2024-06-03 16:44:18

by Manivannan Sadhasivam

Subject: [PATCH] bus: mhi: ep: Do not allocate memory for MHI objects from DMA zone

MHI endpoint stack accidentally started allocating memory for objects from
DMA zone since commit 62210a26cd4f ("bus: mhi: ep: Use slab allocator
where applicable"). But there is no real need to allocate memory from this
naturally limited DMA zone. This also causes the MHI endpoint stack to run
out of memory while doing high bandwidth transfers.

So let's switch over to normal memory.

Cc: [email protected] # 6.8
Fixes: 62210a26cd4f ("bus: mhi: ep: Use slab allocator where applicable")
Signed-off-by: Manivannan Sadhasivam <[email protected]>
---
drivers/bus/mhi/ep/main.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/bus/mhi/ep/main.c b/drivers/bus/mhi/ep/main.c
index f8f674adf1d4..4acfac73ca9a 100644
--- a/drivers/bus/mhi/ep/main.c
+++ b/drivers/bus/mhi/ep/main.c
@@ -90,7 +90,7 @@ static int mhi_ep_send_completion_event(struct mhi_ep_cntrl *mhi_cntrl, struct m
struct mhi_ring_element *event;
int ret;

- event = kmem_cache_zalloc(mhi_cntrl->ev_ring_el_cache, GFP_KERNEL | GFP_DMA);
+ event = kmem_cache_zalloc(mhi_cntrl->ev_ring_el_cache, GFP_KERNEL);
if (!event)
return -ENOMEM;

@@ -109,7 +109,7 @@ int mhi_ep_send_state_change_event(struct mhi_ep_cntrl *mhi_cntrl, enum mhi_stat
struct mhi_ring_element *event;
int ret;

- event = kmem_cache_zalloc(mhi_cntrl->ev_ring_el_cache, GFP_KERNEL | GFP_DMA);
+ event = kmem_cache_zalloc(mhi_cntrl->ev_ring_el_cache, GFP_KERNEL);
if (!event)
return -ENOMEM;

@@ -127,7 +127,7 @@ int mhi_ep_send_ee_event(struct mhi_ep_cntrl *mhi_cntrl, enum mhi_ee_type exec_e
struct mhi_ring_element *event;
int ret;

- event = kmem_cache_zalloc(mhi_cntrl->ev_ring_el_cache, GFP_KERNEL | GFP_DMA);
+ event = kmem_cache_zalloc(mhi_cntrl->ev_ring_el_cache, GFP_KERNEL);
if (!event)
return -ENOMEM;

@@ -146,7 +146,7 @@ static int mhi_ep_send_cmd_comp_event(struct mhi_ep_cntrl *mhi_cntrl, enum mhi_e
struct mhi_ring_element *event;
int ret;

- event = kmem_cache_zalloc(mhi_cntrl->ev_ring_el_cache, GFP_KERNEL | GFP_DMA);
+ event = kmem_cache_zalloc(mhi_cntrl->ev_ring_el_cache, GFP_KERNEL);
if (!event)
return -ENOMEM;

@@ -438,7 +438,7 @@ static int mhi_ep_read_channel(struct mhi_ep_cntrl *mhi_cntrl,
read_offset = mhi_chan->tre_size - mhi_chan->tre_bytes_left;
write_offset = len - buf_left;

- buf_addr = kmem_cache_zalloc(mhi_cntrl->tre_buf_cache, GFP_KERNEL | GFP_DMA);
+ buf_addr = kmem_cache_zalloc(mhi_cntrl->tre_buf_cache, GFP_KERNEL);
if (!buf_addr)
return -ENOMEM;

@@ -1481,14 +1481,14 @@ int mhi_ep_register_controller(struct mhi_ep_cntrl *mhi_cntrl,

mhi_cntrl->ev_ring_el_cache = kmem_cache_create("mhi_ep_event_ring_el",
sizeof(struct mhi_ring_element), 0,
- SLAB_CACHE_DMA, NULL);
+ 0, NULL);
if (!mhi_cntrl->ev_ring_el_cache) {
ret = -ENOMEM;
goto err_free_cmd;
}

mhi_cntrl->tre_buf_cache = kmem_cache_create("mhi_ep_tre_buf", MHI_EP_DEFAULT_MTU, 0,
- SLAB_CACHE_DMA, NULL);
+ 0, NULL);
if (!mhi_cntrl->tre_buf_cache) {
ret = -ENOMEM;
goto err_destroy_ev_ring_el_cache;
--
2.25.1

2024-06-03 21:58:34

by Mayank Rana

Subject: Re: [PATCH] bus: mhi: ep: Do not allocate memory for MHI objects from DMA zone

