On Wed, Jul 04, 2018 at 02:36:27PM +0200, Michal Hocko wrote: > [CC Andrew - email thread starts > http://lkml.kernel.org/r/1530685696-14672-1-git-send-email-rppt@xxxxxxxxxxxxxxxxxx] > > OK, so here we go with the full patch. > > From 0e8432b875d98a7a0d3f757fce2caa8d16a8de15 Mon Sep 17 00:00:00 2001 > From: Michal Hocko <mhocko@xxxxxxxx> > Date: Wed, 4 Jul 2018 14:31:46 +0200 > Subject: [PATCH] memblock: do not complain about top-down allocations for > !MEMORY_HOTREMOVE > > Mike Rapoport is converting architectures from bootmem to noboodmem > 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 is there is no point to warn > about it. > > Make the warning conditional only to configurations that care. > > Reported-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> > Tested-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> > Signed-off-by: Michal Hocko <mhocko@xxxxxxxx> > --- > mm/memblock.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/mm/memblock.c b/mm/memblock.c > index 03d48d8835ba..2acec4033389 100644 > --- a/mm/memblock.c > +++ b/mm/memblock.c > @@ -227,7 +227,8 @@ phys_addr_t __init_memblock memblock_find_in_range_node(phys_addr_t size, > * 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"); nit: isn't the warning indented too much? > } > > return __memblock_find_range_top_down(start, end, size, align, nid, > -- > 2.18.0 > > -- > Michal Hocko > SUSE Labs > -- Sincerely yours, Mike.
