Re: [openib-general] Re: [PATCH][RFC][0/4] InfiniBand userspace verbs implementation

Bernhard Fischer
2005-04-18T20:07:36Z

On Mon, Apr 18, 2005 at 09:40:40PM +0200, Arjan van de Ven wrote:
>On Mon, 2005-04-18 at 11:25 -0500, Timur Tabi wrote:
>> Arjan van de Ven wrote:
>>
>> > this is a myth; linux is free to move the page about in physical memory
>> > even if it's mlock()ed!!
darn, yes, this is true.
I know people who introduced
#define VM_RESERVED 0x00080000 /* Don't unmap it from swap_out
*/
to vm_flags just because of this. I'll just hold my breath and won't
delve further.
>>
>> Then Linux has a very odd definition of the word "locked".
>>
>> > And even then, the user can munlock the memory from another thread etc
>> > etc. Not a good idea.
>>
>> Well, that's okay, because then the app is doing something stupid, so we don't worry about
>> that.
>
>you should since that physical page can be reused, say by a root
>process, and you'd be majorly screwed