On Mon, 3 Jul 2000, Jens Axboe wrote:
> On Sat, Jul 01 2000, Marcelo Tosatti wrote:
> > Hi,
> >
> > This silly patch avoids that by making ll_rw_block() ignore the IO if the
> > request queue is full, causing the process to search for more freeable
> > pages instead blocking.
> >
> > --- fs/buffer.c.orig Sat Jul 1 20:49:19 2000
> > +++ fs/buffer.c Sat Jul 1 20:28:36 2000
> > @@ -1517,7 +1517,7 @@
> > if (wait)
> > __wait_on_buffer(p);
> > } else if (buffer_dirty(p))
> > - ll_rw_block(WRITE, 1, &p);
> > + ll_rw_block(WRITEA, 1, &p);
> > } while (tmp != bh);
> >
> > do {
>
> This is wrong -- if the buffer is not queued because we are out of
> free request slots, it has still already been locked at this point
> (and _Req).
if (!req) {
if (rw_ahead)
goto end_io;
req = __get_request_wait(max_req, bh->b_rdev);
}
In case we fail to find a free request, bh->b_end_io is called, and
it unlocks the buffer.
-
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This archive was generated by hypermail 2b29 : Fri Jul 07 2000 - 21:00:13 EST