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authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2017-09-29 17:08:16 +0300
committerIngo Molnar <mingo@kernel.org>2017-10-20 14:07:09 +0300
commit83e3c48729d9ebb7af5a31a504f3fd6aff0348c4 (patch)
tree9e42ac40f3bb837359325e0b247ec8e16c1c0b52 /mm/sparse.c
parent967535223f9a8d95c187a8728480b569164cd4f4 (diff)
downloadlinux-83e3c48729d9ebb7af5a31a504f3fd6aff0348c4.tar.xz
mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y
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@linux.intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@suse.de> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20170929140821.37654-2-kirill.shutemov@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'mm/sparse.c')
-rw-r--r--mm/sparse.c17
1 files changed, 11 insertions, 6 deletions
diff --git a/mm/sparse.c b/mm/sparse.c
index 83b3bf6461af..b00a97398795 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -22,8 +22,7 @@
* 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;
@@ -100,7 +99,7 @@ static inline int sparse_index_init(unsigned long section_nr, int nid)
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);
@@ -111,7 +110,7 @@ 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);
}
@@ -329,11 +328,17 @@ 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)