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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id DC464C636D3 for ; Tue, 31 Jan 2023 15:16:16 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 783206B0074; Tue, 31 Jan 2023 10:16:16 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 7338B6B0075; Tue, 31 Jan 2023 10:16:16 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5AD5B6B0078; Tue, 31 Jan 2023 10:16:16 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 42EB96B0074 for ; Tue, 31 Jan 2023 10:16:16 -0500 (EST) Received: from smtpin29.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 0E6BB80907 for ; Tue, 31 Jan 2023 15:16:16 +0000 (UTC) X-FDA: 80415445152.29.8FFD781 Received: from mail-vs1-f47.google.com (mail-vs1-f47.google.com [209.85.217.47]) by imf30.hostedemail.com (Postfix) with ESMTP id 4A6258001C for ; Tue, 31 Jan 2023 15:16:14 +0000 (UTC) Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b="JtZQ/lBm"; spf=pass (imf30.hostedemail.com: domain of glider@google.com designates 209.85.217.47 as permitted sender) smtp.mailfrom=glider@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1675178174; h=from:from:sender: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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=hqSkLxxkS4WxXckkEqwqJ2FoqZVZdDRCF2SZ/0LGP88=; b=aPwEs1zepXfJZWYC9etETt08CEqmKZxv5NihMn8zKID3nf0tnK28gQK4UumlW1oqM7MN/f ltBvY2F4cA+Fzmf66UX0Dm2jWEFBIzsONGv+7XyYjYyrlY7g1gDCxDt2rWcYVtZC52GXOC f/MzlQUGzcsO8omS3JWpXucb56Tfxzc= ARC-Authentication-Results: i=1; imf30.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b="JtZQ/lBm"; spf=pass (imf30.hostedemail.com: domain of glider@google.com designates 209.85.217.47 as permitted sender) smtp.mailfrom=glider@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1675178174; a=rsa-sha256; cv=none; b=jaHC1BeDQZxxqQcPQSBpqWhd4QYq6Z17EqHe7vQ8ZK/qZzGpUcTSVwmhVvBZTSoFr2fhZO K+d7M5tskno8QqJCFIBfUGvFlBrAPejFnCq1+OL1BhLIfFRozjG7GW5qzR+yH3OMI7AkRZ OH0PjsuvDljUc4pCyVbd858CalKD7EQ= Received: by mail-vs1-f47.google.com with SMTP id d66so16348259vsd.9 for ; Tue, 31 Jan 2023 07:16:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=hqSkLxxkS4WxXckkEqwqJ2FoqZVZdDRCF2SZ/0LGP88=; b=JtZQ/lBmt1byjRUtXNuodezmFLI68Y4U1n9cV4QC89Jrp7zRN+opOXcshCLau26tiK Nd7XZH0XhmPh/ylPrymz6yitRCTAk77brQH6Y7T9Rwe3+PBn1kmbTPPEa5n39WSpbPC/ 3UVWX2vsjw2pYxx03h0V6D3FqfEWNxMiI4V+1HfBhQ7IPqlBbu3/6JtPVaSx9TOUQRxf 2mhIwkexBZz2BsG43yqbCb10cc/be7/cOMguEs3i6vHqPgytYuZugK70wSwuExWwjz2Y zsQhqw+EG63ShEJ2r0cpRtXL/S2Fd3ulNRqK5Gi2R4vnSEqOzBBhRqgx2w0+r7or3E81 nYJQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=hqSkLxxkS4WxXckkEqwqJ2FoqZVZdDRCF2SZ/0LGP88=; b=s/zG1SLiJL8XBVxuZ8D9IoIyJ62hHl6Nfnc82aC42YRYnHKsV9P1zuWp9IT94j/xmF RnGwXnoFz4d3aXlrVx0tEIqrkTx+jPthLBQuFw5BCy5KgRlegdw28ajJBP2tQbkUg8a8 Sg/96WYgVPkwzyCXKMuIV8I/fwnYnuSqM8WMzidgG/sRwgmIAGP9817Qn7dIG0iaiNUf eB4XcuS67VEf8+ooXpRcBqgh57CY4vOdg60HqUD0PhB1U09sUwJ5yvwEHOjvEaUmMmtP ENBXtbnICvLhfE9ezNtV4hwEPbgrxWoMFZITT+qF7M3fJ5TBPDzWzkPIDoNSPi0a0B67 