Messages in this thread | | | Date | Sat, 14 Jun 2003 06:49:27 -0700 | From | William Lee Irwin III <> | Subject | Re: [RFC] recursive pagetables for x86 PAE |
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Am Freitag, 13. Juni 2003 23:47 schrieb Dave Hansen: >> When you have lots of tasks, the pagetables start taking up lots of >> lowmem. We have the ability to push the PTE pages into highmem, but >> that exacts a penalty from the atomic kmaps which, depending on >> workload, can be a 10-15% performance hit. >> The following patches implement something which we like to call UKVA. >> It's a Kernel Virtual Area which is private to a process, just like >> Userspace. You can put any process-local data that you want in the >> area. But, for now, I just put PTE pages in there.
On Sat, Jun 14, 2003 at 01:27:48PM +0200, Oliver Neukum wrote: > If you put only such pages there, do you really want that memory to > be per task? IMHO it should be per memory context to aid threading > performance.
Per-process is essentially per-mm.
On Sat, Jun 14, 2003 at 01:27:48PM +0200, Oliver Neukum wrote: > Secondly, doesn't this scream for using large pages?
No, 2MB/4MB pages are not useful here.
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