From patchwork Sun Mar 22 01:22:41 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 11451529 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9B4A11392 for ; Sun, 22 Mar 2020 01:22:45 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5AB9A20757 for ; Sun, 22 Mar 2020 01:22:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="WQeCG085" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5AB9A20757 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 44BE56B0032; Sat, 21 Mar 2020 21:22:44 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 3FBDC6B0036; Sat, 21 Mar 2020 21:22:44 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 33BC96B0037; Sat, 21 Mar 2020 21:22:44 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0140.hostedemail.com [216.40.44.140]) by kanga.kvack.org (Postfix) with ESMTP id 1CB846B0032 for ; Sat, 21 Mar 2020 21:22:44 -0400 (EDT) Received: from smtpin14.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id D9891180AD815 for ; Sun, 22 Mar 2020 01:22:43 +0000 (UTC) X-FDA: 76621248606.14.crown80_17cb5f6bdbe50 X-Spam-Summary: 2,0,0,29ba9f8e2b9a29a5,d41d8cd98f00b204,akpm@linux-foundation.org,,RULES_HIT:2:41:355:379:800:960:966:967:968:973:988:989:1260:1263:1345:1359:1381:1431:1437:1535:1605:1730:1747:1777:1792:2196:2199:2393:2525:2559:2565:2682:2685:2859:2902:2933:2937:2939:2942:2945:2947:2951:2954:3022:3138:3139:3140:3141:3142:3167:3503:3504:3865:3866:3867:3868:3870:3871:3872:3874:3934:3936:3938:3941:3944:3947:3950:3953:3956:3959:4037:4049:4118:4250:4321:4385:4605:5007:6117:6119:6261:6653:6737:7576:7903:8599:8660:9010:9025:9040:9545:10004:10913:11026:11473:11658:11914:12043:12048:12291:12296:12297:12438:12517:12519:12555:12663:12679:12783:12986:13141:13148:13161:13221:13229:13230:13846:13972:21080:21451:21627:21740:21939:21990:30003:30054:30064:30070,0,RBL:198.145.29.99:@linux-foundation.org:.lbl8.mailshell.net-62.2.0.100 64.100.201.201,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fp,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:1,LUA_SUMMARY:none X-HE-Tag: crown80_17cb5f6bdbe50 X-Filterd-Recvd-Size: 7585 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf42.hostedemail.com (Postfix) with ESMTP for ; Sun, 22 Mar 2020 01:22:43 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1353520776; Sun, 22 Mar 2020 01:22:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584840162; bh=9fT8MyMAwfLnaCndlC3OQbRwEl4FqN8HcbT6QN8u3Qs=; h=Date:From:To:Subject:In-Reply-To:From; b=WQeCG0852wBnFTWz8KV8wYqXsRIlPoE62NWhjs8R0MEkaH/1BzWvhMpP/amnXi46g QJxA1xgsDbvD0KQlAyHvtsiexutOMU3PgIvWXqUoaRt1nzoEa9peoRgvYDU34SXnuq 65W97lpM7ZBpfVyO4aZF615u0iqYJcFBFmsneDes= Date: Sat, 21 Mar 2020 18:22:41 -0700 From: Andrew Morton To: akpm@linux-foundation.org, bp@suse.de, dave.hansen@linux.intel.com, jroedel@suse.de, linux-mm@kvack.org, luto@kernel.org, mingo@redhat.com, mm-commits@vger.kernel.org, oliver.sang@intel.com, peterz@infradead.org, rafael.j.wysocki@intel.com, shile.zhang@linux.alibaba.com, stable@vger.kernel.org, tglx@linutronix.de, torvalds@linux-foundation.org Subject: [patch 10/10] x86/mm: split vmalloc_sync_all() Message-ID: <20200322012241.7AfzulcPB%akpm@linux-foundation.org> In-Reply-To: <20200321181954.c0564dfd5514cd742b534884@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Joerg Roedel Subject: x86/mm: split vmalloc_sync_all() Commit 3f8fd02b1bf1 ("mm/vmalloc: Sync unmappings in __purge_vmap_area_lazy()") introduced a call to vmalloc_sync_all() in the vunmap() code-path. While this change was necessary to maintain correctness on x86-32-pae kernels, it also adds additional cycles for architectures that don't need it. Specifically on x86-64 with CONFIG_VMAP_STACK=y some people reported severe performance regressions in micro-benchmarks because it now also calls the x86-64 implementation of vmalloc_sync_all() on vunmap(). But the vmalloc_sync_all() implementation on x86-64 is only needed for newly created mappings. To avoid the unnecessary work on x86-64 and to gain the performance back, split up vmalloc_sync_all() into two functions: * vmalloc_sync_mappings(), and * vmalloc_sync_unmappings() Most call-sites to vmalloc_sync_all() only care about new mappings being synchronized. The only exception is the new call-site added in the above mentioned commit. Shile Zhang directed us to a