On Sun, May 21, 2023 at 10:04:35AM +0800, Wang Yugui wrote: > > I don't see it? > > > > size == 1 << 20; > > > > shift = 20; > > return (20 - 12) << 26; > > > > Looks like about 1 << 29 to me. > > sorry that I wrongly > 1) wrongly conside PAGE_SHIFT as 13 from arch/alpha/include/asm/page.h > it should be 12 from arch/x86/include/asm/page_types.h. > > 2) wrongly conside > (20 - 12) << 26 > as > 1<< (20 - 12) << 26 Ah, no problem. Glad I didn't miss something.