1. 30 8月, 2018 1 次提交
  2. 26 8月, 2018 1 次提交
    • L
      mm/cow: don't bother write protecting already write-protected pages · 1b2de5d0
      Linus Torvalds 提交于
      This is not normally noticeable, but repeated forks are unnecessarily
      expensive because they repeatedly dirty the parent page tables during
      the page table copy operation.
      
      It's trivial to just avoid write protecting the page table entry if it
      was already not writable.
      
      This patch was inspired by
      
          https://bugzilla.kernel.org/show_bug.cgi?id=200447
      
      which points to an ancient "waste time re-doing fork" issue in the
      presence of lots of signals.
      
      That bug was fixed by Eric Biederman's signal handling series
      culminating in commit c3ad2c3b ("signal: Don't restart fork when
      signals come in"), but the unnecessary work for repeated forks is still
      work just fixing, particularly since the fix is trivial.
      
      Cc: Eric Biederman <ebiederm@xmission.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      1b2de5d0
  3. 24 8月, 2018 9 次提交
  4. 23 8月, 2018 29 次提交