On 6/3/2024 9:43 AM, Manivannan Sadhasivam wrote:
> MHI endpoint stack accidentally started allocating memory for objects from
> DMA zone since commit 62210a26cd4f ("bus: mhi: ep: Use slab allocator
Going through mentioned commit it seems that it was intended purpose to
use GFP_DMA/SLAB
> where applicable"). But there is no real need to allocate memory from this
> naturally limited DMA zone. This also causes the MHI endpoint stack to run
> out of memory while doing high bandwidth transfers.
>
> So let's switch over to normal memory.
>
> Cc: [email protected] # 6.8
> Fixes: 62210a26cd4f ("bus: mhi: ep: Use slab allocator where applicable")
> Signed-off-by: Manivannan Sadhasivam <[email protected]>
> ---
> drivers/bus/mhi/ep/main.c | 14 +++++++-------
> 1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/bus/mhi/ep/main.c b/drivers/bus/mhi/ep/main.c
> index f8f674adf1d4..4acfac73ca9a 100644
> --- a/drivers/bus/mhi/ep/main.c
> +++ b/drivers/bus/mhi/ep/main.c
> @@ -90,7 +90,7 @@ static int mhi_ep_send_completion_event(struct mhi_ep_cntrl *mhi_cntrl, struct m
> struct mhi_ring_element *event;
> int ret;
>
> - event = kmem_cache_zalloc(mhi_cntrl->ev_ring_el_cache, GFP_KERNEL | GFP_DMA);
> + event = kmem_cache_zalloc(mhi_cntrl->ev_ring_el_cache, GFP_KERNEL);
> if (!event)
> return -ENOMEM;
>
> @@ -109,7 +109,7 @@ int mhi_ep_send_state_change_event(struct mhi_ep_cntrl *mhi_cntrl, enum mhi_stat
> struct mhi_ring_element *event;
> int ret;
>
> - event = kmem_cache_zalloc(mhi_cntrl->ev_ring_el_cache, GFP_KERNEL | GFP_DMA);
> + event = kmem_cache_zalloc(mhi_cntrl->ev_ring_el_cache, GFP_KERNEL);
> if (!event)
> return -ENOMEM;
>
> @@ -127,7 +127,7 @@ int mhi_ep_send_ee_event(struct mhi_ep_cntrl *mhi_cntrl, enum mhi_ee_type exec_e
> struct mhi_ring_element *event;
> int ret;
>
> - event = kmem_cache_zalloc(mhi_cntrl->ev_ring_el_cache, GFP_KERNEL | GFP_DMA);
> + event = kmem_cache_zalloc(mhi_cntrl->ev_ring_el_cache, GFP_KERNEL);
> if (!event)
> return -ENOMEM;
>
> @@ -146,7 +146,7 @@ static int mhi_ep_send_cmd_comp_event(struct mhi_ep_cntrl *mhi_cntrl, enum mhi_e
> struct mhi_ring_element *event;
> int ret;
>
> - event = kmem_cache_zalloc(mhi_cntrl->ev_ring_el_cache, GFP_KERNEL | GFP_DMA);
> + event = kmem_cache_zalloc(mhi_cntrl->ev_ring_el_cache, GFP_KERNEL);
> if (!event)
> return -ENOMEM;
>
> @@ -438,7 +438,7 @@ static int mhi_ep_read_channel(struct mhi_ep_cntrl *mhi_cntrl,
> read_offset = mhi_chan->tre_size - mhi_chan->tre_bytes_left;
> write_offset = len - buf_left;
>
> - buf_addr = kmem_cache_zalloc(mhi_cntrl->tre_buf_cache, GFP_KERNEL | GFP_DMA);
> + buf_addr = kmem_cache_zalloc(mhi_cntrl->tre_buf_cache, GFP_KERNEL);
> if (!buf_addr)
> return -ENOMEM;
>
> @@ -1481,14 +1481,14 @@ int mhi_ep_register_controller(struct mhi_ep_cntrl *mhi_cntrl,
>
> mhi_cntrl->ev_ring_el_cache = kmem_cache_create("mhi_ep_event_ring_el",
> sizeof(struct mhi_ring_element), 0,
> - SLAB_CACHE_DMA, NULL);
> + 0, NULL);
> if (!mhi_cntrl->ev_ring_el_cache) {
> ret = -ENOMEM;
> goto err_free_cmd;
> }
>
> mhi_cntrl->tre_buf_cache = kmem_cache_create("mhi_ep_tre_buf", MHI_EP_DEFAULT_MTU, 0,
> - SLAB_CACHE_DMA, NULL);
> + 0, NULL);
> if (!mhi_cntrl->tre_buf_cache) {
> ret = -ENOMEM;
> goto err_destroy_ev_ring_el_cache;
Reviewed-by: Mayank Rana <[email protected]>