Re: [PATCH v2 2/2] mm: speed up mremap by 500x on large regions

2018-10-12 Thread Daniel Colascione
On Fri, Oct 12, 2018 at 7:10 PM, Joel Fernandes wrote: > On Fri, Oct 12, 2018 at 06:54:33PM -0700, Daniel Colascione wrote: >> I wonder whether it makes sense to expose to userspace somehow whether >> mremap is "fast" for a particular architecture. If a feature relies on

Re: [PATCH v2 2/2] mm: speed up mremap by 500x on large regions

2018-10-12 Thread Daniel Colascione
rming very poorly. If we're disabling fast mremap when THP is enabled, the userland component can't just rely on an architecture switch and some kind of runtime feature detection becomes even more important. On Fri, Oct 12, 2018 at 6:44 PM, Joel Fernandes wrote: > On Fri, Oct 12, 2018 at 0

Re: [PATCH v2 2/2] mm: speed up mremap by 500x on large regions

2018-10-12 Thread Daniel Colascione
Not 32-bit ARM? On Fri, Oct 12, 2018 at 6:35 PM, Joel Fernandes wrote: > On Fri, Oct 12, 2018 at 11:18:36AM -0700, David Miller wrote: >> From: Joel Fernandes > [...] >> > Also, do we not flush the caches from any path when we munmap >> > address space? We do call do_munmap on the old mapping f