IB/mlx5: Implement on demand paging by adding support for MMU notifiers (b4cfe447) · Commits · 戴 / test

drivers/infiniband/hw/mlx5/main.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -574,6 +574,10 @@ static struct ib_ucontext mlx5_ib_alloc_ucontext(struct ib_device ibdev,
		goto out_count;
		}

		#ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING
		context->ibucontext.invalidate_range = &mlx5_ib_invalidate_range;
		#endif

		INIT_LIST_HEAD(&context->db_page_list);
		mutex_init(&context->db_page_mutex);

drivers/infiniband/hw/mlx5/mlx5_ib.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -325,6 +325,7 @@ struct mlx5_ib_mr {
		struct mlx5_ib_dev *dev;
		struct mlx5_create_mkey_mbox_out out;
		struct mlx5_core_sig_ctx *sig;
		int live;
		};

		struct mlx5_ib_fast_reg_page_list {
		@@ -629,6 +630,8 @@ int __init mlx5_ib_odp_init(void);
		void mlx5_ib_odp_cleanup(void);
		void mlx5_ib_qp_disable_pagefaults(struct mlx5_ib_qp *qp);
		void mlx5_ib_qp_enable_pagefaults(struct mlx5_ib_qp *qp);
		void mlx5_ib_invalidate_range(struct ib_umem *umem, unsigned long start,
		unsigned long end);

		#else /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */
		static inline int mlx5_ib_internal_query_odp_caps(struct mlx5_ib_dev *dev)

drivers/infiniband/hw/mlx5/mr.c

+74 −5

Original line number	Diff line number	Diff line
		@@ -37,6 +37,7 @@
		#include <linux/export.h>
		#include <linux/delay.h>
		#include <rdma/ib_umem.h>
		#include <rdma/ib_umem_odp.h>
		#include <rdma/ib_verbs.h>
		#include "mlx5_ib.h"

		@@ -54,6 +55,18 @@ static DEFINE_MUTEX(mlx5_ib_update_mtt_emergency_buffer_mutex);

		static int clean_mr(struct mlx5_ib_mr *mr);

		static int destroy_mkey(struct mlx5_ib_dev dev, struct mlx5_ib_mr mr)
		{
		int err = mlx5_core_destroy_mkey(dev->mdev, &mr->mmr);

		#ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING
		/* Wait until all page fault handlers using the mr complete. */
		synchronize_srcu(&dev->mr_srcu);
		#endif

		return err;
		}

		static int order2idx(struct mlx5_ib_dev *dev, int order)
		{
		struct mlx5_mr_cache *cache = &dev->cache;
		@@ -191,7 +204,7 @@ static void remove_keys(struct mlx5_ib_dev *dev, int c, int num)
		ent->cur--;
		ent->size--;
		spin_unlock_irq(&ent->lock);
		err = mlx5_core_destroy_mkey(dev->mdev, &mr->mmr);
		err = destroy_mkey(dev, mr);
		if (err)
		mlx5_ib_warn(dev, "failed destroy mkey\n");
		else
		@@ -482,7 +495,7 @@ static void clean_keys(struct mlx5_ib_dev *dev, int c)
		ent->cur--;
		ent->size--;
		spin_unlock_irq(&ent->lock);
		err = mlx5_core_destroy_mkey(dev->mdev, &mr->mmr);
		err = destroy_mkey(dev, mr);
		if (err)
		mlx5_ib_warn(dev, "failed destroy mkey\n");
		else
		@@ -812,6 +825,8 @@ static struct mlx5_ib_mr reg_umr(struct ib_pd pd, struct ib_umem *umem,
		mr->mmr.size = len;
		mr->mmr.pd = to_mpd(pd)->pdn;

		mr->live = 1;

		unmap_dma:
		up(&umrc->sem);
		dma_unmap_single(ddev, dma, size, DMA_TO_DEVICE);
		@@ -997,6 +1012,7 @@ static struct mlx5_ib_mr reg_create(struct ib_pd pd, u64 virt_addr,
		goto err_2;
		}
		mr->umem = umem;
		mr->live = 1;
		kvfree(in);

		mlx5_ib_dbg(dev, "mkey = 0x%x\n", mr->mmr.key);
		@@ -1074,10 +1090,47 @@ struct ib_mr mlx5_ib_reg_user_mr(struct ib_pd pd, u64 start, u64 length,
		mr->ibmr.lkey = mr->mmr.key;
		mr->ibmr.rkey = mr->mmr.key;

		#ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING
		if (umem->odp_data) {
		/*
		* This barrier prevents the compiler from moving the
		* setting of umem->odp_data->private to point to our
		* MR, before reg_umr finished, to ensure that the MR
		* initialization have finished before starting to
		* handle invalidations.
		*/
		smp_wmb();
		mr->umem->odp_data->private = mr;
		/*
		* Make sure we will see the new
		* umem->odp_data->private value in the invalidation
		* routines, before we can get page faults on the
		* MR. Page faults can happen once we put the MR in
		* the tree, below this line. Without the barrier,
		* there can be a fault handling and an invalidation
		* before umem->odp_data->private == mr is visible to
		* the invalidation handler.
		*/
		smp_wmb();
		}
		#endif

		return &mr->ibmr;

		error:
		/*
		* Destroy the umem before destroying the MR, to ensure we
		* will not have any in-flight notifiers when destroying the
		* MR.
		*
		* As the MR is completely invalid to begin with, and this
		* error path is only taken if we can't push the mr entry into
		* the pagefault tree, this is safe.
		*/

		ib_umem_release(umem);
		/* Kill the MR, and return an error code. */
		clean_mr(mr);
		return ERR_PTR(err);
		}

		@@ -1121,7 +1174,7 @@ static int clean_mr(struct mlx5_ib_mr *mr)
		int err;

		if (!umred) {
		err = mlx5_core_destroy_mkey(dev->mdev, &mr->mmr);
		err = destroy_mkey(dev, mr);
		if (err) {
		mlx5_ib_warn(dev, "failed to destroy mkey 0x%x (%d)\n",
		mr->mmr.key, err);
		@@ -1150,9 +1203,25 @@ int mlx5_ib_dereg_mr(struct ib_mr *ibmr)
		struct ib_umem *umem = mr->umem;

		#ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING
		if (umem)
		if (umem && umem->odp_data) {
		/* Prevent new page faults from succeeding */
		mr->live = 0;
		/* Wait for all running page-fault handlers to finish. */
		synchronize_srcu(&dev->mr_srcu);
		/* Destroy all page mappings */
		mlx5_ib_invalidate_range(umem, ib_umem_start(umem),
		ib_umem_end(umem));
		/*
		* We kill the umem before the MR for ODP,
		* so that there will not be any invalidations in
		* flight, looking at the *mr struct.
		*/
		ib_umem_release(umem);
		atomic_sub(npages, &dev->mdev->priv.reg_pages);

		/* Avoid double-freeing the umem. */
		umem = NULL;
		}
		#endif

		clean_mr(mr);
		@@ -1269,7 +1338,7 @@ int mlx5_ib_destroy_mr(struct ib_mr *ibmr)
		kfree(mr->sig);
		}

		err = mlx5_core_destroy_mkey(dev->mdev, &mr->mmr);
		err = destroy_mkey(dev, mr);
		if (err) {
		mlx5_ib_warn(dev, "failed to destroy mkey 0x%x (%d)\n",
		mr->mmr.key, err);

drivers/infiniband/hw/mlx5/odp.c

+117 −11

Original line number	Diff line number	Diff line
		@@ -37,8 +37,78 @@

		#define MAX_PREFETCH_LEN (410241024U)

		/* Timeout in ms to wait for an active mmu notifier to complete when handling
		* a pagefault. */
		#define MMU_NOTIFIER_TIMEOUT 1000

		struct workqueue_struct *mlx5_ib_page_fault_wq;

		void mlx5_ib_invalidate_range(struct ib_umem *umem, unsigned long start,
		unsigned long end)
		{
		struct mlx5_ib_mr *mr;
		const u64 umr_block_mask = (MLX5_UMR_MTT_ALIGNMENT / sizeof(u64)) - 1;
		u64 idx = 0, blk_start_idx = 0;
		int in_block = 0;
		u64 addr;

		if (!umem \|\| !umem->odp_data) {
		pr_err("invalidation called on NULL umem or non-ODP umem\n");
		return;
		}

		mr = umem->odp_data->private;

		if (!mr \|\| !mr->ibmr.pd)
		return;

		start = max_t(u64, ib_umem_start(umem), start);
		end = min_t(u64, ib_umem_end(umem), end);

		/*
		* Iteration one - zap the HW's MTTs. The notifiers_count ensures that
		* while we are doing the invalidation, no page fault will attempt to
		* overwrite the same MTTs. Concurent invalidations might race us,
		* but they will write 0s as well, so no difference in the end result.
		*/

		for (addr = start; addr < end; addr += (u64)umem->page_size) {
		idx = (addr - ib_umem_start(umem)) / PAGE_SIZE;
		/*
		* Strive to write the MTTs in chunks, but avoid overwriting
		* non-existing MTTs. The huristic here can be improved to
		* estimate the cost of another UMR vs. the cost of bigger
		* UMR.
		*/
		if (umem->odp_data->dma_list[idx] &
		(ODP_READ_ALLOWED_BIT \| ODP_WRITE_ALLOWED_BIT)) {
		if (!in_block) {
		blk_start_idx = idx;
		in_block = 1;
		}
		} else {
		u64 umr_offset = idx & umr_block_mask;

		if (in_block && umr_offset == 0) {
		mlx5_ib_update_mtt(mr, blk_start_idx,
		idx - blk_start_idx, 1);
		in_block = 0;
		}
		}
		}
		if (in_block)
		mlx5_ib_update_mtt(mr, blk_start_idx, idx - blk_start_idx + 1,
		1);

