1. 07 Nov, 2005 6 commits
    • David Gibson's avatar
      [PATCH] ppc64: Fix bug in SLB miss handler for hugepages · 7d24f0b8
      David Gibson authored
      This patch, however, should be applied on top of the 64k-page-size patch to
      fix some problems with hugepage (some pre-existing, another introduced by
      this patch).
      
      The patch fixes a bug in the SLB miss handler for hugepages on ppc64
      introduced by the dynamic hugepage patch (commit id
      c594adad) due to a misunderstanding of the
      srd instruction's behaviour (mea culpa).  The problem arises when a 64-bit
      process maps some hugepages in the low 4GB of the address space (unusual).
      In this case, as well as the 256M segment in question being marked for
      hugepages, other segments at 32G intervals will be incorrectly marked for
      hugepages.
      
      In the process, this patch tweaks the semantics of the hugepage bitmaps to
      be more sensible.  Previously, an address below 4G was marked for hugepages
      if the appropriate segment bit in the "low areas" bitmask was set *or* if
      the low bit in the "high areas" bitmap was set (which would mark all
      addresses below 1TB for hugepage).  With this patch, any given address is
      governed by a single bitmap.  Addresses below 4GB are marked for hugepage
      if and only if their bit is set in the "low areas" bitmap (256M
      granularity).  Addresses between 4GB and 1TB are marked for hugepage iff
      the low bit in the "high areas" bitmap is set.  Higher addresses are marked
      for hugepage iff their bit in the "high areas" bitmap is set (1TB
      granularity).
      
      To avoid conflicts, this patch must be applied on top of BenH's pending
      patch for 64k base page size [0].  As such, this patch also addresses a
      hugepage problem introduced by that patch.  That patch allows hugepages of
      1MB in size on hardware which supports it, however, that won't work when
      using 4k pages (4 level pagetable), because in that case hugepage PTEs are
      stored at the PMD level, and each PMD entry maps 2MB.  This patch simply
      disallows hugepages in that case (we can do something cleverer to re-enable
      them some other day).
      
      Built, booted, and a handful of hugepage related tests passed on POWER5
      LPAR (both ARCH=powerpc and ARCH=ppc64).
      
      [0] http://gate.crashing.org/~benh/ppc64-64k-pages.diffSigned-off-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Paul Mackerras <paulus@samba.org>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      7d24f0b8
    • Linus Torvalds's avatar
    • Linus Torvalds's avatar
      6adfd34e
    • Linus Torvalds's avatar
      b54a063d
    • Linus Torvalds's avatar
      085f20e4
    • Benjamin Herrenschmidt's avatar
      [PATCH] ppc64: support 64k pages · 3c726f8d
      Benjamin Herrenschmidt authored
      Adds a new CONFIG_PPC_64K_PAGES which, when enabled, changes the kernel
      base page size to 64K.  The resulting kernel still boots on any
      hardware.  On current machines with 4K pages support only, the kernel
      will maintain 16 "subpages" for each 64K page transparently.
      
      Note that while real 64K capable HW has been tested, the current patch
      will not enable it yet as such hardware is not released yet, and I'm
      still verifying with the firmware architects the proper to get the
      information from the newer hypervisors.
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      3c726f8d
  2. 06 Nov, 2005 14 commits
  3. 05 Nov, 2005 20 commits