On Wed, 2022-10-12 at 18:50 +0300, Jarkko Sakkinen wrote: > On Wed, Oct 12, 2022 at 05:50:19PM +0300, Jarkko Sakkinen wrote: > > On Wed, Oct 12, 2022 at 07:13:26AM -0700, Dave Hansen wrote: > > > On 10/12/22 00:15, Jarkko Sakkinen wrote: > > > > There's no data to show that this change would be useful to do. > > > > > > Jarkko, I think the overall transition to kmap_local_page() is a > > > good > > > one. It is a superior API and having it around will pave the way > > > for > > > new features. I don't think we should demand 'data' for each and > > > every > > > one of these. > > > > > > Please take a look around the tree and see how other maintainers > > > are > > > handling these patches. They're not limited to SGX. > > > > Sure, I'll take a look for comparison. > > Yeah, I think it is pretty solid idea. > > Looking at the decription: > > "It is not necessary to disable page faults or preemption when > using kmap calls, so replace kmap_atomic() and kunmap_atomic() > calls with more the more appropriate kmap_local_page() and > kunmap_local() calls." > > We did not pick kmap_atomic() because it disables preeemption, > i.e. it was not a "design choice". I'd rather phrase this as > along the lines: > > "Migrate to the newer kmap_local_page() interface from kmap_atomic() > in order to move away from per-CPU maps to pre-task_struct maps. > This in effect removes the need to disable preemption in the > local CPU while kmap is active, and thus vastly reduces overall > system latency." > > Can be improved or written completely otherwise. I just wrote it > in the way that I had understood the whole deal in the first place. > > BR, Jarkko Thanks for looking into this Jarkko - I will update the commit log for the next version. Kristen
