From mboxrd@z Thu Jan 1 00:00:00 1970 From: Khalid Aziz Subject: Re: [PATCH RESEND v4] sched/fair: Add advisory flag for borrowing a timeslice Date: Thu, 18 Dec 2014 15:42:10 -0700 Message-ID: <54935842.5020507@oracle.com> References: <1418928259-6311-1-git-send-email-khalid.aziz@oracle.com> <20141218222846.GH30905@twins.programming.kicks-ass.net> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20141218222846.GH30905@twins.programming.kicks-ass.net> Sender: linux-kernel-owner@vger.kernel.org To: Peter Zijlstra Cc: tglx@linutronix.de, corbet@lwn.net, mingo@redhat.com, hpa@zytor.com, riel@redhat.com, akpm@linux-foundation.org, rientjes@google.com, ak@linux.intel.com, mgorman@suse.de, raistlin@linux.it, kirill.shutemov@linux.intel.com, atomlin@redhat.com, avagin@openvz.org, gorcunov@openvz.org, serge.hallyn@canonical.com, athorlton@sgi.com, oleg@redhat.com, vdavydov@parallels.com, daeseok.youn@gmail.com, keescook@chromium.org, yangds.fnst@cn.fujitsu.com, sbauer@eng.utah.edu, vishnu.ps@samsung.com, axboe@fb.com, paulmck@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-api@vger.kernel.org List-Id: linux-api@vger.kernel.org On 12/18/2014 03:28 PM, Peter Zijlstra wrote: > On Thu, Dec 18, 2014 at 11:44:19AM -0700, Khalid Aziz wrote: >> sched/fair: Add advisory flag for borrowing a timeslice > > yuck hatred and much of that. > > Also, you fail to explain why a kernel side spin futex-lock is not an > option. > I had explained that when this question came up in the last round of discussions. The queuing problem I am trying to solve stems from userspace locks. Java and databases implement their own userspace locks that do not use futex. Solving this with futex will not help the primary users of this solution. Hope this helps. Thanks, Khalid