Theory of operation
Read the virtual mappings out of /proc/pid/smaps. Then read the corresponding physical mappings out of /proc/pid/pagemap and physical page flags out of /proc/kpageflags. Prints statistics and optionally list all physical page ranges. Only works for regular data pages, swapped or file mapped pages are ignored.
Usage
syntax: ./pagestat.py [-a] [-m] [PID]
-a List all memory segments (default shows only the largest)
-m List all physical page mappings
Example
QEMU with THP (default config) with fragmented memory:
./pagestat.py 14341
SEGMENT: 7f4fc6e00000-7f5237e00000 rw-p 00000000 00:00 0
SMAPS PROPERTY VALUE
Size 10485760000
KernelPageSize 4096
MMUPageSize 4096
Rss 10485760000
Pss 10485760000
Shared_Clean 0
Shared_Dirty 0
Private_Clean 0
Private_Dirty 10485760000
Referenced 10485760000
Anonymous 10485760000
LazyFree 0
AnonHugePages 6861881344
ShmemPmdMapped 0
Shared_Hugetlb 0
Private_Hugetlb 0
Swap 0
SwapPss 0
Locked 10485760000
VmFlags rd wr mr mw me dc ac dd hg mg
NUM_PAGES PAGE_SIZE TOTAL_USAGE PAGE_SIZE_PERCENT
3272 2 MiB 6544 MiB 65.4 %
884736 4 KiB 3456 MiB 34.6 %
QEMU with 1G static hugepages:
./pagestat.py -m 15626
SEGMENT: 7f6f00000000-7f7000000000 rw-p 00000000 00:2b 19096 /dev/hugepages/libvirt/qemu/4-mordor/qemu_back_mem.pc.ram.vrCDvT (deleted)
SMAPS PROPERTY VALUE
Size 4294967296
KernelPageSize 1073741824
MMUPageSize 1073741824
Rss 0
Pss 0
Shared_Clean 0
Shared_Dirty 0
Private_Clean 0
Private_Dirty 0
Referenced 0
Anonymous 0
LazyFree 0
AnonHugePages 0
ShmemPmdMapped 0
Shared_Hugetlb 0
Private_Hugetlb 4294967296
Swap 0
SwapPss 0
Locked 0
VmFlags rd wr mr mw me dc de ht dd hg
NUM_PAGES PAGE_SIZE TOTAL_USAGE PAGE_SIZE_PERCENT
4 1024 MiB 4096 MiB 100.0 %
PHYS_ADDR PHYS_LENGTH PAGE_SIZE PAGE_COUNT
300000000 4096 MiB 1024 MiB 4
QEMU with 2M static hugepages:
./pagestat.py -m 2440
SEGMENT: 7ff00be00000-7ff10be00000 rw-p 00000000 00:2b 18936 /dev/hugepages/libvirt/qemu/2-mordor/qemu_back_mem.pc.ram.oDAqHr (deleted)
SMAPS PROPERTY VALUE
Size 4294967296
KernelPageSize 2097152
MMUPageSize 2097152
Rss 0
Pss 0
Shared_Clean 0
Shared_Dirty 0
Private_Clean 0
Private_Dirty 0
Referenced 0
Anonymous 0
LazyFree 0
AnonHugePages 0
ShmemPmdMapped 0
Shared_Hugetlb 0
Private_Hugetlb 4294967296
Swap 0
SwapPss 0
Locked 0
VmFlags rd wr mr mw me dc de ht dd hg
NUM_PAGES PAGE_SIZE TOTAL_USAGE PAGE_SIZE_PERCENT
2048 2 MiB 4096 MiB 100.0 %
PHYS_ADDR PHYS_LENGTH PAGE_SIZE PAGE_COUNT
30AC00000 3972 MiB 2 MiB 1986
404800000 124 MiB 2 MiB 62