From owner-svn-src-all@freebsd.org Sun Nov 3 22:59:29 2019 Return-Path: Delivered-To: svn-src-all@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 8FFE51AAB9E; Sun, 3 Nov 2019 22:59:29 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from kib.kiev.ua (kib.kiev.ua [IPv6:2001:470:d5e7:1::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 475rwJ3zT4z4v8X; Sun, 3 Nov 2019 22:59:28 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from tom.home (kib@localhost [127.0.0.1]) by kib.kiev.ua (8.15.2/8.15.2) with ESMTPS id xA3MxLvH046748 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Mon, 4 Nov 2019 00:59:24 +0200 (EET) (envelope-from kostikbel@gmail.com) DKIM-Filter: OpenDKIM Filter v2.10.3 kib.kiev.ua xA3MxLvH046748 Received: (from kostik@localhost) by tom.home (8.15.2/8.15.2/Submit) id xA3MxLle046747; Mon, 4 Nov 2019 00:59:21 +0200 (EET) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: tom.home: kostik set sender to kostikbel@gmail.com using -f Date: Mon, 4 Nov 2019 00:59:21 +0200 From: Konstantin Belousov To: Vladimir Kondratyev Cc: Vladimir Kondratyev , src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r354322 - head/sys/dev/ichiic Message-ID: <20191103225921.GZ73312@kib.kiev.ua> References: <201911032117.xA3LHpKK078186@repo.freebsd.org> <20191103220222.GX73312@kib.kiev.ua> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.12.2 (2019-09-21) X-Spam-Status: No, score=-1.0 required=5.0 tests=ALL_TRUSTED,BAYES_00, DKIM_ADSP_CUSTOM_MED,FORGED_GMAIL_RCVD,FREEMAIL_FROM, NML_ADSP_CUSTOM_MED autolearn=no autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on tom.home X-Rspamd-Queue-Id: 475rwJ3zT4z4v8X X-Spamd-Bar: - Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=fail reason="No valid SPF, No valid DKIM" header.from=gmail.com (policy=none); spf=softfail (mx1.freebsd.org: 2001:470:d5e7:1::1 is neither permitted nor denied by domain of kostikbel@gmail.com) smtp.mailfrom=kostikbel@gmail.com X-Spamd-Result: default: False [-2.00 / 15.00]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-1.000,0]; RCVD_TLS_ALL(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; FREEMAIL_FROM(0.00)[gmail.com]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; MIME_GOOD(-0.10)[text/plain]; HAS_XAW(0.00)[]; R_SPF_SOFTFAIL(0.00)[~all]; RCPT_COUNT_FIVE(0.00)[5]; IP_SCORE_FREEMAIL(0.00)[]; TO_MATCH_ENVRCPT_SOME(0.00)[]; IP_SCORE(0.00)[ip: (-2.64), ipnet: 2001:470::/32(-4.61), asn: 6939(-3.47), country: US(-0.05)]; FROM_EQ_ENVFROM(0.00)[]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:6939, ipnet:2001:470::/32, country:US]; RCVD_COUNT_TWO(0.00)[2]; FREEMAIL_ENVFROM(0.00)[gmail.com]; DMARC_POLICY_SOFTFAIL(0.10)[gmail.com : No valid SPF, No valid DKIM,none] X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 03 Nov 2019 22:59:29 -0000 On Mon, Nov 04, 2019 at 01:46:14AM +0300, Vladimir Kondratyev wrote: > On 04.11.2019 01:02, Konstantin Belousov wrote: > > On Sun, Nov 03, 2019 at 09:17:51PM +0000, Vladimir Kondratyev wrote: > >> Author: wulf > >> Date: Sun Nov 3 21:17:50 2019 > >> New Revision: 354322 > >> URL: https://svnweb.freebsd.org/changeset/base/354322 > >> > >> Log: > >> [ig4] Convert ithread interrupt handler to filter based one. > > And why ? > > > > You need some reason to use filters/spinlocks, otherwise it only > > taxes system latency. > > > The only thing ig4 interrupt handler does is a waking up the user > thread, so postponing it to ithread looks like a wasting of CPU cycles. > > Spinlock here is acting as condition variable not as a data protection > lock. It is taken around msleep(). I can replace it with cv_* calls if > current usage confuses someone > > Ig4 access is serialized with sx lock so it is impossible to get any > congestion on spinlock > You need to lock the same spinlock in the sleeping thread and in the interrupt context. I do not remember why these drivers ended up using sx for their main data synchronization, I suspect it was due to copyouts.