GSbw== X-Gm-Message-State: AO0yUKW2VKZ6o/z74SuXDsIrNnx7AuS60iKWkcBZB9/pExYOIz8EN5mQ fVH2YcDNKghsd8VVcQQvZC+vHU8bEKyRNRKW1DiWlw== X-Google-Smtp-Source: AK7set9TuI801MQUIobSqj1yTStH7qsNvDVpmcS4/LrfPrPNvx2T47lNeSF2Vu2NdDktr05dS0mA/2X+cH7Q7NH14kc= X-Received: by 2002:a67:c31e:0:b0:3ed:1e92:a87f with SMTP id r30-20020a67c31e000000b003ed1e92a87fmr2427528vsj.1.1675178173210; Tue, 31 Jan 2023 07:16:13 -0800 (PST) MIME-Version: 1.0 References: <167467815773.463042.7022545814443036382.stgit@dwillia2-xfh.jf.intel.com> In-Reply-To: <167467815773.463042.7022545814443036382.stgit@dwillia2-xfh.jf.intel.com> From: Alexander Potapenko Date: Tue, 31 Jan 2023 16:15:36 +0100 Message-ID: Subject: Re: [PATCH v2] nvdimm: Support sizeof(struct page) > MAX_STRUCT_PAGE_SIZE To: Dan Williams Cc: nvdimm@lists.linux.dev, stable@vger.kernel.org, Marco Elver , Jeff Moyer , linux-mm@kvack.org, kasan-dev@googlegroups.com, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, gregkh@linuxfoundation.org Content-Type: text/plain; charset="UTF-8" X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 4A6258001C X-Stat-Signature: mj4c3d4pzq9jg34e9mi91ihdohh7hraq X-HE-Tag: 1675178174-289815 X-HE-Meta: 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 Eh326nUu qpI3A1i88Ek2Tj9igFVwLDzWzFptCrjx27IeGzSUOMPdxg0LxEmBpRaYDPtImdZ4bLQ3JEgwrYnCzzVKSiqadqPIjUTzBfRScszfCBGxmdJNvM4uB5AgKtcxERON9UqoEyJcZCROly32L96mY7Yng920wcBWQ89GLgFEVoLCMrcq2y/HY+xTEeO/hAps8B4ZuOY5tfkJBIDEX28WEMiHzpMXoALzqFf7QyOSbRZxEeVEjIiQva9jRapUp0KktLGC6/Axgau9rF2fcFXuT3kqTay1OO7XAzEzWHrOsgrXicB24XnQRcohNtDfLwuDLO/hUpVfnHeEjIiP0IejkioHpghcKWrDBpXOnnoooEuM9fYm9UXx23ExeD6IsdIAx9kuJFRLGYVDPWECSzqncPv//v5gYSm+pj2fl3SVI 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: On Wed, Jan 25, 2023 at 9:23 PM Dan Williams wrote: > > Commit 6e9f05dc66f9 ("libnvdimm/pfn_dev: increase MAX_STRUCT_PAGE_SIZE") > > ...updated MAX_STRUCT_PAGE_SIZE to account for sizeof(struct page) > potentially doubling in the case of CONFIG_KMSAN=y. Unfortunately this > doubles the amount of capacity stolen from user addressable capacity for > everyone, regardless of whether they are using the debug option. Revert > that change, mandate that MAX_STRUCT_PAGE_SIZE never exceed 64, but > allow for debug scenarios to proceed with creating debug sized page maps > with a compile option to support debug scenarios. > > Note that this only applies to cases where the page map is permanent, > i.e. stored in a reservation of the pmem itself ("--map=dev" in "ndctl > create-namespace" terms). For the "--map=mem" case, since the allocation > is ephemeral for the lifespan of the namespace, there are no explicit > restriction. However, the implicit restriction, of having enough > available "System RAM" to store the page map for the typically large > pmem, still applies. > > Fixes: 6e9f05dc66f9 ("libnvdimm/pfn_dev: increase MAX_STRUCT_PAGE_SIZE") > Cc: > Cc: Alexander Potapenko > Cc: Marco Elver > Reported-by: Jeff Moyer Acked-by: Alexander Potapenko