From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-3646879-1520439812-2-16406690609604772339 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.25, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='198.145.29.99', Host='mail.kernel.org', Country='US', FromHeader='org', MailFrom='org' X-Spam-charsets: plain='us-ascii' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: SRS0=N/wy=F5=infradead.org=peterz@kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1520439812; b=iZSPyPdOAHdUOvIKMe2SUlzTWMFLA9g6CnV7U5ujmGzXJEb oxtJG9LMmkcivkYJyKvhsAo8qObtPcHx0IXqncBGWrjPKwLtUlpdKzF24mdFg+VX RxNRbiqhysimVYTJGgdHKVX5PW5GniS4Bjmiacu45TGOYKjFmt5iAblqHGdslGE1 KPrNbqqkz9oDqr5f5g88l4PbHnaIYSJGknqZoVkPMCdr+txr3e2d2bYaZXXOFhUz yBCJXJQhhhlQVFujVugUOqhla994LkIBwMo5NThQjLU7y8fpFVX7BA1pw3hjb+S1 65QFnpZTL7zfzlLEbkjj0B/C9usd3c7wRSvL32Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=date:from:to:cc:subject:message-id :references:mime-version:content-type:in-reply-to; s=arctest; t= 1520439812; bh=2rPOtI8590p41XwN68QNVxm3wuWuFXjjZ35XAfRJX/E=; b=i Rgfs/RXXofzXhKpYBaUG5qZJ0Ct5qPTQp+iBntyEB3ovjolBVBxuPUGTZbrEM69t FSnGU+obTjlIOQQAl+xCa04r/6633rVROhXc6uJ4MIv/GUsQZJcfPpiE3jNAgz1l M7TAPhx3Ga3bEQp6xTdbOHoAUTUydEADX1YPaHQYWLS+D9Fw/t1/MIp/kkNuGCfq L0AvXoTpM4JPRHtD2+q7yXElVkVKfTBnJwpANm7IdxeVG+FzlSB6bUmVak+MVJzz 7l8U5sRvBZeWkhfhUzQHB7Ei/gpffC7+iBQywbhp+28S3nB+ZfozxjDOvR4svqpb P4fCBY3wScXw4C9aJT9NQ== ARC-Authentication-Results: i=1; mx2.messagingengine.com; arc=none (no signatures found); dkim=pass (2048-bit rsa key sha256) header.d=infradead.org header.i=@infradead.org header.b=GKMVo/VK x-bits=2048 x-keytype=rsa x-algorithm=sha256 x-selector=merlin.20170209; dmarc=none (p=none,d=none) header.from=infradead.org; iprev=pass policy.iprev=198.145.29.99 (mail.kernel.org); spf=none smtp.mailfrom=SRS0=N/wy=F5=infradead.org=peterz@kernel.org smtp.helo=mail.kernel.org; x-aligned-from=fail; x-category=clean score=-100 state=0; x-ptr=pass x-ptr-helo=mail.kernel.org x-ptr-lookup=mail.kernel.org; x-return-mx=pass smtp.domain=kernel.org smtp.result=pass smtp_is_org_domain=yes header.domain=infradead.org header.result=pass header_is_org_domain=yes; x-tls=pass version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128 Authentication-Results: mx2.messagingengine.com; arc=none (no signatures found); dkim=pass (2048-bit rsa key sha256) header.d=infradead.org header.i=@infradead.org header.b=GKMVo/VK x-bits=2048 x-keytype=rsa x-algorithm=sha256 x-selector=merlin.20170209; dmarc=none (p=none,d=none) header.from=infradead.org; iprev=pass policy.iprev=198.145.29.99 (mail.kernel.org); spf=none smtp.mailfrom=SRS0=N/wy=F5=infradead.org=peterz@kernel.org smtp.helo=mail.kernel.org; x-aligned-from=fail; x-category=clean score=-100 state=0; x-ptr=pass x-ptr-helo=mail.kernel.org x-ptr-lookup=mail.kernel.org; x-return-mx=pass smtp.domain=kernel.org smtp.result=pass smtp_is_org_domain=yes header.domain=infradead.org header.result=pass header_is_org_domain=yes; x-tls=pass version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128 X-Remote-Delivered-To: security@kernel.org DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1F6D72172D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=peterz@infradead.org Date: Wed, 7 Mar 2018 17:23:17 +0100 From: Peter Zijlstra To: "Paul E. McKenney" Cc: Lai Jiangshan , Tejun Heo , torvalds@linux-foundation.org, jannh@google.com, bcrl@kvack.org, viro@zeniv.linux.org.uk, kent.overstreet@gmail.com, security@kernel.org, LKML , kernel-team@fb.com Subject: Re: [PATCH 7/7] RCU, workqueue: Implement rcu_work Message-ID: <20180307162317.GO25181@hirez.programming.kicks-ass.net> References: <20180306172657.3060270-1-tj@kernel.org> <20180306173316.3088458-1-tj@kernel.org> <20180306173316.3088458-7-tj@kernel.org> <20180307145408.GC3918@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180307145408.GC3918@linux.vnet.ibm.com> User-Agent: Mutt/1.9.2 (2017-12-15) X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Wed, Mar 07, 2018 at 06:54:08AM -0800, Paul E. McKenney wrote: > One downside of allowing RCU callback functions to sleep is that > one poorly written callback can block a bunch of other ones. Not to mention that we really want the RCU callbacks to be simple and short. Needing fancy things in the callback really should be the exception not the rule.