On Thu, Jan 21, 2021 at 10:21:50PM +0530, Prathu Baronia wrote: > This patch removes the unnecessary kmap calls in the hugepage zeroing path and > improves the timing by 62%. > > I had proposed a similar change in Apr-May'20 timeframe in memory.c where I > proposed to clear out a hugepage by directly calling a memset over the whole > hugepage but got the opposition that the change was not architecturally > neutral. > > Upon revisiting this now I see significant improvement by removing around 2k > barrier calls from the zeroing path. So hereby I propose an arm64 specific > definition of clear_user_highpage().
Given that barrier() is purely a thing for the compiler, wouldn't the same change yield a benefit on any other architecture without HIGHMEM? In which case, I think this sort of change belongs in the core code if it's actually worthwhile. Will
