[Linux-cachefs] Issues

[David Howells]

"Edward \"Koko\" Konetzko" <konetzed at quixoticagony.com> wrote:

> Acquire: n=266672 nul=0 noc=133334 ok=133338 nbf=133334 oom=0
> ...
> The only real change I see between the two is the Acquire line, noc and nbf
> count rise.

If you look in Documentation/filesystems/caching/fscache.txt, you'll see a
description of each of the counters:

	Acquire	n=N	Number of acquire cookie requests seen
		nul=N	Number of acq reqs given a NULL parent
		noc=N	Number of acq reqs rejected due to no cache available
		ok=N	Number of acq reqs succeeded
		nbf=N	Number of acq reqs rejected due to error
		oom=N	Number of acq reqs failed on ENOMEM

So, nbf>0 means that a number of requests were rejected due to an error
somewhere, presumably there being no cache available as noc>0.  Can you check
your dmesg?


Also, in the first pass, I see:

	Cookies: idx=2 dat=133335 spc=0

and in the second, I see:

	Cookies: idx=2 dat=266670 spc=0

so I would guess you didn't unload the FS-Cache module between goes, which
would have reset the counters to 0.  I should probably add a facility to allow
the counters to be reset to 0 without having to resort to unloading.

David