On Thu, May 02, 2019 at 04:20:03PM -0700, Dan Williams wrote:
> On Thu, May 2, 2019 at 3:46 PM Pavel Tatashin <pasha.tatashin@xxxxxxxxxx> wrote:
> >
> > Hi Dan,
> >
> > How do you test these patches? Do you have any instructions?
>
> Yes, I briefly mentioned this in the cover letter, but here is the
> test I am using:
>
> >
> > I see for example that check_hotplug_memory_range() still enforces
> > memory_block_size_bytes() alignment.
> >
> > Also, after removing check_hotplug_memory_range(), I tried to online
> > 16M aligned DAX memory, and got the following panic:
>
> Right, this functionality is currently strictly limited to the
> devm_memremap_pages() case where there are guarantees that the memory
> will never be onlined. This is due to the fact that the section size
> is entangled with the memblock api. That said I would have expected
> you to trigger the warning in subsection_check() before getting this
> far into the hotplug process.
> >
> > # echo online > /sys/devices/system/memory/memory7/state
> > [ 202.193132] WARNING: CPU: 2 PID: 351 at drivers/base/memory.c:207
> > memory_block_action+0x110/0x178
> > [ 202.193391] Modules linked in:
> > [ 202.193698] CPU: 2 PID: 351 Comm: sh Not tainted
> > 5.1.0-rc7_pt_devdax-00038-g865af4385544-dirty #9
> > [ 202.193909] Hardware name: linux,dummy-virt (DT)
> > [ 202.194122] pstate: 60000005 (nZCv daif -PAN -UAO)
> > [ 202.194243] pc : memory_block_action+0x110/0x178
> > [ 202.194404] lr : memory_block_action+0x90/0x178
> > [ 202.194506] sp : ffff000016763ca0
> > [ 202.194592] x29: ffff000016763ca0 x28: ffff80016fd29b80
> > [ 202.194724] x27: 0000000000000000 x26: 0000000000000000
> > [ 202.194838] x25: ffff000015546000 x24: 00000000001c0000
> > [ 202.194949] x23: 0000000000000000 x22: 0000000000040000
> > [ 202.195058] x21: 00000000001c0000 x20: 0000000000000008
> > [ 202.195168] x19: 0000000000000007 x18: 0000000000000000
> > [ 202.195281] x17: 0000000000000000 x16: 0000000000000000
> > [ 202.195393] x15: 0000000000000000 x14: 0000000000000000
> > [ 202.195505] x13: 0000000000000000 x12: 0000000000000000
> > [ 202.195614] x11: 0000000000000000 x10: 0000000000000000
> > [ 202.195744] x9 : 0000000000000000 x8 : 0000000180000000
> > [ 202.195858] x7 : 0000000000000018 x6 : ffff000015541930
> > [ 202.195966] x5 : ffff000015541930 x4 : 0000000000000001
> > [ 202.196074] x3 : 0000000000000001 x2 : 0000000000000000
> > [ 202.196185] x1 : 0000000000000070 x0 : 0000000000000000
> > [ 202.196366] Call trace:
> > [ 202.196455] memory_block_action+0x110/0x178
> > [ 202.196589] memory_subsys_online+0x3c/0x80
> > [ 202.196681] device_online+0x6c/0x90
> > [ 202.196761] state_store+0x84/0x100
> > [ 202.196841] dev_attr_store+0x18/0x28
> > [ 202.196927] sysfs_kf_write+0x40/0x58
> > [ 202.197010] kernfs_fop_write+0xcc/0x1d8
> > [ 202.197099] __vfs_write+0x18/0x40
> > [ 202.197187] vfs_write+0xa4/0x1b0
> > [ 202.197295] ksys_write+0x64/0xd8
> > [ 202.197430] __arm64_sys_write+0x18/0x20
> > [ 202.197521] el0_svc_common.constprop.0+0x7c/0xe8
> > [ 202.197621] el0_svc_handler+0x28/0x78
> > [ 202.197706] el0_svc+0x8/0xc
> > [ 202.197828] ---[ end trace 57719823dda6d21e ]---
This warning relates to:
for (; section_nr < section_nr_end; section_nr++) {
if (WARN_ON_ONCE(!pfn_valid(pfn)))
return false;
from pages_correctly_probed().
AFAICS, this is orthogonal to subsection_check().
--
Oscar Salvador
SUSE L3
