A simple tool to print the page table content for a process in Linux.
Works by attaching to a process and printing each memory area. Optionally, memory areas can be restricted via a filter.
$ go get github.com/gianlucaborello/ptexplore/cmd/ptexplore
- Explore what portion of mapped memory areas of a process are actually present in memory
- Check if a memory address dereference will cause a page fault
- Analyze what portion of mapped memory areas are swapped out
- Look up the physical address corresponding to a virtual address (useful for NUMA)
$ ptexplore --help
Explore page table of a process under Linux.
Works by attaching to a process and printing each memory area. Optionally, memory areas can be restricted via a filter.
Usage of ptexplore:
-address string
Analyze a single address (e.g. '0x7f66a002ab70')
-areas string
Comma separated list of memory areas (even patterns) to analyze (e.g. 'stack,heap,libc')
-pid int
Pid of the process to analyze (e.g. 42)
-quiet
Don't print page table details, just a summary of the memory areas
Print a summary of all the memory areas (similar to /proc/PID/maps):
$ ptexplore -pid 121361 --quiet
Area '/usr/bin/cadvisor', range 0x0000000000400000 - 0x00000000010a7000 (13 MB)
Area '/usr/bin/cadvisor', range 0x00000000012a6000 - 0x0000000001343000 (643 kB)
Area 'anonymous', range 0x0000000001343000 - 0x0000000001370000 (184 kB)
Area '[heap]', range 0x000000000290c000 - 0x000000000292f000 (143 kB)
Area 'anonymous', range 0x000000c000000000 - 0x000000c000005000 (20 kB)
Area 'anonymous', range 0x000000c41ff68000 - 0x000000c421200000 (20 MB)
Area '/usr/glibc-compat/lib/libc-2.23.so', range 0x00007f669e3bc000 - 0x00007f669e3c0000 (16 kB)
Area '/usr/glibc-compat/lib/libc-2.23.so', range 0x00007f669e3c0000 - 0x00007f669e3c2000 (8.2 kB)
Area '[stack]', range 0x00007fff5e57d000 - 0x00007fff5e59e000 (135 kB)
Area '[vvar]', range 0x00007fff5e5e4000 - 0x00007fff5e5e7000 (12 kB)
Area '[vdso]', range 0x00007fff5e5e7000 - 0x00007fff5e5e9000 (8.2 kB)
Print a filtered summary of all the memory areas:
$ ptexplore -pid 121361 --areas stack,heap --quiet
Area '[stack]', range 0x00007fff5e57d000 - 0x00007fff5e59e000 (135 kB)
Area '[heap]', range 0x000000000290c000 - 0x000000000292f000 (143 kB)
Print a filtered view of the page table by memory area. For every memory areas, present and swapped pages are shown, along with their count, physical address and flags:
$ ptexplore -pid 121361 --areas stack,heap
Area '[stack]', range 0x00007fff5e57d000 - 0x00007fff5e59e000 (135 kB)
... 30 non mapped pages ...
0x00007fff5e59b000: physical address: 0x000000022762a000 exclusive soft-dirty count:1 flags:UPTODATE,LRU,ACTIVE,MMAP,ANON,SWAPBACKED
0x00007fff5e59c000: physical address: 0x0000000221c39000 exclusive soft-dirty count:1 flags:UPTODATE,LRU,ACTIVE,MMAP,ANON,SWAPBACKED
0x00007fff5e59d000: physical address: 0x00000001a3f4b000 exclusive soft-dirty count:1 flags:REFERENCED,UPTODATE,LRU,ACTIVE,MMAP,ANON,SWAPBACKED
Area '[heap]', range 0x000000000290c000 - 0x000000000292f000 (143 kB)
0x000000000290c000: physical address: 0x00000002282fe000 exclusive soft-dirty count:1 flags:UPTODATE,LRU,ACTIVE,MMAP,ANON,SWAPBACKED
0x000000000290d000: physical address: 0x000000022bbae000 exclusive soft-dirty count:1 flags:REFERENCED,UPTODATE,LRU,ACTIVE,MMAP,ANON,SWAPBACKED
0x000000000290e000: physical address: 0x000000022bbaf000 exclusive soft-dirty count:1 flags:UPTODATE,LRU,ACTIVE,MMAP,ANON,SWAPBACKED
0x000000000290f000: physical address: 0x0000000199fce000 exclusive soft-dirty count:1 flags:REFERENCED,UPTODATE,LRU,ACTIVE,MMAP,ANON,SWAPBACKED
0x0000000002910000: physical address: 0x00000001aa074000 exclusive soft-dirty count:1 flags:REFERENCED,UPTODATE,LRU,ACTIVE,MMAP,ANON,SWAPBACKED
0x0000000002911000: physical address: 0x000000022006e000 exclusive soft-dirty count:1 flags:REFERENCED,UPTODATE,LRU,ACTIVE,MMAP,ANON,SWAPBACKED
... 29 non mapped pages ...
Print the details for a specific page given a virtual memory address:
$ ptexplore --pid 121361 --address 0x7f66a002ab70
Area 'anonymous', range 0x00007f669f82c000 - 0x00007f66a002c000 (8.4 MB)
0x00007f66a002a000: physical address: 0x000000019fe8c000 exclusive soft-dirty count:1 flags:UPTODATE,LRU,ACTIVE,MMAP,ANON,SWAPBACKED