From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965097Ab1GMIhP (ORCPT ); Wed, 13 Jul 2011 04:37:15 -0400 Received: from mail-iw0-f174.google.com ([209.85.214.174]:48355 "EHLO mail-iw0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965029Ab1GMIhN convert rfc822-to-8bit (ORCPT ); Wed, 13 Jul 2011 04:37:13 -0400 MIME-Version: 1.0 In-Reply-To: <5C4C569E8A4B9B42A84A977CF070A35B2C17AAE59A@USINDEVS01.corp.hds.com> References: <5C4C569E8A4B9B42A84A977CF070A35B2C17AAE59A@USINDEVS01.corp.hds.com> Date: Wed, 13 Jul 2011 16:37:12 +0800 Message-ID: Subject: Re: [RFC][PATCH] Replace a function call chain of kmsg_dump(KMSG_DUMP_KEXEC) with static function calls From: =?UTF-8?Q?Am=C3=A9rico_Wang?= To: Seiji Aguchi Cc: "kexec@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "Eric W. Biederman" , Vivek Goyal , KOSAKI Motohiro , Matthew Garrett , "tony.luck@intel.com" , Andrew Morton , Jarod Wilson , "hpa@zytor.com" , "dle-develop@lists.sourceforge.net" , Satoru Moriya 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 2011/7/11 Seiji Aguchi : > Hi, > Hi, > > [Patch Description] > >  For meeting Eric/Vivek's requirements and solving issues of pstore/efivars driver,  I propose a following patch. > >    - Remove kmsg_dump(KMSG_DUMP_KEXEC) from crash_kexec() It is already removed in -mm, can you rebase your patch against -mm? >    - Add kmsg_dump_kexec() to crash_kexec() >        kmsg_dump_kexec() moved behind machine_crash_shutdown() so that >        we can output kernel messages without getting any locks. > >    - Introduce CONFIG_KMSG_DUMP_KEXEC >        - CONFIG_KMSG_DUMP_KEXEC depends on CONFIG_PRINTK which is required for kmsg_dumper. > >        - CONFIG_KMSG_DUMP_KEXEC=n (default) >          Kernel message logging feature doesn't work in kdump path. > >        - CONFIG_KMSG_DUMP_KEXEC=y >          following static functions are called in kdump path. >          - kmsg_dump_kexec(): This is based on kmsg_dump() and just removed spinlock and a function call chain from it. >          - do_kmsg_dump_kexec(): This is based on pstore_dump() and just removed mutex lock from it. > >        Some people who are not familiar with kexec may add function calls getting spin_lock/mutex_lock in kexec path. >        These function calls causes failure of kexec. >        So, I suggest replace a call chain with static function calls so that we can keep