From owner-svn-src-head@freebsd.org Tue May 2 17:07:27 2017 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id DA153D5A333; Tue, 2 May 2017 17:07:27 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from kib.kiev.ua (kib.kiev.ua [IPv6:2001:470:d5e7:1::1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 68B6769C; Tue, 2 May 2017 17:07:27 +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 v42H7Lcp040956 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Tue, 2 May 2017 20:07:21 +0300 (EEST) (envelope-from kostikbel@gmail.com) DKIM-Filter: OpenDKIM Filter v2.10.3 kib.kiev.ua v42H7Lcp040956 Received: (from kostik@localhost) by tom.home (8.15.2/8.15.2/Submit) id v42H7Lkh040955; Tue, 2 May 2017 20:07:21 +0300 (EEST) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: tom.home: kostik set sender to kostikbel@gmail.com using -f Date: Tue, 2 May 2017 20:07:21 +0300 From: Konstantin Belousov To: Bruce Evans Cc: Alan Somers , Gleb Smirnoff , "src-committers@freebsd.org" , "svn-src-all@freebsd.org" , "svn-src-head@freebsd.org" Subject: Re: svn commit: r317061 - in head: libexec/rpc.rstatd sys/amd64/amd64 sys/amd64/include sys/arm/arm sys/arm/include sys/arm64/include sys/cddl/contrib/opensolaris/uts/common/fs/zfs sys/compat/linprocfs... Message-ID: <20170502170721.GI1622@kib.kiev.ua> References: <20170419130428.J956@besplex.bde.org> <20170430201324.GV1622@kib.kiev.ua> <20170501163725.U972@besplex.bde.org> <20170502095527.GB1622@kib.kiev.ua> <20170502203703.I1176@besplex.bde.org> <20170502121711.GE1622@kib.kiev.ua> <20170502223324.P1508@besplex.bde.org> <20170502144823.GH1622@kib.kiev.ua> <20170503005322.K1968@besplex.bde.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170503005322.K1968@besplex.bde.org> User-Agent: Mutt/1.8.2 (2017-04-18) X-Spam-Status: No, score=-2.0 required=5.0 tests=ALL_TRUSTED,BAYES_00, DKIM_ADSP_CUSTOM_MED,FREEMAIL_FROM,NML_ADSP_CUSTOM_MED autolearn=no autolearn_force=no version=3.4.1 X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on tom.home X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.23 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: Tue, 02 May 2017 17:07:28 -0000 On Wed, May 03, 2017 at 01:31:10AM +1000, Bruce Evans wrote: > > > On Tue, 2 May 2017, Konstantin Belousov wrote: > I also thought of changing the scale when the values get high. The values > would increase slower above about 2G instead of stabilizing at 4G-1. > This is basically floating point and too complicated since nothing would > understand it. > > Which counters wrap faster than a reasonable refresh interval of 1-10 > seconds (which should be shorter if wrapping is a problem)? Things like various counters for pages freed due to a reason can. E.g. freed due to the process exit is the counter which I saw changing fast. Wire counts might fluctuate relatively quickly, but I think that wiring is slower. Unwiring might be fast. > Style: > - redundant cast. Especially not needed with the commit. Compilers might > warn about this since they don't trust programmers, but don't because > implicit downwards conversions are used often. > - comment not indented > > I would also omit the ifdefs, and rename 'out' to out64, and may rename > 'out*' to val*. Ok. > I just noticed that this sysctl is r/o (I thought I was preserving support > for resetting 64-bit counters using a 32-bit size in my fix in > sysctl_handle_counter_64(). That function has the dubious feature of not > checking the size, so it allows writes of any length (0 to SIZE_MAX, > possibly larger than the user data) to reset the counter to zero.) > > The r/o misfeature goes back to at least FreeBSD-3. 64-bit counters need > resetting less than 32-bit ones, and it is more useful to ever reset them > since they can hold the full counts since boot time, but there is no reason > to limit resetting them now that the low-level code supports it. Is there > already a better atomic reset of all vm stats? I do not see why vmstat counters ever need to be reset. I do not think that truncating the value to present small values to 32bit readers is a reasonable cause. diff --git a/sys/vm/vm_meter.c b/sys/vm/vm_meter.c index 5f4cd46ab1e..b4666a400b2 100644 --- a/sys/vm/vm_meter.c +++ b/sys/vm/vm_meter.c @@ -266,8 +266,27 @@ static SYSCTL_NODE(_vm_stats, OID_AUTO, vm, CTLFLAG_RW, 0, "VM meter vm stats"); SYSCTL_NODE(_vm_stats, OID_AUTO, misc, CTLFLAG_RW, 0, "VM meter misc stats"); +static int +sysctl_handle_vmstat(SYSCTL_HANDLER_ARGS) +{ + uint64_t val; +#ifdef COMPAT_FREEBSD11 + uint32_t val32; +#endif + + val = counter_u64_fetch(*(counter_u64_t *)arg1); +#ifdef COMPAT_FREEBSD11 + if (req->oldlen == sizeof(val32)) { + val32 = val; /* truncate */ + return (SYSCTL_OUT(req, &val32, sizeof(val32))); + } +#endif + return (SYSCTL_OUT(req, &val, sizeof(val))); +} + #define VM_STATS(parent, var, descr) \ - SYSCTL_COUNTER_U64(parent, OID_AUTO, var, CTLFLAG_RD, &vm_cnt.var, descr) + SYSCTL_OID(parent, OID_AUTO, var, CTLTYPE_U64 | CTLFLAG_MPSAFE | \ + CTLFLAG_RD, &vm_cnt.var, 0, sysctl_handle_vmstat, "QU", descr); #define VM_STATS_VM(var, descr) VM_STATS(_vm_stats_vm, var, descr) #define VM_STATS_SYS(var, descr) VM_STATS(_vm_stats_sys, var, descr)