From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f51.google.com (mail-wm0-f51.google.com [74.125.82.51]) by kanga.kvack.org (Postfix) with ESMTP id 7CDA66B0260 for ; Fri, 13 Nov 2015 10:33:34 -0500 (EST) Received: by wmvv187 with SMTP id v187so87011313wmv.1 for ; Fri, 13 Nov 2015 07:33:34 -0800 (PST) Received: from e06smtp08.uk.ibm.com (e06smtp08.uk.ibm.com. [195.75.94.104]) by mx.google.com with ESMTPS id 5si6178871wml.80.2015.11.13.07.33.33 for (version=TLS1 cipher=AES128-SHA bits=128/128); Fri, 13 Nov 2015 07:33:33 -0800 (PST) Received: from localhost by e06smtp08.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 13 Nov 2015 15:33:32 -0000 Received: from b06cxnps4075.portsmouth.uk.ibm.com (d06relay12.portsmouth.uk.ibm.com [9.149.109.197]) by d06dlp02.portsmouth.uk.ibm.com (Postfix) with ESMTP id EF1C9219004D for ; Fri, 13 Nov 2015 15:33:25 +0000 (GMT) Received: from d06av05.portsmouth.uk.ibm.com (d06av05.portsmouth.uk.ibm.com [9.149.37.229]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id tADFXUPH7012736 for ; Fri, 13 Nov 2015 15:33:30 GMT Received: from d06av05.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av05.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id tADFXUMc003462 for ; Fri, 13 Nov 2015 08:33:30 -0700 Received: from d50lp01.ny.us.ibm.com ([146.89.104.207]) by d06av05.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id tADFXTGY001678 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Fri, 13 Nov 2015 08:33:30 -0700 Message-Id: <201511131533.tADFXTGY001678@d06av05.portsmouth.uk.ibm.com> Received: from /spool/local by d50lp01.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 13 Nov 2015 10:32:42 -0500 Received: from /spool/local by smtp.notes.na.collabserv.com with smtp.notes.na.collabserv.com ESMTP for from ; Fri, 13 Nov 2015 15:32:39 -0000 In-Reply-To: Subject: Re: [linux-next:master 12891/13017] mm/slub.c:2396:1: warning: '___slab_alloc' uses dynamic stack allocation From: "Andreas Krebbel1" Date: Fri, 13 Nov 2015 16:32:33 +0100 References: <201511111413.65wysS6A%fengguang.wu@intel.com><20151111124108.53df1f48218c1366f9e763f0@linux-foundation.org> <20151113125200.319a3101@mschwide> <201511131513.tADFDwJN030997@d06av03.portsmouth.uk.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="US-ASCII" Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Lameter Cc: Andrew Morton , kbuild test robot , heicars2@linux.vnet.ibm.com, kbuild-all@01.org, Linux Memory Management List , mschwid2@linux.vnet.ibm.com > On Fri, 13 Nov 2015, Andreas Krebbel1 wrote: >=20 > > this appears to be the result of aligning struct page to more than 8=20 bytes > > and putting it onto the stack - wich is only 8 bytes aligned. The > > compiler has to perform runtime alignment to achieve that. It=20 allocates > > memory using *alloca* and does the math with the returned pointer. Our > > dynamic stack allocation option basically only checks if there is an > > alloca user. >=20 > The slub uses of struct page only require an alignment of the page=20 struct > on the stack to a word. So its fine. Our compare and swap double hardware instruction unfortunately requires 16 = byte alignment. That's probably the reason why this alignment has been=20 picked. So I don't think that we can easily get rid of it. -Andreas- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org