reliability of kexec. > >     - Add efi_kmsg_dump_kexec() which outputs kernel messages into NVRAM with EFI. >       This is called by do_kmsg_dump_kexec() statically. >       By applying to Matthew Garret's patch below, its kernel messages in NVRAM are visible through /dev/pstore. This looks weird, kmsg_dump_kexec() calls do_kmsg_dump_kexec() which then calls efi_kmsg_dump_kexec(), so, why not just call efi_kmsg_dump_kexec()? since there is no other user of kmsg_dump_kexec(). >>From the name CONFIG_KMSG_DUMP_KEXEC, you seem to provide a generic method, but actually only efi_kmsg_dump_kexec() is and can be called. Thanks. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-iw0-f177.google.com ([209.85.214.177]) by casper.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1QguxJ-0001EZ-HL for kexec@lists.infradead.org; Wed, 13 Jul 2011 08:38:10 +0000 Received: by iwn35 with SMTP id 35so6262837iwn.36 for ; Wed, 13 Jul 2011 01:37:12 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <5C4C569E8A4B9B42A84A977CF070A35B2C17AAE59A@USINDEVS01.corp.hds.com> References: <5C4C569E8A4B9B42A84A977CF070A35B2C17AAE59A@USINDEVS01.corp.hds.com> Date: Wed, 13 Jul 2011 16:37:12 +0800 Message-ID: Subject: Re: [RFC][PATCH] Replace a function call chain of kmsg_dump(KMSG_DUMP_KEXEC) with static function calls From: =?UTF-8?Q?Am=C3=A9rico_Wang?= List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: kexec-bounces@lists.infradead.org Errors-To: kexec-bounces+dwmw2=twosheds.infradead.org@lists.infradead.org To: Seiji Aguchi Cc: "dle-develop@lists.sourceforge.net" , "tony.luck@intel.com" , "kexec@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Satoru Moriya , "Eric W. Biederman" , KOSAKI Motohiro , "hpa@zytor.com" , Jarod Wilson , Andrew Morton , Vivek Goyal , Matthew Garrett MjAxMS83LzExIFNlaWppIEFndWNoaSA8c2VpamkuYWd1Y2hpQGhkcy5jb20+Ogo+IEhpLAo+CgpI aSwKCj4KPiBbUGF0Y2ggRGVzY3JpcHRpb25dCj4KPiDCoEZvciBtZWV0aW5nIEVyaWMvVml2ZWsn cyByZXF1aXJlbWVudHMgYW5kIHNvbHZpbmcgaXNzdWVzIG9mIHBzdG9yZS9lZml2YXJzIGRyaXZl ciwgwqBJIHByb3Bvc2UgYSBmb2xsb3dpbmcgcGF0Y2guCj4KPiDCoCDCoC0gUmVtb3ZlIGttc2df ZHVtcChLTVNHX0RVTVBfS0VYRUMpIGZyb20gY3Jhc2hfa2V4ZWMoKQoKSXQgaXMgYWxyZWFkeSBy ZW1vdmVkIGluIC1tbSwgY2FuIHlvdSByZWJhc2UgeW91ciBwYXRjaCBhZ2FpbnN0IC1tbT8KCj4g wqAgwqAtIEFkZCBrbXNnX2R1bXBfa2V4ZWMoKSB0byBjcmFzaF9rZXhlYygpCj4gwqAgwqAgwqAg wqBrbXNnX2R1bXBfa2V4ZWMoKSBtb3ZlZCBiZWhpbmQgbWFjaGluZV9jcmFzaF9zaHV0ZG93bigp