Re: [PATCH] [0/6] HUGETLB memory commitment

From: Andrew Morton
Date: Thu Mar 25 2004 - 16:04:05 EST

Andy Whitcroft <apw@xxxxxxxxxxxx> wrote:
> HUGETLB Overcommit Handling
> ---------------------------
> When building mappings the kernel tracks committed but not yet
> allocated pages against available memory and swap preventing memory
> allocation problems later. The introduction of hugetlb pages has
> has significant ramifications for this accounting as the pages used
> to back them are already removed from the available memory pool.

Sorry, but I just don't see why we need all this complexity and generality.

If there was any likelihood that there would be additional memory domains
in the 2.6 future then OK. But I don't think there will be. We simply
need some little old patch which fixes this bug.

Such as adding a `vma' arg to vm_enough_memory() and vm_unacct_memory() and

if (is_vm_hugetlb_page(vma))


- allowed = totalram_pages * sysctl_overcommit_ratio / 100;
+ allowed = (totalram_pages - htlbpagemem << HPAGE_SHIFT) *
+ sysctl_overcommit_ratio / 100;

in cap_vm_enough_memory().

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