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 X-Spam-Level: X-Spam-Status: No, score=-11.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B5827C433DF for ; Tue, 13 Oct 2020 11:40:56 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3B25720E65 for ; Tue, 13 Oct 2020 11:40:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="rxgVknoA" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3B25720E65 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=22ZdKe59vWyEFRk+ru81diMAM8DBmq80oMSNA8MN0+I=; b=rxgVknoAqBDT3KVkv7JZcRsVo D0+6QhQhFVVIenWOOg3f9TbQgLqowbQwJV2BSNF0UCd0shpYvs5Y9mdwe2kbuwpsajDL6ZmJOrRoz L2+z3eW4JtkTTJ23OJuz8PdvVRzp58AH7B+ADcipWrkOSAf2SV6ye78bx+sHEh+4R+3oBayPRY2hA 5FiBJAF4vOcbOvppfyzMToWXHMWfl/Bl1TIjUdx8RTvYJk3PRVmEEjb9B1Fp+gzIXdhCabTZAd8DP oUQzz4d2cUTgDIJOIlDTr7Z2s1A8XKJRVDjj64pyXcmVuh7XUP/lQydOJY1sSI+NJEjUqozWcZJt6 eZoYLn+1Q==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kSIed-0005CB-9H; Tue, 13 Oct 2020 11:39:43 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kSIeb-0005BI-Ex for linux-arm-kernel@lists.infradead.org; Tue, 13 Oct 2020 11:39:42 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B34DF1FB; Tue, 13 Oct 2020 04:39:38 -0700 (PDT) Received: from [10.163.75.237] (unknown [10.163.75.237]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id A619F3F719; Tue, 13 Oct 2020 04:39:35 -0700 (PDT) Subject: Re: [PATCH v3] arm64/mm: add fallback option to allocate virtually contiguous memory To: Sudarshan Rajagopalan , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <339118202d0a4741ec22f215830dc8d9ba1ccd49.1602542734.git.sudaraja@codeaurora.org> From: Anshuman Khandual Message-ID: Date: Tue, 13 Oct 2020 17:08:59 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <339118202d0a4741ec22f215830dc8d9ba1ccd49.1602542734.git.sudaraja@codeaurora.org> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201013_073941_557488_E5FE12BE X-CRM114-Status: GOOD ( 22.44 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Gavin Shan , Will Deacon , David Hildenbrand , Catalin Marinas , Steven Price , Andrew Morton , Logan Gunthorpe Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 10/13/2020 04:35 AM, Sudarshan Rajagopalan wrote: > When section mappings are enabled, we allocate vmemmap pages from physically > continuous memory of size PMD_SIZE using vmemmap_alloc_block_buf(). Section > mappings are good to reduce TLB pressure. But when system is highly fragmented > and memory blocks are being hot-added at runtime, its possible that such > physically continuous memory allocations can fail. Rather than failing the > memory hot-add procedure, add a fallback option to allocate vmemmap pages from > discontinuous pages using vmemmap_populate_basepages(). There is a checkpatch warning here, which could be fixed while merging ? WARNING: Possible unwrapped commit description (prefer a maximum 75 chars per line) #7: When section mappings are enabled, we allocate vmemmap pages from physically total: 0 errors, 1 warnings, 13 lines checked > > Signed-off-by: Sudarshan Rajagopalan > Reviewed-by: Gavin Shan > Cc: Catalin Marinas > Cc: Will Deacon > Cc: Anshuman Khandual > Cc: Mark Rutland > Cc: Logan Gunthorpe > Cc: David Hildenbrand > Cc: Andrew Morton > Cc: Steven Price Nonetheless, this looks fine. Did not see any particular problem while creating an experimental vmemmap with interleaving section and base page mapping. Reviewed-by: Anshuman Khandual > --- > arch/arm64/mm/mmu.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > index 75df62fea1b6..44486fd0e883 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c > @@ -1121,8 +1121,11 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, > void *p = NULL; > > p = vmemmap_alloc_block_buf(PMD_SIZE, node, altmap); > - if (!p) > - return -ENOMEM; > + if (!p) { > + if (vmemmap_populate_basepages(addr, next, node, altmap)) > + return -ENOMEM; > + continue; > + } > > pmd_set_huge(pmdp, __pa(p), __pgprot(PROT_SECT_NORMAL)); > } else > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel