From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752592AbdEILTi (ORCPT ); Tue, 9 May 2017 07:19:38 -0400 Received: from mx2.suse.de ([195.135.220.15]:35996 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751306AbdEILTg (ORCPT ); Tue, 9 May 2017 07:19:36 -0400 Date: Tue, 9 May 2017 13:19:34 +0200 From: Michal Hocko To: Andrew Morton Cc: kbuild-all@01.org, kbuild test robot , Vlastimil Babka , linux-mm@kvack.org, LKML Subject: Re: [PATCH] mm, vmalloc: properly track vmalloc users Message-ID: <20170509111934.GI6481@dhcp22.suse.cz> References: <20170502134657.12381-1-mhocko@kernel.org> <201705030806.pzzQRBiN%fengguang.wu@intel.com> <20170503063750.GC1236@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170503063750.GC1236@dhcp22.suse.cz> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 03-05-17 08:37:50, Michal Hocko wrote: > From 33a6239135cb444654f48d5e942e7f34898e24ea Mon Sep 17 00:00:00 2001 > From: Michal Hocko > Date: Tue, 2 May 2017 11:18:29 +0200 > Subject: [PATCH] mm, vmalloc: properly track vmalloc users > > __vmalloc_node_flags used to be static inline but this has changed by > "mm: introduce kv[mz]alloc helpers" because kvmalloc_node needs to use > it as well and the code is outside of the vmalloc proper. I haven't > realized that changing this will lead to a subtle bug though. The > function is responsible to track the caller as well. This caller is > then printed by /proc/vmallocinfo. If __vmalloc_node_flags is not inline > then we would get only direct users of __vmalloc_node_flags as callers > (e.g. v[mz]alloc) which reduces usefulness of this debugging feature > considerably. It simply doesn't help to see that the given range belongs > to vmalloc as a caller: > 0xffffc90002c79000-0xffffc90002c7d000 16384 vmalloc+0x16/0x18 pages=3 vmalloc N0=3 > 0xffffc90002c81000-0xffffc90002c85000 16384 vmalloc+0x16/0x18 pages=3 vmalloc N1=3 > 0xffffc90002c8d000-0xffffc90002c91000 16384 vmalloc+0x16/0x18 pages=3 vmalloc N1=3 > 0xffffc90002c95000-0xffffc90002c99000 16384 vmalloc+0x16/0x18 pages=3 vmalloc N1=3 > > We really want to catch the _caller_ of the vmalloc function. Fix this > issue by making __vmalloc_node_flags static inline again and export > __vmalloc_node_flags_caller for kvmalloc_node(). > The "mm: introduce kv[mz]alloc helpers" got merged in the mean time so I believe the patch should mention Fixes: a7c3e901a46f ("mm: introduce kv[mz]alloc helpers") > Signed-off-by: Michal Hocko > --- > include/linux/vmalloc.h | 16 +++++++++++++++- > mm/util.c | 3 ++- > mm/vmalloc.c | 8 +++++++- > 3 files changed, 24 insertions(+), 3 deletions(-) > > diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h > index 46991ad3ddd5..4a0fabeb1e92 100644 > --- a/include/linux/vmalloc.h > +++ b/include/linux/vmalloc.h > @@ -80,7 +80,21 @@ extern void *__vmalloc_node_range(unsigned long size, unsigned long align, > unsigned long start, unsigned long end, gfp_t gfp_mask, > pgprot_t prot, unsigned long vm_flags, int node, > const void *caller); > -extern void *__vmalloc_node_flags(unsigned long size, int node, gfp_t flags); > +#ifndef CONFIG_MMU > +extern void *__vmalloc_node_flags_caller(unsigned long size, int node, gfp_t flags); > +static inline void *__vmalloc_node_flags_caller(unsigned long size, int node, gfp_t flags, void* caller) > +{ > + return __vmalloc_node_flags(size, node, flags); > +} > +#else > +/* > + * We really want to have this inlined due to caller tracking. This > + * function is used by the highlevel vmalloc apis and so we want to track > + * their callers and inlining will achieve that. > + */ > +extern void *__vmalloc_node_flags_caller(unsigned long size, > + int node, gfp_t flags, void* caller); > +#endif > > extern void vfree(const void *addr); > extern void vfree_atomic(const void *addr); > diff --git a/mm/util.c b/mm/util.c > index 3022051da938..c35e5870921d 100644 > --- a/mm/util.c > +++ b/mm/util.c > @@ -380,7 +380,8 @@ void *kvmalloc_node(size_t size, gfp_t flags, int node) > if (ret || size <= PAGE_SIZE) > return ret; > > - return __vmalloc_node_flags(size, node, flags); > + return __vmalloc_node_flags_caller(size, node, flags, > + __builtin_return_address(0)); > } > EXPORT_SYMBOL(kvmalloc_node); > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 65912eb93a2c..1a97d4a31406 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -1809,13 +1809,19 @@ void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot) > } > EXPORT_SYMBOL(__vmalloc); > > -void *__vmalloc_node_flags(unsigned long size, > +static inline void *__vmalloc_node_flags(unsigned long size, > int node, gfp_t flags) > { > return __vmalloc_node(size, 1, flags, PAGE_KERNEL, > node, __builtin_return_address(0)); > } > > + > +void *__vmalloc_node_flags_caller(unsigned long size, int node, gfp_t flags, void *caller) > +{ > + return __vmalloc_node(size, 1, flags, PAGE_KERNEL, node, caller); > +} > + > /** > * vmalloc - allocate virtually contiguous memory > * @size: allocation size > -- > 2.11.0 > > -- > Michal Hocko > SUSE Labs -- Michal Hocko SUSE Labs