• Chen, Kenneth W's avatar
    [PATCH] shared page table for hugetlb page · 39dde65c
    Chen, Kenneth W authored
    Following up with the work on shared page table done by Dave McCracken.  This
    set of patch target shared page table for hugetlb memory only.
    The shared page table is particular useful in the situation of large number of
    independent processes sharing large shared memory segments.  In the normal
    page case, the amount of memory saved from process' page table is quite
    significant.  For hugetlb, the saving on page table memory is not the primary
    objective (as hugetlb itself already cuts down page table overhead
    significantly), instead, the purpose of using shared page table on hugetlb is
    to allow faster TLB refill and smaller cache pollution upon TLB miss.
    With PT sharing, pte entries are shared among hundreds of processes, the cache
    consumption used by all the page table is smaller and in return, application
    gets much higher cache hit ratio.  One other effect is that cache hit ratio
    with hardware page walker hitting on pte in cache will be higher and this
    helps to reduce tlb miss latency.  These two effects contribute to higher
    application performance.
    Signed-off-by: default avatarKen Chen <kenneth.w.chen@intel.com>
    Acked-by: default avatarHugh Dickins <hugh@veritas.com>
    Cc: Dave McCracken <dmccr@us.ibm.com>
    Cc: William Lee Irwin III <wli@holomorphy.com>
    Cc: "Luck, Tony" <tony.luck@intel.com>
    Cc: Paul Mackerras <paulus@samba.org>
    Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
    Cc: David Gibson <david@gibson.dropbear.id.au>
    Cc: Adam Litke <agl@us.ibm.com>
    Cc: Paul Mundt <lethal@linux-sh.org>
    Cc: "David S. Miller" <davem@davemloft.net>
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>