diff options
| author | Yang Shi <yang@os.amperecomputing.com> | 2023-12-20 22:59:43 -0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-01-25 23:52:20 -0800 |
| commit | c4608d1bf7c6536d1a3d233eb21e50678681564e (patch) | |
| tree | 641888c2d653c4700733dd57821f30f09052fa9f | |
| parent | 4dca82d14174fe53f656a6bc32398db1bdd8f481 (diff) | |
mm: mmap: map MAP_STACK to VM_NOHUGEPAGE
commit efa7df3e3bb5 ("mm: align larger anonymous mappings on THP
boundaries") incured regression for stress-ng pthread benchmark [1]. It
is because THP get allocated to pthread's stack area much more possible
than before. Pthread's stack area is allocated by mmap without
VM_GROWSDOWN or VM_GROWSUP flag, so kernel can't tell whether it is a
stack area or not.
The MAP_STACK flag is used to mark the stack area, but it is a no-op on
Linux. Mapping MAP_STACK to VM_NOHUGEPAGE to prevent from allocating THP
for such stack area.
With this change the stack area looks like:
fffd18e10000-fffd19610000 rw-p 00000000 00:00 0
Size: 8192 kB
KernelPageSize: 4 kB
MMUPageSize: 4 kB
Rss: 12 kB
Pss: 12 kB
Pss_Dirty: 12 kB
Shared_Clean: 0 kB
Shared_Dirty: 0 kB
Private_Clean: 0 kB
Private_Dirty: 12 kB
Referenced: 12 kB
Anonymous: 12 kB
KSM: 0 kB
LazyFree: 0 kB
AnonHugePages: 0 kB
ShmemPmdMapped: 0 kB
FilePmdMapped: 0 kB
Shared_Hugetlb: 0 kB
Private_Hugetlb: 0 kB
Swap: 0 kB
SwapPss: 0 kB
Locked: 0 kB
THPeligible: 0
VmFlags: rd wr mr mw me ac nh
The "nh" flag is set.
[1] https://lore.kernel.org/linux-mm/202312192310.56367035-oliver.sang@intel.com/
Link: https://lkml.kernel.org/r/20231221065943.2803551-2-shy828301@gmail.com
Fixes: efa7df3e3bb5 ("mm: align larger anonymous mappings on THP boundaries")
Signed-off-by: Yang Shi <yang@os.amperecomputing.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Tested-by: Oliver Sang <oliver.sang@intel.com>
Reviewed-by: Yin Fengwei <fengwei.yin@intel.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Christopher Lameter <cl@linux.com>
Cc: Huang, Ying <ying.huang@intel.com>
Cc: <stable@vger.kerenl.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | include/linux/mman.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/mman.h b/include/linux/mman.h index 40d94411d492..dc7048824be8 100644 --- a/include/linux/mman.h +++ b/include/linux/mman.h @@ -156,6 +156,7 @@ calc_vm_flag_bits(unsigned long flags) return _calc_vm_trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN ) | _calc_vm_trans(flags, MAP_LOCKED, VM_LOCKED ) | _calc_vm_trans(flags, MAP_SYNC, VM_SYNC ) | + _calc_vm_trans(flags, MAP_STACK, VM_NOHUGEPAGE) | arch_calc_vm_flag_bits(flags); } |