> On Tue, 2025-04-15 at 14:51 +0300, Elena Reshetova wrote: > > sgx_nr_free_pages is an atomic that is used to keep track of > > free EPC pages and detect whenever page reclaiming should start. > > Since successful execution of ENCLS[EUPDATESVN] requires empty > > The mentioning of ENCLS[EUPDATESVN] is kinda out of blue here. It's better > to > introduce it first like the next patch does.
Thank you, will expand more. > > > EPC and preferably a fast lockless way of checking for this > > condition in all code paths where EPC is already used, change the > > reclaiming code to track the number of used pages via > > sgx_nr_used_pages instead of sgx_nr_free_pages. > > For this change to work in the page reclamation code, add a new > > variable, sgx_nr_total_pages, that will keep track of total > > number of EPC pages. > > > > It would have been possible to implement ENCLS[EUPDATESVN] using > > existing sgx_nr_free_pages counter and a new sgx_nr_total_pages > > counter, but it won't be possible to avoid taking a lock *every time* > > a new EPC page is being allocated. The conversion of sgx_nr_free_pages > > into sgx_nr_used_pages allows avoiding the lock in all cases except > > when it is the first EPC page being allocated via a quick > > atomic_long_inc_not_zero check. > > > > Note: The serialization for sgx_nr_total_pages is not needed because > > the variable is only updated during the initialization and there's no > > concurrent access. > > > > Signed-off-by: Elena Reshetova <elena.reshet...@intel.com> > > Reviewed-by: Kai Huang <kai.hu...@intel.com> Thank you very much for your review!
