* [PATCH net-next v4 0/7] dma: skip calling no-op sync ops when possible
@ 2024-04-23 13:58 Alexander Lobakin
2024-04-23 13:58 ` [PATCH net-next v4 1/7] dma: compile-out DMA sync op calls when not used Alexander Lobakin
` (6 more replies)
0 siblings, 7 replies; 15+ messages in thread
From: Alexander Lobakin @ 2024-04-23 13:58 UTC (permalink / raw)
To: David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni
Cc: Alexander Lobakin, Christoph Hellwig, Marek Szyprowski,
Robin Murphy, Joerg Roedel, Will Deacon, Rafael J. Wysocki,
Magnus Karlsson, nex.sw.ncis.osdt.itp.upstreaming, bpf, netdev,
iommu, linux-kernel
The series grew from Eric's idea and patch at [0]. The idea of using the
shortcut for direct DMA as well belongs to Chris.
When an architecture doesn't need DMA synchronization and the buffer is
not an SWIOTLB buffer, most of times the kernel and the drivers end up
calling DMA sync operations for nothing.
Even when DMA is direct, this involves a good non-inline call ladder and
eats a bunch of CPU time. With IOMMU, this results in calling indirect
calls on hotpath just to check what is already known and return.
XSk is been using a custom shortcut for that for quite some time.
I recently wanted to introduce a similar one for Page Pool. Let's combine
all this into one generic shortcut, which would cover all DMA sync ops
and all types of DMA (direct, IOMMU, ...).
* #1 adds stub inlines to be able to compile DMA sync ops out when not
needed.
* #2 adds generic shortcut and enables it for direct DMA.
* #3 adds ability to skip DMA syncs behind an IOMMU.
* #4-5 are just cleanups for Page Pool to avoid merge conflicts in future.
* #6 checks for the shortcut as early as possible in the Page Pool code to
make sure no cycles wasted.
* #7 replaces XSk's shortcut with the generic one.
On 100G NIC, the result is +3-5% for direct DMA and +10-11% for IOMMU.
As a bonus, XSk core now allows batched buffer allocations for IOMMU
setups.
If the shortcut is not available on some system, there should be no
visible performance regressions.
[0] https://lore.kernel.org/netdev/20221115182841.2640176-1-edumazet@google.com
Alexander Lobakin (7):
dma: compile-out DMA sync op calls when not used
dma: avoid redundant calls for sync operations
iommu/dma: avoid expensive indirect calls for sync operations
page_pool: make sure frag API fields don't span between cachelines
page_pool: don't use driver-set flags field directly
page_pool: check for DMA sync shortcut earlier
xsk: use generic DMA sync shortcut instead of a custom one
kernel/dma/Kconfig | 5 +
include/net/page_pool/types.h | 25 ++++-
include/linux/device.h | 4 +
include/linux/dma-map-ops.h | 12 ++
include/linux/dma-mapping.h | 105 +++++++++++++-----
include/net/xdp_sock_drv.h | 7 +-
include/net/xsk_buff_pool.h | 14 +--
drivers/iommu/dma-iommu.c | 3 +-
drivers/net/ethernet/engleder/tsnep_main.c | 2 +-
.../net/ethernet/freescale/dpaa2/dpaa2-xsk.c | 2 +-
drivers/net/ethernet/intel/i40e/i40e_xsk.c | 2 +-
drivers/net/ethernet/intel/ice/ice_xsk.c | 2 +-
drivers/net/ethernet/intel/igc/igc_main.c | 2 +-
drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c | 2 +-
.../ethernet/mellanox/mlx5/core/en/xsk/rx.c | 4 +-
.../net/ethernet/mellanox/mlx5/core/en_rx.c | 2 +-
drivers/net/ethernet/netronome/nfp/nfd3/xsk.c | 2 +-
.../net/ethernet/stmicro/stmmac/stmmac_main.c | 2 +-
kernel/dma/mapping.c | 69 +++++++++---
kernel/dma/swiotlb.c | 6 +
net/core/page_pool.c | 76 ++++++++-----
net/xdp/xsk_buff_pool.c | 28 +----
22 files changed, 243 insertions(+), 133 deletions(-)
---
From v3[1]:
* #1:
* don't prefix DMA sync ops with '__', just define them as empty inlines
when !DMA_NEED_SYNC (Chris, Robin);
* always select DMA_NEED_SYNC when DMA_API_DEBUG (^);
* #2:
* don't use BIT(), keep the style consistent (^);
* check for dma_map_ops::sync_sg_*() in dma_setup_need_sync() (^);
* don't reset the flag in swiotlb_alloc() as it's not streaming API (^);
* instead of 'dma_skip_sync', name the flag 'dma_need_sync' and inverse
the logic (^);
* setup the shortcut in dma_set_mask() (assuming every driver using DMA
must call it on probe) (^);
* combine dma_direct() and (ops->flags & CAN_SKIP_SYNC) checks (Robin);
* #3:
- pick Acked-by (Robin).
From v2[2]:
* #1:
* use two tabs for indenting multi-line function prototypes (Chris);
* #2:
* make shortcut clearing function generic and move it out of the
SWIOTLB code (Chris);
* remove dma_set_skip_sync(): use direct assignment during the initial
setup, not used anywhere else (Chris);
* commitmsg: remove "NIC" and the workaround paragraph (Chris).
From v1[3]:
* #1:
* use static inlines instead of macros (Chris);
* move CONFIG_DMA_NEED_SYNC check into dma_skip_sync() (Robin);
* #2:
* use a new dma_map_ops flag instead of new callback, assume the same
conditions as for direct DMA are enough (Petr, Robin);
* add more code comments to make sure the whole idea and path are
clear (Petr, Robin, Chris);
* #2, #3: correct the Git tags and the authorship a bit.
Not addressed in v2:
* #1:
* dma_sync_*range_*() are still wrapped, as some subsystems may want
to call the underscored versions directly (e.g. Page Pool);
* #2:
* the new dev->dma_skip_sync bit is still preferred over checking for
READ_ONCE(dev->dma_uses_io_tlb) + dev_is_dma_coherent() on hotpath
as a faster solution.
[1] https://lore.kernel.org/netdev/20240214162201.4168778-1-aleksander.lobakin@intel.com
[2] https://lore.kernel.org/netdev/20240205110426.764393-1-aleksander.lobakin@intel.com
[3] https://lore.kernel.org/netdev/20240126135456.704351-1-aleksander.lobakin@intel.com
--
2.44.0
^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH net-next v4 1/7] dma: compile-out DMA sync op calls when not used
2024-04-23 13:58 [PATCH net-next v4 0/7] dma: skip calling no-op sync ops when possible Alexander Lobakin
@ 2024-04-23 13:58 ` Alexander Lobakin
2024-04-23 13:58 ` [PATCH net-next v4 2/7] dma: avoid redundant calls for sync operations Alexander Lobakin
` (5 subsequent siblings)
6 siblings, 0 replies; 15+ messages in thread
From: Alexander Lobakin @ 2024-04-23 13:58 UTC (permalink / raw)
To: David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni
Cc: Alexander Lobakin, Christoph Hellwig, Marek Szyprowski,
Robin Murphy, Joerg Roedel, Will Deacon, Rafael J. Wysocki,
Magnus Karlsson, nex.sw.ncis.osdt.itp.upstreaming, bpf, netdev,
iommu, linux-kernel
Some platforms do have DMA, but DMA there is always direct and coherent.
Currently, even on such platforms DMA sync operations are compiled and
called.
Add a new hidden Kconfig symbol, DMA_NEED_SYNC, and set it only when
either sync operations are needed or there is DMA ops or swiotlb
or DMA debug is enabled. Compile global dma_sync_*() and dma_need_sync()
only when it's set, otherwise provide empty inline stubs.
The change allows for future optimizations of DMA sync calls depending
on runtime conditions.
