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Re: [Xen-devel] barriers before {req/rsp}_cons = cons?
| To: | Samuel Thibault <samuel.thibault@xxxxxxxxxxxxx> |
|---|---|
| Subject: | Re: [Xen-devel] barriers before {req/rsp}_cons = cons? |
| From: | Keir Fraser <keir.fraser@xxxxxxxxxxxxx> |
| Date: | Mon, 21 Jul 2008 09:28:38 +0100 |
| Cc: | xen-devel@xxxxxxxxxxxxxxxxxxx |
| Delivery-date: | Mon, 21 Jul 2008 01:29:03 -0700 |
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| In-reply-to: | <20080718193304.GI4576@implementation> |
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| Thread-topic: | [Xen-devel] barriers before {req/rsp}_cons = cons? |
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On 18/7/08 20:33, "Samuel Thibault" <samuel.thibault@xxxxxxxxxxxxx> wrote: >> Could you describe the race you believe is made possible by the absence of >> the barrier? > > It is very unlikely, but the write into req_cons could happen before > actually doing the memcpy, and so another processor could try to reuse > the same request slot. req_cons is not shared with the frontend driver, and most accesses within the backend are serialised within the transmit tasklet. -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel |
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