[PATCH v2 for-next 4/6] RDMA/hns: Support flexible umem page size

From: Junxian Huang
Date: Sat Jan 13 2024 - 04:05:05 EST


From: Chengchang Tang <tangchengchang@xxxxxxxxxx>

In the current implementation, a fixed page size is used to
configure the umem PBL, which is not flexible enough and is
not conducive to the performance of the HW. Find a best page
size to get better performance.

Signed-off-by: Chengchang Tang <tangchengchang@xxxxxxxxxx>
Signed-off-by: Junxian Huang <huangjunxian6@xxxxxxxxxxxxx>
---
drivers/infiniband/hw/hns/hns_roce_device.h | 9 ++
drivers/infiniband/hw/hns/hns_roce_mr.c | 121 ++++++++++++++------
2 files changed, 92 insertions(+), 38 deletions(-)

diff --git a/drivers/infiniband/hw/hns/hns_roce_device.h b/drivers/infiniband/hw/hns/hns_roce_device.h
index dd652dc090b0..1a8516019516 100644
--- a/drivers/infiniband/hw/hns/hns_roce_device.h
+++ b/drivers/infiniband/hw/hns/hns_roce_device.h
@@ -179,6 +179,7 @@ enum {

#define HNS_ROCE_CMD_SUCCESS 1

+#define HNS_ROCE_MAX_HOP_NUM 3
/* The minimum page size is 4K for hardware */
#define HNS_HW_PAGE_SHIFT 12
#define HNS_HW_PAGE_SIZE (1 << HNS_HW_PAGE_SHIFT)
@@ -269,6 +270,11 @@ struct hns_roce_hem_list {
dma_addr_t root_ba; /* pointer to the root ba table */
};

+enum mtr_type {
+ MTR_DEFAULT = 0,
+ MTR_PBL,
+};
+
struct hns_roce_buf_attr {
struct {
size_t size; /* region size */
@@ -277,7 +283,10 @@ struct hns_roce_buf_attr {
unsigned int region_count; /* valid region count */
unsigned int page_shift; /* buffer page shift */
unsigned int user_access; /* umem access flag */
+ u64 iova;
+ enum mtr_type type;
bool mtt_only; /* only alloc buffer-required MTT memory */
+ bool adaptive; /* adaptive for page_shift and hopnum */
};

struct hns_roce_hem_cfg {
diff --git a/drivers/infiniband/hw/hns/hns_roce_mr.c b/drivers/infiniband/hw/hns/hns_roce_mr.c
index 74ea9d8482b9..d00b4aa7214b 100644
--- a/drivers/infiniband/hw/hns/hns_roce_mr.c
+++ b/drivers/infiniband/hw/hns/hns_roce_mr.c
@@ -32,6 +32,7 @@
*/

#include <linux/vmalloc.h>
+#include <linux/count_zeros.h>
#include <rdma/ib_umem.h>
#include <linux/math.h>
#include "hns_roce_device.h"
@@ -103,6 +104,10 @@ static int alloc_mr_pbl(struct hns_roce_dev *hr_dev, struct hns_roce_mr *mr,
buf_attr.user_access = mr->access;
/* fast MR's buffer is alloced before mapping, not at creation */
buf_attr.mtt_only = is_fast;
+ buf_attr.iova = mr->iova;
+ /* pagesize and hopnum is fixed for fast MR */
+ buf_attr.adaptive = !is_fast;
+ buf_attr.type = MTR_PBL;

err = hns_roce_mtr_create(hr_dev, &mr->pbl_mtr, &buf_attr,
hr_dev->caps.pbl_ba_pg_sz + PAGE_SHIFT,
@@ -721,6 +726,16 @@ static int cal_mtr_pg_cnt(struct hns_roce_mtr *mtr)
return page_cnt;
}