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
---
kernel/dma/Kconfig | 5 +++
include/linux/dma-mapping.h | 62 ++++++++++++++++++++-----------------
kernel/dma/mapping.c | 22 +++++++------
3 files changed, 50 insertions(+), 39 deletions(-)
diff --git a/kernel/dma/Kconfig b/kernel/dma/Kconfig
index d62f5957f36b..c06e56be0ca1 100644
--- a/kernel/dma/Kconfig
+++ b/kernel/dma/Kconfig
@@ -107,6 +107,11 @@ config DMA_BOUNCE_UNALIGNED_KMALLOC
bool
depends on SWIOTLB
+config DMA_NEED_SYNC
+ def_bool ARCH_HAS_SYNC_DMA_FOR_DEVICE || ARCH_HAS_SYNC_DMA_FOR_CPU || \
+ ARCH_HAS_SYNC_DMA_FOR_CPU_ALL || DMA_API_DEBUG || DMA_OPS || \
+ SWIOTLB
+
config DMA_RESTRICTED_POOL
bool "DMA Restricted Pool"
depends on OF && OF_RESERVED_MEM && SWIOTLB
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 4a658de44ee9..a569b56b25e2 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -117,14 +117,6 @@ dma_addr_t dma_map_resource(struct device *dev, phys_addr_t phys_addr,
size_t size, enum dma_data_direction dir, unsigned long attrs);
void dma_unmap_resource(struct device *dev, dma_addr_t addr, size_t size,
enum dma_data_direction dir, unsigned long attrs);
-void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr, size_t size,
- enum dma_data_direction dir);
-void dma_sync_single_for_device(struct device *dev, dma_addr_t addr,
- size_t size, enum dma_data_direction dir);
-void dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
- int nelems, enum dma_data_direction dir);
-void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
- int nelems, enum dma_data_direction dir);
void *dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
gfp_t flag, unsigned long attrs);
void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
@@ -147,7 +139,6 @@ u64 dma_get_required_mask(struct device *dev);
bool dma_addressing_limited(struct device *dev);
size_t dma_max_mapping_size(struct device *dev);
size_t dma_opt_mapping_size(struct device *dev);
-bool dma_need_sync(struct device *dev, dma_addr_t dma_addr);
unsigned long dma_get_merge_boundary(struct device *dev);
struct sg_table *dma_alloc_noncontiguous(struct device *dev, size_t size,
enum dma_data_direction dir, gfp_t gfp, unsigned long attrs);
@@ -195,22 +186,6 @@ static inline void dma_unmap_resource(struct device *dev, dma_addr_t addr,
size_t size, enum dma_data_direction dir, unsigned long attrs)
{
}
-static inline void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr,
- size_t size, enum dma_data_direction dir)
-{
-}
-static inline void dma_sync_single_for_device(struct device *dev,
- dma_addr_t addr, size_t size, enum dma_data_direction dir)
-{
-}
-static inline void dma_sync_sg_for_cpu(struct device *dev,
- struct scatterlist *sg, int nelems, enum dma_data_direction dir)
-{
-}
-static inline void dma_sync_sg_for_device(struct device *dev,
- struct scatterlist *sg, int nelems, enum dma_data_direction dir)
-{
-}
static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
{
return -ENOMEM;
@@ -277,10 +252,6 @@ static inline size_t dma_opt_mapping_size(struct device *dev)
{
return 0;
}
-static inline bool dma_need_sync(struct device *dev, dma_addr_t dma_addr)
-{
- return false;
-}
static inline unsigned long dma_get_merge_boundary(struct device *dev)
{
return 0;
@@ -310,6 +281,39 @@ static inline int dma_mmap_noncontiguous(struct device *dev,
}
#endif /* CONFIG_HAS_DMA */
+#if defined(CONFIG_HAS_DMA) && defined(CONFIG_DMA_NEED_SYNC)
+void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr, size_t size,
+ enum dma_data_direction dir);
+void dma_sync_single_for_device(struct device *dev, dma_addr_t addr,
+ size_t size, enum dma_data_direction dir);
+void dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
+ int nelems, enum dma_data_direction dir);
+void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
+ int nelems, enum dma_data_direction dir);
+bool dma_need_sync(struct device *dev, dma_addr_t dma_addr);
+#else /* !CONFIG_HAS_DMA || !CONFIG_DMA_NEED_SYNC */
+static inline void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr,
+ size_t size, enum dma_data_direction dir)
+{
+}
+static inline void dma_sync_single_for_device(struct device *dev,
+ dma_addr_t addr, size_t size, enum dma_data_direction dir)
+{
+}
+static inline void dma_sync_sg_for_cpu(struct device *dev,
+ struct scatterlist *sg, int nelems, enum dma_data_direction dir)
+{
+}
+static inline void dma_sync_sg_for_device(struct device *dev,
+ struct scatterlist *sg, int nelems, enum dma_data_direction dir)
+{
+}
+static inline bool dma_need_sync(struct device *dev, dma_addr_t dma_addr)
+{
+ return false;
+}
+#endif /* !CONFIG_HAS_DMA || !CONFIG_DMA_NEED_SYNC */
+
struct page *dma_alloc_pages(struct device *dev, size_t size,
dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp);
void dma_free_pages(struct device *dev, size_t size, struct page *page,
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index 58db8fd70471..c78b78e95a26 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -329,6 +329,7 @@ void dma_unmap_resource(struct device *dev, dma_addr_t addr, size_t size,
}
EXPORT_SYMBOL(dma_unmap_resource);
+#ifdef CONFIG_DMA_NEED_SYNC
void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr, size_t size,
enum dma_data_direction dir)
{
@@ -385,6 +386,17 @@ void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
}
EXPORT_SYMBOL(dma_sync_sg_for_device);
+bool dma_need_sync(struct device *dev, dma_addr_t dma_addr)
+{
+ const struct dma_map_ops *ops = get_dma_ops(dev);
+
+ if (dma_map_direct(dev, ops))
+ return dma_direct_need_sync(dev, dma_addr);
+ return ops->sync_single_for_cpu || ops->sync_single_for_device;
+}
+EXPORT_SYMBOL_GPL(dma_need_sync);
+#endif /* CONFIG_DMA_NEED_SYNC */
+
/*
* The whole dma_get_sgtable() idea is fundamentally unsafe - it seems
* that the intention is to allow exporting memory allocated via the
@@ -841,16 +853,6 @@ size_t dma_opt_mapping_size(struct device *dev)
}
EXPORT_SYMBOL_GPL(dma_opt_mapping_size);
-bool dma_need_sync(struct device *dev, dma_addr_t dma_addr)
-{
- const struct dma_map_ops *ops = get_dma_ops(dev);
-
- if (dma_map_direct(dev, ops))
- return dma_direct_need_sync(dev, dma_addr);
- return ops->sync_single_for_cpu || ops->sync_single_for_device;
-}
-EXPORT_SYMBOL_GPL(dma_need_sync);
-
unsigned long dma_get_merge_boundary(struct device *dev)
{
const struct dma_map_ops *ops = get_dma_ops(dev);
--
2.44.0
^ permalink raw reply related [flat|nested] 15+ messages in thread
* [PATCH net-next v4 2/7] dma: avoid redundant calls for sync operations
2024-04-23 13:58 [PATCH net-next v4 0/7] dma: skip calling no-op sync ops when possible Alexander Lobakin
2024-04-23 13:58 ` [PATCH net-next v4 1/7] dma: compile-out DMA sync op calls when not used Alexander Lobakin
@ 2024-04-23 13:58 ` Alexander Lobakin
2024-04-23 13:58 ` [PATCH net-next v4 3/7] iommu/dma: avoid expensive indirect " Alexander Lobakin
` (4 subsequent siblings)
6 siblings, 0 replies; 15+ messages in thread
From: Alexander Lobakin @ 2024-04-23 13:58 UTC (permalink / raw)
To: David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni
Cc: Alexander Lobakin, Christoph Hellwig, Marek Szyprowski,
Robin Murphy, Joerg Roedel, Will Deacon, Rafael J. Wysocki,
Magnus Karlsson, nex.sw.ncis.osdt.itp.upstreaming, bpf, netdev,
iommu, linux-kernel
Quite often, devices do not need dma_sync operations on x86_64 at least.
Indeed, when dev_is_dma_coherent(dev) is true and
dev_use_swiotlb(dev) is false, iommu_dma_sync_single_for_cpu()
and friends do nothing.
However, indirectly calling them when CONFIG_RETPOLINE=y consumes about
10% of cycles on a cpu receiving packets from softirq at ~100Gbit rate.
Even if/when CONFIG_RETPOLINE is not set, there is a cost of about 3%.
Add dev->need_dma_sync boolean and turn it off during the device
initialization (dma_set_mask()) depending on the setup:
dev_is_dma_coherent() for the direct DMA, !(sync_single_for_device ||
sync_single_for_cpu) or the new dma_map_ops flag, %DMA_F_CAN_SKIP_SYNC,
advertised for non-NULL DMA ops.
Then later, if/when swiotlb is used for the first time, the flag
is reset back to on, from swiotlb_tbl_map_single().
On iavf, the UDP trafficgen with XDP_DROP in skb mode test shows
+3-5% increase for direct DMA.
Suggested-by: Christoph Hellwig <hch@lst.de> # direct DMA shortcut
Co-developed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
---
include/linux/device.h | 4 +++
include/linux/dma-map-ops.h | 12 ++++++++
include/linux/dma-mapping.h | 53 +++++++++++++++++++++++++++++++----
kernel/dma/mapping.c | 55 +++++++++++++++++++++++++++++--------
kernel/dma/swiotlb.c | 6 ++++
5 files changed, 113 insertions(+), 17 deletions(-)
diff --git a/include/linux/device.h b/include/linux/device.h
index b9f5464f44ed..ed95b829f05b 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -691,6 +691,7 @@ struct device_physical_location {
* and optionall (if the coherent mask is large enough) also
* for dma allocations. This flag is managed by the dma ops
* instance from ->dma_supported.
+ * @dma_need_sync: The device needs performing DMA sync operations.
*
* At the lowest level, every device in a Linux system is represented by an
* instance of struct device. The device structure contains the information
@@ -803,6 +804,9 @@ struct device {
#ifdef CONFIG_DMA_OPS_BYPASS
bool dma_ops_bypass : 1;
#endif
+#ifdef CONFIG_DMA_NEED_SYNC
+ bool dma_need_sync:1;
+#endif
};
/**
diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h
index 4abc60f04209..4893cb89cb52 100644
--- a/include/linux/dma-map-ops.h
+++ b/include/linux/dma-map-ops.h
@@ -18,8 +18,11 @@ struct iommu_ops;
*
* DMA_F_PCI_P2PDMA_SUPPORTED: Indicates the dma_map_ops implementation can
* handle PCI P2PDMA pages in the map_sg/unmap_sg operation.
+ * DMA_F_CAN_SKIP_SYNC: DMA sync operations can be skipped if the device is
+ * coherent and it's not an SWIOTLB buffer.
