Messages in this thread | | | From | KOSAKI Motohiro <> | Subject | Re: [PATCH][RFC] add MAP_UNLOCKED mmap flag | Date | Tue, 6 Oct 2009 19:27:56 +0900 (JST) |
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> On Tue, Oct 06, 2009 at 07:11:06PM +0900, KOSAKI Motohiro wrote: > > Hi > > > > > If application does mlockall(MCL_FUTURE) it is no longer possible to > > > mmap file bigger than main memory or allocate big area of anonymous > > > memory. Sometimes it is desirable to lock everything related to program > > > execution into memory, but still be able to mmap big file or allocate > > > huge amount of memory and allow OS to swap them on demand. MAP_UNLOCKED > > > allows to do that. > > > > > > Signed-off-by: Gleb Natapov <gleb@redhat.com> > > > > Why don't you use explicit munlock()? > Because mmap will fail before I'll have a chance to run munlock on it. > Actually when I run my process inside memory limited container host dies > (I suppose trashing, but haven't checked). > > > Plus, Can you please elabrate which workload nedd this feature? > > > I wanted to run kvm with qemu process locked in memory, but guest memory > unlocked. And guest memory is bigger then host memory in the case I am > testing. I found out that it is impossible currently.
1. process creation (qemu) 2. load all library 3. mlockall(MCL_CURRENT) 4. load guest OS
is impossible? why?
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