1. 22 Sep, 2002 16 commits
    • Andrew Morton's avatar
      [PATCH] infrastructure for monitoring queue congestion state · 4cef1b04
      Andrew Morton authored
      The patch provides a means for the VM to be able to determine whether a
      request queue is in a "congested" state.  If it is congested, then a
      write to (or read from) the queue may cause blockage in
      get_request_wait().
      
      So the VM can do:
      
      	if (!bdi_write_congested(page->mapping->backing_dev_info))
      		writepage(page);
      
      This is not exact.  The code assumes that if the request queue still
      has 1/4 of its capacity (queue_nr_requests) available then a request
      will be non-blocking.  There is a small chance that another CPU could
      zoom in and consume those requests.  But on the rare occasions where
      that may happen the result will mereley be some unexpected latency -
      it's not worth doing anything elaborate to prevent this.
      
      The patch decreases the size of `batch_requests'.  batch_requests is
      positively harmful - when a "heavy" writer and a "light" writer are
      both writing to the same queue, batch_requests provides a means for the
      heavy writer to massively stall the light writer.  Instead of waiting
      for one or two requests to come free, the light writer has to wait for
      32 requests to complete.
      
      Plus batch_requests generally makes things harder to tune, understand
      and predict.  I wanted to kill it altogether, but Jens says that it is
      important for some hardware - it allows decent size requests to be
      submitted.
      
      The VM changes which go along with this code cause batch_requests to be
      not so painful anyway - the only processes which sleep in
      get_request_wait() are the ones which we elect, by design, to wait in
      there - typically heavy writers.
      
      
      The patch changes the meaning of `queue_nr_requests'.  It used to mean
      "total number of requests per queue".  Half of these are for reads, and
      half are for writes.  This always confused the heck out of me, and the
      code needs to divide queue_nr_requests by two all over the place.
      
      So queue_nr_requests now means "the number of write requests per queue"
      and "the number of read requests per queue".  ie: I halved it.
      
      Also, queue_nr_requests was converted to static scope.  Nothing else
      uses it.
      
      
      The accuracy of bdi_read_congested() and bdi_write_congested() depends
      upon the accuracy of mapping->backing_dev_info.  With complex block
      stacking arrangements it is possible that ->backing_dev_info is
      pointing at the wrong queue.  I don't know.
      
      But the cost of getting this wrong is merely latency, and if it is a
      problem we can fix it up in the block layer, by getting stacking
      devices to communicate their congestion state upwards in some manner.
      4cef1b04
    • Andrew Morton's avatar
      [PATCH] don't hold mapping->private_lock while marking a page dirty · b5742733
      Andrew Morton authored
      __set_page_dirty_buffers() is calling __mark_inode_dirty under
      mapping->private_lock.
      
      We don't need to hold ->private_lock across that call.  It's only there
      to pin page->buffers.
      
      This simplifies the VM locking heirarchy.
      b5742733
    • Andrew Morton's avatar
      [PATCH] fix ext3 in data=writeback mode · c8b254cc
      Andrew Morton authored
      When I converted ext3 to use to use direct-to-BIO writeback for
      data=writeback mode I forgot that we need to hold a transaction open on
      behalf of MAP_SHARED pages.  The fileystem is BUGging in get_block()
      because there is no transaction open.
      
      So let's forget that idea for now and send data=writeback mode back to
      ext3_writepage.
      c8b254cc
    • Alexander Viro's avatar
      [PATCH] blk_size[] is gone · f5076217
      Alexander Viro authored
      it is an ex-parrot
      f5076217
    • Alexander Viro's avatar
      [PATCH] compile fixes for ftl · 981de136
      Alexander Viro authored
      assorted compile fixes
      981de136
    • Alexander Viro's avatar
      [PATCH] gendisk for mtdblock · b55a9a52
      Alexander Viro authored
      mtdblock switched to use of gendisks + compile fixes
      b55a9a52
    • Alexander Viro's avatar
      [PATCH] gendisk for z2ram · 6ebe755c
      Alexander Viro authored
      z2ram.c switched to use of gendisks
      6ebe755c
    • Alexander Viro's avatar
      [PATCH] gendisk for ataflop · 3f028def
      Alexander Viro authored
      ataflop.c switched to use of gendisks
      3f028def
    • Alexander Viro's avatar
      [PATCH] gendisk for amiflop · b7264cd3
      Alexander Viro authored
      amiflop.c switched to use of gendisks
      b7264cd3
    • Alexander Viro's avatar
      [PATCH] cleanup of pd.c · 8e273c4e
      Alexander Viro authored
      macroectomy a-la pf.c and pcd.c ones, ditto for passing pointers to
      structures instead of minors.
      8e273c4e
    • Alexander Viro's avatar
      [PATCH] Lindent pd.c · 91c42c4d
      Alexander Viro authored
      pd.c fed through Lindent
      91c42c4d
    • Alexander Viro's avatar
      [PATCH] kills CURRENT in floppy.c · f299adc6
      Alexander Viro authored
      dumb expansion of macro - it had #define CURRENT current_req
      f299adc6
    • Alexander Viro's avatar
      [PATCH] tapeblock blk_size removal · 0beb090c
      Alexander Viro authored
      tapeblock never assignes anything to its elements of blk_size[][]; we could
      not bother allocating it in the first place.
      0beb090c
    • Alexander Viro's avatar
      [PATCH] Re: Linux 2.5.38 · 1751d060
      Alexander Viro authored
      More trivial fixes: typos in partitions/check.c, block/floppy.c and
      acorn/block/fd1772.c + replacement of #define with inline in block/floppy.c
      (fd_eject()).
      1751d060
    • Adrian Bunk's avatar
      [PATCH] gendisk typo fixes · e2d496c5
      Adrian Bunk authored
      Some trivial fixes for some typos introduced by Al's gendisk changes..
      
       - missing comma in cdu31a
       - missing semicolon in cdu31a
       - comma instead of colon in gscd
       - semicolon instead of comma in mcd
       - missing closing bracket in sonycd535
      e2d496c5
    • Linus Torvalds's avatar
      b890a32b
  2. 21 Sep, 2002 24 commits