*/
#define DMA_F_PCI_P2PDMA_SUPPORTED (1 << 0)
+#define DMA_F_CAN_SKIP_SYNC (1 << 1)
struct dma_map_ops {
unsigned int flags;
@@ -273,6 +276,15 @@ static inline bool dev_is_dma_coherent(struct device *dev)
}
#endif /* CONFIG_ARCH_HAS_DMA_COHERENCE_H */
+static inline void dma_reset_need_sync(struct device *dev)
+{
+#ifdef CONFIG_DMA_NEED_SYNC
+ /* Reset it only once so that the function can be called on hotpath */
+ if (unlikely(!dev->dma_need_sync))
+ dev->dma_need_sync = true;
+#endif
+}
+
/*
* Check whether potential kmalloc() buffers are safe for non-coherent DMA.
*/
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index a569b56b25e2..eb4e15893b6c 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -282,16 +282,59 @@ static inline int dma_mmap_noncontiguous(struct device *dev,
#endif /* CONFIG_HAS_DMA */
#if defined(CONFIG_HAS_DMA) && defined(CONFIG_DMA_NEED_SYNC)
-void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr, size_t size,
+void __dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr, size_t size,
enum dma_data_direction dir);
-void dma_sync_single_for_device(struct device *dev, dma_addr_t addr,
+void __dma_sync_single_for_device(struct device *dev, dma_addr_t addr,
size_t size, enum dma_data_direction dir);
-void dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
+void __dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
int nelems, enum dma_data_direction dir);
-void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
+void __dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
int nelems, enum dma_data_direction dir);
-bool dma_need_sync(struct device *dev, dma_addr_t dma_addr);
+bool __dma_need_sync(struct device *dev, dma_addr_t dma_addr);
+
+static inline bool dma_dev_need_sync(const struct device *dev)
+{
+ /* Always call DMA sync operations when debugging is enabled */
+ return dev->dma_need_sync || IS_ENABLED(CONFIG_DMA_API_DEBUG);
+}
+
+static inline void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr,
+ size_t size, enum dma_data_direction dir)
+{
+ if (dma_dev_need_sync(dev))
+ __dma_sync_single_for_cpu(dev, addr, size, dir);
+}
+
+static inline void dma_sync_single_for_device(struct device *dev,
+ dma_addr_t addr, size_t size, enum dma_data_direction dir)
+{
+ if (dma_dev_need_sync(dev))
+ __dma_sync_single_for_device(dev, addr, size, dir);
+}
+
+static inline void dma_sync_sg_for_cpu(struct device *dev,
+ struct scatterlist *sg, int nelems, enum dma_data_direction dir)
+{
+ if (dma_dev_need_sync(dev))
+ __dma_sync_sg_for_cpu(dev, sg, nelems, dir);
+}
+
+static inline void dma_sync_sg_for_device(struct device *dev,
+ struct scatterlist *sg, int nelems, enum dma_data_direction dir)
+{
+ if (dma_dev_need_sync(dev))
+ __dma_sync_sg_for_device(dev, sg, nelems, dir);
+}
+
+static inline bool dma_need_sync(struct device *dev, dma_addr_t dma_addr)
+{
+ return dma_dev_need_sync(dev) ? __dma_need_sync(dev, dma_addr) : false;
+}
#else /* !CONFIG_HAS_DMA || !CONFIG_DMA_NEED_SYNC */
+static inline bool dma_dev_need_sync(const struct device *dev)
+{
+ return false;
+}
static inline void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr,
size_t size, enum dma_data_direction dir)
{
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index c78b78e95a26..3524bc92c37f 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -330,7 +330,7 @@ void dma_unmap_resource(struct device *dev, dma_addr_t addr, size_t size,
EXPORT_SYMBOL(dma_unmap_resource);
#ifdef CONFIG_DMA_NEED_SYNC
-void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr, size_t size,
+void __dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr, size_t size,
enum dma_data_direction dir)
{
const struct dma_map_ops *ops = get_dma_ops(dev);
@@ -342,9 +342,9 @@ void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr, size_t size,
ops->sync_single_for_cpu(dev, addr, size, dir);
debug_dma_sync_single_for_cpu(dev, addr, size, dir);
}
-EXPORT_SYMBOL(dma_sync_single_for_cpu);
+EXPORT_SYMBOL(__dma_sync_single_for_cpu);
-void dma_sync_single_for_device(struct device *dev, dma_addr_t addr,
+void __dma_sync_single_for_device(struct device *dev, dma_addr_t addr,
size_t size, enum dma_data_direction dir)
{
const struct dma_map_ops *ops = get_dma_ops(dev);
@@ -356,9 +356,9 @@ void dma_sync_single_for_device(struct device *dev, dma_addr_t addr,
ops->sync_single_for_device(dev, addr, size, dir);
debug_dma_sync_single_for_device(dev, addr, size, dir);
}
-EXPORT_SYMBOL(dma_sync_single_for_device);
+EXPORT_SYMBOL(__dma_sync_single_for_device);
-void dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
+void __dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
int nelems, enum dma_data_direction dir)
{
const struct dma_map_ops *ops = get_dma_ops(dev);
@@ -370,9 +370,9 @@ void dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
ops->sync_sg_for_cpu(dev, sg, nelems, dir);
debug_dma_sync_sg_for_cpu(dev, sg, nelems, dir);
}
-EXPORT_SYMBOL(dma_sync_sg_for_cpu);
+EXPORT_SYMBOL(__dma_sync_sg_for_cpu);
-void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
+void __dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
int nelems, enum dma_data_direction dir)
{
const struct dma_map_ops *ops = get_dma_ops(dev);
@@ -384,18 +384,47 @@ void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
ops->sync_sg_for_device(dev, sg, nelems, dir);
debug_dma_sync_sg_for_device(dev, sg, nelems, dir);
}
-EXPORT_SYMBOL(dma_sync_sg_for_device);
+EXPORT_SYMBOL(__dma_sync_sg_for_device);
-bool dma_need_sync(struct device *dev, dma_addr_t dma_addr)
+bool __dma_need_sync(struct device *dev, dma_addr_t dma_addr)
{
const struct dma_map_ops *ops = get_dma_ops(dev);
if (dma_map_direct(dev, ops))
+ /*
+ * dma_need_sync could've been reset on first SWIOTLB buffer
+ * mapping, but @dma_addr is not necessary an SWIOTLB buffer.
+ * In this case, fall back to more granular check.
+ */
return dma_direct_need_sync(dev, dma_addr);
- return ops->sync_single_for_cpu || ops->sync_single_for_device;
+ return true;
}
-EXPORT_SYMBOL_GPL(dma_need_sync);
-#endif /* CONFIG_DMA_NEED_SYNC */
+EXPORT_SYMBOL_GPL(__dma_need_sync);
+
+static void dma_setup_need_sync(struct device *dev)
+{
+ const struct dma_map_ops *ops = get_dma_ops(dev);
+
+ if (dma_map_direct(dev, ops) || (ops->flags & DMA_F_CAN_SKIP_SYNC))
+ /*
+ * dma_need_sync will be reset to %true on first SWIOTLB buffer
+ * mapping, if any. During the device initialization, it's
+ * enough to check only for the DMA coherence.
+ */
+ dev->dma_need_sync = !dev_is_dma_coherent(dev);
+ else if (!ops->sync_single_for_device && !ops->sync_single_for_cpu &&
+ !ops->sync_sg_for_device && !ops->sync_sg_for_cpu)
+ /*
+ * Synchronization is not possible when none of DMA sync ops
+ * is set.
+ */
+ dev->dma_need_sync = false;
+ else
+ dev->dma_need_sync = true;
+}
+#else /* !CONFIG_DMA_NEED_SYNC */
+static inline void dma_setup_need_sync(struct device *dev) { }
+#endif /* !CONFIG_DMA_NEED_SYNC */
/*
* The whole dma_get_sgtable() idea is fundamentally unsafe - it seems
@@ -785,6 +814,8 @@ int dma_set_mask(struct device *dev, u64 mask)
arch_dma_set_mask(dev, mask);
*dev->dma_mask = mask;
+ dma_setup_need_sync(dev);
+
return 0;
}
EXPORT_SYMBOL(dma_set_mask);
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index a5e0dfc44d24..3b9dddbcdda7 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -1379,6 +1379,12 @@ phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr,
return (phys_addr_t)DMA_MAPPING_ERROR;
}
+ /*
+ * If dma_need_sync wasn't set, reset it on first SWIOTLB buffer
+ * mapping to always sync SWIOTLB buffers.
+ */
+ dma_reset_need_sync(dev);
+
/*
* Save away the mapping from the original address to the DMA address.