report of an 80% regression in reaim throughput. Link: http://lkml.kernel.org/r/20191009124418.8286-1-joro@8bytes.org Link: https://lists.01.org/hyperkitty/list/lkp@lists.01.org/thread/4D3JPPHBNOSPFK2KEPC6KGKS6J25AIDB/ Link: http://lkml.kernel.org/r/20191113095530.228959-1-shile.zhang@linux.alibaba.com Fixes: 3f8fd02b1bf1 ("mm/vmalloc: Sync unmappings in __purge_vmap_area_lazy()") Signed-off-by: Joerg Roedel Reported-by: kernel test robot Reported-by: Shile Zhang Acked-by: Rafael J. Wysocki [GHES] Tested-by: Borislav Petkov Cc: Dave Hansen Cc: Andy Lutomirski Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Signed-off-by: Andrew Morton --- arch/x86/mm/fault.c | 26 ++++++++++++++++++++++++-- drivers/acpi/apei/ghes.c | 2 +- include/linux/vmalloc.h | 5 +++-- kernel/notifier.c | 2 +- mm/nommu.c | 10 +++++++--- mm/vmalloc.c | 11 +++++++---- 6 files changed, 43 insertions(+), 13 deletions(-) --- a/arch/x86/mm/fault.c~x86-mm-split-vmalloc_sync_all +++ a/arch/x86/mm/fault.c @@ -190,7 +190,7 @@ static inline pmd_t *vmalloc_sync_one(pg return pmd_k; } -void vmalloc_sync_all(void) +static void vmalloc_sync(void) { unsigned long address; @@ -217,6 +217,16 @@ void vmalloc_sync_all(void) } } +void vmalloc_sync_mappings(void) +{ + vmalloc_sync(); +} + +void vmalloc_sync_unmappings(void) +{ + vmalloc_sync(); +} + /* * 32-bit: * @@ -319,11 +329,23 @@ out: #else /* CONFIG_X86_64: */ -void vmalloc_sync_all(void) +void vmalloc_sync_mappings(void) { + /* + * 64-bit mappings might allocate new p4d/pud pages + * that need to be propagated to all tasks' PGDs. + */ sync_global_pgds(VMALLOC_START & PGDIR_MASK, VMALLOC_END); } +void vmalloc_sync_unmappings(void) +{ + /* + * Unmappings never allocate or free p4d/pud pages. + * No work is required here. + */ +} + /* * 64-bit: * --- a/drivers/acpi/apei/ghes.c~x86-mm-split-vmalloc_sync_all +++ a/drivers/acpi/apei/ghes.c @@ -171,7 +171,7 @@ int ghes_estatus_pool_init(int num_ghes) * New allocation must be visible in all pgd before it can be found by * an NMI allocating from the pool. */ - vmalloc_sync_all(); + vmalloc_sync_mappings(); rc = gen_pool_add(ghes_estatus_pool, addr, PAGE_ALIGN(len), -1); if (rc) --- a/include/linux/vmalloc.h~x86-mm-split-vmalloc_sync_all +++ a/include/linux/vmalloc.h @@ -141,8 +141,9 @@ extern int remap_vmalloc_range_partial(s extern int remap_vmalloc_range(struct vm_area_struct *vma, void *addr, unsigned long pgoff); -void vmalloc_sync_all(void); - +void vmalloc_sync_mappings(void); +void vmalloc_sync_unmappings(void); + /* * Lowlevel-APIs (not for driver use!) */ --- a/kernel/notifier.c~x86-mm-split-vmalloc_sync_all +++ a/kernel/notifier.c @@ -519,7 +519,7 @@ NOKPROBE_SYMBOL(notify_die); int register_die_notifier(struct notifier_block *nb) { - vmalloc_sync_all(); + vmalloc_sync_mappings(); return atomic_notifier_chain_register(&die_chain, nb); } EXPORT_SYMBOL_GPL(register_die_notifier); --- a/mm/nommu.c~x86-mm-split-vmalloc_sync_all +++ a/mm/nommu.c @@ -370,10 +370,14 @@ void vm_unmap_aliases(void) EXPORT_SYMBOL_GPL(vm_unmap_aliases); /* - * Implement a stub for vmalloc_sync_all() if the architecture chose not to - * have one. + * Implement a stub for vmalloc_sync_[un]mapping() if the architecture + * chose not to have one. */ -void __weak vmalloc_sync_all(void) +void __weak vmalloc_sync_mappings(void) +{ +} + +void __weak vmalloc_sync_unmappings(void) { } --- a/mm/vmalloc.c~x86-mm-split-vmalloc_sync_all +++ a/mm/vmalloc.c @@ -1295,7 +1295,7 @@ static bool __purge_vmap_area_lazy(unsig * First make sure the mappings are removed from all page-tables * before they are freed. */ - vmalloc_sync_all(); + vmalloc_sync_unmappings(); /* * TODO: to calculate a flush range without looping. @@ -3128,16 +3128,19 @@ int remap_vmalloc_range(struct vm_area_s EXPORT_SYMBOL(remap_vmalloc_range); /* - * Implement a stub for vmalloc_sync_all() if the architecture chose not to - * have one. + * Implement stubs for vmalloc_sync_[un]mappings () if the architecture chose + * not to have one. * * The purpose of this function is to make sure the vmalloc area * mappings are identical in all page-tables in the system. */ -void __weak vmalloc_sync_all(void) +void __weak vmalloc_sync_mappings(void) { } +void __weak vmalloc_sync_unmappings(void) +{ +} static int f(pte_t *pte, unsigned long addr, void *data) {