y...@mwd.biglobe.ne.jp (YAMAMOTO Takashi) wrote: > > > > Here is the updated patch after your changes: > > > > http://www.netbsd.org/~rmind/uvm_anon_freelst2.diff > > > > As you noted, uvm_anfree() can temporarily release the amap lock - that > > can happen in amap_copy(). Patch closes the race by moving uvm_anfree > > () further, and changes the semantics of the function, now called > > uvm_anon_freelst(), to return with amap lock released (plus free anons > > without lock held). > > the temporary release of the amap lock is only for O->A loan > which you disabled, isn't it?
Right, uvm_anon_locklaonpg() dance can happen only in O->A case. However, having uvm_anfree() able to release the lock by its interface definition is potentially defective. It is the main motivation why I want to slightly rework the code into uvm_anon_freelst() which would always drop the lock and move freeing of anons to the end point. Cleaner, less error prone. -- Mindaugas
