&shadow_table_allocation_lock); - if (pud_none(*pud)) + if (pud_none(*pud)) { set_pud(pud, __pud(_KERNPG_TABLE | __pa(new_pmd_page))); - else - free_page(new_pmd_page); + new_pmd_page = 0; + } spin_unlock(&shadow_table_allocation_lock); + if (new_pmd_page) + free_page(new_pmd_page); } pmd = pmd_offset(pud, address); @@ -234,11 +238,13 @@ static pte_t *kaiser_shadow_pagetable_walk(unsigned long address, return NULL; spin_lock(&shadow_table_allocation_lock); - if (pmd_none(*pmd)) + if (pmd_none(*pmd)) { set_pmd(pmd, __pmd(_KERNPG_TABLE | __pa(new_pte_page))); - else - free_page(new_pte_page); + new_pte_page = 0; + } spin_unlock(&shadow_table_allocation_lock); + if (new_pte_page) + free_page(new_pte_page); } pte = pte_offset_kernel(pmd, address); -- 2.14.1