* This is needed when we sync the memory. Then we sync the buffer if
--
2.44.0
^ permalink raw reply related [flat|nested] 15+ messages in thread
* [PATCH net-next v4 3/7] iommu/dma: avoid expensive indirect calls for sync operations
2024-04-23 13:58 [PATCH net-next v4 0/7] dma: skip calling no-op sync ops when possible Alexander Lobakin
2024-04-23 13:58 ` [PATCH net-next v4 1/7] dma: compile-out DMA sync op calls when not used Alexander Lobakin
2024-04-23 13:58 ` [PATCH net-next v4 2/7] dma: avoid redundant calls for sync operations Alexander Lobakin
@ 2024-04-23 13:58 ` Alexander Lobakin
2024-04-23 13:58 ` [PATCH net-next v4 4/7] page_pool: make sure frag API fields don't span between cachelines Alexander Lobakin
` (3 subsequent siblings)
6 siblings, 0 replies; 15+ messages in thread
From: Alexander Lobakin @ 2024-04-23 13:58 UTC (permalink / raw)
To: David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni
Cc: Alexander Lobakin, Christoph Hellwig, Marek Szyprowski,
Robin Murphy, Joerg Roedel, Will Deacon, Rafael J. Wysocki,
Magnus Karlsson, nex.sw.ncis.osdt.itp.upstreaming, bpf, netdev,
iommu, linux-kernel
When IOMMU is on, the actual synchronization happens in the same cases
as with the direct DMA. Advertise %DMA_F_CAN_SKIP_SYNC in IOMMU DMA to
skip sync ops calls (indirect) for non-SWIOTLB buffers.
perf profile before the patch:
18.53% [kernel] [k] gq_rx_skb
14.77% [kernel] [k] napi_reuse_skb
8.95% [kernel] [k] skb_release_data
5.42% [kernel] [k] dev_gro_receive
5.37% [kernel] [k] memcpy
<*> 5.26% [kernel] [k] iommu_dma_sync_sg_for_cpu
4.78% [kernel] [k] tcp_gro_receive
<*> 4.42% [kernel] [k] iommu_dma_sync_sg_for_device
4.12% [kernel] [k] ipv6_gro_receive
3.65% [kernel] [k] gq_pool_get
3.25% [kernel] [k] skb_gro_receive
2.07% [kernel] [k] napi_gro_frags
1.98% [kernel] [k] tcp6_gro_receive
1.27% [kernel] [k] gq_rx_prep_buffers
1.18% [kernel] [k] gq_rx_napi_handler
0.99% [kernel] [k] csum_partial
0.74% [kernel] [k] csum_ipv6_magic
0.72% [kernel] [k] free_pcp_prepare
0.60% [kernel] [k] __napi_poll
0.58% [kernel] [k] net_rx_action
0.56% [kernel] [k] read_tsc
<*> 0.50% [kernel] [k] __x86_indirect_thunk_r11
0.45% [kernel] [k] memset
After patch, lines with <*> no longer show up, and overall
cpu usage looks much better (~60% instead of ~72%):
25.56% [kernel] [k] gq_rx_skb
9.90% [kernel] [k] napi_reuse_skb
7.39% [kernel] [k] dev_gro_receive
6.78% [kernel] [k] memcpy
6.53% [kernel] [k] skb_release_data
6.39% [kernel] [k] tcp_gro_receive
5.71% [kernel] [k] ipv6_gro_receive
4.35% [kernel] [k] napi_gro_frags
4.34% [kernel] [k] skb_gro_receive
3.50% [kernel] [k] gq_pool_get
3.08% [kernel] [k] gq_rx_napi_handler
2.35% [kernel] [k] tcp6_gro_receive
2.06% [kernel] [k] gq_rx_prep_buffers
1.32% [kernel] [k] csum_partial
0.93% [kernel] [k] csum_ipv6_magic
0.65% [kernel] [k] net_rx_action
iavf yields +10% of Mpps on Rx. This also unblocks batched allocations
of XSk buffers when IOMMU is active.
Co-developed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
---
drivers/iommu/dma-iommu.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index e4cb26f6a943..0516e3e859b5 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -1720,7 +1720,8 @@ static size_t iommu_dma_max_mapping_size(struct device *dev)
}
static const struct dma_map_ops iommu_dma_ops = {
- .flags = DMA_F_PCI_P2PDMA_SUPPORTED,
+ .flags = DMA_F_PCI_P2PDMA_SUPPORTED |
+ DMA_F_CAN_SKIP_SYNC,
.alloc = iommu_dma_alloc,
.free = iommu_dma_free,
.alloc_pages = dma_common_alloc_pages,
--
2.44.0
^ permalink raw reply related [flat|nested] 15+ messages in thread
* [PATCH net-next v4 4/7] page_pool: make sure frag API fields don't span between cachelines
2024-04-23 13:58 [PATCH net-next v4 0/7] dma: skip calling no-op sync ops when possible Alexander Lobakin
` (2 preceding siblings ...)
2024-04-23 13:58 ` [PATCH net-next v4 3/7] iommu/dma: avoid expensive indirect " Alexander Lobakin
@ 2024-04-23 13:58 ` Alexander Lobakin
2024-04-23 13:58 ` [PATCH net-next v4 5/7] page_pool: don't use driver-set flags field directly Alexander Lobakin
` (2 subsequent siblings)
6 siblings, 0 replies; 15+ messages in thread
From: Alexander Lobakin @ 2024-04-23 13:58 UTC (permalink / raw)
To: David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni
Cc: Alexander Lobakin, Christoph Hellwig, Marek Szyprowski,
Robin Murphy, Joerg Roedel, Will Deacon, Rafael J. Wysocki,
Magnus Karlsson, nex.sw.ncis.osdt.itp.upstreaming, bpf, netdev,
iommu, linux-kernel
After commit 5027ec19f104 ("net: page_pool: split the page_pool_params
into fast and slow") that made &page_pool contain only "hot" params at
the start, cacheline boundary chops frag API fields group in the middle
again.
To not bother with this each time fast params get expanded or shrunk,
let's just align them to `4 * sizeof(long)`, the closest upper pow-2 to
their actual size (2 longs + 1 int). This ensures 16-byte alignment for
the 32-bit architectures and 32-byte alignment for the 64-bit ones,
excluding unnecessary false-sharing.
::page_state_hold_cnt is used quite intensively on hotpath no matter if
frag API is used, so move it to the newly created hole in the first
cacheline.
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
---
include/net/page_pool/types.h | 12 +++++++++++-
net/core/page_pool.c | 10 ++++++++++
2 files changed, 21 insertions(+), 1 deletion(-)
diff --git a/include/net/page_pool/types.h b/include/net/page_pool/types.h
index a6ebed002216..548321f7c49d 100644
--- a/include/net/page_pool/types.h
+++ b/include/net/page_pool/types.h
@@ -130,12 +130,22 @@ struct page_pool {
struct page_pool_params_fast p;
int cpuid;
+ u32 pages_state_hold_cnt;
bool has_init_callback;
+ /* The following block must stay within one cacheline. On 32-bit
+ * systems, sizeof(long) == sizeof(int), so that the block size is
+ * ``3 * sizeof(long)``. On 64-bit systems, the actual size is
+ * ``2 * sizeof(long) + sizeof(int)``. The closest pow-2 to both of
+ * them is ``4 * sizeof(long)``, so just use that one for simplicity.
+ * Having it aligned to a cacheline boundary may be excessive and
+ * doesn't bring any good.
+ */
+ __cacheline_group_begin(frag) __aligned(4 * sizeof(long));
long frag_users;
struct page *frag_page;
unsigned int frag_offset;
- u32 pages_state_hold_cnt;
+ __cacheline_group_end(frag);
struct delayed_work release_dw;
void (*disconnect)(void *pool);
diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index 273c24429bce..35c9d61853c8 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c
@@ -172,12 +172,22 @@ static void page_pool_producer_unlock(struct page_pool *pool,
spin_unlock_bh(&pool->ring.producer_lock);
}
+static void page_pool_struct_check(void)
+{
+ CACHELINE_ASSERT_GROUP_MEMBER(struct page_pool, frag, frag_users);
+ CACHELINE_ASSERT_GROUP_MEMBER(struct page_pool, frag, frag_page);
+ CACHELINE_ASSERT_GROUP_MEMBER(struct page_pool, frag, frag_offset);
+ CACHELINE_ASSERT_GROUP_SIZE(struct page_pool, frag, 4 * sizeof(long));
+}
+
static int page_pool_init(struct page_pool *pool,
const struct page_pool_params *params,
int cpuid)
{
unsigned int ring_qsize = 1024; /* Default */
+ page_pool_struct_check();
+
memcpy(&pool->p, ¶ms->fast, sizeof(pool->p));
memcpy(&pool->slow, ¶ms->slow, sizeof(pool->slow));
--
2.44.0
^ permalink raw reply related [flat|nested] 15+ messages in thread
* [PATCH net-next v4 5/7] page_pool: don't use driver-set flags field directly
2024-04-23 13:58 [PATCH net-next v4 0/7] dma: skip calling no-op sync ops when possible Alexander Lobakin
` (3 preceding siblings ...)
2024-04-23 13:58 ` [PATCH net-next v4 4/7] page_pool: make sure frag API fields don't span between cachelines Alexander Lobakin
@ 2024-04-23 13:58 ` Alexander Lobakin
2024-04-23 13:58 ` [PATCH net-next v4 6/7] page_pool: check for DMA sync shortcut earlier Alexander Lobakin
2024-04-23 13:58 ` [PATCH net-next v4 7/7] xsk: use generic DMA sync shortcut instead of a custom one Alexander Lobakin
6 siblings, 0 replies; 15+ messages in thread
From: Alexander Lobakin @ 2024-04-23 13:58 UTC (permalink / raw)
To: David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni
Cc: Alexander Lobakin, Christoph Hellwig, Marek Szyprowski,
Robin Murphy, Joerg Roedel, Will Deacon, Rafael J. Wysocki,
Magnus Karlsson, nex.sw.ncis.osdt.itp.upstreaming, bpf, netdev,
iommu, linux-kernel, Alexander Duyck
page_pool::p is driver-defined params, copied directly from the
structure passed to page_pool_create(). The structure isn't meant
to be modified by the Page Pool core code and this even might look
confusing[0][1].
In order to be able to alter some flags, let's define our own, internal
fields the same way as the already existing one (::has_init_callback).
They are defined as bits in the driver-set params, leave them so here
as well, to not waste byte-per-bit or so. Almost 30 bits are still free
for future extensions.
We could've defined only new flags here or only the ones we may need
to alter, but checking some flags in one place while others in another
doesn't sound convenient or intuitive. ::flags passed by the driver can
now go to the "slow" PP params.
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Link[0]: https://lore.kernel.org/netdev/20230703133207.4f0c54ce@kernel.org
Suggested-by: Alexander Duyck <alexanderduyck@fb.com>
Link[1]: https://lore.kernel.org/netdev/CAKgT0UfZCGnWgOH96E4GV3ZP6LLbROHM7SHE8NKwq+exX+Gk_Q@mail.gmail.com
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
---
include/net/page_pool/types.h | 13 ++++++++---
net/core/page_pool.c | 41 +++++++++++++++++++----------------
2 files changed, 32 insertions(+), 22 deletions(-)
diff --git a/include/net/page_pool/types.h b/include/net/page_pool/types.h
index 548321f7c49d..b088d131aeb0 100644
--- a/include/net/page_pool/types.h
+++ b/include/net/page_pool/types.h
@@ -45,7 +45,6 @@ struct pp_alloc_cache {
/**
* struct page_pool_params - page pool parameters
- * @flags: PP_FLAG_DMA_MAP, PP_FLAG_DMA_SYNC_DEV
* @order: 2^order pages on allocation
* @pool_size: size of the ptr_ring
* @nid: NUMA node id to allocate from pages from
@@ -55,10 +54,11 @@ struct pp_alloc_cache {
* @dma_dir: DMA mapping direction
* @max_len: max DMA sync memory size for PP_FLAG_DMA_SYNC_DEV
* @offset: DMA sync address offset for PP_FLAG_DMA_SYNC_DEV
+ * @netdev: corresponding &net_device for Netlink introspection
+ * @flags: PP_FLAG_DMA_MAP, PP_FLAG_DMA_SYNC_DEV, PP_FLAG_SYSTEM_POOL
*/
struct page_pool_params {
struct_group_tagged(page_pool_params_fast, fast,
- unsigned int flags;
unsigned int order;
unsigned int pool_size;
int nid;
@@ -70,6 +70,7 @@ struct page_pool_params {
);
struct_group_tagged(page_pool_params_slow, slow,
struct net_device *netdev;
+ unsigned int flags;
/* private: used by test code only */
void (*init_callback)(struct page *page, void *arg);
void *init_arg;
@@ -131,7 +132,13 @@ struct page_pool {
int cpuid;
u32 pages_state_hold_cnt;
- bool has_init_callback;
+
+ bool has_init_callback:1; /* slow::init_callback is set */
+ bool dma_map:1; /* Perform DMA mapping */
+ bool dma_sync:1; /* Perform DMA sync */
+#ifdef CONFIG_PAGE_POOL_STATS
+ bool system:1; /* This is a global percpu pool */
+#endif
/* The following block must stay within one cacheline. On 32-bit
* systems, sizeof(long) == sizeof(int), so that the block size is
diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index 35c9d61853c8..6cf26a68fa91 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c
@@ -194,7 +194,7 @@ static int page_pool_init(struct page_pool *pool,
pool->cpuid = cpuid;
/* Validate only known flags were used */
- if (pool->p.flags & ~(PP_FLAG_ALL))
+ if (pool->slow.flags & ~PP_FLAG_ALL)
return -EINVAL;
if (pool->p.pool_size)
@@ -208,22 +208,26 @@ static int page_pool_init(struct page_pool *pool,
* DMA_BIDIRECTIONAL is for allowing page used for DMA sending,
* which is the XDP_TX use-case.
*/
- if (pool->p.flags & PP_FLAG_DMA_MAP) {
+ if (pool->slow.flags & PP_FLAG_DMA_MAP) {
if ((pool->p.dma_dir != DMA_FROM_DEVICE) &&
(pool->p.dma_dir != DMA_BIDIRECTIONAL))
return -EINVAL;
+
+ pool->dma_map = true;
}
- if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV) {
+ if (pool->slow.flags & PP_FLAG_DMA_SYNC_DEV) {
/* In order to request DMA-sync-for-device the page
* needs to be mapped
*/
- if (!(pool->p.flags & PP_FLAG_DMA_MAP))
+ if (!(pool->slow.flags & PP_FLAG_DMA_MAP))
return -EINVAL;
if (!pool->p.max_len)
return -EINVAL;
+ pool->dma_sync = true;
+
/* pool->p.offset has to be set according to the address
* offset used by the DMA engine to start copying rx data
*/
@@ -232,7 +236,7 @@ static int page_pool_init(struct page_pool *pool,
pool->has_init_callback = !!pool->slow.init_callback;
#ifdef CONFIG_PAGE_POOL_STATS
- if (!(pool->p.flags & PP_FLAG_SYSTEM_POOL)) {
+ if (!(pool->slow.flags & PP_FLAG_SYSTEM_POOL)) {
pool->recycle_stats = alloc_percpu(struct page_pool_recycle_stats);
if (!pool->recycle_stats)
return -ENOMEM;
@@ -242,12 +246,13 @@ static int page_pool_init(struct page_pool *pool,
* (also percpu) page pool instance.
*/
pool->recycle_stats = &pp_system_recycle_stats;
+ pool->system = true;
}
#endif
if (ptr_ring_init(&pool->ring, ring_qsize, GFP_KERNEL) < 0) {
#ifdef CONFIG_PAGE_POOL_STATS
- if (!(pool->p.flags & PP_FLAG_SYSTEM_POOL))
+ if (!pool->system)
free_percpu(pool->recycle_stats);
#endif
return -ENOMEM;
@@ -258,7 +263,7 @@ static int page_pool_init(struct page_pool *pool,
/* Driver calling page_pool_create() also call page_pool_destroy() */
refcount_set(&pool->user_cnt, 1);
- if (pool->p.flags & PP_FLAG_DMA_MAP)
+ if (pool->dma_map)
get_device(pool->p.dev);
return 0;
@@ -268,11 +273,11 @@ static void page_pool_uninit(struct page_pool *pool)
{
ptr_ring_cleanup(&pool->ring, NULL);
- if (pool->p.flags & PP_FLAG_DMA_MAP)
+ if (pool->dma_map)
put_device(pool->p.dev);
#ifdef CONFIG_PAGE_POOL_STATS
- if (!(pool->p.flags & PP_FLAG_SYSTEM_POOL))
+ if (!pool->system)
free_percpu(pool->recycle_stats);
#endif
}
@@ -424,7 +429,7 @@ static bool page_pool_dma_map(struct page_pool *pool, struct page *page)
if (page_pool_set_dma_addr(page, dma))
goto unmap_failed;
- if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV)
+ if (pool->dma_sync)
page_pool_dma_sync_for_device(pool, page, pool->p.max_len);
return true;
@@ -470,8 +475,7 @@ static struct page *__page_pool_alloc_page_order(struct page_pool *pool,
if (unlikely(!page))
return NULL;
- if ((pool->p.flags & PP_FLAG_DMA_MAP) &&
- unlikely(!page_pool_dma_map(pool, page))) {
+ if (pool->dma_map && unlikely(!page_pool_dma_map(pool, page))) {
put_page(page);
return NULL;
}
@@ -491,8 +495,8 @@ static struct page *__page_pool_alloc_pages_slow(struct page_pool *pool,
gfp_t gfp)
{
const int bulk = PP_ALLOC_CACHE_REFILL;
- unsigned int pp_flags = pool->p.flags;
unsigned int pp_order = pool->p.order;
+ bool dma_map = pool->dma_map;
struct page *page;
int i, nr_pages;
@@ -517,8 +521,7 @@ static struct page *__page_pool_alloc_pages_slow(struct page_pool *pool,
*/
for (i = 0; i < nr_pages; i++) {
page = pool->alloc.cache[i];
- if ((pp_flags & PP_FLAG_DMA_MAP) &&
- unlikely(!page_pool_dma_map(pool, page))) {
+ if (dma_map && unlikely(!page_pool_dma_map(pool, page))) {
put_page(page);
continue;
}
@@ -590,7 +593,7 @@ void __page_pool_release_page_dma(struct page_pool *pool, struct page *page)
{
dma_addr_t dma;
- if (!(pool->p.flags & PP_FLAG_DMA_MAP))
+ if (!pool->dma_map)
/* Always account for inflight pages, even if we didn't
* map them
*/
@@ -673,7 +676,7 @@ static bool __page_pool_page_can_be_recycled(const struct page *page)
}
/* If the page refcnt == 1, this will try to recycle the page.
- * if PP_FLAG_DMA_SYNC_DEV is set, we'll try to sync the DMA area for
+ * If pool->dma_sync is set, we'll try to sync the DMA area for
* the configured size min(dma_sync_size, pool->max_len).
* If the page refcnt != 1, then the page will be returned to memory
* subsystem.
@@ -696,7 +699,7 @@ __page_pool_put_page(struct page_pool *pool, struct page *page,
if (likely(__page_pool_page_can_be_recycled(page))) {
/* Read barrier done in page_ref_count / READ_ONCE */
- if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV)
+ if (pool->dma_sync)
page_pool_dma_sync_for_device(pool, page,
dma_sync_size);
@@ -837,7 +840,7 @@ static struct page *page_pool_drain_frag(struct page_pool *pool,
return NULL;
if (__page_pool_page_can_be_recycled(page)) {
- if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV)
+ if (pool->dma_sync)
page_pool_dma_sync_for_device(pool, page, -1);
return page;
--
2.44.0
^ permalink raw reply related [flat|nested] 15+ messages in thread
* [PATCH net-next v4 6/7] page_pool: check for DMA sync shortcut earlier
2024-04-23 13:58 [PATCH net-next v4 0/7] dma: skip calling no-op sync ops when possible Alexander Lobakin
` (4 preceding siblings ...)
2024-04-23 13:58 ` [PATCH net-next v4 5/7] page_pool: don't use driver-set flags field directly Alexander Lobakin
@ 2024-04-23 13:58 ` Alexander Lobakin
2024-04-24 8:52 ` Alexander Lobakin
2024-04-23 13:58 ` [PATCH net-next v4 7/7] xsk: use generic DMA sync shortcut instead of a custom one Alexander Lobakin
6 siblings, 1 reply; 15+ messages in thread
From: Alexander Lobakin @ 2024-04-23 13:58 UTC (permalink / raw)
To: David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni
Cc: Alexander Lobakin, Christoph Hellwig, Marek Szyprowski,
Robin Murphy, Joerg Roedel, Will Deacon, Rafael J. Wysocki,
Magnus Karlsson, nex.sw.ncis.osdt.itp.upstreaming, bpf, netdev,
iommu, linux-kernel
We can save a couple more function calls in the Page Pool code if we
check for dma_need_sync() earlier, just when we test pp->p.dma_sync.
Move both these checks into an inline wrapper and call the PP wrapper
over the generic DMA sync function only when both are true.
You can't cache the result of dma_need_sync() in &page_pool, as it may
change anytime if an SWIOTLB buffer is allocated or mapped.
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
---
net/core/page_pool.c | 31 +++++++++++++++++--------------
1 file changed, 17 insertions(+), 14 deletions(-)
diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index 6cf26a68fa91..87319c6365e0 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c
@@ -398,16 +398,24 @@ static struct page *__page_pool_get_cached(struct page_pool *pool)
return page;
}
-static void page_pool_dma_sync_for_device(const struct page_pool *pool,
- const struct page *page,
- unsigned int dma_sync_size)
+static void __page_pool_dma_sync_for_device(const struct page_pool *pool,
+ const struct page *page,
+ u32 dma_sync_size)
{
dma_addr_t dma_addr = page_pool_get_dma_addr(page);
dma_sync_size = min(dma_sync_size, pool->p.max_len);
- dma_sync_single_range_for_device(pool->p.dev, dma_addr,
- pool->p.offset, dma_sync_size,
- pool->p.dma_dir);
+ __dma_sync_single_for_device(pool->p.dev, dma_addr + pool->p.offset,
+ dma_sync_size, pool->p.dma_dir);
+}
+
+static __always_inline void
+page_pool_dma_sync_for_device(const struct page_pool *pool,
+ const struct page *page,
+ u32 dma_sync_size)
+{
+ if (pool->dma_sync && dma_dev_need_sync(pool->p.dev))
+ __page_pool_dma_sync_for_device(pool, page, dma_sync_size);
}
static bool page_pool_dma_map(struct page_pool *pool, struct page *page)
@@ -429,8 +437,7 @@ static bool page_pool_dma_map(struct page_pool *pool, struct page *page)
if (page_pool_set_dma_addr(page, dma))
goto unmap_failed;
- if (pool->dma_sync)
- page_pool_dma_sync_for_device(pool, page, pool->p.max_len);
+ page_pool_dma_sync_for_device(pool, page, pool->p.max_len);
return true;
@@ -699,9 +706,7 @@ __page_pool_put_page(struct page_pool *pool, struct page *page,
if (likely(__page_pool_page_can_be_recycled(page))) {
/* Read barrier done in page_ref_count / READ_ONCE */
- if (pool->dma_sync)
- page_pool_dma_sync_for_device(pool, page,
- dma_sync_size);
+ page_pool_dma_sync_for_device(pool, page, dma_sync_size);
if (allow_direct && page_pool_recycle_in_cache(page, pool))
return NULL;
@@ -840,9 +845,7 @@ static struct page *page_pool_drain_frag(struct page_pool *pool,
return NULL;
if (__page_pool_page_can_be_recycled(page)) {
- if (pool->dma_sync)
- page_pool_dma_sync_for_device(pool, page, -1);
-
+ page_pool_dma_sync_for_device(pool, page, -1);
return page;
}
--
2.44.0
^ permalink raw reply related [flat|nested] 15+ messages in thread
* [PATCH net-next v4 7/7] xsk: use generic DMA sync shortcut instead of a custom one
2024-04-23 13:58 [PATCH net-next v4 0/7] dma: skip calling no-op sync ops when possible Alexander Lobakin
` (5 preceding siblings ...)
2024-04-23 13:58 ` [PATCH net-next v4 6/7] page_pool: check for DMA sync shortcut earlier Alexander Lobakin
@ 2024-04-23 13:58 ` Alexander Lobakin
6 siblings, 0 replies; 15+ messages in thread
From: Alexander Lobakin @ 2024-04-23 13:58 UTC (permalink / raw)
To: David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni
Cc: Alexander Lobakin, Christoph Hellwig, Marek Szyprowski,
Robin Murphy, Joerg Roedel, Will Deacon, Rafael J. Wysocki,
Magnus Karlsson, nex.sw.ncis.osdt.itp.upstreaming, bpf, netdev,
iommu, linux-kernel
XSk infra's been using its own DMA sync shortcut to try avoiding
redundant function calls. Now that there is a generic one, remove
the custom implementation and rely on the generic helpers.
xsk_buff_dma_sync_for_cpu() doesn't need the second argument anymore,
remove it.
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
---
include/net/xdp_sock_drv.h | 7 ++---
include/net/xsk_buff_pool.h | 14 +++-------
drivers/net/ethernet/engleder/tsnep_main.c | 2 +-
.../net/ethernet/freescale/dpaa2/dpaa2-xsk.c | 2 +-
drivers/net/ethernet/intel/i40e/i40e_xsk.c | 2 +-
drivers/net/ethernet/intel/ice/ice_xsk.c | 2 +-
drivers/net/ethernet/intel/igc/igc_main.c | 2 +-
drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c | 2 +-
.../ethernet/mellanox/mlx5/core/en/xsk/rx.c | 4 +--
.../net/ethernet/mellanox/mlx5/core/en_rx.c | 2 +-
drivers/net/ethernet/netronome/nfp/nfd3/xsk.c | 2 +-
.../net/ethernet/stmicro/stmmac/stmmac_main.c | 2 +-
net/xdp/xsk_buff_pool.c | 28 ++-----------------
13 files changed, 20 insertions(+), 51 deletions(-)
diff --git a/include/net/xdp_sock_drv.h b/include/net/xdp_sock_drv.h
index c9aec9ab6191..0a5dca2b2b3f 100644
--- a/include/net/xdp_sock_drv.h
+++ b/include/net/xdp_sock_drv.h
@@ -219,13 +219,10 @@ static inline struct xsk_tx_metadata *xsk_buff_get_metadata(struct xsk_buff_pool
return meta;
}
-static inline void xsk_buff_dma_sync_for_cpu(struct xdp_buff *xdp, struct xsk_buff_pool *pool)
+static inline void xsk_buff_dma_sync_for_cpu(struct xdp_buff *xdp)
{
struct xdp_buff_xsk *xskb = container_of(xdp, struct xdp_buff_xsk, xdp);
- if (!pool->dma_need_sync)
- return;
-
xp_dma_sync_for_cpu(xskb);
}
@@ -402,7 +399,7 @@ static inline struct xsk_tx_metadata *xsk_buff_get_metadata(struct xsk_buff_pool
return NULL;
}
-static inline void xsk_buff_dma_sync_for_cpu(struct xdp_buff *xdp, struct xsk_buff_pool *pool)
+static inline void xsk_buff_dma_sync_for_cpu(struct xdp_buff *xdp)
{
}
diff --git a/include/net/xsk_buff_pool.h b/include/net/xsk_buff_pool.h
index 99dd7376df6a..bacb33f1e3e5 100644
--- a/include/net/xsk_buff_pool.h
+++ b/include/net/xsk_buff_pool.h
@@ -43,7 +43,6 @@ struct xsk_dma_map {
refcount_t users;
struct list_head list; /* Protected by the RTNL_LOCK */
u32 dma_pages_cnt;
- bool dma_need_sync;
};
struct xsk_buff_pool {
@@ -82,7 +81,6 @@ struct xsk_buff_pool {
u8 tx_metadata_len; /* inherited from umem */
u8 cached_need_wakeup;
bool uses_need_wakeup;
- bool dma_need_sync;
bool unaligned;
bool tx_sw_csum;
void *addrs;
@@ -155,21 +153,17 @@ static inline dma_addr_t xp_get_frame_dma(struct xdp_buff_xsk *xskb)
return xskb->frame_dma;
}
-void xp_dma_sync_for_cpu_slow(struct xdp_buff_xsk *xskb);
static inline void xp_dma_sync_for_cpu(struct xdp_buff_xsk *xskb)
{
- xp_dma_sync_for_cpu_slow(xskb);
+ dma_sync_single_for_cpu(xskb->pool->dev, xskb->dma,
+ xskb->pool->frame_len,
+ DMA_BIDIRECTIONAL);
}
-void xp_dma_sync_for_device_slow(struct xsk_buff_pool *pool, dma_addr_t dma,
- size_t size);
static inline void xp_dma_sync_for_device(struct xsk_buff_pool *pool,
dma_addr_t dma, size_t size)
{
- if (!pool->dma_need_sync)
- return;
-
- xp_dma_sync_for_device_slow(pool, dma, size);
+ dma_sync_single_for_device(pool->dev, dma, size, DMA_BIDIRECTIONAL);
}
/* Masks for xdp_umem_page flags.
diff --git a/drivers/net/ethernet/engleder/tsnep_main.c b/drivers/net/ethernet/engleder/tsnep_main.c
index 4b15af6b7122..44da335d66bd 100644
--- a/drivers/net/ethernet/engleder/tsnep_main.c
+++ b/drivers/net/ethernet/engleder/tsnep_main.c
@@ -1587,7 +1587,7 @@ static int tsnep_rx_poll_zc(struct tsnep_rx *rx, struct napi_struct *napi,
length = __le32_to_cpu(entry->desc_wb->properties) &
TSNEP_DESC_LENGTH_MASK;
xsk_buff_set_size(entry->xdp, length - ETH_FCS_LEN);
- xsk_buff_dma_sync_for_cpu(entry->xdp, rx->xsk_pool);
+ xsk_buff_dma_sync_for_cpu(entry->xdp);
/* RX metadata with timestamps is in front of actual data,
* subtract metadata size to get length of actual data and
diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-xsk.c b/drivers/net/ethernet/freescale/dpaa2/dpaa2-xsk.c
index 051748b997f3..a466c2379146 100644
--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-xsk.c
+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-xsk.c
@@ -55,7 +55,7 @@ static u32 dpaa2_xsk_run_xdp(struct dpaa2_eth_priv *priv,
xdp_set_data_meta_invalid(xdp_buff);
xdp_buff->rxq = &ch->xdp_rxq;
- xsk_buff_dma_sync_for_cpu(xdp_buff, ch->xsk_pool);
+ xsk_buff_dma_sync_for_cpu(xdp_buff);
xdp_act = bpf_prog_run_xdp(xdp_prog, xdp_buff);
/* xdp.data pointer may have changed */
diff --git a/drivers/net/ethernet/intel/i40e/i40e_xsk.c b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
index a85b425794df..4e885df789ef 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_xsk.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
@@ -482,7 +482,7 @@ int i40e_clean_rx_irq_zc(struct i40e_ring *rx_ring, int budget)
bi = *i40e_rx_bi(rx_ring, next_to_process);
xsk_buff_set_size(bi, size);
- xsk_buff_dma_sync_for_cpu(bi, rx_ring->xsk_pool);
+ xsk_buff_dma_sync_for_cpu(bi);
if (!first)
first = bi;
diff --git a/drivers/net/ethernet/intel/ice/ice_xsk.c b/drivers/net/ethernet/intel/ice/ice_xsk.c
index aa81d1162b81..7541f223bf4f 100644
--- a/drivers/net/ethernet/intel/ice/ice_xsk.c
+++ b/drivers/net/ethernet/intel/ice/ice_xsk.c
@@ -878,7 +878,7 @@ int ice_clean_rx_irq_zc(struct ice_rx_ring *rx_ring, int budget)
ICE_RX_FLX_DESC_PKT_LEN_M;
xsk_buff_set_size(xdp, size);
- xsk_buff_dma_sync_for_cpu(xdp, xsk_pool);
+ xsk_buff_dma_sync_for_cpu(xdp);
if (!first) {
first = xdp;
diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index d9bd001af7ba..303404752deb 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -2812,7 +2812,7 @@ static int igc_clean_rx_irq_zc(struct igc_q_vector *q_vector, const int budget)
}
bi->xdp->data_end = bi->xdp->data + size;
- xsk_buff_dma_sync_for_cpu(bi->xdp, ring->xsk_pool);
+ xsk_buff_dma_sync_for_cpu(bi->xdp);
res = __igc_xdp_run_prog(adapter, prog, bi->xdp);
switch (res) {
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c
index 397cb773fabb..3e3b471e53f0 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c
@@ -303,7 +303,7 @@ int ixgbe_clean_rx_irq_zc(struct ixgbe_q_vector *q_vector,
}
bi->xdp->data_end = bi->xdp->data + size;
- xsk_buff_dma_sync_for_cpu(bi->xdp, rx_ring->xsk_pool);
+ xsk_buff_dma_sync_for_cpu(bi->xdp);
xdp_res = ixgbe_run_xdp_zc(adapter, rx_ring, bi->xdp);
if (likely(xdp_res & (IXGBE_XDP_TX | IXGBE_XDP_REDIR))) {
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c b/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c
index b8dd74453655..1b7132fa70de 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c
@@ -270,7 +270,7 @@ struct sk_buff *mlx5e_xsk_skb_from_cqe_mpwrq_linear(struct mlx5e_rq *rq,
/* mxbuf->rq is set on allocation, but cqe is per-packet so set it here */
mxbuf->cqe = cqe;
xsk_buff_set_size(&mxbuf->xdp, cqe_bcnt);
- xsk_buff_dma_sync_for_cpu(&mxbuf->xdp, rq->xsk_pool);
+ xsk_buff_dma_sync_for_cpu(&mxbuf->xdp);
net_prefetch(mxbuf->xdp.data);
/* Possible flows:
@@ -319,7 +319,7 @@ struct sk_buff *mlx5e_xsk_skb_from_cqe_linear(struct mlx5e_rq *rq,
/* mxbuf->rq is set on allocation, but cqe is per-packet so set it here */
mxbuf->cqe = cqe;
xsk_buff_set_size(&mxbuf->xdp, cqe_bcnt);
- xsk_buff_dma_sync_for_cpu(&mxbuf->xdp, rq->xsk_pool);
+ xsk_buff_dma_sync_for_cpu(&mxbuf->xdp);
net_prefetch(mxbuf->xdp.data);
prog = rcu_dereference(rq->xdp_prog);
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
index d601b5faaed5..b5333da20e8a 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
@@ -917,7 +917,7 @@ INDIRECT_CALLABLE_SCOPE bool mlx5e_post_rx_wqes(struct mlx5e_rq *rq)
if (!rq->xsk_pool) {
count = mlx5e_refill_rx_wqes(rq, head, wqe_bulk);
- } else if (likely(!rq->xsk_pool->dma_need_sync)) {
+ } else if (likely(!dma_dev_need_sync(rq->pdev))) {
mlx5e_xsk_free_rx_wqes(rq, head, wqe_bulk);
count = mlx5e_xsk_alloc_rx_wqes_batched(rq, head, wqe_bulk);
} else {
diff --git a/drivers/net/ethernet/netronome/nfp/nfd3/xsk.c b/drivers/net/ethernet/netronome/nfp/nfd3/xsk.c
index 45be6954d5aa..01cfa9cc1b5e 100644
--- a/drivers/net/ethernet/netronome/nfp/nfd3/xsk.c
+++ b/drivers/net/ethernet/netronome/nfp/nfd3/xsk.c
@@ -184,7 +184,7 @@ nfp_nfd3_xsk_rx(struct nfp_net_rx_ring *rx_ring, int budget,
xrxbuf->xdp->data += meta_len;
xrxbuf->xdp->data_end = xrxbuf->xdp->data + pkt_len;
xdp_set_data_meta_invalid(xrxbuf->xdp);
- xsk_buff_dma_sync_for_cpu(xrxbuf->xdp, r_vec->xsk_pool);
+ xsk_buff_dma_sync_for_cpu(xrxbuf->xdp);
net_prefetch(xrxbuf->xdp->data);
if (meta_len) {
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 2ea9f0fa0cf9..cfda1a0956e4 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -5354,7 +5354,7 @@ static int stmmac_rx_zc(struct stmmac_priv *priv, int limit, u32 queue)
/* RX buffer is good and fit into a XSK pool buffer */
buf->xdp->data_end = buf->xdp->data + buf1_len;
- xsk_buff_dma_sync_for_cpu(buf->xdp, rx_q->xsk_pool);
+ xsk_buff_dma_sync_for_cpu(buf->xdp);
prog = READ_ONCE(priv->xdp_prog);
res = __stmmac_xdp_run_prog(priv, prog, buf->xdp);
diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c
index ce60ecd48a4d..b2cce6dbe6d8 100644
--- a/net/xdp/xsk_buff_pool.c
+++ b/net/xdp/xsk_buff_pool.c
@@ -338,7 +338,6 @@ static struct xsk_dma_map *xp_create_dma_map(struct device *dev, struct net_devi
dma_map->netdev = netdev;
dma_map->dev = dev;
- dma_map->dma_need_sync = false;
dma_map->dma_pages_cnt = nr_pages;
refcount_set(&dma_map->users, 1);
list_add(&dma_map->list, &umem->xsk_dma_list);
@@ -424,7 +423,6 @@ static int xp_init_dma_info(struct xsk_buff_pool *pool, struct xsk_dma_map *dma_
pool->dev = dma_map->dev;
pool->dma_pages_cnt = dma_map->dma_pages_cnt;
- pool->dma_need_sync = dma_map->dma_need_sync;
memcpy(pool->dma_pages, dma_map->dma_pages,
pool->dma_pages_cnt * sizeof(*pool->dma_pages));
@@ -460,8 +458,6 @@ int xp_dma_map(struct xsk_buff_pool *pool, struct device *dev,
__xp_dma_unmap(dma_map, attrs);
return -ENOMEM;
}
- if (dma_need_sync(dev, dma))
- dma_map->dma_need_sync = true;
dma_map->dma_pages[i] = dma;
}
@@ -557,11 +553,8 @@ struct xdp_buff *xp_alloc(struct xsk_buff_pool *pool)
xskb->xdp.data_meta = xskb->xdp.data;
xskb->xdp.flags = 0;
- if (pool->dma_need_sync) {
- dma_sync_single_range_for_device(pool->dev, xskb->dma, 0,
- pool->frame_len,
- DMA_BIDIRECTIONAL);
- }
+ xp_dma_sync_for_device(pool, xskb->dma, pool->frame_len);
+
return &xskb->xdp;
}
EXPORT_SYMBOL(xp_alloc);
@@ -633,7 +626,7 @@ u32 xp_alloc_batch(struct xsk_buff_pool *pool, struct xdp_buff **xdp, u32 max)
{
u32 nb_entries1 = 0, nb_entries2;
- if (unlikely(pool->dma_need_sync)) {
+ if (unlikely(dma_dev_need_sync(pool->dev))) {
struct xdp_buff *buff;
/* Slow path */
@@ -693,18 +686,3 @@ dma_addr_t xp_raw_get_dma(struct xsk_buff_pool *pool, u64 addr)
(addr & ~PAGE_MASK);
}
EXPORT_SYMBOL(xp_raw_get_dma);
-
-void xp_dma_sync_for_cpu_slow(struct xdp_buff_xsk *xskb)
-{
- dma_sync_single_range_for_cpu(xskb->pool->dev, xskb->dma, 0,
- xskb->pool->frame_len, DMA_BIDIRECTIONAL);
-}
-EXPORT_SYMBOL(xp_dma_sync_for_cpu_slow);
-
-void xp_dma_sync_for_device_slow(struct xsk_buff_pool *pool, dma_addr_t dma,
- size_t size)
-{
- dma_sync_single_range_for_device(pool->dev, dma, 0,
- size, DMA_BIDIRECTIONAL);
-}
-EXPORT_SYMBOL(xp_dma_sync_for_device_slow);
--
2.44.0
^ permalink raw reply related [flat|nested] 15+ messages in thread
* Re: [PATCH net-next v4 6/7] page_pool: check for DMA sync shortcut earlier
2024-04-23 13:58 ` [PATCH net-next v4 6/7] page_pool: check for DMA sync shortcut earlier Alexander Lobakin
@ 2024-04-24 8:52 ` Alexander Lobakin
2024-04-26 5:02 ` Christoph Hellwig
2024-05-02 15:49 ` Robin Murphy
0 siblings, 2 replies; 15+ messages in thread
From: Alexander Lobakin @ 2024-04-24 8:52 UTC (permalink / raw)
To: David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni
Cc: Christoph Hellwig, Marek Szyprowski, Robin Murphy, Joerg Roedel,
Will Deacon, Rafael J. Wysocki, Magnus Karlsson,
nex.sw.ncis.osdt.itp.upstreaming, bpf, netdev, iommu,
linux-kernel
From: Alexander Lobakin <aleksander.lobakin@intel.com>
Date: Tue, 23 Apr 2024 15:58:31 +0200
> We can save a couple more function calls in the Page Pool code if we
> check for dma_need_sync() earlier, just when we test pp->p.dma_sync.