		/*
		* We are now sure that the device will not access the
		* memory. We can safely unmap it, and mark it as dirty if
		* needed.
		*/

		ib_umem_odp_unmap_dma_pages(umem, start, end);
		}

		#define COPY_ODP_BIT_MLX_TO_IB(reg, ib_caps, field_name, bit_name) do { \
		if (be32_to_cpu(reg.field_name) & MLX5_ODP_SUPPORT_##bit_name) \
		ib_caps->field_name \|= IB_ODP_SUPPORT_##bit_name; \
		@@ -59,9 +129,18 @@ int mlx5_ib_internal_query_odp_caps(struct mlx5_ib_dev *dev)
		if (err)
		goto out;

		/* At this point we would copy the capability bits that the driver
		* supports from the hw_caps struct to the caps struct. However, no
		* such capabilities are supported so far. */
		caps->general_caps = IB_ODP_SUPPORT;
		COPY_ODP_BIT_MLX_TO_IB(hw_caps, caps, per_transport_caps.ud_odp_caps,
		SEND);
		COPY_ODP_BIT_MLX_TO_IB(hw_caps, caps, per_transport_caps.rc_odp_caps,
		SEND);
		COPY_ODP_BIT_MLX_TO_IB(hw_caps, caps, per_transport_caps.rc_odp_caps,
		RECV);
		COPY_ODP_BIT_MLX_TO_IB(hw_caps, caps, per_transport_caps.rc_odp_caps,
		WRITE);
		COPY_ODP_BIT_MLX_TO_IB(hw_caps, caps, per_transport_caps.rc_odp_caps,
		READ);

		out:
		return err;
		}
		@@ -71,8 +150,9 @@ static struct mlx5_ib_mr mlx5_ib_odp_find_mr_lkey(struct mlx5_ib_dev dev,
		{
		u32 base_key = mlx5_base_mkey(key);
		struct mlx5_core_mr *mmr = __mlx5_mr_lookup(dev->mdev, base_key);
		struct mlx5_ib_mr *mr = container_of(mmr, struct mlx5_ib_mr, mmr);

		if (!mmr \|\| mmr->key != key)
		if (!mmr \|\| mmr->key != key \|\| !mr->live)
		return NULL;

		return container_of(mmr, struct mlx5_ib_mr, mmr);
		@@ -143,6 +223,11 @@ static int pagefault_single_data_segment(struct mlx5_ib_qp *qp,
		}

		current_seq = ACCESS_ONCE(mr->umem->odp_data->notifiers_seq);
		/*
		* Ensure the sequence number is valid for some time before we call
		* gup.
		*/
		smp_rmb();

		/*
		* Avoid branches - this code will perform correctly
		@@ -165,14 +250,19 @@ static int pagefault_single_data_segment(struct mlx5_ib_qp *qp,

		if (npages > 0) {
		mutex_lock(&mr->umem->odp_data->umem_mutex);
		if (!ib_umem_mmu_notifier_retry(mr->umem, current_seq)) {
		/*
		* No need to check whether the MTTs really belong to
		* this MR, since ib_umem_odp_map_dma_pages already
		* checks this.
		*/
		ret = mlx5_ib_update_mtt(mr, start_idx, npages, 0);
		} else {
		ret = -EAGAIN;
		}
		mutex_unlock(&mr->umem->odp_data->umem_mutex);
		if (ret < 0) {
		if (ret != -EAGAIN)
		pr_err("Failed to update mkey page tables\n");
		goto srcu_unlock;
		}
		@@ -185,6 +275,22 @@ static int pagefault_single_data_segment(struct mlx5_ib_qp *qp,
		}

		srcu_unlock:
		if (ret == -EAGAIN) {
		if (!mr->umem->odp_data->dying) {
		struct ib_umem_odp *odp_data = mr->umem->odp_data;
		unsigned long timeout =
		msecs_to_jiffies(MMU_NOTIFIER_TIMEOUT);

		if (!wait_for_completion_timeout(
		&odp_data->notifier_completion,
		timeout)) {
		pr_warn("timeout waiting for mmu notifier completion\n");
		}
		} else {
		/* The MR is being killed, kill the QP as well. */
		ret = -EFAULT;
		}
		}
		srcu_read_unlock(&mib_dev->mr_srcu, srcu_key);
		pfault->mpfault.bytes_committed = 0;
		return ret ? ret : npages;

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