Messages in this thread | | | Date | Fri, 6 Jul 2007 09:20:22 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: [BUGFIX][PATCH] DO flush icache before set_pte() on ia64. |
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On Fri, 6 Jul 2007 07:18:53 +0900 KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:
> On Thu, 5 Jul 2007 12:13:09 -0600 > Mike Stroyan <mike@stroyan.net> wrote: > > The L3 cache is involved in the HP-UX defect description because the > > earlier HP-UX patch PHKL_33781 added flushing of the instruction cache > > when an executable mapping was removed. Linux never added that > > unsuccessfull attempt at montecito cache coherency. In the current > > linux situation it can execute old cache lines straight from L2 icache. > > > Hmm... I couldn't understand "why icache includes old lines in a new page." > This happens at > - a file is newly loaded into page-cache. > - only on NFS. > - happens very *often* if the program is unlucky. > > So I wrote my understainding as I think. > I'll remove reference to HP-UX in the next post. And rewrite all description.
> > > > The only defect that I see in the current implementation of > > lazy_mmu_prot_update() is that it is called too late in some > > functions that are already calling it. Are your large changes > > attempting to correct other defects? Or are you simplifying > > away potentially valuable code because you don't understand it? > > > I know your *simple* patch in April wasn't included. So I wrote this. > In April thread, commenter's advices was "implement flush_icache_page()" I think. > If you have a better patch, please post. > I'll check callers of lazy_mmu_prot_update() again and remove uncecessary calls. But, basically, i-cache flush will be necessary when VM_EXEC is on. PG_arch_1 will help us for optimization.
-Kame
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