From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DE1ECC433EF for ; Fri, 15 Oct 2021 02:31:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C0A49610D1 for ; Fri, 15 Oct 2021 02:31:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235078AbhJOCd1 (ORCPT ); Thu, 14 Oct 2021 22:33:27 -0400 Received: from szxga02-in.huawei.com ([45.249.212.188]:24318 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231730AbhJOCd0 (ORCPT ); Thu, 14 Oct 2021 22:33:26 -0400 Received: from dggemv703-chm.china.huawei.com (unknown [172.30.72.56]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4HVqsP2BGZzRfBJ; Fri, 15 Oct 2021 10:26:49 +0800 (CST) Received: from dggpemm500002.china.huawei.com (7.185.36.229) by dggemv703-chm.china.huawei.com (10.3.19.46) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.8; Fri, 15 Oct 2021 10:31:18 +0800 Received: from [10.174.178.178] (10.174.178.178) by dggpemm500002.china.huawei.com (7.185.36.229) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.8; Fri, 15 Oct 2021 10:31:18 +0800 Message-ID: Date: Fri, 15 Oct 2021 10:31:17 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.0.3 Subject: Re: [PATCH] mm/vmalloc: fix numa spreading for large hash tables To: Nicholas Piggin , Shakeel Butt CC: Andrew Morton , Eric Dumazet , , LKML , Linux MM , Kefeng Wang References: <20210928121040.2547407-1-chenwandun@huawei.com> <8fc5e1ae-a356-6225-2e50-cf0e5ee26208@huawei.com> <1634261360.fed2opbgxw.astroid@bobo.none> From: Chen Wandun In-Reply-To: <1634261360.fed2opbgxw.astroid@bobo.none> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.178.178] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To dggpemm500002.china.huawei.com (7.185.36.229) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2021/10/15 9:34, Nicholas Piggin 写道: > Excerpts from Chen Wandun's message of October 14, 2021 6:59 pm: >> >> >> 在 2021/10/14 5:46, Shakeel Butt 写道: >>> On Tue, Sep 28, 2021 at 5:03 AM Chen Wandun wrote: >>>> >>>> Eric Dumazet reported a strange numa spreading info in [1], and found >>>> commit 121e6f3258fe ("mm/vmalloc: hugepage vmalloc mappings") introduced >>>> this issue [2]. >>>> >>>> Dig into the difference before and after this patch, page allocation has >>>> some difference: >>>> >>>> before: >>>> alloc_large_system_hash >>>> __vmalloc >>>> __vmalloc_node(..., NUMA_NO_NODE, ...) >>>> __vmalloc_node_range >>>> __vmalloc_area_node >>>> alloc_page /* because NUMA_NO_NODE, so choose alloc_page branch */ >>>> alloc_pages_current >>>> alloc_page_interleave /* can be proved by print policy mode */ >>>> >>>> after: >>>> alloc_large_system_hash >>>> __vmalloc >>>> __vmalloc_node(..., NUMA_NO_NODE, ...) >>>> __vmalloc_node_range >>>> __vmalloc_area_node >>>> alloc_pages_node /* choose nid by nuam_mem_id() */ >>>> __alloc_pages_node(nid, ....) >>>> >>>> So after commit 121e6f3258fe ("mm/vmalloc: hugepage vmalloc mappings"), >>>> it will allocate memory in current node instead of interleaving allocate >>>> memory. >>>> >>>> [1] >>>> https://lore.kernel.org/linux-mm/CANn89iL6AAyWhfxdHO+jaT075iOa3XcYn9k6JJc7JR2XYn6k_Q@mail.gmail.com/ >>>> >>>> [2] >>>> https://lore.kernel.org/linux-mm/CANn89iLofTR=AK-QOZY87RdUZENCZUT4O6a0hvhu3_EwRMerOg@mail.gmail.com/ >>>> >>>> Fixes: 121e6f3258fe ("mm/vmalloc: hugepage vmalloc mappings") >>>> Reported-by: Eric Dumazet >>>> Signed-off-by: Chen Wandun >>>> --- >>>> mm/vmalloc.c | 33 ++++++++++++++++++++++++++------- >>>> 1 file changed, 26 insertions(+), 7 deletions(-) >>>> >>>> diff --git a/mm/vmalloc.c b/mm/vmalloc.c >>>> index f884706c5280..48e717626e94 100644 >>>> --- a/mm/vmalloc.c >>>> +++ b/mm/vmalloc.c >>>> @@ -2823,6 +2823,8 @@ vm_area_alloc_pages(gfp_t gfp, int nid, >>>> unsigned int order, unsigned int nr_pages, struct page **pages) >>>> { >>>> unsigned int nr_allocated = 0; >>>> + struct page *page; >>>> + int i; >>>> >>>> /* >>>> * For order-0 pages we make use of bulk allocator, if >>>> @@ -2833,6 +2835,7 @@ vm_area_alloc_pages(gfp_t gfp, int nid, >>>> if (!order) { >>> >>> Can you please replace the above with if (!order && nid != NUMA_NO_NODE)? >>> >>>> while (nr_allocated < nr_pages) { >>>> unsigned int nr, nr_pages_request; >>>> + page = NULL; >>>> >>>> /* >>>> * A maximum allowed request is hard-coded and is 100 >>>> @@ -2842,9 +2845,23 @@ vm_area_alloc_pages(gfp_t gfp, int nid, >>>> */ >>>> nr_pages_request = min(100U, nr_pages - nr_allocated); >>>> >>> >>> Undo the following change in this if block. >> >> Yes, It seem like more simpler as you suggested, But it still have >> performance regression, I plan to change the following to consider >> both mempolcy and alloc_pages_bulk. > > Thanks for finding and debugging this. These APIs are a maze of twisty > little passages, all alike so I could be as confused as I was when I > wrote that patch, but doesn't a minimal fix look something like this? Yes, I sent a patch，it looks like as you show, besides it also contains some performance optimization. [PATCH] mm/vmalloc: introduce alloc_pages_bulk_array_mempolicy to accelerate memory allocation Thanks, Wandun > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index d77830ff604c..75ee9679f521 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -2860,7 +2860,10 @@ vm_area_alloc_pages(gfp_t gfp, int nid, > struct page *page; > int i; > > - page = alloc_pages_node(nid, gfp, order); > + if (nid == NUMA_NO_NODE) > + page = alloc_pages(gfp, order); > + else > + page = alloc_pages_node(nid, gfp, order); > if (unlikely(!page)) > break; > > > Thanks, > Nick > . >