Re: Mach VM management question
Re: Mach VM management question
- Subject: Re: Mach VM management question
- From: Pejvan BEIGUI <email@hidden>
- Date: Mon, 29 Jul 2002 20:04:33 +0200
>
> Hi guys,
>
>
Thank you, Jim and Justin, for you kind replies
>
> I have a question regarding the VM management in Mach/Darwin.
>
> Since I don't like to reboot my mac, and since I use a lot of different
>
> applications, not at the same time, I'm surprised to see that the VM
>
> storage
>
> on my drives keeps going up, and never fall down.
>
>
>
> I have a tibook 500MHz, with 512MB of RAM, so I don't think that it's
>
> normal
>
> to have so many VM used at the same time on my machine :
>
>
>
>> ...[list of swap files deleted]...
>
>
>
> So, is there a way to tell the system to update the VM ? Or tell him to
>
> remove the unused VM swapfiles ?
>
>
It happens automatically as the space is released. But this is
>
controlled by a user-level daemon process (dynamic_pager). If that
>
got killed off somehow, you would neither free up any unused ones or
>
allocate any new ones. While I've never seen that happen, its
>
something to look for in extremely weird cases.
>
Ok, it's not that, since my VM goes up very easily ;-)
Thanks for the info though :-)
>
> Plus here's the output of my top :
>
>
>
>> [... Top outpout deleted ...]
>
>
>
> So what is this kernel_tasks using 400M VSize ?
>
>
The kernel allocates some virtual address space (space in submaps, not
>
actual memory) for efficient future memory allocation and wiring later
>
on. Top picks that up and reports it. Kernel leaks would most likely
>
cause a rise in wired memory. With 512MB of memory, the 59.6MB of
>
wired memory is not a major concern (some wired data structure counts
>
scale up with amount of physical memory).
>
>
There are uses of true virtual (pageable) memory within the kernel.
>
Specifically, some of the (not currently in-use) texture maps for
>
graphics acceleration are stored in kernel pageable memory. And some
>
(sent, but not-yet-received) Mach IPC data is stored in pagable kernel
>
memory.
>
>
There is no way to distinguish between over-commit virtual address
>
space allocations in the kernel, and true pageable memory allocations
>
using top. So we can't tell how much of that 400MB of kernel virtual
>
falls into each of the two categories above. In fact, it isn't
>
possible to tell that for any other task/process either. Since your
>
maximum "dirty virtual" memory size of ~1GB (7*76MB swap files + 512MB
>
of physical memory) is less than the 1.69GB of all virtual allocations
>
reported by top (even when you remove the 400MB of potentially unused
>
space in the kernel), it may be correct.
>
Thanks for the explanation
>
Your top says there are 55 processes, and you only show 14 of them. Is
>
there anything else of interest in those other 41 processes?
>
As an attachment, you'll find the outuput of "top -l -n 60"
All the processes are there. Unfortunately, I had to reboot after saving
this data, since AppleTalk went nuts ;-)
BTW, yes, I have an MS Keyboard, and an MS Mouse, please don't blame me for
that ;-)
Pejvan
[demime 0.98b removed an attachment of type application/octet-stream which had a name of top-l-60.txt]
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