Messages in this thread | | | Date | Fri, 6 Dec 2002 02:44:29 +0100 | From | Andrea Arcangeli <> | Subject | Re: Maybe a VM bug in 2.4.18-18 from RH 8.0? |
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On Thu, Dec 05, 2002 at 05:34:34PM -0800, Andrew Morton wrote: > Andrea Arcangeli wrote: > > > > ... > > He may still suffer other known problems besides > > the above two critical highmem fixes (for example if > > lower_zone_reserve_ratio is not applied and there's no other fix around > > it IMHO, that's generic OS problem not only for linux, and that was my > > only sensible solution to fix it, the approch in mainline is way too > > weak to make a real difference) > > argh. I hate that one ;) Giving away 100 megabytes of memory > hurts.
100M hurts on a 4G box? No-way ;)
it hurts when such 100M of normal zone are mlocked by an highmem-capable users and you can't allocate one more inode but you have still 3G free of highmem (google is doing this, they even drop a check so they can mlock > half of the ram).
Or it hurts when you can't allocate an inode because such 100M are in pagetables on a 64G box and you still have 60G free of highmem.
> I've never been able to find the workload which makes this > necessary. Can you please describe an "exploit" against
ask google...
> 2.4.20 which demonstrates the need for this?
even simpler, swapoff -a and malloc and have fun! ;) (again ask google, they run w/o swap for obvious good reasons)
Or if you have enough time, wait those 100M to be filled by pagetables on a 64G box.
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