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Commit d1b47a7c authored by Pavel Tatashin's avatar Pavel Tatashin Committed by Linus Torvalds
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mm: don't do zero_resv_unavail if memmap is not allocated 



Moving zero_resv_unavail before memmap_init_zone(), caused a regression on
x86-32.

The cause is that we access struct pages before they are allocated when
CONFIG_FLAT_NODE_MEM_MAP is used.

free_area_init_nodes()
  zero_resv_unavail()
    mm_zero_struct_page(pfn_to_page(pfn)); <- struct page is not alloced
  free_area_init_node()
    if CONFIG_FLAT_NODE_MEM_MAP
      alloc_node_mem_map()
        memblock_virt_alloc_node_nopanic() <- struct page alloced here

On the other hand memblock_virt_alloc_node_nopanic() zeroes all the memory
that it returns, so we do not need to do zero_resv_unavail() here.

Fixes: e181ae0c ("mm: zero unavailable pages before memmap init")
Signed-off-by: default avatarPavel Tatashin <pasha.tatashin@oracle.com>
Tested-by: default avatarMatt Hart <matt@mattface.org>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 9d3cce1e

include/linux/mm.h

+1 −1
Original line number Diff line number Diff line
@@ -2132,7 +2132,7 @@ extern int __meminit __early_pfn_to_nid(unsigned long pfn, 
					struct mminit_pfnnid_cache *state);

#endif



#ifdef CONFIG_HAVE_MEMBLOCK

#if defined(CONFIG_HAVE_MEMBLOCK) && !defined(CONFIG_FLAT_NODE_MEM_MAP)

void zero_resv_unavail(void);

#else

static inline void zero_resv_unavail(void) {}

mm/page_alloc.c

+2 −2
Original line number Diff line number Diff line
@@ -6383,7 +6383,7 @@ void __paginginit free_area_init_node(int nid, unsigned long *zones_size, 
	free_area_init_core(pgdat);

}



#ifdef CONFIG_HAVE_MEMBLOCK

#if defined(CONFIG_HAVE_MEMBLOCK) && !defined(CONFIG_FLAT_NODE_MEM_MAP)

/*

 * Only struct pages that are backed by physical memory are zeroed and

 * initialized by going through __init_single_page(). But, there are some
@@ -6421,7 +6421,7 @@ void __paginginit zero_resv_unavail(void) 
	if (pgcnt)

		pr_info("Reserved but unavailable: %lld pages", pgcnt);

}

#endif /* CONFIG_HAVE_MEMBLOCK */

#endif /* CONFIG_HAVE_MEMBLOCK && !CONFIG_FLAT_NODE_MEM_MAP */



#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP