From: Jérôme Glisse <[email protected]> When range of virtual address is updated read only and corresponding user ptr object are already read only it is pointless to do anything. Optimize this case out.
Signed-off-by: Jérôme Glisse <[email protected]> Cc: Christian König <[email protected]> Cc: Jan Kara <[email protected]> Cc: Felix Kuehling <[email protected]> Cc: Jason Gunthorpe <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Matthew Wilcox <[email protected]> Cc: Ross Zwisler <[email protected]> Cc: Dan Williams <[email protected]> Cc: Paolo Bonzini <[email protected]> Cc: Radim Krčmář <[email protected]> Cc: Michal Hocko <[email protected]> Cc: Ralph Campbell <[email protected]> Cc: John Hubbard <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: Arnd Bergmann <[email protected]> --- drivers/infiniband/core/umem_odp.c | 22 +++++++++++++++++++--- include/rdma/ib_umem_odp.h | 1 + 2 files changed, 20 insertions(+), 3 deletions(-) diff --git a/drivers/infiniband/core/umem_odp.c b/drivers/infiniband/core/umem_odp.c index a4ec43093cb3..fa4e7fdcabfc 100644 --- a/drivers/infiniband/core/umem_odp.c +++ b/drivers/infiniband/core/umem_odp.c @@ -140,8 +140,15 @@ static void ib_umem_notifier_release(struct mmu_notifier *mn, static int invalidate_range_start_trampoline(struct ib_umem_odp *item, u64 start, u64 end, void *cookie) { + bool update_to_read_only = *((bool *)cookie); + ib_umem_notifier_start_account(item); - item->umem.context->invalidate_range(item, start, end); + /* + * If it is already read only and we are updating to read only then we + * do not need to change anything. So save time and skip this one. + */ + if (!update_to_read_only || !item->read_only) + item->umem.context->invalidate_range(item, start, end); return 0; } @@ -150,6 +157,7 @@ static int ib_umem_notifier_invalidate_range_start(struct mmu_notifier *mn, { struct ib_ucontext_per_mm *per_mm = container_of(mn, struct ib_ucontext_per_mm, mn); + bool update_to_read_only; if (range->blockable) down_read(&per_mm->umem_rwsem); @@ -166,10 +174,13 @@ static int ib_umem_notifier_invalidate_range_start(struct mmu_notifier *mn, return 0; } + update_to_read_only = mmu_notifier_range_update_to_read_only(range); + return rbt_ib_umem_for_each_in_range(&per_mm->umem_tree, range->start, range->end, invalidate_range_start_trampoline, - range->blockable, NULL); + range->blockable, + &update_to_read_only); } static int invalidate_range_end_trampoline(struct ib_umem_odp *item, u64 start, @@ -363,6 +374,9 @@ struct ib_umem_odp *ib_alloc_odp_umem(struct ib_ucontext_per_mm *per_mm, goto out_odp_data; } + /* Assume read only at first, each time GUP is call this is updated. */ + odp_data->read_only = true; + odp_data->dma_list = vzalloc(array_size(pages, sizeof(*odp_data->dma_list))); if (!odp_data->dma_list) { @@ -619,8 +633,10 @@ int ib_umem_odp_map_dma_pages(struct ib_umem_odp *umem_odp, u64 user_virt, goto out_put_task; } - if (access_mask & ODP_WRITE_ALLOWED_BIT) + if (access_mask & ODP_WRITE_ALLOWED_BIT) { + umem_odp->read_only = false; flags |= FOLL_WRITE; + } start_idx = (user_virt - ib_umem_start(umem)) >> page_shift; k = start_idx; diff --git a/include/rdma/ib_umem_odp.h b/include/rdma/ib_umem_odp.h index 0b1446fe2fab..8256668c6170 100644 --- a/include/rdma/ib_umem_odp.h +++ b/include/rdma/ib_umem_odp.h @@ -76,6 +76,7 @@ struct ib_umem_odp { struct completion notifier_completion; int dying; struct work_struct work; + bool read_only; }; static inline struct ib_umem_odp *to_ib_umem_odp(struct ib_umem *umem) -- 2.17.2
