Re: [PATCH for-next v3 4/7] RDMA/rxe: Add page invalidation support

[Jason Gunthorpe]

On Fri, Dec 23, 2022 at 03:51:55PM +0900, Daisuke Matsuda wrote:

> +static bool rxe_ib_invalidate_range(struct mmu_interval_notifier *mni,
> + const struct mmu_notifier_range *range,
> + unsigned long cur_seq)
> +{
> + struct ib_umem_odp *umem_odp =
> + container_of(mni, struct ib_umem_odp, notifier);
> + unsigned long start;
> + unsigned long end;
> +
> + if (!mmu_notifier_range_blockable(range))
> + return false;
> +
> + mutex_lock(_odp->umem_mutex);
> + mmu_interval_set_seq(mni, cur_seq);
> +
> + start = max_t(u64, ib_umem_start(umem_odp), range->start);
> + end = min_t(u64, ib_umem_end(umem_odp), range->end);
> +
> + ib_umem_odp_unmap_dma_pages(umem_odp, start, end);

After bob's xarray conversion this can be done alot faster, it just an
xa_for_each_range and make the xarray items non-present

non-present is probably just a null struct page in the xarray.

Jason

[PATCH for-next v3 4/7] RDMA/rxe: Add page invalidation support

[Daisuke Matsuda]

On page invalidation, an MMU notifier callback is invoked to unmap DMA
addresses and update the driver page table(umem_odp->dma_list). The
callback is registered when an ODP-enabled MR is created.

Signed-off-by: Daisuke Matsuda 
---
 drivers/infiniband/sw/rxe/Makefile  |  2 ++
 drivers/infiniband/sw/rxe/rxe_odp.c | 34 +
 2 files changed, 36 insertions(+)
 create mode 100644 drivers/infiniband/sw/rxe/rxe_odp.c

diff --git a/drivers/infiniband/sw/rxe/Makefile 
b/drivers/infiniband/sw/rxe/Makefile
index 5395a581f4bb..93134f1d1d0c 100644
--- a/drivers/infiniband/sw/rxe/Makefile
+++ b/drivers/infiniband/sw/rxe/Makefile
@@ -23,3 +23,5 @@ rdma_rxe-y := \
rxe_task.o \
rxe_net.o \
rxe_hw_counters.o
+
+rdma_rxe-$(CONFIG_INFINIBAND_ON_DEMAND_PAGING) += rxe_odp.o
diff --git a/drivers/infiniband/sw/rxe/rxe_odp.c 
b/drivers/infiniband/sw/rxe/rxe_odp.c
new file mode 100644
index ..0787a9b19646
--- /dev/null
+++ b/drivers/infiniband/sw/rxe/rxe_odp.c
@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
+/*
+ * Copyright (c) 2022 Fujitsu Ltd. All rights reserved.
+ */
+
+#include 
+
+static bool rxe_ib_invalidate_range(struct mmu_interval_notifier *mni,
+   const struct mmu_notifier_range *range,
+   unsigned long cur_seq)
+{
+   struct ib_umem_odp *umem_odp =
+   container_of(mni, struct ib_umem_odp, notifier);
+   unsigned long start;
+   unsigned long end;
+
+   if (!mmu_notifier_range_blockable(range))
+   return false;
+
+   mutex_lock(_odp->umem_mutex);
+   mmu_interval_set_seq(mni, cur_seq);
+
+   start = max_t(u64, ib_umem_start(umem_odp), range->start);
+   end = min_t(u64, ib_umem_end(umem_odp), range->end);
+
+   ib_umem_odp_unmap_dma_pages(umem_odp, start, end);
+
+   mutex_unlock(_odp->umem_mutex);
+   return true;
+}
+
+const struct mmu_interval_notifier_ops rxe_mn_ops = {
+   .invalidate = rxe_ib_invalidate_range,
+};
-- 
2.31.1