RDMA/mlx5: Use ib_umem_find_best_pgoff() for SRQ

SRQ uses a quantized and scaled page_offset, which is another variation of
ib_umem_find_best_pgsz(). Add mlx5_umem_find_best_quantized_pgoff() to
perform this calculation for each mailbox. A macro shows how the
calculation is directly connected to the mailbox format.

This new routine replaces the limited mlx5_ib_cont_pages() and
mlx5_ib_get_buf_offset() pairing which would reject valid configurations
rather than adjust the page_size to make it work.

In turn this is much more aggressive about choosing large page sizes for
these objects and when THP is enabled it will now often find a single page
solution.

Link: https://lore.kernel.org/r/20201115114311.136250-2-leon@kernel.org
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
This commit is contained in:
Jason Gunthorpe 2020-11-15 13:43:05 +02:00
parent 8c030d780a
commit b045db62f6
4 changed files with 128 additions and 10 deletions

View file

@ -107,6 +107,51 @@ void mlx5_ib_populate_pas(struct ib_umem *umem, size_t page_size, __be64 *pas,
}
}
/*
* Compute the page shift and page_offset for mailboxes that use a quantized
* page_offset. The granulatity of the page offset scales according to page
* size.
*/
unsigned long __mlx5_umem_find_best_quantized_pgoff(
struct ib_umem *umem, unsigned long pgsz_bitmap,
unsigned int page_offset_bits, u64 pgoff_bitmask, unsigned int scale,
unsigned int *page_offset_quantized)
{
const u64 page_offset_mask = (1 << page_offset_bits) - 1;
unsigned long page_size;
u64 page_offset;
page_size = ib_umem_find_best_pgoff(umem, pgsz_bitmap, pgoff_bitmask);
if (!page_size)
return 0;
/*
* page size is the largest possible page size.
*
* Reduce the page_size, and thus the page_offset and quanta, until the
* page_offset fits into the mailbox field. Once page_size < scale this
* loop is guaranteed to terminate.
*/
page_offset = ib_umem_dma_offset(umem, page_size);
while (page_offset & ~(u64)(page_offset_mask * (page_size / scale))) {
page_size /= 2;
page_offset = ib_umem_dma_offset(umem, page_size);
}
/*
* The address is not aligned, or otherwise cannot be represented by the
* page_offset.
*/
if (!(pgsz_bitmap & page_size))
return 0;
*page_offset_quantized =
(unsigned long)page_offset / (page_size / scale);
if (WARN_ON(*page_offset_quantized > page_offset_mask))
return 0;
return page_size;
}
int mlx5_ib_get_buf_offset(u64 addr, int page_shift, u32 *offset)
{
u64 page_size;

View file

@ -69,6 +69,37 @@ __mlx5_log_page_size_to_bitmap(unsigned int log_pgsz_bits,
pgsz_shift), \
iova)
static __always_inline unsigned long
__mlx5_page_offset_to_bitmask(unsigned int page_offset_bits,
unsigned int offset_shift)
{
unsigned int largest_offset_shift =
min_t(unsigned long, page_offset_bits - 1 + offset_shift,
BITS_PER_LONG - 1);
return GENMASK(largest_offset_shift, offset_shift);
}
/*
* QP/CQ/WQ/etc type commands take a page offset that satisifies:
* page_offset_quantized * (page_size/scale) = page_offset
* Which restricts allowed page sizes to ones that satisify the above.
*/
unsigned long __mlx5_umem_find_best_quantized_pgoff(
struct ib_umem *umem, unsigned long pgsz_bitmap,
unsigned int page_offset_bits, u64 pgoff_bitmask, unsigned int scale,
unsigned int *page_offset_quantized);
#define mlx5_umem_find_best_quantized_pgoff(umem, typ, log_pgsz_fld, \
pgsz_shift, page_offset_fld, \
scale, page_offset_quantized) \
__mlx5_umem_find_best_quantized_pgoff( \
umem, \
__mlx5_log_page_size_to_bitmap( \
__mlx5_bit_sz(typ, log_pgsz_fld), pgsz_shift), \
__mlx5_bit_sz(typ, page_offset_fld), \
GENMASK(31, order_base_2(scale)), scale, \
page_offset_quantized)
enum {
MLX5_IB_MMAP_OFFSET_START = 9,
MLX5_IB_MMAP_OFFSET_END = 255,

