Re: Ascertaining dirty pages
Re: Ascertaining dirty pages
- Subject: Re: Ascertaining dirty pages
- From: Vincent Coetzee <email@hidden>
- Date: Mon, 18 Feb 2008 17:39:28 +0200
Hi Steven,
I am aware of vmmap, but perhaps I did not make the nature of my
problem very clear. My application needs to know about these pages,
and needs to be able to access information about the pages.
Additionally vmmap does not tell one which pages are dirty, ,it just
tells you about virtual memory allocated to a process. I need to know
on a page by page basis (i.e. currently 4096 bytes per page) which
pages have been written to and the exact address of the changes within
the page.
Thanks anyway
Vincent
On 18 Feb 2008, at 3:38 PM, Steven Bytnar wrote:
man vmmap
vmmap has been around since at least 10.2.
Here's an example of the output:
% vmmap -pages screen
Virtual Memory Map of process 5755 (screen)
Output report format: 2.2 -- 32-bit process
==== Non-writable regions for process 5755
__PAGEZERO 00000000-00001000 [ 1] ---/---
SM=NUL .../bin/screen
__TEXT 00001000-00046000 [ 69] r-x/rwx
SM=COW .../bin/screen
__LINKEDIT 0004e000-00051000 [ 3] r--/rwx
SM=COW .../bin/screen
STACK GUARD 00051000-00052000 [ 1] ---/rwx SM=NUL
STACK GUARD 00053000-00054000 [ 1] ---/rwx SM=NUL
STACK GUARD 00068000-00069000 [ 1] ---/rwx SM=NUL
STACK GUARD 0006a000-0006b000 [ 1] ---/rwx SM=NUL
__TEXT 8fe00000-8fe31000 [ 49] r-x/rwx SM=COW /
usr/lib/dyld
__LINKEDIT 8fe68000-8fe76000 [ 14] r--/rwx SM=COW /
usr/lib/dyld
__TEXT 91a5c000-91bf6000 [ 410] r-x/r-x
SM=COW ...tem.B.dylib
__TEXT 93735000-93767000 [ 50] r-x/r-x
SM=COW ...s.5.4.dylib
__TEXT 93ff4000-94000000 [ 12] r-x/r-x
SM=COW ...c_s.1.dylib
__TEXT 9611c000-96122000 [ 6] r-x/r-x
SM=COW ...mon.A.dylib
__LINKEDIT 96e6e000-972da000 [ 1132] r--/r--
SM=COW ...mon.A.dylib
STACK GUARD bc000000-bf800000 [ 14336] ---/rwx SM=NUL
STACK GUARD fffec000-ffff0000 [ 4] ---/rwx SM=NUL
shared memory ffff8000-ffffa000 [ 2] r-x/r-x SM=SHM
==== Writable regions for process 5755
__DATA 00046000-0004e000 [ 8] rw-/rwx
SM=COW .../bin/screen
MALLOC (freed?) 00052000-00053000 [ 1] rw-/rwx SM=PRV
MALLOC_LARGE 00054000-00068000 [ 20] rw-/rwx
SM=COW ...ne_0x100000
MALLOC (freed?) 00069000-0006a000 [ 1] rw-/rwx SM=COW
MALLOC_TINY 00100000-00200000 [ 256] rw-/rwx
SM=PRV ...ne_0x100000
MALLOC_TINY 00200000-00300000 [ 256] rw-/rwx SM=COW
zone_0x0
MALLOC_SMALL 00800000-01000000 [ 2048] rw-/rwx
SM=PRV ...ne_0x100000
__DATA 8fe31000-8fe68000 [ 55] rw-/rwx SM=COW /
usr/lib/dyld
__DATA a0336000-a0377000 [ 65] rw-/rwx
SM=COW ...tem.B.dylib
__DATA a0767000-a0770000 [ 9] rw-/rwx
SM=COW ...s.5.4.dylib
__DATA a0890000-a0891000 [ 1] rw-/rwx
SM=COW ...c_s.1.dylib
__DATA a0c02000-a0c03000 [ 1] rw-/rwx
SM=COW ...mon.A.dylib
Stack bf800000-c0000000 [ 2048] rw-/rwx SM=COW
thread 0
==== Legend
SM=sharing mode:
COW=copy_on_write PRV=private NUL=empty ALI=aliased
SHM=shared ZER=zero_filled S/A=shared_alias
==== Summary for process 5755
ReadOnly portion of Libraries: Total=6980K resident=6700K(96%)
swapped_out_or_unallocated=280K(4%)
Writable regions: Total=18.3M written=224K(1%) resident=356K(2%)
swapped_out=0K(0%) unallocated=18.0M(98%)
REGION TYPE [ VIRTUAL]
=========== [ =======]
MALLOC [ 2582]
STACK GUARD [ 14344]
Stack [ 2048]
__DATA [ 139]
__LINKEDIT [ 1149]
__PAGEZERO [ 1]
__TEXT [ 596]
shared memory [ 2]
--Steve
On Mon, Feb 18, 2008 at 01:43:00PM +0200, Vincent Coetzee wrote:
Dear List,
I am hoping someone on these lists can assist me with my little
problem. If the problem is not appropriate to these lists, could
someone please point me in the right direction. I have a requirement
to know which memory pages (allocated by my application) have been
written to during the execution of my application, I also need to
know
the addresses of the areas of the pages that have been changed. I
have
spent hours perusing the BSD and Darwin documents without finding
anything that seems to allow for this. Does anyone know how to do
this
or can suggest something please, I am at my wits end.
Thanks in advance
Vince
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