From nobody Tue Nov 15 17:56:46 2022 X-Original-To: freebsd-arch@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4NBYlw4KJNz4hMPy for ; Tue, 15 Nov 2022 17:57:00 +0000 (UTC) (envelope-from carpeddiem@gmail.com) Received: from mail-pg1-f171.google.com (mail-pg1-f171.google.com [209.85.215.171]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "smtp.gmail.com", Issuer "GTS CA 1D4" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4NBYlw2Cs6z45gr for ; Tue, 15 Nov 2022 17:57:00 +0000 (UTC) (envelope-from carpeddiem@gmail.com) Authentication-Results: mx1.freebsd.org; none Received: by mail-pg1-f171.google.com with SMTP id 136so13964740pga.1 for ; Tue, 15 Nov 2022 09:57:00 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding: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=LIkk0PBuHeQ3YTPpkaa5SLH8dtSyRAiIdzmiBmlWH3M=; b=AWhHrh+236WUsLMvKR87uXN1RXTkXFZEaI/QRq4w2JdOSMOWAlHdV2UKf2YYXaf1ug iFjevff0B4oas6BA6ucu2WGgaH58Sd1f7xtyO2ooJHOfewDW/MN5Dz1nP+mGDYEZbols z5gOI7XNr9Rk7LqDT2DVNL3tAQgxWX3PD+IZS8JxE7pCjXU744sl66RjSeuV3evMev2S DGy0ItusiI3ntDDEcbiX5lUs7Nl9FVHKPlGT+86Bc2dkzEw9co6sgHVF8jLDTHrHPxU/ vSMOZ7PG7e2aLkTtNj1xZXQfWqVI6ZXsxzccEbqivvmWUNW06oZqQ+7MMoR0gGAI1U3n ZkQQ== X-Gm-Message-State: ANoB5pnQInJgkipdsPlqdECsuoQ81UAXGq+yMOyYCcXCCaCkk25eEkQx KxhE8bMyBtjleUV5EdS/CJUVsiTwRTpy7cZ4cYc= X-Google-Smtp-Source: AA0mqf4WGmmNk7pCa8MEoWEMUXyPO+JD52RbPjs9EohmE6GSk3rY4Hx+PEpiq75c3vuVPbWLwqu4gmRw6ogSV8V7K7k= X-Received: by 2002:a63:ec03:0:b0:473:e2bb:7fc7 with SMTP id j3-20020a63ec03000000b00473e2bb7fc7mr16755602pgh.40.1668535018678; Tue, 15 Nov 2022 09:56:58 -0800 (PST) List-Id: Discussion related to FreeBSD architecture List-Archive: https://lists.freebsd.org/archives/freebsd-arch List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-arch@freebsd.org MIME-Version: 1.0 References: In-Reply-To: From: Ed Maste Date: Tue, 15 Nov 2022 12:56:46 -0500 Message-ID: Subject: Re: Giant Locked drivers To: Warner Losh Cc: "freebsd-arch@freebsd.org" Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 4NBYlw2Cs6z45gr X-Spamd-Bar: ---- X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[]; ASN(0.00)[asn:15169, ipnet:209.85.128.0/17, country:US] X-Rspamd-Pre-Result: action=no action; module=replies; Message is reply to one we originated X-ThisMailContainsUnwantedMimeParts: N On Tue, 15 Nov 2022 at 12:37, Warner Losh wrote: > > Greetings, > > It's no secret Giant-locked drivers' days are numbered. We've been more s= luggish about eliminating Giant than had been hoped. I plan in the coming w= eeks to add a tunable 'debug.giant_drivers' which initially will be set to = enable/disable giant-locked drivers in the tree. > > When set to 0, you get today's behavior. If set to 1, it will no longer a= llow drivers that don't request MPSAFE interrupt handlers from registering = (the interrupt setup will return an error). I think having such a tunable is a good idea, but let's use positive-sense sysctls, so that we set the enable sysctl to 1 to allow Giant-locked drivers and to 0 to disable.