Hi,
I agree with you this is a bug.
I think we should change the following code:
// KISS: if [lower,upper] spans our target effort, evict it.
if (atime_lower >= agent_state->evict_effort)
return false;
to something like this:
if (1000000 - atime_upper >= agent_state->evict_effort)
return false;
cc the ceph-devel list for comments.
________________________________________
Date: Mon, 27 Oct 2014 10:20:01 +0800
Subject: Cache pool bug?
From: xmdxcxz@xxxxxxxxx
To: wonzhq@xxxxxxxxxxx
hi, zhiqiang：
When I read the ReplicatedPG::agent_maybe_evic, I found than the newest object has
more probability to be evicted. For Example:
the object in hit_set is newest object, call
the funtion agent_estimate_atime_temp(soid, &atime, NULL /*FIXME &temp*/); atime is 0 when return.
agent_state->atime_hist.get_position_micro(atime, &atime_lower, &atime_upper), the atime_lower is 0 when return.
// KISS: if [lower,upper] spans our target effort, evict it.
if (atime_lower >= agent_state->evict_effort)
return false;
Above, the newest object in hit_set is evicted.
Is there a bug? Or, whether I skip something?
Thanks
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