Date: Fri, 14 Aug 1998 19:15:53 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: karl@mcs.net (Karl Denninger) Cc: tlambert@primenet.com, current@FreeBSD.ORG Subject: Re: Tentative fix for VM bug Message-ID: <199808141915.MAA29937@usr05.primenet.com> In-Reply-To: <19980814111421.45977@mcs.net> from "Karl Denninger" at Aug 14, 98 11:14:21 am
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> > Note: If I have lost my mind, there are two other places where this > > could be happening instead. > > > > If I have lost my mind, then I expect an increase in the occurance > > "vm_page_free: freeing free page", and I will have to go back to > > the other places (which are vastly more complicated to fix). > > I can confirm that the propounded fix doesn't, at least not for the case of > a Diablo news server which gets files whacked with either zeros or random > trash contents from time to time. > > With the "fix" in I see no change of significance in behavior. John assures me that the fix will only mask a couple of the bugs I was aiming for (including the EOF bug). Your results are good (at least the "vm_page_free: freeing free page" isn't calling me a total idiot). But it's bad, in that it means the problem with the page aliases is most likely in vm_object.c, unless the code John Dyson sent me is correct (I have reservations; there is an order of operation discepancy between one part and the other of the patch, and I need John to tell me which was intended). To get the gist of why this is bad, do this: cd /sys/vm grep -5 busy *.c | more 8-(. In any case, there could be (and probably is) a seperate file extension with mmap bug. In theory, in a unified VM and buffer cache, it should never be necessary to have non-null msync() code. 8-(. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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