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=-9.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 CD903C433E7 for ; Thu, 15 Oct 2020 00:54:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 83F3222242 for ; Thu, 15 Oct 2020 00:54:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="cQ47C5YF" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729045AbgJOAyT (ORCPT ); Wed, 14 Oct 2020 20:54:19 -0400 Received: from z5.mailgun.us ([104.130.96.5]:56312 "EHLO z5.mailgun.us" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726018AbgJOAyS (ORCPT ); Wed, 14 Oct 2020 20:54:18 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1602723258; h=Message-ID: References: In-Reply-To: Subject: Cc: To: From: Date: Content-Transfer-Encoding: Content-Type: MIME-Version: Sender; bh=+HO83zVozbjmjmrTw3BXSFRiDICh8PBslnNPmAVQkMY=; b=cQ47C5YFi8rncif2vBTIzoSZSBKKr2/PJKCEZl0HRdQS/nTFgN/ZFN8QR5tnMdLMOE1Ys1mE 7Nwe9MlAaqClIEjWOJr1pheIHZPQJtp+0H4difaLGoNbERZ+MRGj0VcrSF79/PQOGNNPnUyX 72vNB2zNXrocDFETUihSnqKiTj8= X-Mailgun-Sending-Ip: 104.130.96.5 X-Mailgun-Sid: WyI0MWYwYSIsICJsaW51eC1rZXJuZWxAdmdlci5rZXJuZWwub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n02.prod.us-east-1.postgun.com with SMTP id 5f879dba4f8cc67c31d6f00f (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Thu, 15 Oct 2020 00:54:18 GMT Sender: sudaraja=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id A92AEC433FE; Thu, 15 Oct 2020 00:54:17 +0000 (UTC) Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: sudaraja) by smtp.codeaurora.org (Postfix) with ESMTPSA id D433FC433C9; Thu, 15 Oct 2020 00:54:16 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Wed, 14 Oct 2020 17:54:16 -0700 From: Sudarshan Rajagopalan To: Anshuman Khandual Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Gavin Shan , Catalin Marinas , Will Deacon , Mark Rutland , Logan Gunthorpe , David Hildenbrand , Andrew Morton , Steven Price Subject: Re: [PATCH v3] arm64/mm: add fallback option to allocate virtually contiguous memory In-Reply-To: References: <339118202d0a4741ec22f215830dc8d9ba1ccd49.1602542734.git.sudaraja@codeaurora.org> Message-ID: X-Sender: sudaraja@codeaurora.org User-Agent: Roundcube Webmail/1.3.9 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020-10-13 04:38, Anshuman Khandual wrote: > 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 > Thanks Anshuman for the review. I sent out an updated patch fixing the checkpatch warning. >> >> 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 >> Sudarshan -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project