+static bool need_split_huge_page(struct hns_roce_mtr *mtr)
+{
+ /* When HEM buffer uses 0-level addressing, the page size is
+ * equal to the whole buffer size. If the current MTR has multiple
+ * regions, we split the buffer into small pages(4k, required by hns
+ * ROCEE). These pages will be used in multiple regions.
+ */
+ return mtr->hem_cfg.is_direct && mtr->hem_cfg.region_count > 1;
+}
+
static int mtr_map_bufs(struct hns_roce_dev *hr_dev, struct hns_roce_mtr *mtr)
{
struct ib_device *ibdev = &hr_dev->ib_dev;
@@ -730,14 +745,8 @@ static int mtr_map_bufs(struct hns_roce_dev *hr_dev, struct hns_roce_mtr *mtr)
int npage;
int ret;

- /* When HEM buffer uses 0-level addressing, the page size is
- * equal to the whole buffer size, and we split the buffer into
- * small pages which is used to check whether the adjacent
- * units are in the continuous space and its size is fixed to
- * 4K based on hns ROCEE's requirement.
- */
- page_shift = mtr->hem_cfg.is_direct ? HNS_HW_PAGE_SHIFT :
- mtr->hem_cfg.buf_pg_shift;
+ page_shift = need_split_huge_page(mtr) ? HNS_HW_PAGE_SHIFT :
+ mtr->hem_cfg.buf_pg_shift;
/* alloc a tmp array to store buffer's dma address */
pages = kvcalloc(page_count, sizeof(dma_addr_t), GFP_KERNEL);
if (!pages)
@@ -757,7 +766,7 @@ static int mtr_map_bufs(struct hns_roce_dev *hr_dev, struct hns_roce_mtr *mtr)
goto err_alloc_list;
}

- if (mtr->hem_cfg.is_direct && npage > 1) {
+ if (need_split_huge_page(mtr) && npage > 1) {
ret = mtr_check_direct_pages(pages, npage, page_shift);
if (ret) {
ibdev_err(ibdev, "failed to check %s page: %d / %d.\n",
@@ -915,56 +924,89 @@ int hns_roce_mtr_find(struct hns_roce_dev *hr_dev, struct hns_roce_mtr *mtr,
return ret;
}

-static int mtr_init_buf_cfg(struct hns_roce_dev *hr_dev,
- struct hns_roce_buf_attr *attr,
- struct hns_roce_hem_cfg *cfg, u64 unalinged_size)
+static int get_best_page_shift(struct hns_roce_dev *hr_dev,
+ struct hns_roce_mtr *mtr,
+ struct hns_roce_buf_attr *buf_attr)
+{
+ unsigned int page_sz;
+
+ if (!buf_attr->adaptive || buf_attr->type != MTR_PBL || !mtr->umem)
+ return 0;
+
+ page_sz = ib_umem_find_best_pgsz(mtr->umem,
+ hr_dev->caps.page_size_cap,
+ buf_attr->iova);
+ if (!page_sz)
+ return -EINVAL;
+
+ buf_attr->page_shift = order_base_2(page_sz);
+ return 0;
+}
+
+static bool is_buf_attr_valid(struct hns_roce_dev *hr_dev,
+ struct hns_roce_buf_attr *attr)
{
struct ib_device *ibdev = &hr_dev->ib_dev;
+
+ if (attr->region_count > ARRAY_SIZE(attr->region) ||
+ attr->region_count < 1 || attr->page_shift < HNS_HW_PAGE_SHIFT) {
+ ibdev_err(ibdev,
+ "invalid buf attr, region count %d, page shift %u.\n",
+ attr->region_count, attr->page_shift);
+ return false;
+ }
+
+ return true;
+}
+
+static int mtr_init_buf_cfg(struct hns_roce_dev *hr_dev,
+ struct hns_roce_mtr *mtr,
+ struct hns_roce_buf_attr *attr)
+{
+ struct hns_roce_hem_cfg *cfg = &mtr->hem_cfg;
struct hns_roce_buf_region *r;
- u64 first_region_padding;
- int page_cnt, region_cnt;
size_t buf_pg_sz;
size_t buf_size;
+ int page_cnt, i;
+ u64 pgoff = 0;
+
+ if (!is_buf_attr_valid(hr_dev, attr))
+ return -EINVAL;

