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Subject: Re: [PATCH for 2.6.18] [8/8] MM: Remove rogue readahead printk - msg#00124List: linux.ports.x86-64.general> On Sun, 30 Jul 2006 00:22:14 -0400 > Trond Myklebust <trond.myklebust@xxxxxxxxxx> wrote: > > > > of course, it could be that some quirk of the NFS client VFS interface > > > causes "spurious" -EIO returns. either way, i'd rather see it fixed > > > rather than the printk removed, since it is useful to point out that > > > some performance degradation is occuring. > > > > We have no way of telling. That printk doesn't give us any useful > > information whatsoever for debugging that sort of problem. It should > > either be replaced with something that does, or it should be thrown out. > > err, the printk has found a probable bug in NFS. That was pretty useful > of it. Not necessarily. AFAICS, the spam could be triggered by perfectly legitimate activity. For instance, someone on the server may have revoked your read permissions to the file, or may have deleted it. > Do we know why nfs's readpage isn't bringing the page up to date? It may be that other lurking issues were also triggering the printk. For instance I know of a couple of corner cases in the krb5 privacy code that could result in readpage failing. Those issues are being looked into. Cheers, Trond Thread at a glance:
Previous Message by Date: click to view message previewRe: [PATCH for 2.6.18] [8/8] MM: Remove rogue readahead printkOn Sun, 30 Jul 2006 00:22:14 -0400 Trond Myklebust <trond.myklebust@xxxxxxxxxx> wrote: > > of course, it could be that some quirk of the NFS client VFS interface > > causes "spurious" -EIO returns. either way, i'd rather see it fixed > > rather than the printk removed, since it is useful to point out that > > some performance degradation is occuring. > > We have no way of telling. That printk doesn't give us any useful > information whatsoever for debugging that sort of problem. It should > either be replaced with something that does, or it should be thrown out. err, the printk has found a probable bug in NFS. That was pretty useful of it. Do we know why nfs's readpage isn't bringing the page up to date? Next Message by Date: click to view message previewRe: [discuss] Re: [PATCH for 2.6.18] [8/8] MM: Remove rogue readahead printk> Not necessarily. AFAICS, the spam could be triggered by perfectly > legitimate activity. For instance, someone on the server may have > revoked your read permissions to the file, or may have deleted it. I don't think any of this was the case in the cases I saw it. It would be probably good to investigate post 2.6.18, but for 2.6.18 itself I think removing the printk was the best short term "fix". > > Do we know why nfs's readpage isn't bringing the page up to date? > > It may be that other lurking issues were also triggering the printk. For > instance I know of a couple of corner cases in the krb5 privacy code > that could result in readpage failing. Those issues are being looked > into. I don't use kerberos either. -Andi Previous Message by Thread: click to view message previewRe: [PATCH for 2.6.18] [8/8] MM: Remove rogue readahead printkOn Sun, 30 Jul 2006 00:22:14 -0400 Trond Myklebust <trond.myklebust@xxxxxxxxxx> wrote: > > of course, it could be that some quirk of the NFS client VFS interface > > causes "spurious" -EIO returns. either way, i'd rather see it fixed > > rather than the printk removed, since it is useful to point out that > > some performance degradation is occuring. > > We have no way of telling. That printk doesn't give us any useful > information whatsoever for debugging that sort of problem. It should > either be replaced with something that does, or it should be thrown out. err, the printk has found a probable bug in NFS. That was pretty useful of it. Do we know why nfs's readpage isn't bringing the page up to date? Next Message by Thread: click to view message previewRe: [discuss] Re: [PATCH for 2.6.18] [8/8] MM: Remove rogue readahead printk> Not necessarily. AFAICS, the spam could be triggered by perfectly > legitimate activity. For instance, someone on the server may have > revoked your read permissions to the file, or may have deleted it. I don't think any of this was the case in the cases I saw it. It would be probably good to investigate post 2.6.18, but for 2.6.18 itself I think removing the printk was the best short term "fix". > > Do we know why nfs's readpage isn't bringing the page up to date? > > It may be that other lurking issues were also triggering the printk. For > instance I know of a couple of corner cases in the krb5 privacy code > that could result in readpage failing. Those issues are being looked > into. I don't use kerberos either. -Andi Loading Comments...
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