On Wed, Feb 24, 2021 at 01:18:10PM -0800, Darrick J. Wong wrote: > On Tue, Feb 23, 2021 at 02:34:42PM +1100, Dave Chinner wrote: > > From: Dave Chinner <dchinner@xxxxxxxxxx> > > > > A hang with tasks stuck on the CIL hard throttle was reported and > > largely diagnosed by Donald Buczek, who discovered that it was a > > result of the CIL context space usage decrementing in committed > > transactions once the hard throttle limit had been hit and processes > > were already blocked. This resulted in the CIL push not waking up > > those waiters because the CIL context was no longer over the hard > > throttle limit. > > > > The surprising aspect of this was the CIL space usage going > > backwards regularly enough to trigger this situation. Assumptions > > had been made in design that the relogging process would only > > increase the size of the objects in the CIL, and so that space would > > only increase. > > > > This change and commit message fixes the issue and documents the > > result of an audit of the triggers that can cause the CIL space to > > go backwards, how large the backwards steps tend to be, the > > frequency in which they occur, and what the impact on the CIL > > accounting code is. .... > Does this whole series fix the Donald's problem? No, just this patch is needed to fix that problem. Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx
