From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id 7A6366B00A5 for ; Mon, 18 Oct 2010 21:27:49 -0400 (EDT) Received: by qyk34 with SMTP id 34so278359qyk.14 for ; Mon, 18 Oct 2010 18:27:47 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20101018164647.bc928c78.akpm@linux-foundation.org> References: <20101016043331.GA3177@darkstar> <20101018164647.bc928c78.akpm@linux-foundation.org> Date: Tue, 19 Oct 2010 09:27:47 +0800 Message-ID: Subject: Re: [PATCH 1/2] Add vzalloc shortcut From: Dave Young Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org To: Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, kvm@vger.kernel.org List-ID: On Tue, Oct 19, 2010 at 7:46 AM, Andrew Morton wrote: > On Sat, 16 Oct 2010 12:33:31 +0800 > Dave Young wrote: > >> Add vzalloc for convinience of vmalloc-then-memset-zero case >> >> Use __GFP_ZERO in vzalloc to zero fill the allocated memory. >> >> Signed-off-by: Dave Young >> --- >> =C2=A0include/linux/vmalloc.h | =C2=A0 =C2=A01 + >> =C2=A0mm/vmalloc.c =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0| =C2=A0 13 = +++++++++++++ >> =C2=A02 files changed, 14 insertions(+) >> >> --- linux-2.6.orig/include/linux/vmalloc.h =C2=A0 =C2=A02010-08-22 15:31= :38.000000000 +0800 >> +++ linux-2.6/include/linux/vmalloc.h 2010-10-16 10:50:54.739996121 +080= 0 >> @@ -53,6 +53,7 @@ static inline void vmalloc_init(void) >> =C2=A0#endif >> >> =C2=A0extern void *vmalloc(unsigned long size); >> +extern void *vzalloc(unsigned long size); >> =C2=A0extern void *vmalloc_user(unsigned long size); >> =C2=A0extern void *vmalloc_node(unsigned long size, int node); >> =C2=A0extern void *vmalloc_exec(unsigned long size); >> --- linux-2.6.orig/mm/vmalloc.c =C2=A0 =C2=A0 =C2=A0 2010-08-22 15:31:39= .000000000 +0800 >> +++ linux-2.6/mm/vmalloc.c =C2=A0 =C2=A02010-10-16 10:51:57.126665918 +0= 800 >> @@ -1604,6 +1604,19 @@ void *vmalloc(unsigned long size) >> =C2=A0EXPORT_SYMBOL(vmalloc); >> >> =C2=A0/** >> + * =C2=A0 vzalloc =C2=A0- =C2=A0allocate virtually contiguous memory wi= th zero filled > > s/filled/fill/ Thanks, Will fix > >> + * =C2=A0 @size: =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0allocation size >> + * =C2=A0 Allocate enough pages to cover @size from the page level >> + * =C2=A0 allocator and map them into contiguous kernel virtual space. >> + */ >> +void *vzalloc(unsigned long size) >> +{ >> + =C2=A0 =C2=A0 return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_HIGHME= M | __GFP_ZERO, >> + =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 PAGE_KERNEL, -1, __builtin_return_address(0)); >> +} >> +EXPORT_SYMBOL(vzalloc); > > We'd need to add the same interface to nommu, please. Ok, will do Minchan kim, thanks as well. I missed your comments about nommu before. > > Also, a slightly better implementation would be > > static inline void *__vmalloc_node_flags(unsigned long size, gfp_t flags) > { > =C2=A0 =C2=A0 =C2=A0 =C2=A0return __vmalloc_node(size, 1, flags, PAGE_KER= NEL, -1, > =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0__builtin_return_address(0)); > } > > void *vzalloc(unsigned long size) > { > =C2=A0 =C2=A0 =C2=A0 =C2=A0return __vmalloc_node_flags(size, > =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZE= RO); > } > > void *vmalloc(unsigned long size) > { > =C2=A0 =C2=A0 =C2=A0 =C2=A0return __vmalloc_node_flags(size, GFP_KERNEL |= __GFP_HIGHMEM); > } > > just to avoid code duplication (and possible later errors derived from it= ). > > Perhaps it should be always_inline, so the __builtin_return_address() > can't get broken. > > Or just leave it the way you had it :) Andrew, your suggestion is cleaner and better. I will do as yours. --=20 Regards dave -- 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