From owner-svn-src-projects@FreeBSD.ORG Mon Jul 30 14:51:24 2012 Return-Path: Delivered-To: svn-src-projects@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id D426A106566B; Mon, 30 Jul 2012 14:51:24 +0000 (UTC) (envelope-from asmrookie@gmail.com) Received: from mail-lpp01m010-f54.google.com (mail-lpp01m010-f54.google.com [209.85.215.54]) by mx1.freebsd.org (Postfix) with ESMTP id E75718FC16; Mon, 30 Jul 2012 14:51:23 +0000 (UTC) Received: by laai10 with SMTP id i10so4148813laa.13 for ; Mon, 30 Jul 2012 07:51:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:reply-to:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type; bh=cNhVkKGni0ROivhGKiZ8ayTTliRdjjeu47rtvJX70PI=; b=a4P8A0U7MahVNodt6KEYyk2oqRIpZkbcBKFzIEwubkwR0I/QyxTAy7FSjCJnWn2VZV 0jwqu4CR1MjKsMmp7S6KyEw6gUZD6L8nCDNYKtwf3rXVG2vsSrEB69qBHcjfaTtnmyHV Epnr4MLluisCfVaZMQbDt5czf69R8Si4TWrPcyuwGRUELVoYtoTrBXBokUmgzDOucKGM AOfpBOnQtLq9ijaFRcFj0tnQLdMotlrOEDMYly1D59pofz5kDCb9ueEXe62mlU0TXLv4 gONiA5h8/yRftJcObj4g7rH9FCf37v3vfmtsNJL7v1WihGtgAV4OABGrJpPEWNQME3gH eIgQ== MIME-Version: 1.0 Received: by 10.152.48.6 with SMTP id h6mr11727528lan.30.1343659882957; Mon, 30 Jul 2012 07:51:22 -0700 (PDT) Sender: asmrookie@gmail.com Received: by 10.112.27.65 with HTTP; Mon, 30 Jul 2012 07:51:22 -0700 (PDT) In-Reply-To: <20120730143943.GY2676@deviant.kiev.zoral.com.ua> References: <201207301350.q6UDobCI099069@svn.freebsd.org> <20120730143943.GY2676@deviant.kiev.zoral.com.ua> Date: Mon, 30 Jul 2012 15:51:22 +0100 X-Google-Sender-Auth: BSjMuGE_nzl2W4L-idS82vYPO4E Message-ID: From: Attilio Rao To: Konstantin Belousov Content-Type: text/plain; charset=UTF-8 Cc: Davide Italiano , svn-src-projects@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r238907 - projects/calloutng/sys/kern X-BeenThere: svn-src-projects@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: attilio@FreeBSD.org List-Id: "SVN commit messages for the src " projects" tree" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 30 Jul 2012 14:51:24 -0000 On 7/30/12, Konstantin Belousov wrote: > On Mon, Jul 30, 2012 at 03:24:26PM +0100, Attilio Rao wrote: >> On 7/30/12, Davide Italiano wrote: >> > On Mon, Jul 30, 2012 at 4:02 PM, Attilio Rao >> > wrote: >> > Thanks for the comment, Attilio. >> > Yes, it's exactly what you thought. If direct flag is equal to one >> > you're sure you're processing a callout which runs directly from >> > hardware interrupt context. In this case, the running thread cannot >> > sleep and it's likely you have TDP_NOSLEEPING flags set, failing the >> > KASSERT() in THREAD_NO_SLEEPING() and leading to panic if kernel is >> > compiled with INVARIANTS. >> > In case you're running from SWI context (direct equals to zero) code >> > remains the same as before. >> > I think what I'm doing works due the assumption thread running never >> > sleeps. Do you suggest some other way to handle this? >> >> Possibly the quicker way to do this is to have a way to deal with the >> TDP_NOSLEEPING flag in recursed way, thus implement the same logic as >> VFS_LOCK_GIANT() does, for example. >> You will need to change the few callers of THREAD_NO_SLEEPING(), but >> the patch should be no longer than 10/15 lines. > > There are already curthread_pflags_set/restore KPI designed exactly to > handle > nested private thread flags. Yes, however I would use curthread_pflags* KPI within THREAD_NO_SLEEPING() as this name is much more explicit. > Also, I wonder, should you assert somehow that direct dispatch cannot block > as well ? Yes, it would be optimal, but I don't think we have a flag for that right now, do we? Thanks, Attilio -- Peace can only be achieved by understanding - A. Einstein