Messages in this thread | | | From | "Aneesh Kumar K.V" <> | Subject | Re: hugepage related lockdep trace. | Date | Fri, 19 Jul 2013 08:50:02 +0530 |
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Hillf Danton <dhillf@gmail.com> writes:
> On Fri, Jul 19, 2013 at 1:42 AM, Aneesh Kumar K.V > <aneesh.kumar@linux.vnet.ibm.com> wrote: >> Minchan Kim <minchan@kernel.org> writes: >>> IMHO, it's a false positive because i_mmap_mutex was held by kswapd >>> while one in the middle of fault path could be never on kswapd context. >>> >>> It seems lockdep for reclaim-over-fs isn't enough smart to identify >>> between background and direct reclaim. >>> >>> Wait for other's opinion. >> >> Is that reasoning correct ?. We may not deadlock because hugetlb pages >> cannot be reclaimed. So the fault path in hugetlb won't end up >> reclaiming pages from same inode. But the report is correct right ? >> >> >> Looking at the hugetlb code we have in huge_pmd_share >> >> out: >> pte = (pte_t *)pmd_alloc(mm, pud, addr); >> mutex_unlock(&mapping->i_mmap_mutex); >> return pte; >> >> I guess we should move that pmd_alloc outside i_mmap_mutex. Otherwise >> that pmd_alloc can result in a reclaim which can call shrink_page_list ? >> > Hm, can huge pages be reclaimed, say by kswapd currently?
No we don't reclaim hugetlb pages.
-aneesh
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