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    "list_archive_url": "https://lore.kernel.org/linuxppc-dev/1504910713-7094-1-git-send-email-linuxram@us.ibm.com/",
    "date": "2017-09-08T22:44:40",
    "name": "[0/7] powerpc: Free up RPAGE_RSV bits",
    "submitter": {
        "id": 2667,
        "url": "http://patchwork.ozlabs.org/api/people/2667/?format=api",
        "name": "Ram Pai",
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            "date": "2017-09-08T22:44:40",
            "name": "powerpc: Free up RPAGE_RSV bits",
            "version": 1,
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        "From": "Ram Pai <linuxram@us.ibm.com>",
        "To": "mpe@ellerman.id.au,\n\tlinuxppc-dev@lists.ozlabs.org",
        "Subject": "[PATCH 0/7] powerpc: Free up RPAGE_RSV bits",
        "Date": "Fri,  8 Sep 2017 15:44:40 -0700",
        "Message-Id": "<1504910713-7094-1-git-send-email-linuxram@us.ibm.com>",
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        "Cc": "ebiederm@xmission.com, linuxram@us.ibm.com, mhocko@kernel.org,\n\tpaulus@samba.org, aneesh.kumar@linux.vnet.ibm.com,\n\tbauerman@linux.vnet.ibm.com, khandual@linux.vnet.ibm.com",
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    "content": "RPAGE_RSV0..4 pte bits are currently used for hpte slot\ntracking. We  need  these bits   for  memory-protection\nkeys. Luckily these  four bits   are  relatively easier \nto move among all the other candidate bits.\n\nFor  64K   linux-ptes   backed  by 4k hptes, these bits\nare   used for tracking the  validity of the slot value\nstored   in the second-part-of-the-pte. We device a new\nmechanism for  tracking   the   validity  without using\nthose bits. The    mechanism  is explained in the patch.\n\nFor 64K  linux-pte  backed by 64K hptes, we simply move\nthe   slot  tracking bits to the second-part-of-the-pte.\n\nThe above  mechanism  is also used to free the bits for\nhugetlb linux-ptes.\n\nFor 4k linux-pte, we  have only 3 free  bits  available.\nWe swizzle around the bits and release RPAGE_RSV{2,3,4}\nfor memory protection keys.\n\nTesting:\n--------\nhas survived  kernel  compilation on multiple platforms\np8 powernv hash-mode, p9 powernv hash-mode,  p7 powervm,\np8-powervm, p8-kvm-guest.\n\nHas survived git-bisect on p8  power-nv  with  64K page\nand 4K page.\n\nHistory:\n-------\nThis patchset  is  a  spin-off from the memkey patchset.\n\nversion v9:\n\t(1) rearranged the patch order. First the helper\n\t\troutines are defined followed   by  the\n\t\tpatches that make use of the helpers.\n\nversion v8:\n\t(1) an  additional  patch   added  to  free  up\n             RSV{2,3,4} on 4K linux-pte.\n\nversion v7:\n\t(1) GIX bit reset change  moved  to  the second\n\t\tpatch  -- noticed by Aneesh.\n\t(2) Separated this patches from memkey patchset\n\t(3) merged a  bunch  of  patches, that used the\n       \t\thelper function, into one.\nversion v6:\n\t(1) No changes related to pte.\n\nversion v5:\n\t(1) No changes related to pte.\n\nversion v4:\n\t(1) No changes related to pte.\n\nversion v3:\n\t(1) split the patches into smaller consumable\n\t\tpatches.\n\t(2) A bug fix while  invalidating a hpte slot\n\t\tin __hash_page_4K()\n       \t\t-- noticed by Aneesh\n\t\n\nversion v2:\n \t(1) fixed a  bug  in 4k  hpte  backed 64k pte\n       \t\twhere  page    invalidation   was not\n\t\tdone  correctly,  and  initialization\n\t       \tof    second-part-of-the-pte  was not\n\t\tdone    correctly  if the pte was not\n\t       \tyet Hashed with a hpte.\n\t       \t   --\tReported by Aneesh.\n\t\n\nversion v1: Initial version\n\nRam Pai (7):\n  powerpc: introduce pte_set_hash_slot() helper\n  powerpc: introduce pte_get_hash_gslot() helper\n  powerpc: Free up four 64K PTE bits in 4K backed HPTE pages\n  powerpc: Free up four 64K PTE bits in 64K backed HPTE pages\n  powerpc: Swizzle around 4K PTE bits to free up bit 5 and bit 6\n  powerpc: use helper functions to get and set hash slots\n  powerpc: capture the PTE format changes in the dump pte report\n\n arch/powerpc/include/asm/book3s/64/hash-4k.h  |   21 ++++\n arch/powerpc/include/asm/book3s/64/hash-64k.h |   61 ++++++++----\n arch/powerpc/include/asm/book3s/64/hash.h     |    8 +-\n arch/powerpc/mm/dump_linuxpagetables.c        |    3 +-\n arch/powerpc/mm/hash64_4k.c                   |   14 +--\n arch/powerpc/mm/hash64_64k.c                  |  131 +++++++++++++------------\n arch/powerpc/mm/hash_utils_64.c               |   35 +++++--\n arch/powerpc/mm/hugetlbpage-hash64.c          |   18 ++--\n 8 files changed, 171 insertions(+), 120 deletions(-)"
}