iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

dmaengine: IOATDMA: Removing descriptor ring reshape

Browse Source 
Moving to contingous memory backed descriptor rings. This makes is really
difficult and complex to do reshape. Going to remove this as I don't think
we need to do it anymore.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
Dave Jiang 2016-02-10 15:00:26 -07:00 committed by Vinod Koul
parent 679cfbf79b
commit cd60cd9613
3 changed files with 1 additions and 157 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

143
drivers/dma/ioat/dma.c
View File

@ -332,9 +332,6 @@ ioat_alloc_ring(struct dma_chan *c, int order, gfp_t flags)
int descs = 1 << order;
int i;
if (order > ioat_get_max_alloc_order())
return NULL;
/* allocate the array to hold the software ring */
ring = kcalloc(descs, sizeof(*ring), flags);
if (!ring)
@ -362,114 +359,6 @@ ioat_alloc_ring(struct dma_chan *c, int order, gfp_t flags)
return ring;
}
static bool reshape_ring(struct ioatdma_chan *ioat_chan, int order)
{
/* reshape differs from normal ring allocation in that we want
* to allocate a new software ring while only
* extending/truncating the hardware ring
*/
struct dma_chan *c = &ioat_chan->dma_chan;
const u32 curr_size = ioat_ring_size(ioat_chan);
const u16 active = ioat_ring_active(ioat_chan);
const u32 new_size = 1 << order;
struct ioat_ring_ent **ring;
u32 i;
if (order > ioat_get_max_alloc_order())
return false;
/* double check that we have at least 1 free descriptor */
if (active == curr_size)
return false;
/* when shrinking, verify that we can hold the current active
* set in the new ring
*/
if (active >= new_size)
return false;
/* allocate the array to hold the software ring */
ring = kcalloc(new_size, sizeof(*ring), GFP_NOWAIT);
if (!ring)
return false;
/* allocate/trim descriptors as needed */
if (new_size > curr_size) {
/* copy current descriptors to the new ring */
for (i = 0; i < curr_size; i++) {
u16 curr_idx = (ioat_chan->tail+i) & (curr_size-1);
u16 new_idx = (ioat_chan->tail+i) & (new_size-1);
ring[new_idx] = ioat_chan->ring[curr_idx];
set_desc_id(ring[new_idx], new_idx);
}
/* add new descriptors to the ring */
for (i = curr_size; i < new_size; i++) {
u16 new_idx = (ioat_chan->tail+i) & (new_size-1);
ring[new_idx] = ioat_alloc_ring_ent(c, GFP_NOWAIT);
if (!ring[new_idx]) {
while (i--) {
u16 new_idx = (ioat_chan->tail+i) &
(new_size-1);
ioat_free_ring_ent(ring[new_idx], c);
}
kfree(ring);
return false;
}
set_desc_id(ring[new_idx], new_idx);
}
/* hw link new descriptors */
for (i = curr_size-1; i < new_size; i++) {
u16 new_idx = (ioat_chan->tail+i) & (new_size-1);
struct ioat_ring_ent *next =
ring[(new_idx+1) & (new_size-1)];
struct ioat_dma_descriptor *hw = ring[new_idx]->hw;
hw->next = next->txd.phys;
}
} else {
struct ioat_dma_descriptor *hw;
struct ioat_ring_ent *next;
/* copy current descriptors to the new ring, dropping the
* removed descriptors
*/
for (i = 0; i < new_size; i++) {
u16 curr_idx = (ioat_chan->tail+i) & (curr_size-1);
u16 new_idx = (ioat_chan->tail+i) & (new_size-1);
ring[new_idx] = ioat_chan->ring[curr_idx];
set_desc_id(ring[new_idx], new_idx);
}
/* free deleted descriptors */
for (i = new_size; i < curr_size; i++) {
struct ioat_ring_ent *ent;
ent = ioat_get_ring_ent(ioat_chan, ioat_chan->tail+i);
ioat_free_ring_ent(ent, c);
}
/* fix up hardware ring */
hw = ring[(ioat_chan->tail+new_size-1) & (new_size-1)]->hw;
next = ring[(ioat_chan->tail+new_size) & (new_size-1)];
hw->next = next->txd.phys;
}
dev_dbg(to_dev(ioat_chan), "%s: allocated %d descriptors\n",
__func__, new_size);
kfree(ioat_chan->ring);
ioat_chan->ring = ring;
ioat_chan->alloc_order = order;
return true;
}
/**
* ioat_check_space_lock - verify space and grab ring producer lock
* @ioat: ioat,3 channel (ring) to operate on
@ -478,9 +367,6 @@ static bool reshape_ring(struct ioatdma_chan *ioat_chan, int order)
int ioat_check_space_lock(struct ioatdma_chan *ioat_chan, int num_descs)
__acquires(&ioat_chan->prep_lock)
{
bool retry;
retry:
spin_lock_bh(&ioat_chan->prep_lock);
/* never allow the last descriptor to be consumed, we need at
* least one free at all times to allow for on-the-fly ring
@ -493,24 +379,8 @@ int ioat_check_space_lock(struct ioatdma_chan *ioat_chan, int num_descs)
ioat_chan->produce = num_descs;
return 0; /* with ioat->prep_lock held */
}
retry = test_and_set_bit(IOAT_RESHAPE_PENDING, &ioat_chan->state);
spin_unlock_bh(&ioat_chan->prep_lock);
/* is another cpu already trying to expand the ring? */
if (retry)
goto retry;
spin_lock_bh(&ioat_chan->cleanup_lock);
spin_lock_bh(&ioat_chan->prep_lock);
retry = reshape_ring(ioat_chan, ioat_chan->alloc_order + 1);
clear_bit(IOAT_RESHAPE_PENDING, &ioat_chan->state);
spin_unlock_bh(&ioat_chan->prep_lock);
spin_unlock_bh(&ioat_chan->cleanup_lock);
/* if we were able to expand the ring retry the allocation */
if (retry)
goto retry;
dev_dbg_ratelimited(to_dev(ioat_chan),
"%s: ring full! num_descs: %d (%x:%x:%x)\n",
__func__, num_descs, ioat_chan->head,
@ -823,19 +693,6 @@ static void check_active(struct ioatdma_chan *ioat_chan)
if (test_and_clear_bit(IOAT_CHAN_ACTIVE, &ioat_chan->state))
mod_timer(&ioat_chan->timer, jiffies + IDLE_TIMEOUT);
else if (ioat_chan->alloc_order > ioat_get_alloc_order()) {
/* if the ring is idle, empty, and oversized try to step
* down the size
*/
reshape_ring(ioat_chan, ioat_chan->alloc_order - 1);
/* keep shrinking until we get back to our minimum
* default size
*/
if (ioat_chan->alloc_order > ioat_get_alloc_order())
mod_timer(&ioat_chan->timer, jiffies + IDLE_TIMEOUT);
}
}
void ioat_timer_event(unsigned long data)

