Messages in this thread | | | Date | Mon, 6 Feb 2006 14:30:22 -0800 | From | Andrew Morton <> | Subject | Re: OOM behavior in constrained memory situations |
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Christoph Lameter <clameter@engr.sgi.com> wrote: > > On Mon, 6 Feb 2006, Andi Kleen wrote: > > > At least remnants from my old 80% hack to avoid this (huge_page_needed) > > seem to be still there in mainline: > > > > fs/hugetlbfs/inode.c:hugetlbfs_file_mmap > > > > bytes = huge_pages_needed(mapping, vma); > > if (!is_hugepage_mem_enough(bytes)) > > return -ENOMEM; > > > > > > So something must be broken if this doesn't work. Or did you allocate > > the pages in some other way? > > huge pages are now allocated in the huge fault handler. If it would be > returning an OOM then the OOM killer may be activated.
?
The oom-killer is invoked from the page allocator. A hugetlb pagefault won't use the page allocator. So there shouldn't be an oom-killing on hugepage exhaustion.
I think this comment is just wrong:
/* Logically this is OOM, not a SIGBUS, but an OOM * could cause the kernel to go killing other * processes which won't help the hugepage situation * at all (?) */
A VM_FAULT_OOM from there won't cause the oom-killer to do anything. We should return VM_FAULT_OOM and let do_page_fault() commit suicide with SIGKILL. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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