On Tue, Oct 06, 2009 at 07:27:56PM +0900, KOSAKI Motohiro wrote: > > 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@xxxxxxxxxx> > > > > > > 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 Can't control this if program has plugging. Not qemu case though. > 3. mlockall(MCL_CURRENT) > 4. load guest OS And what about all other allocations qemu does during its life time? Not all of them will be small enough to be from brk area. > > is impossible? why? > Because what you are proposing is not the same as mlockall(MCL_CURRENT|MCL_FUTURE); You essentially say that MCL_FUTURE is not needed. -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