View file

@ -51,8 +51,8 @@ static int create_srq_user(struct ib_pd *pd, struct mlx5_ib_srq *srq,
udata, struct mlx5_ib_ucontext, ibucontext);
size_t ucmdlen;
int err;
int page_shift;
u32 offset;
unsigned int page_offset_quantized;
unsigned int page_size;
u32 uidx = MLX5_IB_DEFAULT_UIDX;
ucmdlen = min(udata->inlen, sizeof(ucmd));
@ -85,22 +85,22 @@ static int create_srq_user(struct ib_pd *pd, struct mlx5_ib_srq *srq,
return err;
}
mlx5_ib_cont_pages(srq->umem, ucmd.buf_addr, 0, &page_shift);
err = mlx5_ib_get_buf_offset(ucmd.buf_addr, page_shift,
&offset);
if (err) {
page_size = mlx5_umem_find_best_quantized_pgoff(
srq->umem, srqc, log_page_size, MLX5_ADAPTER_PAGE_SHIFT,
page_offset, 64, &page_offset_quantized);
if (!page_size) {
mlx5_ib_warn(dev, "bad offset\n");
goto err_umem;
}
in->pas = kvcalloc(ib_umem_num_dma_blocks(srq->umem, 1UL << page_shift),
in->pas = kvcalloc(ib_umem_num_dma_blocks(srq->umem, page_size),
sizeof(*in->pas), GFP_KERNEL);
if (!in->pas) {
err = -ENOMEM;
goto err_umem;
}
mlx5_ib_populate_pas(srq->umem, 1UL << page_shift, in->pas, 0);
mlx5_ib_populate_pas(srq->umem, page_size, in->pas, 0);
err = mlx5_ib_db_map_user(ucontext, udata, ucmd.db_addr, &srq->db);
if (err) {
@ -108,8 +108,8 @@ static int create_srq_user(struct ib_pd *pd, struct mlx5_ib_srq *srq,
goto err_in;
}
in->log_page_size = page_shift - MLX5_ADAPTER_PAGE_SHIFT;
in->page_offset = offset;
in->log_page_size = order_base_2(page_size) - MLX5_ADAPTER_PAGE_SHIFT;
in->page_offset = page_offset_quantized;
in->uid = (in->type != IB_SRQT_XRC) ? to_mpd(pd)->uid : 0;
if (MLX5_CAP_GEN(dev->mdev, cqe_version) == MLX5_CQE_VERSION_V1 &&
in->type != IB_SRQT_BASIC)

View file

@ -34,6 +34,13 @@ static inline int ib_umem_offset(struct ib_umem *umem)
return umem->address & ~PAGE_MASK;
}
static inline unsigned long ib_umem_dma_offset(struct ib_umem *umem,
unsigned long pgsz)
{
return (sg_dma_address(umem->sg_head.sgl) + ib_umem_offset(umem)) &
(pgsz - 1);
}
static inline size_t ib_umem_num_dma_blocks(struct ib_umem *umem,
unsigned long pgsz)
{
@ -79,6 +86,35 @@ int ib_umem_copy_from(void *dst, struct ib_umem *umem, size_t offset,
unsigned long ib_umem_find_best_pgsz(struct ib_umem *umem,
unsigned long pgsz_bitmap,
unsigned long virt);
/**
* ib_umem_find_best_pgoff - Find best HW page size
*
* @umem: umem struct
* @pgsz_bitmap bitmap of HW supported page sizes
* @pgoff_bitmask: Mask of bits that can be represented with an offset
*
* This is very similar to ib_umem_find_best_pgsz() except instead of accepting
* an IOVA it accepts a bitmask specifying what address bits can be represented
* with a page offset.
*
* For instance if the HW has multiple page sizes, requires 64 byte alignemnt,
* and can support aligned offsets up to 4032 then pgoff_bitmask would be
* "111111000000".
*
* If the pgoff_bitmask requires either alignment in the low bit or an
* unavailable page size for the high bits, this function returns 0.
*/
static inline unsigned long ib_umem_find_best_pgoff(struct ib_umem *umem,
unsigned long pgsz_bitmap,
u64 pgoff_bitmask)
{
struct scatterlist *sg = umem->sg_head.sgl;
dma_addr_t dma_addr;
dma_addr = sg_dma_address(sg) + (umem->address & ~PAGE_MASK);
return ib_umem_find_best_pgsz(umem, pgsz_bitmap,
dma_addr & pgoff_bitmask);
}
#else /* CONFIG_INFINIBAND_USER_MEM */
@ -101,6 +137,12 @@ static inline unsigned long ib_umem_find_best_pgsz(struct ib_umem *umem,
{
return 0;
}
static inline unsigned long ib_umem_find_best_pgoff(struct ib_umem *umem,
unsigned long pgsz_bitmap,
u64 pgoff_bitmask)
{
return 0;
}
#endif /* CONFIG_INFINIBAND_USER_MEM */