On Tue, 29 Jul 2014, Wang, Zhiqiang wrote:
> This fixes a bug when the time of the OSDs and clients are not synchronized
> (especially when client is ahead of OSD), and the cache tier dirty ratio
> reaches the threshold, the agent skips the flush work because it thinks
> the object is too young.
>
> The skipping flush code is as following:
>
> if (obc->obs.oi.mtime + utime_t(pool.info.cache_min_flush_age, 0) > now) {
> dout(20) << __func__ << " skip (too young) " << obc->obs.oi << dendl;
> osd->logger->inc(l_osd_agent_skip);
> return false;
> }
Hmm, I think the use of the client mtime is an important property we want
to maintain for the benefit of the rest of the system. Two other
possibilities:
1) If cache_min_flush_age is 0, skip the check, so we avoid mtimes in the
future in that case.
2) Add an additional field to object_info_t that is an mtime based on the
OSD's clock, and use that for these checks.
What do you think?
sage
>
> Signed-off-by: Zhiqiang Wang <wonzhq@xxxxxxxxxxx>
> ---
> src/osd/ReplicatedPG.cc | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/src/osd/ReplicatedPG.cc b/src/osd/ReplicatedPG.cc
> index 5d822c1..1c7c527 100644
> --- a/src/osd/ReplicatedPG.cc
> +++ b/src/osd/ReplicatedPG.cc
> @@ -1805,7 +1805,7 @@ void ReplicatedPG::execute_ctx(OpContext *ctx)
>
> // version
> ctx->at_version = get_next_version();
> - ctx->mtime = m->get_mtime();
> + ctx->mtime = ceph_clock_now(cct);
>
> dout(10) << "do_op " << soid << " " << ctx->ops
> << " ov " << obc->obs.oi.version << " av " << ctx->at_version
> --
> 1.9.1
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