Messages in this thread | | | Date | Tue, 15 Jan 2013 13:50:41 -0700 | From | John McCorquodale <> | Subject | Transparent Hugepage Nit |
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Suppose a hugepage-aligned mmap(MAP_ANONYMOUS) mapping has been madvise()d HUGEPAGE. If a subeqeuent call to mremap() grows the mapping and has to move the mapping, the hugepage-alignment is not preserved in the choice of new address (in 3.7.2).
I can workaround this by doing a 1-hugepage-oversized remap to find a new aligned address and then size it back down MREMAP_FIXED, but that's probably a lot of frags to 4k pages and back that aren't necessary.
Should it not be the case that mremap(MAYMOVE) on something advised hugepage ALWAYS chooses a hugepage-aligned address? This would be handy when doing the initial allocation too: mmap, madvise, mremap (to the same size) to get alignment.
Cheers,
-mcq
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