Re: ZFS L2ARC - incorrect size and abnormal system load on r255173

Correct, there's clearly some other cases which sets
ARC_L2COMPRESS on b_flags for write, but I cant see
where unless its some how gets through from the read
cases.

Attached is a patch which removes all paths which
set ARC_L2COMPRESS on b_flags for both read and write.

Revert the last patch and try this one.

To be clear l2_compress_failures are only a failure
to compress the data, which is not an error.

Have you seen any l2_io_error or l2_cksum_bad since
applying the ashift patch?

    Regards
    Steve

----- Original Message ----- 
From: "Vitalij Satanivskij" <satan_at_ukr.net>
>
> So that's patch not disabling compresion on l2arc?
>
>
> Steven Hartland wrote:
> SH> I would have expected zero for all l2_compress values.
> SH>
> SH>     Regards
> SH>     Steve
> SH>
> SH> ----- Original Message ----- 
> SH> From: "Vitalij Satanivskij" <satan_at_ukr.net>
> SH> To: "Steven Hartland" <killing_at_multiplay.co.uk>
> SH> Cc: "Vitalij Satanivskij" <satan_at_ukr.net>; "Dmitriy Makarov" <supportme_at_ukr.net>; <freebsd-current_at_freebsd.org>
> SH> Sent: Friday, October 25, 2013 8:32 AM
> SH> Subject: Re: ZFS L2ARC - incorrect size and abnormal system load on r255173
> SH>
> SH>
> SH> > Just after system reboot with this patch
> SH> >
> SH> > found
> SH> > kstat.zfs.misc.arcstats.l2_compress_successes: 6083
> SH> > kstat.zfs.misc.arcstats.l2_compress_zeros: 1
> SH> > kstat.zfs.misc.arcstats.l2_compress_failures: 296
> SH> >
> SH> > compression on test pool (where I'm test this patch) is lz4
> SH> >
> SH> > so is it ok ?
> SH> >
> SH> >
> SH> >
> SH> > Steven Hartland wrote:
> SH> > SH> If you are still seeing high load try commenting out the following
> SH> > SH> which should disable l2arc compression.
> SH> > SH> sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c
> SH> > SH>         if (l2arc_compress)
> SH> > SH>                 hdr->b_flags |= ARC_L2COMPRESS;
> SH> > SH>
> SH> >
> SH>
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