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 88C80EB64DA for ; Thu, 29 Jun 2023 01:38:27 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6204F8D0002; Wed, 28 Jun 2023 21:38:26 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5D0858D0001; Wed, 28 Jun 2023 21:38:26 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 497BC8D0002; Wed, 28 Jun 2023 21:38:26 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 3764B8D0001 for ; Wed, 28 Jun 2023 21:38:26 -0400 (EDT) Received: from smtpin04.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id E4B14160AD1 for ; Thu, 29 Jun 2023 01:38:25 +0000 (UTC) X-FDA: 80954075370.04.452F651 Received: from mail-pg1-f182.google.com (mail-pg1-f182.google.com [209.85.215.182]) by imf19.hostedemail.com (Postfix) with ESMTP id AE2B51A0007 for ; Thu, 29 Jun 2023 01:38:23 +0000 (UTC) Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=rivosinc-com.20221208.gappssmtp.com header.s=20221208 header.b=KpJvJ8jT; spf=pass (imf19.hostedemail.com: domain of charlie@rivosinc.com designates 209.85.215.182 as permitted sender) smtp.mailfrom=charlie@rivosinc.com; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1688002703; a=rsa-sha256; cv=none; b=b04mtUeJUan0sBuy8hSUzfmfgMaNVThNNPD/zrA/cglKWQNH03U10HgCjWc53qVybwb3HI 9pizhvs3qZ60cVjVG9alIcE5SgrQ4kriShLKhMyKIEGKXGrhikEnABOxzyMhBtJzcBRdh+ NGyVg6mOtgzUPNAEr+aQDKwRlaTgbgA= ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=pass header.d=rivosinc-com.20221208.gappssmtp.com header.s=20221208 header.b=KpJvJ8jT; spf=pass (imf19.hostedemail.com: domain of charlie@rivosinc.com designates 209.85.215.182 as permitted sender) smtp.mailfrom=charlie@rivosinc.com; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1688002703; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=oTkD0d6a9ryiTvtazmiArPDTMy644oSqj+e8VQliv+Y=; b=ip+qReN/zFzflG9Kh7HaBFSrMp6Z2DQAGvmzP7Zrh5j0M1BkQt8ie7sXbTztjQOdfKGMdU SGut80kfyilHeUyu/dTANNzFMP2L7WIsIu55yHhN4PM69CD+fiQsBMWXj6XKDfzpCbqyrI jGsgqkPwWyu5MxbUGSabzxwvr/q1qkY= Received: by mail-pg1-f182.google.com with SMTP id 41be03b00d2f7-55adfa61199so120848a12.2 for ; Wed, 28 Jun 2023 18:38:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rivosinc-com.20221208.gappssmtp.com; s=20221208; t=1688002702; x=1690594702; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:from:to :cc:subject:date:message-id:reply-to; bh=oTkD0d6a9ryiTvtazmiArPDTMy644oSqj+e8VQliv+Y=; b=KpJvJ8jTi0MYXdSPmYdS2cWuT55tn80Cox9G2xRB90uAn5H8xsr6sSgb2Jo1YcreBT lPxMFbCj5knzwuvCX4HsvoU27uF8PumefIrT7pgGEc7TuZmDZthy8YejthW5JotaZ8j1 YIJ+m7XpeHokGhV/X8hi4HCVO38ZFYbLHr3aCYcrWcvq+lv+//ZUp4jnoZgJITetIuf/ 5KtwK8enoBIZNPm80Rozgwc91uqpnR7whP+cppW8ZGEt6rH7egLHPp56RShF1aPkiBS/ xrcv6xhcH6TOnOOrBWQr1GBrII1Z9qItEF9ajAQpmaIQP74D5uQDTj6gcTPYZyAs15te 7MgQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1688002702; x=1690594702; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=oTkD0d6a9ryiTvtazmiArPDTMy644oSqj+e8VQliv+Y=; b=lj6Z3e1dV+hFrSJ5oRMJ4sWeAEAwZk7wuViggIcl4lve3P577hzXkGKGDRDNzafhO0 uGjlP7F5SqJBpz8YK3Dc4i5waIkkO/9B1+a7TYf99udu2v1lK7XybjAWrQN8afuZCSen xCfLjLTO8JvCQH0CHE4q2mSWZ4wzaRqkPKwRGpR61Oua93suL+oroYMcV/JAjoSo9rGw WvDFac76HfPzeeogmE4Tk7XM1YSiS2YABXD2l9e49vTcYJSyu8NSIExfSwybGIAXnSsD 89yJWwY1YSC28P0XJhaE7xiuM3pUagbHYgBpu98ZB4S9dgBQCdQH3NgJUCamZK8gMIbp