Messages in this thread | | | Date | Fri, 16 Mar 2001 03:58:51 -0300 (BRT) | From | Marcelo Tosatti <> | Subject | Re: Reserved memory for highmem bouncing (fwd) |
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Ok.
Going to write a patch and send you to test RSN.
On Fri, 16 Mar 2001, Ingo Molnar wrote:
> > On Thu, 15 Mar 2001, Marcelo Tosatti wrote: > > > The old create_bounce code used to set PF_MEMALLOC on the task flags > > and call wakeup_bdflush(1) in case GFP_BUFFER page allocation failed. > > That was broken because flush_dirty_buffers() could try to flush a > > buffer pointing to highmem page, which would end up in create_bounce > > again, but with PF_MEMALLOC. > > > > Have you tried to make flush_dirty_buffers() only flush buffers > > pointing to lowmem pages in case the caller wants it to do so? > > this makes sense too - although an emergency pool of some sort never > hurts, given that highmem buffers cannot be written out without allocating > bounce buffers. (this makes them more volatile wrt. resource shortages > than lowmem buffers.) Also, there is no guarantee that flushing lowmem > buffers yields any free pages. > > > This way you can call flush_dirty_buffers() with the guarantee you're > > going to free useful (lowmem) memory. This also throttles high mem > > writes giving priority to low mem ones. > > yep, i think we should do this in addition to the emergency pool thing, it > should improve balance. > > Ingo >
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