IHNvIHRoYXQKPiDCoCDCoCDCoCDCoHdlIGNhbiBvdXRwdXQga2VybmVsIG1lc3NhZ2VzIHdpdGhv dXQgZ2V0dGluZyBhbnkgbG9ja3MuCj4KPiDCoCDCoC0gSW50cm9kdWNlIENPTkZJR19LTVNHX0RV TVBfS0VYRUMKPiDCoCDCoCDCoCDCoC0gQ09ORklHX0tNU0dfRFVNUF9LRVhFQyBkZXBlbmRzIG9u IENPTkZJR19QUklOVEsgd2hpY2ggaXMgcmVxdWlyZWQgZm9yIGttc2dfZHVtcGVyLgo+Cj4gwqAg wqAgwqAgwqAtIENPTkZJR19LTVNHX0RVTVBfS0VYRUM9biAoZGVmYXVsdCkKPiDCoCDCoCDCoCDC oCDCoEtlcm5lbCBtZXNzYWdlIGxvZ2dpbmcgZmVhdHVyZSBkb2Vzbid0IHdvcmsgaW4ga2R1bXAg cGF0aC4KPgo+IMKgIMKgIMKgIMKgLSBDT05GSUdfS01TR19EVU1QX0tFWEVDPXkKPiDCoCDCoCDC oCDCoCDCoGZvbGxvd2luZyBzdGF0aWMgZnVuY3Rpb25zIGFyZSBjYWxsZWQgaW4ga2R1bXAgcGF0 aC4KPiDCoCDCoCDCoCDCoCDCoC0ga21zZ19kdW1wX2tleGVjKCk6IFRoaXMgaXMgYmFzZWQgb24g a21zZ19kdW1wKCkgYW5kIGp1c3QgcmVtb3ZlZCBzcGlubG9jayBhbmQgYSBmdW5jdGlvbiBjYWxs IGNoYWluIGZyb20gaXQuCj4gwqAgwqAgwqAgwqAgwqAtIGRvX2ttc2dfZHVtcF9rZXhlYygpOiBU aGlzIGlzIGJhc2VkIG9uIHBzdG9yZV9kdW1wKCkgYW5kIGp1c3QgcmVtb3ZlZCBtdXRleCBsb2Nr IGZyb20gaXQuCj4KPiDCoCDCoCDCoCDCoFNvbWUgcGVvcGxlIHdobyBhcmUgbm90IGZhbWlsaWFy IHdpdGgga2V4ZWMgbWF5IGFkZCBmdW5jdGlvbiBjYWxscyBnZXR0aW5nIHNwaW5fbG9jay9tdXRl eF9sb2NrIGluIGtleGVjIHBhdGguCj4gwqAgwqAgwqAgwqBUaGVzZSBmdW5jdGlvbiBjYWxscyBj YXVzZXMgZmFpbHVyZSBvZiBrZXhlYy4KPiDCoCDCoCDCoCDCoFNvLCBJIHN1Z2dlc3QgcmVwbGFj ZSBhIGNhbGwgY2hhaW4gd2l0aCBzdGF0aWMgZnVuY3Rpb24gY2FsbHMgc28gdGhhdCB3ZSBjYW4g a2VlcCByZWxpYWJpbGl0eSBvZiBrZXhlYy4KPgo+IMKgIMKgIC0gQWRkIGVmaV9rbXNnX2R1bXBf a2V4ZWMoKSB3aGljaCBvdXRwdXRzIGtlcm5lbCBtZXNzYWdlcyBpbnRvIE5WUkFNIHdpdGggRUZJ Lgo+IMKgIMKgIMKgIFRoaXMgaXMgY2FsbGVkIGJ5IGRvX2ttc2dfZHVtcF9rZXhlYygpIHN0YXRp Y2FsbHkuCj4gwqAgwqAgwqAgQnkgYXBwbHlpbmcgdG8gTWF0dGhldyBHYXJyZXQncyBwYXRjaCBi ZWxvdywgaXRzIGtlcm5lbCBtZXNzYWdlcyBpbiBOVlJBTSBhcmUgdmlzaWJsZSB0aHJvdWdoIC9k ZXYvcHN0b3JlLgoKVGhpcyBsb29rcyB3ZWlyZCwga21zZ19kdW1wX2tleGVjKCkgY2FsbHMgZG9f a21zZ19kdW1wX2tleGVjKCkKd2hpY2ggdGhlbiBjYWxscyBlZmlfa21zZ19kdW1wX2tleGVjKCks IHNvLCB3aHkgbm90IGp1c3QgY2FsbAplZmlfa21zZ19kdW1wX2tleGVjKCk/CnNpbmNlIHRoZXJl IGlzIG5vIG90aGVyIHVzZXIgb2Yga21zZ19kdW1wX2tleGVjKCkuCgpGcm9tIHRoZSBuYW1lIENP TkZJR19LTVNHX0RVTVBfS0VYRUMsIHlvdSBzZWVtIHRvIHByb3ZpZGUgYSBnZW5lcmljIG1ldGhv ZCwKYnV0IGFjdHVhbGx5IG9ubHkgZWZpX2ttc2dfZHVtcF9rZXhlYygpIGlzIGFuZCBjYW4gYmUg Y2FsbGVkLgoKVGhhbmtzLgoKX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX18Ka2V4ZWMgbWFpbGluZyBsaXN0CmtleGVjQGxpc3RzLmluZnJhZGVhZC5vcmcKaHR0 cDovL2xpc3RzLmluZnJhZGVhZC5vcmcvbWFpbG1hbi9saXN0aW5mby9rZXhlYwo=