From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f200.google.com (mail-wr0-f200.google.com [209.85.128.200]) by kanga.kvack.org (Postfix) with ESMTP id 3CAB72806E3 for ; Tue, 22 Aug 2017 13:50:38 -0400 (EDT) Received: by mail-wr0-f200.google.com with SMTP id p67so16488495wrb.10 for ; Tue, 22 Aug 2017 10:50:38 -0700 (PDT) Received: from mail-wm0-x243.google.com (mail-wm0-x243.google.com. [2a00:1450:400c:c09::243]) by mx.google.com with ESMTPS id c30si2546645edc.316.2017.08.22.10.50.36 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 22 Aug 2017 10:50:36 -0700 (PDT) Received: by mail-wm0-x243.google.com with SMTP id q189so9257879wmd.0 for ; Tue, 22 Aug 2017 10:50:36 -0700 (PDT) Date: Tue, 22 Aug 2017 20:50:32 +0300 From: "Kirill A. Shutemov" Subject: Re: [PATCHv5 01/19] mm/sparsemem: Allocate mem_section at runtime for SPARSEMEM_EXTREME Message-ID: <20170822175032.jybf4q35s5lxrfun@node.shutemov.name> References: <20170821152916.40124-1-kirill.shutemov@linux.intel.com> <20170821152916.40124-2-kirill.shutemov@linux.intel.com> <20170822162826.umma52xs6qotz2l2@pd.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20170822162826.umma52xs6qotz2l2@pd.tnic> Sender: owner-linux-mm@kvack.org List-ID: To: Borislav Petkov Cc: "Kirill A. Shutemov" , Linus Torvalds , x86@kernel.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Andrew Morton , Andy Lutomirski , Dmitry Safonov , Cyrill Gorcunov , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Tue, Aug 22, 2017 at 06:28:26PM +0200, Borislav Petkov wrote: > On Mon, Aug 21, 2017 at 06:28:58PM +0300, Kirill A. Shutemov wrote: > > Size of mem_section array depends on size of physical address space. > > > > In preparation for boot-time switching between paging modes on x86-64 > > we need to make allocation of mem_section dynamic. > > > > The patch allocates the array on the first call to > > sparse_memory_present_with_active_regions(). > > > > Signed-off-by: Kirill A. Shutemov > > --- > > include/linux/mmzone.h | 6 +++++- > > mm/page_alloc.c | 10 ++++++++++ > > mm/sparse.c | 17 +++++++++++------ > > 3 files changed, 26 insertions(+), 7 deletions(-) > > This patch needs running through checkpatch: > > ERROR: code indent should use tabs where possible > #53: FILE: include/linux/mmzone.h:1148: > + if (!mem_section)$ > > WARNING: please, no spaces at the start of a line > #53: FILE: include/linux/mmzone.h:1148: > + if (!mem_section)$ > > ERROR: code indent should use tabs where possible > #54: FILE: include/linux/mmzone.h:1149: > + return NULL;$ > > WARNING: please, no spaces at the start of a line > #54: FILE: include/linux/mmzone.h:1149: > + return NULL;$ > > ERROR: "foo* bar" should be "foo *bar" > #99: FILE: mm/sparse.c:106: > + struct mem_section* root = NULL; > > ERROR: do not initialise statics to 0 > #118: FILE: mm/sparse.c:335: > + static unsigned long old_usemap_snr = 0; > > ERROR: do not initialise statics to 0 > #119: FILE: mm/sparse.c:336: > + static unsigned long old_pgdat_snr = 0; > > You should integrate it into your patch creation workflow. Sorry for this. > > diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h > > index fc14b8b3f6ce..9799c2c58ce6 100644 > > --- a/include/linux/mmzone.h > > +++ b/include/linux/mmzone.h > > @@ -1137,13 +1137,17 @@ struct mem_section { > > #define SECTION_ROOT_MASK (SECTIONS_PER_ROOT - 1) > > > > #ifdef CONFIG_SPARSEMEM_EXTREME > > -extern struct mem_section *mem_section[NR_SECTION_ROOTS]; > > +extern struct mem_section **mem_section; > > #else > > extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT]; > > #endif > > > > static inline struct mem_section *__nr_to_section(unsigned long nr) > > { > > +#ifdef CONFIG_SPARSEMEM_EXTREME > > + if (!mem_section) > > + return NULL; > > +#endif > > if (!mem_section[SECTION_NR_TO_ROOT(nr)]) > > return NULL; > > return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK]; > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > > index 6d30e914afb6..639fd2dce0c4 100644 > > --- a/mm/page_alloc.c > > +++ b/mm/page_alloc.c > > @@ -5681,6 +5681,16 @@ void __init sparse_memory_present_with_active_regions(int nid) > > unsigned long start_pfn, end_pfn; > > int i, this_nid; > > > > +#ifdef CONFIG_SPARSEMEM_EXTREME > > + if (!mem_section) { > > Any chance this ifdeffery and above can use IS_ENABLED() instead? Unfortunately, no. This case cannot be changed to IS_ENABLED() as we don't define mem_section and NR_SECTION_ROOTS for !SPARSEMEM. The case above cannot be changed as GCC would complain in case of !SPARSEMEM_EXTREME: warning: the address of a??mem_sectiona?? will always evaluate as a??truea?? -- Kirill A. Shutemov -- 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