5
drivers/dma/ioat/dma.h
View File

@ -100,7 +100,6 @@ struct ioatdma_chan {
#define IOAT_COMPLETION_ACK 1
#define IOAT_RESET_PENDING 2
#define IOAT_KOBJ_INIT_FAIL 3
#define IOAT_RESHAPE_PENDING 4
#define IOAT_RUN 5
#define IOAT_CHAN_ACTIVE 6
struct timer_list timer;
@ -302,10 +301,6 @@ static inline bool is_ioat_bug(unsigned long err)
}
#define IOAT_MAX_ORDER 16
#define ioat_get_alloc_order() \
(min(ioat_ring_alloc_order, IOAT_MAX_ORDER))
#define ioat_get_max_alloc_order() \
(min(ioat_ring_max_alloc_order, IOAT_MAX_ORDER))
static inline u32 ioat_ring_size(struct ioatdma_chan *ioat_chan)
{

10
drivers/dma/ioat/init.c
View File

@ -136,14 +136,6 @@ int ioat_pending_level = 4;
module_param(ioat_pending_level, int, 0644);
MODULE_PARM_DESC(ioat_pending_level,
"high-water mark for pushing ioat descriptors (default: 4)");
int ioat_ring_alloc_order = 8;
module_param(ioat_ring_alloc_order, int, 0644);
MODULE_PARM_DESC(ioat_ring_alloc_order,
"ioat+: allocate 2^n descriptors per channel (default: 8 max: 16)");
int ioat_ring_max_alloc_order = IOAT_MAX_ORDER;
module_param(ioat_ring_max_alloc_order, int, 0644);
MODULE_PARM_DESC(ioat_ring_max_alloc_order,
"ioat+: upper limit for ring size (default: 16)");
static char ioat_interrupt_style[32] = "msix";
module_param_string(ioat_interrupt_style, ioat_interrupt_style,
sizeof(ioat_interrupt_style), 0644);
@ -712,7 +704,7 @@ static int ioat_alloc_chan_resources(struct dma_chan *c)
writel(((u64)ioat_chan->completion_dma) >> 32,
ioat_chan->reg_base + IOAT_CHANCMP_OFFSET_HIGH);
order = ioat_get_alloc_order();
order = IOAT_MAX_ORDER;
ring = ioat_alloc_ring(c, order, GFP_KERNEL);
if (!ring)
return -ENOMEM;