From owner-svn-src-head@freebsd.org Sun Dec 9 03:43:26 2018 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 704B6133597B for ; Sun, 9 Dec 2018 03:43:26 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: from mail-qt1-x831.google.com (mail-qt1-x831.google.com [IPv6:2607:f8b0:4864:20::831]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id A4A3276E08 for ; Sun, 9 Dec 2018 03:43:25 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: by mail-qt1-x831.google.com with SMTP id e5so8836977qtr.12 for ; Sat, 08 Dec 2018 19:43:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bsdimp-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=6HUKmTDzhqBXb/l97uVcn4S2Ivnf+U9anVR6/fi+uek=; b=VRv2uzhq2WBrrtbXQg64uV1DOs/g2wgCuLjMuFRxD9zxospNM8hXHfBXlKqRS2yQLl DriLg2gZnvaWjajUhPe9mK2breuxNpdqZO70P5nP2I0WnnpLHr/OkW59NuR/ir5GTGFt dtjKpk50RuplzLJXgbPRwJYFnyCaVSv9uJnlXCl+6RisOY4qmOVnlAW8wlh8hMJpnTNJ 115tYPCNhb6F5nubmXV/KZ091gmAR+ESTvjgr+9dt3DZQ6hFt8OYIz/RVpi6XscOrjwN Mu+AoU2soyI3CI4Vl3ERCRp7sFPhyfe0oJhFDxIzuz7Mt6VPkFwbRhsIDSIQtjmvBsIQ 1DEw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=6HUKmTDzhqBXb/l97uVcn4S2Ivnf+U9anVR6/fi+uek=; b=AfdLc5TUBLmzlWEyfRSCag0+qhvNw0zqw4+Ae6dz2iTIl0vKXl8hYt7QdbExIMl1Jp q7ckZZI9QzSnrWIySHpU0j9PvYCIvvbpPhzEfDVX1F5zCbkXoTW2rLfC8gI95SUHNJSq e/5wqMTKcf/fzhuM0W2IGaQOcwhW66h2u5JVl5CRqGgkOwqKRqTd5pbmSQfa6r2eJ2Aa Ci32Gx//4d1K462P/KkEkAz5S60UVWKefcEBA+P/W5YaM1myihMsgCYFdq5bU1q3aTAz 64+MZTy1t/CtBEnnrT+2pq2/vrYHfsc9eJAGQoZqXGKvEJLxWPlJVgkCVEz1F68GORDy xJHw== X-Gm-Message-State: AA+aEWajm2F8WoquGHCc3UzVg0QwILTFk8fg95//jUtfD6Zqhy4OpXaG TYQHcHCHiLSZ86VKm6HOM+Sc9vabpHaCif6Qd5AiKQ== X-Google-Smtp-Source: AFSGD/U2HtIqvvc1BKD8d2sbsHfpa/+5+yQmaZTWLjPalhWogS0ScrFYpblDXZkGyDuEVmhCKjwNokM3J35ngj+JDX0= X-Received: by 2002:ac8:3f2d:: with SMTP id c42mr7517166qtk.33.1544327004907; Sat, 08 Dec 2018 19:43:24 -0800 (PST) MIME-Version: 1.0 References: <201812071205.wB7C5BvA038350@repo.freebsd.org> <1544206201.1860.288.camel@freebsd.org> In-Reply-To: From: Warner Losh Date: Sat, 8 Dec 2018 20:43:12 -0700 Message-ID: Subject: Re: svn commit: r341682 - head/sys/sys To: Kevin Bowling Cc: Mateusz Guzik , Ian Lepore , svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers , scottl@freebsd.org X-Rspamd-Queue-Id: A4A3276E08 X-Spamd-Result: default: False [-4.40 / 15.00]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-0.999,0]; R_DKIM_ALLOW(-0.20)[bsdimp-com.20150623.gappssmtp.com]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; MIME_GOOD(-0.10)[multipart/alternative,text/plain]; PREVIOUSLY_DELIVERED(0.00)[svn-src-head@freebsd.org]; DMARC_NA(0.00)[bsdimp.com]; NEURAL_HAM_SHORT(-0.50)[-0.505,0]; TO_MATCH_ENVRCPT_SOME(0.00)[]; DKIM_TRACE(0.00)[bsdimp-com.20150623.gappssmtp.com:+]; MX_GOOD(-0.01)[ALT1.aspmx.l.google.com,aspmx.l.google.com,ALT2.aspmx.l.google.com]; RCPT_COUNT_SEVEN(0.00)[7]; RCVD_IN_DNSWL_NONE(0.00)[1.3.8.0.0.0.0.0.0.0.0.0.0.0.0.0.0.2.0.0.4.6.8.4.0.b.8.f.7.0.6.2.list.dnswl.org : 127.0.5.0]; R_SPF_NA(0.00)[]; FORGED_SENDER(0.30)[imp@bsdimp.com,wlosh@bsdimp.com]; RCVD_TLS_LAST(0.00)[]; IP_SCORE(-1.89)[ip: (-6.55), ipnet: 2607:f8b0::/32(-1.49), asn: 15169(-1.30), country: US(-0.09)]; ASN(0.00)[asn:15169, ipnet:2607:f8b0::/32, country:US]; FROM_NEQ_ENVFROM(0.00)[imp@bsdimp.com,wlosh@bsdimp.com]; FREEMAIL_CC(0.00)[gmail.com] X-Rspamd-Server: mx1.freebsd.org Content-Type: text/plain; charset="UTF-8" X-Content-Filtered-By: Mailman/MimeDel 2.1.29 X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 09 Dec 2018 03:43:26 -0000 On Sat, Dec 8, 2018, 8:36 PM Kevin Bowling On Sat, Dec 8, 2018 at 12:09 AM Mateusz Guzik wrote: > > > > > Fully satisfying solution would be that all architectures get 64-bit > > ops, even if in the worst case they end up taking a lock. Then > > subsystems would not have to ifdef on anything. However, there > > was some opposition to this proposal and I don't think this is > > important enough to push. > > Mateusz, > > Who is opposing this particular polyfill solution? Scott Long brought > up a situation in driver development where this would be useful as > well. The polyfills lower the cognitive load and #ifdef soup which > are the right call here regardless of performance on toy ports. > I don't recall seeing the opposition either. It would have to be a global lock for all 64bit atomics.... but I think it would only be 2 atomics on those architectures. Warner >