On Thu, Dec 12, 2019 at 10:32:05AM +0100, Peter Zijlstra wrote: > As described in the comment, the correct order for freeing pages is: > > 1) unhook page > 2) TLB invalidate page > 3) free page > > This order equally applies to page directories. > > Currently there are two correct options: > > - use tlb_remove_page(), when all page directores are full pages and > there are no futher contraints placed by things like software > walkers (HAVE_FAST_GUP). > > - use MMU_GATHER_RCU_TABLE_FREE and tlb_remove_table() when the > architecture does not do IPI based TLB invalidate and has > HAVE_FAST_GUP (or software TLB fill). > > This however leaves architectures that don't have page based > directories but don't need RCU in a bind. For those, provide > MMU_GATHER_TABLE_FREE, which provides the independent batching for > directories without the additional RCU freeing. > > Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> > --- Various sparc64 builds (allnoconfig, tinyconfig, as well as builds with SMP disabled): mm/mmu_gather.c: In function '__tlb_remove_table_free': mm/mmu_gather.c:101:3: error: implicit declaration of function '__tlb_remove_table'; did you mean 'tlb_remove_table'? Guenter
