| Message ID | 20190115181300.27547-1-dave@stgolabs.net (mailing list archive) |
|---|---|
| Headers | show |
| Series | mm: make pinned_vm atomic and simplify users | expand |
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 >
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(-)