From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from out30-132.freemail.mail.aliyun.com ([115.124.30.132]:42493 "EHLO out30-132.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726155AbfKMJzq (ORCPT ); Wed, 13 Nov 2019 04:55:46 -0500 From: Shile Zhang Subject: [PATCH] mm/vmalloc: Fix regression caused by needless vmalloc_sync_all() Date: Wed, 13 Nov 2019 17:55:30 +0800 Message-Id: <20191113095530.228959-1-shile.zhang@linux.alibaba.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kbuild-owner@vger.kernel.org List-ID: To: Andrew Morton , Joerg Roedel Cc: linux-mm@kvack.org, linux-kbuild@vger.kernel.org, Shile Zhang vmalloc_sync_all() was put in the common path in __purge_vmap_area_lazy(), for one sync issue only happened on X86_32 with PTI enabled. It is needless for X86_64, which caused a big regression in UnixBench Shell8 testing on X86_64. Similar regression also reported by 0-day kernel test robot in reaim benchmarking: https://lists.01.org/hyperkitty/list/lkp@lists.01.org/thread/4D3JPPHBNOSPFK2KEPC6KGKS6J25AIDB/ Fix it by adding more conditions. Fixes: 3f8fd02b1bf1 ("mm/vmalloc: Sync unmappings in __purge_vmap_area_lazy()") Signed-off-by: Shile Zhang --- mm/vmalloc.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index a3c70e275f4e..7b9fc7966da6 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -1255,11 +1255,17 @@ static bool __purge_vmap_area_lazy(unsigned long start, unsigned long end) if (unlikely(valist == NULL)) return false; +#if defined(CONFIG_X86_32) && defined(CONFIG_X86_PAE) /* * First make sure the mappings are removed from all page-tables * before they are freed. + * + * This is only needed on x86-32 with !SHARED_KERNEL_PMD, which is + * the case on a PAE kernel with PTI enabled. */ - vmalloc_sync_all(); + if (!SHARED_KERNEL_PMD && boot_cpu_has(X86_FEATURE_PTI)) + vmalloc_sync_all(); +#endif /* * TODO: to calculate a flush range without looping. -- 2.24.0.rc2