1. 08 May, 2017 1 commit
    • Xunlei Pang's avatar
      x86/mm: Add support for gbpages to kernel_ident_mapping_init() · 66aad4fd
      Xunlei Pang authored
      
      
      Kernel identity mappings on x86-64 kernels are created in two
      ways: by the early x86 boot code, or by kernel_ident_mapping_init().
      
      Native kernels (which is the dominant usecase) use the former,
      but the kexec and the hibernation code uses kernel_ident_mapping_init().
      
      There's a subtle difference between these two ways of how identity
      mappings are created, the current kernel_ident_mapping_init() code
      creates identity mappings always using 2MB page(PMD level) - while
      the native kernel boot path also utilizes gbpages where available.
      
      This difference is suboptimal both for performance and for memory
      usage: kernel_ident_mapping_init() needs to allocate pages for the
      page tables when creating the new identity mappings.
      
      This patch adds 1GB page(PUD level) support to kernel_ident_mapping_init()
      to address these concerns.
      
      The primary advantage would be better TLB coverage/performance,
      because we'd utilize 1GB TLBs instead of 2MB ones.
      
      It is also useful for machines with large number of memory to
      save paging structure allocations(around 4MB/TB using 2MB page)
      when setting identity mappings for all the memory, after using
      1GB page it will consume only 8KB/TB.
      
      ( Note that this change alone does not activate gbpages in kexec,
        we are doing that in a separate patch. )
      Signed-off-by: default avatarXunlei Pang <xlpang@redhat.com>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Dave Young <dyoung@redhat.com>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: Eric Biederman <ebiederm@xmission.com>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Josh Poimboeuf <jpoimboe@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Yinghai Lu <yinghai@kernel.org>
      Cc: akpm@linux-foundation.org
      Cc: kexec@lists.infradead.org
      Link: http://lkml.kernel.org/r/1493862171-8799-1-git-send-email-xlpang@redhat.com
      
      Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      66aad4fd
  2. 08 Aug, 2016 1 commit
  3. 29 Jan, 2013 1 commit
  4. 17 Nov, 2012 3 commits
  5. 11 Nov, 2011 1 commit
  6. 24 Feb, 2011 1 commit
    • Yinghai Lu's avatar
      x86: Rename e820_table_* to pgt_buf_* · d1b19426
      Yinghai Lu authored
      
      
      e820_table_{start|end|top}, which are used to buffer page table
      allocation during early boot, are now derived from memblock and don't
      have much to do with e820.  Change the names so that they reflect what
      they're used for.
      
      This patch doesn't introduce any behavior change.
      
      -v2: Ingo found that earlier patch "x86: Use early pre-allocated page
           table buffer top-down" caused crash on 32bit and needed to be
           dropped.  This patch was updated to reflect the change.
      
      -tj: Updated commit description.
      Signed-off-by: default avatarYinghai Lu <yinghai@kernel.org>
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      d1b19426
  7. 05 Mar, 2009 1 commit