1. 05 Feb, 2007 2 commits
  2. 07 Jan, 2007 1 commit
  3. 26 Dec, 2006 13 commits
  4. 02 Dec, 2006 1 commit
  5. 01 Dec, 2006 14 commits
  6. 22 Nov, 2006 1 commit
    • David Howells's avatar
      WorkStruct: Pass the work_struct pointer instead of context data · 65f27f38
      David Howells authored
      
      
      Pass the work_struct pointer to the work function rather than context data.
      The work function can use container_of() to work out the data.
      
      For the cases where the container of the work_struct may go away the moment the
      pending bit is cleared, it is made possible to defer the release of the
      structure by deferring the clearing of the pending bit.
      
      To make this work, an extra flag is introduced into the management side of the
      work_struct.  This governs auto-release of the structure upon execution.
      
      Ordinarily, the work queue executor would release the work_struct for further
      scheduling or deallocation by clearing the pending bit prior to jumping to the
      work function.  This means that, unless the driver makes some guarantee itself
      that the work_struct won't go away, the work function may not access anything
      else in the work_struct or its container lest they be deallocated..  This is a
      problem if the auxiliary data is taken away (as done by the last patch).
      
      However, if the pending bit is *not* cleared before jumping to the work
      function, then the work function *may* access the work_struct and its container
      with no problems.  But then the work function must itself release the
      work_struct by calling work_release().
      
      In most cases, automatic release is fine, so this is the default.  Special
      initiators exist for the non-auto-release case (ending in _NAR).
      Signed-Off-By: default avatarDavid Howells <dhowells@redhat.com>
      65f27f38
  7. 07 Nov, 2006 1 commit
  8. 24 Oct, 2006 5 commits
  9. 21 Oct, 2006 1 commit
  10. 05 Oct, 2006 1 commit
    • David Howells's avatar
      IRQ: Maintain regs pointer globally rather than passing to IRQ handlers · 7d12e780
      David Howells authored
      
      
      Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
      of passing regs around manually through all ~1800 interrupt handlers in the
      Linux kernel.
      
      The regs pointer is used in few places, but it potentially costs both stack
      space and code to pass it around.  On the FRV arch, removing the regs parameter
      from all the genirq function results in a 20% speed up of the IRQ exit path
      (ie: from leaving timer_interrupt() to leaving do_IRQ()).
      
      Where appropriate, an arch may override the generic storage facility and do
      something different with the variable.  On FRV, for instance, the address is
      maintained in GR28 at all times inside the kernel as part of general exception
      handling.
      
      Having looked over the code, it appears that the parameter may be handed down
      through up to twenty or so layers of functions.  Consider a USB character
      device attached to a USB hub, attached to a USB controller that posts its
      interrupts through a cascaded auxiliary interrupt controller.  A character
      device driver may want to pass regs to the sysrq handler through the input
      layer which adds another few layers of parameter passing.
      
      I've build this code with allyesconfig for x86_64 and i386.  I've runtested the
      main part of the code on FRV and i386, though I can't test most of the drivers.
      I've also done partial conversion for powerpc and MIPS - these at least compile
      with minimal configurations.
      
      This will affect all archs.  Mostly the changes should be relatively easy.
      Take do_IRQ(), store the regs pointer at the beginning, saving the old one:
      
      	struct pt_regs *old_regs = set_irq_regs(regs);
      
      And put the old one back at the end:
      
      	set_irq_regs(old_regs);
      
      Don't pass regs through to generic_handle_irq() or __do_IRQ().
      
      In timer_interrupt(), this sort of change will be necessary:
      
      	-	update_process_times(user_mode(regs));
      	-	profile_tick(CPU_PROFILING, regs);
      	+	update_process_times(user_mode(get_irq_regs()));
      	+	profile_tick(CPU_PROFILING);
      
      I'd like to move update_process_times()'s use of get_irq_regs() into itself,
      except that i386, alone of the archs, uses something other than user_mode().
      
      Some notes on the interrupt handling in the drivers:
      
       (*) input_dev() is now gone entirely.  The regs pointer is no longer stored in
           the input_dev struct.
      
       (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking.  It does
           something different depending on whether it's been supplied with a regs
           pointer or not.
      
       (*) Various IRQ handler function pointers have been moved to type
           irq_handler_t.
      Signed-Off-By: default avatarDavid Howells <dhowells@redhat.com>
      (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
      7d12e780