Messages in this thread | | | Subject | Re: [v3,2/3] powerpc: get hugetlbpage handling more generic | From | Christophe LEROY <> | Date | Fri, 25 Nov 2016 09:14:03 +0100 |
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Le 24/11/2016 à 06:23, Scott Wood a écrit : > On Wed, Sep 21, 2016 at 10:11:54AM +0200, Christophe Leroy wrote: >> Today there are two implementations of hugetlbpages which are managed >> by exclusive #ifdefs: >> * FSL_BOOKE: several directory entries points to the same single hugepage >> * BOOK3S: one upper level directory entry points to a table of hugepages >> >> In preparation of implementation of hugepage support on the 8xx, we >> need a mix of the two above solutions, because the 8xx needs both cases >> depending on the size of pages: >> * In 4k page size mode, each PGD entry covers a 4M bytes area. It means >> that 2 PGD entries will be necessary to cover an 8M hugepage while a >> single PGD entry will cover 8x 512k hugepages. >> * In 16 page size mode, each PGD entry covers a 64M bytes area. It means >> that 8x 8M hugepages will be covered by one PGD entry and 64x 512k >> hugepages will be covers by one PGD entry. >> >> This patch: >> * removes #ifdefs in favor of if/else based on the range sizes >> * merges the two huge_pte_alloc() functions as they are pretty similar >> * merges the two hugetlbpage_init() functions as they are pretty similar >> >> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> >> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> > > With this patch on e6500, running the hugetlb testsuite results in the > system hanging in a storm of OOM killer invocations (I'll try to debug > more deeply later). This patch also changes the default hugepage size on > FSL book3e from 4M to 16M. >
Regarding the default hugepage size, it is a result of the merge of the two hugetlbpage_init(). Should I add an ifdef to get 4M on FSL book3e by default ? What's the reason for selecting different hugepage sizes depending on the CPU ? I thought default size was selected based on what was existing.
What testsuite do you run exactly ?
Christophe
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