diff mbox

[2/3] dmaengine: IOATDMA: Removing descriptor ring reshape

Message ID 20160210220026.151003.97822.stgit@djiang5-desk3.ch.intel.com (mailing list archive)
State Accepted
Headers show

Commit Message

Dave Jiang Feb. 10, 2016, 10 p.m. UTC
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>
---
 drivers/dma/ioat/dma.c  |  143 -----------------------------------------------
 drivers/dma/ioat/dma.h  |    5 --
 drivers/dma/ioat/init.c |   10 ---
 3 files changed, 1 insertion(+), 157 deletions(-)


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diff mbox

Patch

diff --git a/drivers/dma/ioat/dma.c b/drivers/dma/ioat/dma.c
index 0074afa..a80b391 100644
--- a/drivers/dma/ioat/dma.c
+++ b/drivers/dma/ioat/dma.c
@@ -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)
diff --git a/drivers/dma/ioat/dma.h b/drivers/dma/ioat/dma.h
index f471092..5f2f9fb 100644
--- a/drivers/dma/ioat/dma.h
+++ b/drivers/dma/ioat/dma.h
@@ -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)
 {
diff --git a/drivers/dma/ioat/init.c b/drivers/dma/ioat/init.c
index b02b63b..6636920 100644
--- a/drivers/dma/ioat/init.c
+++ b/drivers/dma/ioat/init.c
@@ -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;