1. 11 1月, 2006 1 次提交
    • V
      [PATCH] kdump: dynamic per cpu allocation of memory for saving cpu registers · cc571658
      Vivek Goyal 提交于
      - In case of system crash, current state of cpu registers is saved in memory
        in elf note format.  So far memory for storing elf notes was being allocated
        statically for NR_CPUS.
      
      - This patch introduces dynamic allocation of memory for storing elf notes.
        It uses alloc_percpu() interface.  This should lead to better memory usage.
      
      - Introduced based on Andi Kleen's and Eric W. Biederman's suggestions.
      
      - This patch also moves memory allocation for elf notes from architecture
        dependent portion to architecture independent portion.  Now crash_notes is
        architecture independent.  The whole idea is that size of memory to be
        allocated per cpu (MAX_NOTE_BYTES) can be architecture dependent and
        allocation of this memory can be architecture independent.
      Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
      Signed-off-by: NAndrew Morton <akpm@osdl.org>
      Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      cc571658
  2. 30 10月, 2005 1 次提交
    • H
      [PATCH] mm: split page table lock · 4c21e2f2
      Hugh Dickins 提交于
      Christoph Lameter demonstrated very poor scalability on the SGI 512-way, with
      a many-threaded application which concurrently initializes different parts of
      a large anonymous area.
      
      This patch corrects that, by using a separate spinlock per page table page, to
      guard the page table entries in that page, instead of using the mm's single
      page_table_lock.  (But even then, page_table_lock is still used to guard page
      table allocation, and anon_vma allocation.)
      
      In this implementation, the spinlock is tucked inside the struct page of the
      page table page: with a BUILD_BUG_ON in case it overflows - which it would in
      the case of 32-bit PA-RISC with spinlock debugging enabled.
      
      Splitting the lock is not quite for free: another cacheline access.  Ideally,
      I suppose we would use split ptlock only for multi-threaded processes on
      multi-cpu machines; but deciding that dynamically would have its own costs.
      So for now enable it by config, at some number of cpus - since the Kconfig
      language doesn't support inequalities, let preprocessor compare that with
      NR_CPUS.  But I don't think it's worth being user-configurable: for good
      testing of both split and unsplit configs, split now at 4 cpus, and perhaps
      change that to 8 later.
      
      There is a benefit even for singly threaded processes: kswapd can be attacking
      one part of the mm while another part is busy faulting.
      Signed-off-by: NHugh Dickins <hugh@veritas.com>
      Signed-off-by: NAndrew Morton <akpm@osdl.org>
      Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      4c21e2f2
  3. 28 10月, 2005 1 次提交
  4. 29 6月, 2005 1 次提交
  5. 26 6月, 2005 4 次提交