From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f72.google.com (mail-wm0-f72.google.com [74.125.82.72]) by kanga.kvack.org (Postfix) with ESMTP id 5B25E6B0266 for ; Sun, 7 Jan 2018 00:14:32 -0500 (EST) Received: by mail-wm0-f72.google.com with SMTP id w74so2290797wmf.0 for ; Sat, 06 Jan 2018 21:14:32 -0800 (PST) Received: from mout.gmx.net (mout.gmx.net. [212.227.17.20]) by mx.google.com with ESMTPS id v7si3622782wre.538.2018.01.06.21.14.30 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 06 Jan 2018 21:14:30 -0800 (PST) Message-ID: <1515302062.6507.18.camel@gmx.de> Subject: Re: [PATCH 4.14 023/159] mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y From: Mike Galbraith Date: Sun, 07 Jan 2018 06:14:22 +0100 In-Reply-To: <20171222084625.007160464@linuxfoundation.org> References: <20171222084623.668990192@linuxfoundation.org> <20171222084625.007160464@linuxfoundation.org> Content-Type: text/plain; charset="ISO-8859-15" Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: Greg Kroah-Hartman , linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org, "Kirill A. Shutemov" , Andrew Morton , Andy Lutomirski , Borislav Petkov , Cyrill Gorcunov , Linus Torvalds , Peter Zijlstra , Thomas Gleixner , linux-mm@kvack.org, Ingo Molnar On Fri, 2017-12-22 at 09:45 +0100, Greg Kroah-Hartman wrote: > 4.14-stable review patch. If anyone has any objections, please let me kn= ow. FYI, this broke kdump, or rather the makedumpfile part thereof. =A0Forward looking wreckage is par for the kdump course, but... > ------------------ >=20 > From: Kirill A. Shutemov >=20 > commit 83e3c48729d9ebb7af5a31a504f3fd6aff0348c4 upstream. >=20 > Size of the mem_section[] array depends on the size of the physical addre= ss space. >=20 > In preparation for boot-time switching between paging modes on x86-64 > we need to make the allocation of mem_section[] dynamic, because otherwis= e > we waste a lot of RAM: with CONFIG_NODE_SHIFT=3D10, mem_section[] size is= 32kB > for 4-level paging and 2MB for 5-level paging mode. >=20 > The patch allocates the array on the first call to sparse_memory_present_= with_active_regions(). >=20 > Signed-off-by: Kirill A. Shutemov > Cc: Andrew Morton > Cc: Andy Lutomirski > Cc: Borislav Petkov > Cc: Cyrill Gorcunov > Cc: Linus Torvalds > Cc: Peter Zijlstra > Cc: Thomas Gleixner > Cc: linux-mm@kvack.org > Link: http://lkml.kernel.org/r/20170929140821.37654-2-kirill.shutemov@lin= ux.intel.com > Signed-off-by: Ingo Molnar > Signed-off-by: Greg Kroah-Hartman >=20 > --- > include/linux/mmzone.h | 6 +++++- > mm/page_alloc.c | 10 ++++++++++ > mm/sparse.c | 17 +++++++++++------ > 3 files changed, 26 insertions(+), 7 deletions(-) >=20 > --- a/include/linux/mmzone.h > +++ b/include/linux/mmzone.h > @@ -1152,13 +1152,17 @@ struct mem_section { > #define SECTION_ROOT_MASK (SECTIONS_PER_ROOT - 1) > =20 > #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_ROO= T]; > #endif > =20 > 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]; > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -5651,6 +5651,16 @@ void __init sparse_memory_present_with_a > unsigned long start_pfn, end_pfn; > int i, this_nid; > =20 > +#ifdef CONFIG_SPARSEMEM_EXTREME > + if (!mem_section) { > + unsigned long size, align; > + > + size =3D sizeof(struct mem_section) * NR_SECTION_ROOTS; > + align =3D 1 << (INTERNODE_CACHE_SHIFT); > + mem_section =3D memblock_virt_alloc(size, align); > + } > +#endif > + > for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid) > memory_present(this_nid, start_pfn, end_pfn); > } > --- a/mm/sparse.c > +++ b/mm/sparse.c > @@ -23,8 +23,7 @@ > * 1) mem_section - memory sections, mem_map's for valid memory > */ > #ifdef CONFIG_SPARSEMEM_EXTREME > -struct mem_section *mem_section[NR_SECTION_ROOTS] > - ____cacheline_internodealigned_in_smp; > +struct mem_section **mem_section; > #else > struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT] > ____cacheline_internodealigned_in_smp; > @@ -101,7 +100,7 @@ static inline int sparse_index_init(unsi > int __section_nr(struct mem_section* ms) > { > unsigned long root_nr; > - struct mem_section* root; > + struct mem_section *root =3D NULL; > =20 > for (root_nr =3D 0; root_nr < NR_SECTION_ROOTS; root_nr++) { > root =3D __nr_to_section(root_nr * SECTIONS_PER_ROOT); > @@ -112,7 +111,7 @@ int __section_nr(struct mem_section* ms) > break; > } > =20 > - VM_BUG_ON(root_nr =3D=3D NR_SECTION_ROOTS); > + VM_BUG_ON(!root); > =20 > return (root_nr * SECTIONS_PER_ROOT) + (ms - root); > } > @@ -330,11 +329,17 @@ again: > static void __init check_usemap_section_nr(int nid, unsigned long *usema= p) > { > unsigned long usemap_snr, pgdat_snr; > - static unsigned long old_usemap_snr =3D NR_MEM_SECTIONS; > - static unsigned long old_pgdat_snr =3D NR_MEM_SECTIONS; > + static unsigned long old_usemap_snr; > + static unsigned long old_pgdat_snr; > struct pglist_data *pgdat =3D NODE_DATA(nid); > int usemap_nid; > =20 > + /* First call */ > + if (!old_usemap_snr) { > + old_usemap_snr =3D NR_MEM_SECTIONS; > + old_pgdat_snr =3D NR_MEM_SECTIONS; > + } > + > usemap_snr =3D pfn_to_section_nr(__pa(usemap) >> PAGE_SHIFT); > pgdat_snr =3D pfn_to_section_nr(__pa(pgdat) >> PAGE_SHIFT); > if (usemap_snr =3D=3D pgdat_snr) >=20 >=20 -- 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