From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755111Ab3C2DwK (ORCPT ); Thu, 28 Mar 2013 23:52:10 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:9073 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1754426Ab3C2DwJ convert rfc822-to-8bit (ORCPT ); Thu, 28 Mar 2013 23:52:09 -0400 X-IronPort-AV: E=Sophos;i="4.87,370,1363104000"; d="scan'208";a="6966867" Message-ID: <51550F8B.1000402@cn.fujitsu.com> Date: Fri, 29 Mar 2013 11:50:35 +0800 From: Zhang Yanfei User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:10.0.8) Gecko/20121012 Thunderbird/10.0.8 MIME-Version: 1.0 To: Simon Horman CC: Greg KH , "Eric W. Biederman" , vgoyal@redhat.com, "kexec@lists.infradead.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 1/2] sysfs: Add crash_notes_size to export percpu note size References: <5153FC27.70001@cn.fujitsu.com> In-Reply-To: <5153FC27.70001@cn.fujitsu.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2013/03/29 11:51:15, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2013/03/29 11:51:16 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, simon I forgot to add your email in the CC, could you please help reviewing this patch since I will send the kexec-tools patch if this patch is accepted. Thanks Zhang 于 2013年03月28日 16:15, Zhang Yanfei 写道: > For percpu notes, we are exporting only address and not size. So > the userspace tool kexec-tools is putting an upper limit of 1024 > and putting the value in p_memsz and p_filesz fields. So the patch > add the new sysfile crash_notes_size to export the exact percpu > note size and let the kexec-tools parse it intead of using 1024. > > The idea came from Vivek Goyal. And a later patch will be sent to > kexec-tools to let it parse the size. > > Cc: Greg KH > Cc: "Eric W. Biederman" > Cc: Vivek Goyal > Signed-off-by: Zhang Yanfei > --- > drivers/base/cpu.c | 14 ++++++++++++++ > 1 files changed, 14 insertions(+), 0 deletions(-) > > diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c > index fb10728..a55b590 100644 > --- a/drivers/base/cpu.c > +++ b/drivers/base/cpu.c > @@ -132,6 +132,17 @@ static ssize_t show_crash_notes(struct device *dev, struct device_attribute *att > return rc; > } > static DEVICE_ATTR(crash_notes, 0400, show_crash_notes, NULL); > + > +static ssize_t show_crash_notes_size(struct device *dev, > + struct device_attribute *attr, > + char *buf) > +{ > + ssize_t rc; > + > + rc = sprintf(buf, "%lu\n", sizeof(note_buf_t)); > + return rc; > +} > +static DEVICE_ATTR(crash_notes_size, 0400, show_crash_notes_size, NULL); > #endif > > /* > @@ -259,6 +270,9 @@ int __cpuinit register_cpu(struct cpu *cpu, int num) > #ifdef CONFIG_KEXEC > if (!error) > error = device_create_file(&cpu->dev, &dev_attr_crash_notes); > + if (!error) > + error = device_create_file(&cpu->dev, > + &dev_attr_crash_notes_size); > #endif > return error; > }