在 2023/9/6 10:32, Muchun Song 写道:
On Sep 6, 2023, at 08:28, Mike Kravetz <mike.kravetz@xxxxxxxxxx> wrote:
On 09/05/23 17:06, Muchun Song wrote:
On Sep 5, 2023, at 11:13, Yuan Can <yuancan@xxxxxxxxxx> wrote:
The decreasing of hugetlb pages number failed with the following message
given:
sh: page allocation failure: order:0, mode:0x204cc0(GFP_KERNEL|__GFP_RETRY_MAYFAIL|__GFP_THISNODE)
CPU: 1 PID: 112 Comm: sh Not tainted 6.5.0-rc7-... #45
Hardware name: linux,dummy-virt (DT)
Call trace:
dump_backtrace.part.6+0x84/0xe4
show_stack+0x18/0x24
dump_stack_lvl+0x48/0x60
dump_stack+0x18/0x24
warn_alloc+0x100/0x1bc
__alloc_pages_slowpath.constprop.107+0xa40/0xad8
__alloc_pages+0x244/0x2d0
hugetlb_vmemmap_restore+0x104/0x1e4
__update_and_free_hugetlb_folio+0x44/0x1f4
update_and_free_hugetlb_folio+0x20/0x68
update_and_free_pages_bulk+0x4c/0xac
set_max_huge_pages+0x198/0x334
nr_hugepages_store_common+0x118/0x178
nr_hugepages_store+0x18/0x24
kobj_attr_store+0x18/0x2c
sysfs_kf_write+0x40/0x54
kernfs_fop_write_iter+0x164/0x1dc
vfs_write+0x3a8/0x460
ksys_write+0x6c/0x100
__arm64_sys_write+0x1c/0x28
invoke_syscall+0x44/0x100
el0_svc_common.constprop.1+0x6c/0xe4
do_el0_svc+0x38/0x94
el0_svc+0x28/0x74
el0t_64_sync_handler+0xa0/0xc4
el0t_64_sync+0x174/0x178
Mem-Info:
...
The reason is that the hugetlb pages being released are allocated from
movable nodes, and with hugetlb_optimize_vmemmap enabled, vmemmap pages
need to be allocated from the same node during the hugetlb pages
Thanks for your fix, I think it should be a real word issue, it's better
to add a Fixes tag to indicate backporting. Thanks.
I thought we might get get the same error (Unable to allocate on movable
node) when creating the hugetlb page. Why? Because we replace the head
vmemmap page. However, I see that failure to allocate there is not a
fatal error and we fallback to the currently mapped page. We also pass
__GFP_NOWARN to that allocation attempt so there will be no report of the
failure.
We might want to change this as well?
I think yes. I also thought about this yesterday, but I think
this one is not a fetal error, it should be an improvement patch.
So it is better not to fold this change into this patch (a bug fix one).
Thanks.
Sure, let me send another patch passing __GFP_NOWARN.
--
Best regards,
Yuan Can
