From: Michal Hocko <mhocko@xxxxxxxx>
Subject: mm/memblock.c: do not complain about top-down allocations for !MEMORY_HOTREMOVE
Mike Rapoport is converting architectures from bootmem to nobootmem
allocator. While doing so for m68k Geert has noticed that he gets a scary
looking warning:
WARNING: CPU: 0 PID: 0 at mm/memblock.c:230
memblock_find_in_range_node+0x11c/0x1be
memblock: bottom-up allocation failed, memory hotunplug may be affected
Modules linked in:
CPU: 0 PID: 0 Comm: swapper Not tainted
4.18.0-rc3-atari-01343-gf2fb5f2e09a97a3c-dirty #7
Stack from 003c3e20:
003c3e20 0039cf44 00023800 00433000 ffffffff 00001000 00240000 000238aa
00378734 000000e6 004285ac 00000009 00000000 003c3e58 003787c0 003c3e74
003c3ea4 004285ac 00378734 000000e6 003787c0 00000000 00000000 00000001
00000000 00000010 00000000 00428490 003e3856 ffffffff ffffffff 003c3ed0
00044620 003c3ee0 00417a10 00240000 00000010 00000000 00000000 00000001
00000000 00000001 00240000 00000000 00000000 00000000 00001000 003e3856
Call Trace: [<00023800>] __warn+0xa8/0xc2
[<00001000>] kernel_pg_dir+0x0/0x1000
[<00240000>] netdev_lower_get_next+0x2/0x22
[<000238aa>] warn_slowpath_fmt+0x2e/0x36
[<004285ac>] memblock_find_in_range_node+0x11c/0x1be
[<004285ac>] memblock_find_in_range_node+0x11c/0x1be
[<00428490>] memblock_find_in_range_node+0x0/0x1be
[<00044620>] vprintk_func+0x66/0x6e
[<00417a10>] memblock_virt_alloc_internal+0xd0/0x156
[<00240000>] netdev_lower_get_next+0x2/0x22
[<00240000>] netdev_lower_get_next+0x2/0x22
[<00001000>] kernel_pg_dir+0x0/0x1000
[<00417b8c>] memblock_virt_alloc_try_nid_nopanic+0x58/0x7a
[<00240000>] netdev_lower_get_next+0x2/0x22
[<00001000>] kernel_pg_dir+0x0/0x1000
[<00001000>] kernel_pg_dir+0x0/0x1000
[<00010000>] EXPTBL+0x234/0x400
[<00010000>] EXPTBL+0x234/0x400
[<002f3644>] alloc_node_mem_map+0x4a/0x66
[<00240000>] netdev_lower_get_next+0x2/0x22
[<004155ca>] free_area_init_node+0xe2/0x29e
[<00010000>] EXPTBL+0x234/0x400
[<00411392>] paging_init+0x430/0x462
[<00001000>] kernel_pg_dir+0x0/0x1000
[<000427cc>] printk+0x0/0x1a
[<00010000>] EXPTBL+0x234/0x400
[<0041084c>] setup_arch+0x1b8/0x22c
[<0040e020>] start_kernel+0x4a/0x40a
[<0040d344>] _sinittext+0x344/0x9e8
The warning is basically saying that a top-down allocation can break
memory hotremove because memblock allocation is not movable. But m68k
doesn't even support MEMORY_HOTREMOVE so there is no point to warn about
it.
Make the warning conditional only to configurations that care.
Link: http://lkml.kernel.org/r/20180706061750.GH32658@xxxxxxxxxxxxxx
Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
Reported-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Tested-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Cc: Greg Ungerer <gerg@xxxxxxxxxxxxxx>
Cc: Sam Creasey <sammy@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memblock.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff -puN mm/memblock.c~memblock-do-not-complain-about-top-down-allocations-for-memory_hotremove mm/memblock.c
--- a/mm/memblock.c~memblock-do-not-complain-about-top-down-allocations-for-memory_hotremove
+++ a/mm/memblock.c
@@ -227,7 +227,8 @@ phys_addr_t __init_memblock memblock_fin
* so we use WARN_ONCE() here to see the stack trace if
* fail happens.
*/
- WARN_ONCE(1, "memblock: bottom-up allocation failed, memory hotunplug may be affected\n");
+ WARN_ONCE(IS_ENABLED(CONFIG_MEMORY_HOTREMOVE),
+ "memblock: bottom-up allocation failed, memory hotremove may be affected\n");
}
return __memblock_find_range_top_down(start, end, size, align, nid,
_
--
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