/* If mtt is disabled, all pages must be within a continuous range */
cfg->is_direct = !mtr_has_mtt(attr);
+ cfg->region_count = attr->region_count;
buf_size = mtr_bufs_size(attr);
- if (cfg->is_direct) {
+ if (need_split_huge_page(mtr)) {
buf_pg_sz = HNS_HW_PAGE_SIZE;
cfg->buf_pg_count = 1;
/* The ROCEE requires the page size to be 4K * 2 ^ N. */
cfg->buf_pg_shift = HNS_HW_PAGE_SHIFT +
order_base_2(DIV_ROUND_UP(buf_size, HNS_HW_PAGE_SIZE));
- first_region_padding = 0;
} else {
- cfg->buf_pg_count = DIV_ROUND_UP(buf_size + unalinged_size,
- 1 << attr->page_shift);
+ buf_pg_sz = 1 << attr->page_shift;
+ cfg->buf_pg_count = mtr->umem ?
+ ib_umem_num_dma_blocks(mtr->umem, buf_pg_sz) :
+ DIV_ROUND_UP(buf_size, buf_pg_sz);
cfg->buf_pg_shift = attr->page_shift;
- buf_pg_sz = 1 << cfg->buf_pg_shift;
- first_region_padding = unalinged_size;
+ pgoff = mtr->umem ? mtr->umem->address & ~PAGE_MASK : 0;
}

/* Convert buffer size to page index and page count for each region and
* the buffer's offset needs to be appended to the first region.
*/
- for (page_cnt = 0, region_cnt = 0; region_cnt < attr->region_count &&
- region_cnt < ARRAY_SIZE(cfg->region); region_cnt++) {
- r = &cfg->region[region_cnt];
+ for (page_cnt = 0, i = 0; i < attr->region_count; i++) {
+ r = &cfg->region[i];
r->offset = page_cnt;
- buf_size = hr_hw_page_align(attr->region[region_cnt].size +
- first_region_padding);
- r->count = DIV_ROUND_UP(buf_size, buf_pg_sz);
- first_region_padding = 0;
- page_cnt += r->count;
- r->hopnum = to_hr_hem_hopnum(attr->region[region_cnt].hopnum,
- r->count);
- }
+ buf_size = hr_hw_page_align(attr->region[i].size + pgoff);
+ if (attr->type == MTR_PBL && mtr->umem)
+ r->count = ib_umem_num_dma_blocks(mtr->umem, buf_pg_sz);
+ else
+ r->count = DIV_ROUND_UP(buf_size, buf_pg_sz);

- cfg->region_count = region_cnt;
- if (cfg->region_count < 1 || cfg->buf_pg_shift < HNS_HW_PAGE_SHIFT) {
- ibdev_err(ibdev, "failed to init mtr cfg, count %d shift %u.\n",
- cfg->region_count, cfg->buf_pg_shift);
- return -EINVAL;
+ pgoff = 0;
+ page_cnt += r->count;
+ r->hopnum = to_hr_hem_hopnum(attr->region[i].hopnum, r->count);
}

return 0;
@@ -1054,7 +1096,6 @@ int hns_roce_mtr_create(struct hns_roce_dev *hr_dev, struct hns_roce_mtr *mtr,
unsigned int ba_page_shift, struct ib_udata *udata,
unsigned long user_addr)
{
- u64 pgoff = udata ? user_addr & ~PAGE_MASK : 0;
struct ib_device *ibdev = &hr_dev->ib_dev;
int ret;

@@ -1071,9 +1112,13 @@ int hns_roce_mtr_create(struct hns_roce_dev *hr_dev, struct hns_roce_mtr *mtr,
"failed to alloc mtr bufs, ret = %d.\n", ret);
return ret;
}
+
+ ret = get_best_page_shift(hr_dev, mtr, buf_attr);
+ if (ret)
+ goto err_init_buf;
}

- ret = mtr_init_buf_cfg(hr_dev, buf_attr, &mtr->hem_cfg, pgoff);
+ ret = mtr_init_buf_cfg(hr_dev, mtr, buf_attr);
if (ret)
goto err_init_buf;

--
2.30.0