On Fri, Dec 22, 2017 at 09:45:08AM +0100, Greg Kroah-Hartman wrote: > 4.14-stable review patch. If anyone has any objections, please let me know. > > ------------------ > > From: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> > > commit 83e3c48729d9ebb7af5a31a504f3fd6aff0348c4 upstream. > > Size of the mem_section[] array depends on the size of the physical address space. > > In preparation for boot-time switching between paging modes on x86-64 > we need to make the allocation of mem_section[] dynamic, because otherwise > we waste a lot of RAM: with CONFIG_NODE_SHIFT=10, mem_section[] size is 32kB > for 4-level paging and 2MB for 5-level paging mode. > > The patch allocates the array on the first call to sparse_memory_present_with_active_regions(). > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx> > Cc: Borislav Petkov <bp@xxxxxxx> > Cc: Cyrill Gorcunov <gorcunov@xxxxxxxxxx> > Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> > Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > Cc: linux-mm@xxxxxxxxx > Link: http://lkml.kernel.org/r/20170929140821.37654-2-kirill.shutemov@xxxxxxxxxxxxxxx > Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> This patch causes a boot failure on arm64. Please drop this patch, or pick up the fix in: commit 629a359bdb0e0652a8227b4ff3125431995fec6e Author: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Date: Tue Nov 7 11:33:37 2017 +0300 mm/sparsemem: Fix ARM64 boot crash when CONFIG_SPARSEMEM_EXTREME=y See https://www.mail-archive.com/linux-kernel@xxxxxxxxxxxxxxx/msg1527427.html > > --- > include/linux/mmzone.h | 6 +++++- > mm/page_alloc.c | 10 ++++++++++ > mm/sparse.c | 17 +++++++++++------ > 3 files changed, 26 insertions(+), 7 deletions(-) > > --- 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) > > #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]; > --- 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; > > +#ifdef CONFIG_SPARSEMEM_EXTREME > + if (!mem_section) { > + unsigned long size, align; > + > + size = sizeof(struct mem_section) * NR_SECTION_ROOTS; > + align = 1 << (INTERNODE_CACHE_SHIFT); > + mem_section = 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 = NULL; > > for (root_nr = 0; root_nr < NR_SECTION_ROOTS; root_nr++) { > root = __nr_to_section(root_nr * SECTIONS_PER_ROOT); > @@ -112,7 +111,7 @@ int __section_nr(struct mem_section* ms) > break; > } > > - VM_BUG_ON(root_nr == NR_SECTION_ROOTS); > + VM_BUG_ON(!root); > > return (root_nr * SECTIONS_PER_ROOT) + (ms - root); > } > @@ -330,11 +329,17 @@ again: > static void __init check_usemap_section_nr(int nid, unsigned long *usemap) > { > unsigned long usemap_snr, pgdat_snr; > - static unsigned long old_usemap_snr = NR_MEM_SECTIONS; > - static unsigned long old_pgdat_snr = NR_MEM_SECTIONS; > + static unsigned long old_usemap_snr; > + static unsigned long old_pgdat_snr; > struct pglist_data *pgdat = NODE_DATA(nid); > int usemap_nid; > > + /* First call */ > + if (!old_usemap_snr) { > + old_usemap_snr = NR_MEM_SECTIONS; > + old_pgdat_snr = NR_MEM_SECTIONS; > + } > + > usemap_snr = pfn_to_section_nr(__pa(usemap) >> PAGE_SHIFT); > pgdat_snr = pfn_to_section_nr(__pa(pgdat) >> PAGE_SHIFT); > if (usemap_snr == pgdat_snr) > > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. 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