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=-5.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 F3427C433DB for ; Tue, 2 Feb 2021 14:44:08 +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 A7F1664ED7 for ; Tue, 2 Feb 2021 14:44:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A7F1664ED7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.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-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:Subject: From:References:To:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=xYFMSrrOMVEUDEUazxQVf89Bo5MoTZsvQIxmbQUxgjg=; b=I52T0ZcbkDwZ52Yd0oZxALNfU B8ASF8VumDIq1EOEf9HRBaLmb8Cp+uEGzUTVfv/N4JKAimooYwMBYXZwNfejVlx7B7dBM9WAgoXdx ZECCQv09bXxe7vG4Xbkxl/sKfH87my4AuOQJcdz18GAvno/+7W8sT5ol8QrpWchb5j5E5p1Utu3SZ ZMMvlxyWEi3Gd/FXjWid/zxPNFcpF5BwF7s0QxprzOEfZLrg85dMf18UjpC4ta4B1o2DCwCMmMyKo 9E3JNholDFeoASGTt5IVE5K01bW4qZ5zMosUpOg8+8PJQ1KtOWaoiAkFGB/xUvlYxvMQSbO6TwBV9 IVqzbnCHg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l6wtN-0002fT-Lt; Tue, 02 Feb 2021 14:42:57 +0000 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1l6wtK-0002eZ-MM for linux-arm-kernel@lists.infradead.org; Tue, 02 Feb 2021 14:42:55 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612276974; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=p9WVcjtJGSRM6w7F2m39UE8iZCliMcHMPGNuV986qrI=; b=OQo3i10NkK88wXMNXEXmca0BBgYvMgB4aFbJSf0m52DHmfo1XJm2rYtfET6sk+Vc4FE8bC dw8U/PVY0/csMZsHyU3g1o+hhwBOxQAAIT51769OIMxg5xCAw2KRFVBDHOP0s+PC4M6iUr 65LJvmG5s0DHRvV5gms9g+KHUTiST+0= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-521-8AQi4yF_NHCuVEWiuakmOQ-1; Tue, 02 Feb 2021 09:42:42 -0500 X-MC-Unique: 8AQi4yF_NHCuVEWiuakmOQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 46BB9184DBED; Tue, 2 Feb 2021 14:42:36 +0000 (UTC) Received: from [10.36.114.148] (ovpn-114-148.ams2.redhat.com [10.36.114.148]) by smtp.corp.redhat.com (Postfix) with ESMTP id 36D6560916; Tue, 2 Feb 2021 14:42:28 +0000 (UTC) To: Michal Hocko , Mike Rapoport References: <20210121122723.3446-1-rppt@kernel.org> <20210121122723.3446-8-rppt@kernel.org> <20210126114657.GL827@dhcp22.suse.cz> <303f348d-e494-e386-d1f5-14505b5da254@redhat.com> <20210126120823.GM827@dhcp22.suse.cz> <20210128092259.GB242749@kernel.org> <20210129072128.GD242749@kernel.org> From: David Hildenbrand Organization: Red Hat GmbH Subject: Re: [PATCH v16 07/11] secretmem: use PMD-size pages to amortize direct map fragmentation Message-ID: Date: Tue, 2 Feb 2021 15:42:26 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.5.0 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210202_094254_778545_A42AF9E2 X-CRM114-Status: GOOD ( 21.04 ) 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 , Peter Zijlstra , Catalin Marinas , Dave Hansen , linux-mm@kvack.org, linux-kselftest@vger.kernel.org, "H. Peter Anvin" , Christopher Lameter , Shuah Khan , Thomas Gleixner , Elena Reshetova , linux-arch@vger.kernel.org, Tycho Andersen , linux-nvdimm@lists.01.org, Will Deacon , x86@kernel.org, Matthew Wilcox , Mike Rapoport , Ingo Molnar , Michael Kerrisk , Palmer Dabbelt , Arnd Bergmann , James Bottomley , Hagen Paul Pfeifer , Borislav Petkov , Alexander Viro , Andy Lutomirski , Paul Walmsley , "Kirill A. Shutemov" , Dan Williams , linux-arm-kernel@lists.infradead.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, Palmer Dabbelt , linux-fsdevel@vger.kernel.org, Shakeel Butt , Andrew Morton , Rick Edgecombe , Roman Gushchin Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 29.01.21 09:51, Michal Hocko wrote: > On Fri 29-01-21 09:21:28, Mike Rapoport wrote: >> On Thu, Jan 28, 2021 at 02:01:06PM +0100, Michal Hocko wrote: >>> On Thu 28-01-21 11:22:59, Mike Rapoport wrote: >>> >>>> And hugetlb pools may be also depleted by anybody by calling >>>> mmap(MAP_HUGETLB) and there is no any limiting knob for this, while >>>> secretmem has RLIMIT_MEMLOCK. >>> >>> Yes it can fail. But it would fail at the mmap time when the reservation >>> fails. Not during the #PF time which can be at any time. >> >> It may fail at $PF time as well: >> >> hugetlb_fault() >> hugeltb_no_page() >> ... >> alloc_huge_page() >> alloc_gigantic_page() >> cma_alloc() >> -ENOMEM; > > I would have to double check. From what I remember cma allocator is an > optimization to increase chances to allocate hugetlb pages when > overcommiting because pages should be normally pre-allocated in the pool > and reserved during mmap time. But even if a hugetlb page is not pre > allocated then this will get propagated as SIGBUS unless that has > changed. It's an optimization to allocate gigantic pages dynamically later (so not using memblock during boot). Not just for overcommit, but for any kind of allocation. The actual allocation from cma should happen when setting nr_pages: nr_hugepages_store_common()->set_max_huge_pages()->alloc_pool_huge_page()...->alloc_gigantic_page() The path described above seems to be trying to overcommit gigantic pages, something that can be expected to SIGBUS. Reservations are handled via the pre-allocated pool. -- Thanks, David / dhildenb _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel