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Commit 162b96e6 authored by Dan Williams's avatar Dan Williams
Browse files

ioat2,3: cacheline align software descriptor allocations 



All the necessary fields for handling an ioat2,3 ring entry can fit into
one cacheline.  Move ->len prior to ->txd in struct ioat_ring_ent, and
move allocation of these entries to a hw-cache-aligned kmem cache to
reduce the number of cachelines dirtied for descriptor management.

Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 08031727

drivers/dma/ioat/dma_v2.c

+3 −2
Original line number Diff line number Diff line
@@ -399,11 +399,12 @@ static struct ioat_ring_ent *ioat2_alloc_ring_ent(struct dma_chan *chan, gfp_t f 
		return NULL;

	memset(hw, 0, sizeof(*hw));



	desc = kzalloc(sizeof(*desc), flags);

	desc = kmem_cache_alloc(ioat2_cache, flags);

	if (!desc) {

		pci_pool_free(dma->dma_pool, hw, phys);

		return NULL;

	}

	memset(desc, 0, sizeof(*desc));



	dma_async_tx_descriptor_init(&desc->txd, chan);

	desc->txd.tx_submit = ioat2_tx_submit_unlock;
@@ -418,7 +419,7 @@ static void ioat2_free_ring_ent(struct ioat_ring_ent *desc, struct dma_chan *cha 


	dma = to_ioatdma_device(chan->device);

	pci_pool_free(dma->dma_pool, desc->hw, desc->txd.phys);

	kfree(desc);

	kmem_cache_free(ioat2_cache, desc);

}



static struct ioat_ring_ent **ioat2_alloc_ring(struct dma_chan *c, int order, gfp_t flags)

drivers/dma/ioat/dma_v2.h

+2 −1
Original line number Diff line number Diff line
@@ -116,8 +116,8 @@ static inline u16 ioat2_xferlen_to_descs(struct ioat2_dma_chan *ioat, size_t len 


struct ioat_ring_ent {

	struct ioat_dma_descriptor *hw;

	struct dma_async_tx_descriptor txd;

	size_t len;

	struct dma_async_tx_descriptor txd;

	#ifdef DEBUG

	int id;

	#endif
@@ -143,4 +143,5 @@ int __devinit ioat2_dma_probe(struct ioatdma_device *dev, int dca); 
int __devinit ioat3_dma_probe(struct ioatdma_device *dev, int dca);

struct dca_provider * __devinit ioat2_dca_init(struct pci_dev *pdev, void __iomem *iobase);

struct dca_provider * __devinit ioat3_dca_init(struct pci_dev *pdev, void __iomem *iobase);

extern struct kmem_cache *ioat2_cache;

#endif /* IOATDMA_V2_H */

drivers/dma/ioat/pci.c

+15 −1
Original line number Diff line number Diff line
@@ -69,6 +69,8 @@ static int ioat_dca_enabled = 1; 
module_param(ioat_dca_enabled, int, 0644);

MODULE_PARM_DESC(ioat_dca_enabled, "control support of dca service (default: 1)");



struct kmem_cache *ioat2_cache;



#define DRV_NAME "ioatdma"



static struct pci_driver ioat_pci_driver = {
@@ -168,12 +170,24 @@ static void __devexit ioat_remove(struct pci_dev *pdev) 


static int __init ioat_init_module(void)

{

	return pci_register_driver(&ioat_pci_driver);

	int err;



	ioat2_cache = kmem_cache_create("ioat2", sizeof(struct ioat_ring_ent),

					0, SLAB_HWCACHE_ALIGN, NULL);

	if (!ioat2_cache)

		return -ENOMEM;



	err = pci_register_driver(&ioat_pci_driver);

	if (err)

		kmem_cache_destroy(ioat2_cache);



	return err;

}

module_init(ioat_init_module);



static void __exit ioat_exit_module(void)

{

	pci_unregister_driver(&ioat_pci_driver);

	kmem_cache_destroy(ioat2_cache);

}

module_exit(ioat_exit_module);