Changes from v2 (https://patchwork.kernel.org/cover/10774255/): - Added more reviews for patch 1 and also fixed mm/debug.c to use llx insted of lx so gcc doesn't complain. - Re did patch 3 (qib rdma) such that we still have to take mmap_sem as it now uses gup_longterm(). gup_fast() conversion remains for patch 2 which is not infiniband. - Rebased for rdma tree. Changes from v1 (https://patchwork.kernel.org/cover/10764923/): - Converted pinned_vm to atomic64 instead of atomic_long such that infiniband need not worry about overflows. - Rebased patch 1 and added Ira's reviews as well as Parvi's review for patch 5 (thanks!). -------- Hi, The following patches aim to provide cleanups to users that pin pages (mostly infiniband) by converting the counter to atomic -- note that Daniel Jordan also has patches[1] for the locked_vm counterpart and vfio. Apart from removing a source of mmap_sem writer, we benefit in that we can get rid of a lot of code that defers work when the lock cannot be acquired, as well as drivers avoiding mmap_sem altogether by also converting gup to gup_fast() and letting the mm handle it. Users that do the gup_longterm() remain of course under at least reader mmap_sem. Everything has been compile-tested _only_ so I hope I didn't do anything too stupid. Please consider for v5.1. On a similar topic and potential follow up, it would be nice to resurrect Peter's VM_PINNED idea in that the broken semantics that occurred after bc3e53f682 ("mm: distinguish between mlocked and pinned pages") are still present. Also encapsulating internal mm logic via mm[un]pin() instead of drivers having to know about internals and playing nice with compaction are all wins. Applies against rdma's for-next branch. Thanks! [1] https://lkml.org/lkml/2018/11/5/854 Davidlohr Bueso (6): mm: make mm->pinned_vm an atomic64 counter drivers/mic/scif: do not use mmap_sem drivers/IB,qib: optimize mmap_sem usage drivers/IB,hfi1: do not se mmap_sem drivers/IB,usnic: reduce scope of mmap_sem drivers/IB,core: reduce scope of mmap_sem drivers/infiniband/core/umem.c | 47 ++---------------- drivers/infiniband/hw/hfi1/user_pages.c | 12 ++--- drivers/infiniband/hw/qib/qib_user_pages.c | 75 +++++++++++------------------ drivers/infiniband/hw/usnic/usnic_ib_main.c | 2 - drivers/infiniband/hw/usnic/usnic_uiom.c | 60 +++-------------------- drivers/infiniband/hw/usnic/usnic_uiom.h | 1 - drivers/misc/mic/scif/scif_rma.c | 38 +++++---------- fs/proc/task_mmu.c | 2 +- include/linux/mm_types.h | 2 +- kernel/events/core.c | 8 +-- kernel/fork.c | 2 +- mm/debug.c | 5 +- 12 files changed, 65 insertions(+), 189 deletions(-) -- 2.16.4
