Messages in this thread | | | Date | Tue, 1 Feb 2022 08:31:34 -0400 | From | Jason Gunthorpe <> | Subject | Re: [PATCH v2 4/4] mm/gup: remove get_user_pages_locked() |
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On Tue, Feb 01, 2022 at 02:11:08AM -0800, John Hubbard wrote: > There is only one caller of get_user_pages_locked(). The purpose of > get_user_pages_locked() is to allow for unlocking the mmap_lock when > reading a page from the disk during a page fault (hidden behind > VM_FAULT_RETRY). The idea is to reduce contention on the heavily-used > mmap_lock. (Thanks to Jan Kara for clearly pointing that out, and in > fact I've used some of his wording here.) > > However, it is unlikely for lookup_node() to take a page fault. With > that in mind, change over to calling get_user_pages_fast(). This > simplifies the code, runs a little faster in the expected case, and > allows removing get_user_pages_locked() entirely. > > Cc: Jan Kara <jack@suse.cz> > Suggested-by: Jason Gunthorpe <jgg@ziepe.ca> > Signed-off-by: John Hubbard <jhubbard@nvidia.com> > --- > include/linux/mm.h | 2 -- > mm/gup.c | 59 ---------------------------------------------- > mm/mempolicy.c | 21 +++++++---------- > 3 files changed, 9 insertions(+), 73 deletions(-)
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Jason
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