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SubjectRe: [PATCH -next 0/6] mm: make pinned_vm atomic and simplify users
Also Ccing lkml, sorry.

On Tue, 15 Jan 2019, Davidlohr Bueso wrote:

>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.
>
>Thanks!
>
>[1] https://lkml.org/lkml/2018/11/5/854
>
>Davidlohr Bueso (6):
> mm: make mm->pinned_vm an atomic counter
> mic/scif: do not use mmap_sem
> drivers/IB,qib: do not use mmap_sem
> 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 | 69 ++++++++++-------------------
> drivers/infiniband/hw/usnic/usnic_ib_main.c | 2 -
> drivers/infiniband/hw/usnic/usnic_uiom.c | 56 +++--------------------
> 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 | 3 +-
> 12 files changed, 57 insertions(+), 185 deletions(-)
>
>--
>2.16.4
>

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