F7EQ== X-Gm-Message-State: AC+VfDwEJnn45sLaoY4PxsLcaqisxsXQwnnkR3o3roGyss+m/gjMQLrZ ergnUszORKWGzm8WRN2wRXmByQ== X-Google-Smtp-Source: ACHHUZ4vNfduTE+k0DVsS2q3rr0HoQZvJdXf5nxbxIoAWfAIpvWokoxLXXHfyfVQ9d7RUkGEoHJiPQ== X-Received: by 2002:a17:903:22cf:b0:1b8:16c7:a786 with SMTP id y15-20020a17090322cf00b001b816c7a786mr9241423plg.4.1688002702392; Wed, 28 Jun 2023 18:38:22 -0700 (PDT) Received: from ghost ([50.221.140.188]) by smtp.gmail.com with ESMTPSA id f4-20020a170902e98400b001b53029fef1sm2145668plb.172.2023.06.28.18.38.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 28 Jun 2023 18:38:21 -0700 (PDT) Date: Wed, 28 Jun 2023 18:38:19 -0700 From: Charlie Jenkins To: Anup Patel Cc: Jessica Clarke , Alexandre Ghiti , Atish Patra , Conor Dooley , Paul Walmsley , Palmer Dabbelt , Albert Ou , bjorn@rivosinc.com, Evan Green , linux-riscv , konstantin@linuxfoundation.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 1/2] RISC-V: mm: Restrict address space for sv39,sv48,sv57 Message-ID: References: <20230627222152.177716-1-charlie@rivosinc.com> <20230627222152.177716-2-charlie@rivosinc.com> <473F7474-D7AA-4C9F-95A3-320F1741EC50@jrtc27.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: AE2B51A0007 X-Stat-Signature: qg1ee5oe41ey36qyaz9911pat1cjrj8a X-Rspam-User: X-HE-Tag: 1688002703-394469 X-HE-Meta: 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 +hHJY6HE 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000037, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Jun 28, 2023 at 06:04:41PM +0530, Anup Patel wrote: > On Wed, Jun 28, 2023 at 5:09 AM Charlie Jenkins wrote: > > > > Yes it is small to have a default of 38-bits of userspace. I would be > > interesting in the opinions of other people on whether it would be > > acceptable to have the default be sv48 and require applications that > > prefer fewer bits to specify so with the given mmap hinting. > > I think sv48 is a reasonable default instead of sv39. We should fallback > to sv39 only if the underlying host does not support sv48. > > Regards, > Anup I did some research and it appears that Java does work on sv48, but not on sv57. Using the v6.4 kernel I was able to successfully run OpenJDK on both sv38 and sv48, but on sv57 there is a SIGSEGV error on QEMU. Relevant JDK discussion can be seen here https://mail.openjdk.org/pipermail/hotspot-dev/2022-November/067298.html. Go similarly appears to work even on sv57 according to https://go-review.googlesource.com/c/go/+/409055. I have not tried Go myself. The point of contention here I believe is that in v6.4, the highest address space available will be used, causing all of these applications that do not work properly in sv57 to fail when testing in sv57 environments. Given that these applications seem to work in sv48, it seems reasonable to default to sv48, unless there are an abundance of additional applications that are unhappy with this. Using the hint mechanism to mmap will then allow users to change the address space to sv57 if required. It should be possible to allow users to use sv38 if they need it using the same mechanism, but reducing the address space instead of growing it will require more thought from me to implement. Thanks, Charlie