mm: don't do zero_resv_unavail if memmap is not allocated

BugLink: http://bugs.launchpad.net/bugs/1810554
commit d1b47a7c9efcf3c3384b70f6e3c8f1423b44d8c7 upstream.

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: e181ae0c5db9 ("mm: zero unavailable pages before memmap init")
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Tested-by: Matt Hart <matt@mattface.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/include/linux/mm.h b/include/linux/mm.h
index eec91ec0df2a9a7b3bacb343cbd0e966b2f40d02..0d15c7463ccef968f1d4fa22d77864678fe75b23 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2084,7 +2084,7 @@ 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) {}

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 6707a7f307e39f907ae19ec17c5eac02fa5d2ca2..d879129e43f47160755b5fd48f3b5ea877bd1062 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6239,7 +6239,7 @@ 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
@@ -6277,7 +6277,7 @@ 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