| To: | Kaushik Kumar Ram <kaushik@xxxxxxxx> |
|---|---|
| Subject: | Re: [Xen-devel] [PATCH] evtchn_do_upcall: search a snapshot of level 2 bits for pending upcalls |
| From: | Keir Fraser <keir.fraser@xxxxxxxxxxxxx> |
| Date: | 2010年1月31日 08:24:05 +0000 |
| Cc: | "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx> |
| Delivery-date: | 2010年1月31日 00:24:29 -0800 |
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| Thread-topic: | [Xen-devel] [PATCH] evtchn_do_upcall: search a snapshot of level 2 bits for pending upcalls |
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On 31/01/2010 00:40, "Kaushik Kumar Ram" <kaushik@xxxxxxxx> wrote: >> So how about making the clear of l1i in the l1 mask unconditional? I think >> that would be better, but I wasn't sure it is safe, since the first l1i you >> scan you may start halfway through, and thus legitimately have more work to >> do on that l1i on a later iteration of the outer loop. But I think that is >> the only case it is good to leave the l1 unmasked? Also, even better, on >> that second scan of that l1i, you would preferably want to scan only those >> bits in the l2 mask that you didn't scan on the first iteration of the outer >> loop! > > OK. I agree the following is a good compromise. > - Unconditionally clear l1 bits except the first l1i (but only if l2 is > scanned from halfway). > - Remember where the scanning began (both l1i and l2i) and stop scanning at > that point after wrapping around. > - Read active_evtchns() once per l1i (except the first l1i where you might > have to do it twice). Yes, sounds good. Are you going to make the patch? -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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