> -----Original Message----- > From: linux-kselftest-owner@xxxxxxxxxxxxxxx > [mailto:linux-kselftest-owner@xxxxxxxxxxxxxxx] On Behalf Of John Hubbard > Sent: Friday, August 21, 2020 3:51 PM > To: Song Bao Hua (Barry Song) <song.bao.hua@xxxxxxxxxxxxx>; > akpm@xxxxxxxxxxxxxxxxxxxx; linux-mm@xxxxxxxxx; > linux-kselftest@xxxxxxxxxxxxxxx > Cc: Linuxarm <linuxarm@xxxxxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx; Keith > Busch <keith.busch@xxxxxxxxx>; Ira Weiny <ira.weiny@xxxxxxxxx>; Kirill A . > Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> > Subject: Re: [PATCH] mm/gup_benchmark: update the documentation in > Kconfig > > On 8/20/20 8:25 PM, Barry Song wrote: > > In the beginning, mm/gup_benchmark.c supported get_user_pages_fast() > > only, but right now, it supports the benchmarking of a couple of > > get_user_pages() related calls like: > > * get_user_pages_fast() > > * get_user_pages() > > * pin_user_pages_fast() > > * pin_user_pages() > > The documentation is confusing and needs update. > > hmmm, it's not that confusing, given that pin_user_pages() and > get_user_pages() use the same underlying get_user_pages() > implementation. get_user_pages_fast() is not get_user_pages(). It is a specific function :-) In the beginning, gup_benchmark was only for get_user_pages_fast(): https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/mm/gup_benchmark.c?id=64c349f4ae78 > > > > > Cc: John Hubbard <jhubbard@xxxxxxxxxx> > > Cc: Keith Busch <keith.busch@xxxxxxxxx> > > Cc: Ira Weiny <ira.weiny@xxxxxxxxx> > > Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> > > Signed-off-by: Barry Song <song.bao.hua@xxxxxxxxxxxxx> > > --- > > mm/Kconfig | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/mm/Kconfig b/mm/Kconfig > > index 6c974888f86f..f7c9374da7b3 100644 > > --- a/mm/Kconfig > > +++ b/mm/Kconfig > > @@ -831,10 +831,10 @@ config PERCPU_STATS > > be used to help understand percpu memory usage. > > > > config GUP_BENCHMARK > > - bool "Enable infrastructure for get_user_pages_fast() benchmarking" > > + bool "Enable infrastructure for get_user_pages() and related calls > benchmarking" > > If we really want to go to the trouble of tweaking this, then I'd go with > something more like: > > "Enable infrastructure for get_user_pages() and pin_user_pages benchmarking" > > ...but I don't think it really warrants a patch just yet. *However*, my > judgment is skewed right now, because I'm planning a small patchset to split > up gup_benchmark a little bit, and to add some more testing and take > advantage > of parts of it to do a dump_page() test. At which point "related calls" would > make more sense, but then it would be different enough that this patch would > still need changing. Ok. Fair enough. I was copying the "related calls" from: Documentation/core-api/pin_user_pages.rst > > So I'm inclined to just recommend leaving this alone for a bit, but if others > want to put it in, I'm OK with that too. > > > help > > Provides /sys/kernel/debug/gup_benchmark that helps with testing > > - performance of get_user_pages_fast(). > > + performance of get_user_pages() and related calls. > > > > See tools/testing/selftests/vm/gup_benchmark.c > > Thanks Barry
