Re: CVS commit: src/sys/uvm

[Mindaugas Rasiukevicius <rmind%netbsd.org@localhost>]

"Manuel Bouyer" <bouyer%netbsd.org@localhost> wrote:
> Module Name:  src
> Committed By: bouyer
> Date:         Mon Feb 20 19:14:24 UTC 2012
> 
> Modified Files:
>       src/sys/uvm: uvm_km.c uvm_kmguard.c uvm_map.c
> 
> Log Message:
> When using uvm_km_pgremove_intrsafe() make sure mappings are removed
> before returning the pages to the free pool. Otherwise, under Xen,
> a page which still has a writable mapping could be allocated for
> a PDP by another CPU and the hypervisor would refuse it (this is
> PR port-xen/45975).
> For this, move the pmap_kremove() calls inside uvm_km_pgremove_intrsafe(),
> and do pmap_kremove()/uvm_pagefree() in batch of (at most) 16 entries
> (as suggested by Chuck Silvers on tech-kern@, see also
> http://mail-index.netbsd.org/tech-kern/2012/02/17/msg012727.html and
> followups).

Why did you ignore my comment on tech-kern@ about batching?  I still think
it is unnecessary.  Such optimisations should be done in MD side, instead
of adding complexity to MI.

-- 
Mindaugas