From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 25 Jan 2018 07:50:57 +0100 From: "gregkh@linuxfoundation.org" To: "Zhang, Ning A" Cc: Andy Lutomirski , "tglx@linutronix.de" , "stable@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: backport Rewrite sync_core() to use IRET-to-self to stable kernels? Message-ID: <20180125065057.GC24052@kroah.com> References: <027FCDD209E4CC4181A7B9D5DBB880575FDD83D2@SHSMSX104.ccr.corp.intel.com> <20180123072533.GA17566@kroah.com> <027FCDD209E4CC4181A7B9D5DBB880575FDD9DEC@SHSMSX104.ccr.corp.intel.com> <20180124090107.GB30613@kroah.com> <027FCDD209E4CC4181A7B9D5DBB880575FDDBC11@SHSMSX104.ccr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <027FCDD209E4CC4181A7B9D5DBB880575FDDBC11@SHSMSX104.ccr.corp.intel.com> User-Agent: Mutt/1.9.2 (2017-12-15) X-Mailing-List: linux-kernel@vger.kernel.org List-ID: A: Because it messes up the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing in e-mail? A: No. Q: Should I include quotations after my reply? http://daringfireball.net/2007/07/on_top On Thu, Jan 25, 2018 at 02:22:57AM +0000, Zhang, Ning A wrote: > When Linux runs as a guest OS, CPUID is privileged instruction, sync_core() will be very slow. > > If apply this patch, 200ms will be saved for kernel initial, when Linux runs as a guest OS. That's not a regression. Why not just use a newer kernel release if you want to get the feature of "faster boot"? :) thanks, greg k-h