Messages in this thread | | | Date | Thu, 9 Mar 2006 11:30:13 +1100 | From | 'David Gibson' <> | Subject | Re: hugepage: Strict page reservation for hugepage inodes |
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On Wed, Mar 08, 2006 at 04:19:13PM -0800, Chen, Kenneth W wrote: > David Gibson wrote on Wednesday, March 08, 2006 3:52 PM > > But I don't see that recording all the mapped ranges will avoid the > > need for the fault serialization. At least the version of apw's > > reservation patch I looked at most recently would certainly still > > suffer from the alloc/instantiate race on the last hugepage in the > > system. > > No, it doesn't. Because with strict commit accounting, you know that > every hugetlb page is accounted for. So there is no backout path for > multiple instantiation race. Thread that lost in the race will always > go back to retry in hugetlb_no_page(). And since reservation is also > accounted in a global variable, total hugetlb pool won't fall below > what was reserved plus what is in use. Even if sys admin tries to > reduce hugetlb pool, kernel won't release any pages that are > reserved.
Hrm..ok. Clearly I'm looking at the wrong version of the patch - what I have is from the prefaulting days, anyway.
Though.. you must still need a backout path for PRIVATE mappings, which would make the logic rather complex.
-- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson - 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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