From owner-freebsd-hackers@freebsd.org Sat Jan 4 13:39:34 2020 Return-Path: Delivered-To: freebsd-hackers@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 8AEFC1EDCC4 for ; Sat, 4 Jan 2020 13:39:34 +0000 (UTC) (envelope-from jhb@FreeBSD.org) Received: from mailman.nyi.freebsd.org (mailman.nyi.freebsd.org [IPv6:2610:1c1:1:606c::50:13]) by mx1.freebsd.org (Postfix) with ESMTP id 47qjYf3ClBz4Fgp for ; Sat, 4 Jan 2020 13:39:34 +0000 (UTC) (envelope-from jhb@FreeBSD.org) Received: by mailman.nyi.freebsd.org (Postfix) id 6C63B1EDCC3; Sat, 4 Jan 2020 13:39:34 +0000 (UTC) Delivered-To: hackers@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 6C29E1EDCC2 for ; Sat, 4 Jan 2020 13:39:34 +0000 (UTC) (envelope-from jhb@FreeBSD.org) Received: from smtp.freebsd.org (smtp.freebsd.org [96.47.72.83]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "smtp.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 47qjYf2C07z4Fgn; Sat, 4 Jan 2020 13:39:34 +0000 (UTC) (envelope-from jhb@FreeBSD.org) Received: from John-Baldwins-MacBook-Pro-7.local (unknown [IPv6:2601:648:8881:1e90:8d3e:cb31:1f4e:f50]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client did not present a certificate) (Authenticated sender: jhb) by smtp.freebsd.org (Postfix) with ESMTPSA id 00E411F048; Sat, 4 Jan 2020 13:39:33 +0000 (UTC) (envelope-from jhb@FreeBSD.org) Subject: Re: Fixing audio/oss to use callout instead of timeouts To: Chris Rees , hackers@FreeBSD.org References: From: John Baldwin Openpgp: preference=signencrypt Autocrypt: addr=jhb@FreeBSD.org; keydata= mQGiBETQ+XcRBADMFybiq69u+fJRy/0wzqTNS8jFfWaBTs5/OfcV7wWezVmf9sgwn8TW0Dk0 c9MBl0pz+H01dA2ZSGZ5fXlmFIsee1WEzqeJzpiwd/pejPgSzXB9ijbLHZ2/E0jhGBcVy5Yo /Tw5+U/+laeYKu2xb0XPvM0zMNls1ah5OnP9a6Ql6wCgupaoMySb7DXm2LHD1Z9jTsHcAQMD /1jzh2BoHriy/Q2s4KzzjVp/mQO5DSm2z14BvbQRcXU48oAosHA1u3Wrov6LfPY+0U1tG47X 1BGfnQH+rNAaH0livoSBQ0IPI/8WfIW7ub4qV6HYwWKVqkDkqwcpmGNDbz3gfaDht6nsie5Z pcuCcul4M9CW7Md6zzyvktjnbz61BADGDCopfZC4of0Z3Ka0u8Wik6UJOuqShBt1WcFS8ya1 oB4rc4tXfSHyMF63aPUBMxHR5DXeH+EO2edoSwViDMqWk1jTnYza51rbGY+pebLQOVOxAY7k do5Ordl3wklBPMVEPWoZ61SdbcjhHVwaC5zfiskcxj5wwXd2E9qYlBqRg7QeSm9obiBCYWxk d2luIDxqaGJARnJlZUJTRC5vcmc+iGAEExECACAFAkTQ+awCGwMGCwkIBwMCBBUCCAMEFgID AQIeAQIXgAAKCRBy3lIGd+N/BI6RAJ9S97fvbME+3hxzE3JUyUZ6vTewDACdE1stFuSfqMvM jomvZdYxIYyTUpC5Ag0ERND5ghAIAPwsO0B7BL+bz8sLlLoQktGxXwXQfS5cInvL17Dsgnr3 1AKa94j9EnXQyPEj7u0d+LmEe6CGEGDh1OcGFTMVrof2ZzkSy4+FkZwMKJpTiqeaShMh+Goj XlwIMDxyADYvBIg3eN5YdFKaPQpfgSqhT+7El7w+wSZZD8pPQuLAnie5iz9C8iKy4/cMSOrH YUK/tO+Nhw8Jjlw94Ik0T80iEhI2t+XBVjwdfjbq3HrJ0ehqdBwukyeJRYKmbn298KOFQVHO EVbHA4rF/37jzaMadK43FgJ0SAhPPF5l4l89z5oPu0b/+5e2inA3b8J3iGZxywjM+Csq1tqz hltEc7Q+E08AAwUIAL+15XH8bPbjNJdVyg2CMl10JNW2wWg2Q6qdljeaRqeR6zFus7EZTwtX sNzs5bP8y51PSUDJbeiy2RNCNKWFMndM22TZnk3GNG45nQd4OwYK0RZVrikalmJY5Q6m7Z16 4yrZgIXFdKj2t8F+x613/SJW1lIr9/bDp4U9tw0V1g3l2dFtD3p3ZrQ3hpoDtoK70ioIAjjH aIXIAcm3FGZFXy503DOA0KaTWwvOVdYCFLm3zWuSOmrX/GsEc7ovasOWwjPn878qVjbUKWwx Q4QkF4OhUV9zPtf9tDSAZ3x7QSwoKbCoRCZ/xbyTUPyQ1VvNy/mYrBcYlzHodsaqUDjHuW+I SQQYEQIACQUCRND5ggIbDAAKCRBy3lIGd+N/BCO8AJ9j1dWVQWxw/YdTbEyrRKOY8YZNwwCf afMAg8QvmOWnHx3wl8WslCaXaE8= Message-ID: <33a74368-73a7-fdc0-4655-cfce88d865e6@FreeBSD.org> Date: Sat, 4 Jan 2020 05:39:31 -0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:60.0) Gecko/20100101 Thunderbird/60.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 04 Jan 2020 13:39:34 -0000 On 1/2/20 3:47 PM, Chris Rees wrote: > Hi Hackers (and perhaps John, as the author of r355732, sorry for the duplicate), > > I've attempted to use the callout functions instead of the now removed timeout functions for audio/oss, and I *think* that the code already stores and retrieves the list of handlers, so it should be a simple swap out. > > I've made this modification and run the module with mpg123 for a while and it hasn't killed my laptop, but I'd just like to check that I have the principle correct and haven't missed anything obvious. > > Please would you let me know if there is anything else I should have done? > > https://www.bayofrum.net/cgi-bin/fossil/oss/vinfo/ad269d7cbc02bf38?diff=2 > > (This is the change I've made to kernel/OS/FreeBSD/os_freebsd.c in oss) > > https://www.bayofrum.net/cgi-bin/fossil/oss/vinfo/ad269d7cbc02bf38?diff=2&dc=9999 A few suggestions: 1) You should do the callout_init() during a SYSINIT or MOD_LOAD event to initialize all the timers at once instead of doing it in oss_timeout(). 2) You should then add a SYSUNINIT or MOD_UNLOAD that uses callout_drain(). 3) You should add a mutex to protect the tmouts array and timeout_random, etc. and use callout_init_mtx with that lock, but probably use CALLOUT_RETURNUNLOCKED and drop the mutex right before calling the function (you can store the function pointer and void * argument in local variables before dropping the lock to be safe. 4) If possible, you should really alter the oss API so that drivers don't use a timeout()-like interface, but instead use a callout directly (or an interface that wraps callout). This would let drivers take advantage of callout_init_mtx with their own locks, etc. Does audio/oss contain all the code that makes use of oss_timeout? -- John Baldwin