> Move both these checks into an inline wrapper and call the PP wrapper
> over the generic DMA sync function only when both are true.
> You can't cache the result of dma_need_sync() in &page_pool, as it may
> change anytime if an SWIOTLB buffer is allocated or mapped.
>
> Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
> ---
> net/core/page_pool.c | 31 +++++++++++++++++--------------
> 1 file changed, 17 insertions(+), 14 deletions(-)
>
> diff --git a/net/core/page_pool.c b/net/core/page_pool.c
> index 6cf26a68fa91..87319c6365e0 100644
> --- a/net/core/page_pool.c
> +++ b/net/core/page_pool.c
> @@ -398,16 +398,24 @@ static struct page *__page_pool_get_cached(struct page_pool *pool)
> return page;
> }
>
> -static void page_pool_dma_sync_for_device(const struct page_pool *pool,
> - const struct page *page,
> - unsigned int dma_sync_size)
> +static void __page_pool_dma_sync_for_device(const struct page_pool *pool,
> + const struct page *page,
> + u32 dma_sync_size)
> {
> dma_addr_t dma_addr = page_pool_get_dma_addr(page);
>
> dma_sync_size = min(dma_sync_size, pool->p.max_len);
> - dma_sync_single_range_for_device(pool->p.dev, dma_addr,
> - pool->p.offset, dma_sync_size,
> - pool->p.dma_dir);
> + __dma_sync_single_for_device(pool->p.dev, dma_addr + pool->p.offset,
> + dma_sync_size, pool->p.dma_dir);
Breh, this breaks builds on !DMA_NEED_SYNC systems, as this function
isn't defined there, and my CI didn't catch it in time... I'll ifdef
this in the next spin after some reviews for this one.
> +}
> +
> +static __always_inline void
> +page_pool_dma_sync_for_device(const struct page_pool *pool,
> + const struct page *page,
> + u32 dma_sync_size)
> +{
> + if (pool->dma_sync && dma_dev_need_sync(pool->p.dev))
> + __page_pool_dma_sync_for_device(pool, page, dma_sync_size);
> }
>
> static bool page_pool_dma_map(struct page_pool *pool, struct page *page)
> @@ -429,8 +437,7 @@ static bool page_pool_dma_map(struct page_pool *pool, struct page *page)
> if (page_pool_set_dma_addr(page, dma))
> goto unmap_failed;
>
> - if (pool->dma_sync)
> - page_pool_dma_sync_for_device(pool, page, pool->p.max_len);
> + page_pool_dma_sync_for_device(pool, page, pool->p.max_len);
>
> return true;
>
> @@ -699,9 +706,7 @@ __page_pool_put_page(struct page_pool *pool, struct page *page,
> if (likely(__page_pool_page_can_be_recycled(page))) {
> /* Read barrier done in page_ref_count / READ_ONCE */
>
> - if (pool->dma_sync)
> - page_pool_dma_sync_for_device(pool, page,
> - dma_sync_size);
> + page_pool_dma_sync_for_device(pool, page, dma_sync_size);
>
> if (allow_direct && page_pool_recycle_in_cache(page, pool))
> return NULL;
> @@ -840,9 +845,7 @@ static struct page *page_pool_drain_frag(struct page_pool *pool,
> return NULL;
>
> if (__page_pool_page_can_be_recycled(page)) {
> - if (pool->dma_sync)
> - page_pool_dma_sync_for_device(pool, page, -1);
> -
> + page_pool_dma_sync_for_device(pool, page, -1);
> return page;
> }
Thanks,
Olek
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH net-next v4 6/7] page_pool: check for DMA sync shortcut earlier
2024-04-24 8:52 ` Alexander Lobakin
@ 2024-04-26 5:02 ` Christoph Hellwig
2024-05-02 5:58 ` Christoph Hellwig
2024-05-02 15:49 ` Robin Murphy
1 sibling, 1 reply; 15+ messages in thread
From: Christoph Hellwig @ 2024-04-26 5:02 UTC (permalink / raw)
To: Alexander Lobakin
Cc: David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni,
Christoph Hellwig, Marek Szyprowski, Robin Murphy, Joerg Roedel,
Will Deacon, Rafael J. Wysocki, Magnus Karlsson,
nex.sw.ncis.osdt.itp.upstreaming, bpf, netdev, iommu,
linux-kernel
On Wed, Apr 24, 2024 at 10:52:49AM +0200, Alexander Lobakin wrote:
> Breh, this breaks builds on !DMA_NEED_SYNC systems, as this function
> isn't defined there, and my CI didn't catch it in time... I'll ifdef
> this in the next spin after some reviews for this one.
I looked over the dma-mapping parts of the series and it looks fine
to me. So please resend as the fixed up version as soon as you fine
time for it.
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH net-next v4 6/7] page_pool: check for DMA sync shortcut earlier
2024-04-26 5:02 ` Christoph Hellwig
@ 2024-05-02 5:58 ` Christoph Hellwig
2024-05-06 9:38 ` Alexander Lobakin
0 siblings, 1 reply; 15+ messages in thread
From: Christoph Hellwig @ 2024-05-02 5:58 UTC (permalink / raw)
To: Alexander Lobakin
Cc: David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni,
Christoph Hellwig, Marek Szyprowski, Robin Murphy, Joerg Roedel,
Will Deacon, Rafael J. Wysocki, Magnus Karlsson,
nex.sw.ncis.osdt.itp.upstreaming, bpf, netdev, iommu,
linux-kernel
Hi Alexander,
do you have time to resend the series? I'd love to merge it for
6.10 if I can get the updated version ASAP.
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH net-next v4 6/7] page_pool: check for DMA sync shortcut earlier
2024-04-24 8:52 ` Alexander Lobakin
2024-04-26 5:02 ` Christoph Hellwig
@ 2024-05-02 15:49 ` Robin Murphy
2024-05-06 9:40 ` Alexander Lobakin
1 sibling, 1 reply; 15+ messages in thread
From: Robin Murphy @ 2024-05-02 15:49 UTC (permalink / raw)
To: Alexander Lobakin, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni
Cc: Christoph Hellwig, Marek Szyprowski, Joerg Roedel, Will Deacon,
Rafael J. Wysocki, Magnus Karlsson,
nex.sw.ncis.osdt.itp.upstreaming, bpf, netdev, iommu,
linux-kernel
On 24/04/2024 9:52 am, Alexander Lobakin wrote:
> From: Alexander Lobakin <aleksander.lobakin@intel.com>
> Date: Tue, 23 Apr 2024 15:58:31 +0200
>
>> We can save a couple more function calls in the Page Pool code if we
>> check for dma_need_sync() earlier, just when we test pp->p.dma_sync.
>> Move both these checks into an inline wrapper and call the PP wrapper
>> over the generic DMA sync function only when both are true.
>> You can't cache the result of dma_need_sync() in &page_pool, as it may
>> change anytime if an SWIOTLB buffer is allocated or mapped.
>>
>> Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
>> ---
>> net/core/page_pool.c | 31 +++++++++++++++++--------------
>> 1 file changed, 17 insertions(+), 14 deletions(-)
>>
>> diff --git a/net/core/page_pool.c b/net/core/page_pool.c
>> index 6cf26a68fa91..87319c6365e0 100644
>> --- a/net/core/page_pool.c
>> +++ b/net/core/page_pool.c
>> @@ -398,16 +398,24 @@ static struct page *__page_pool_get_cached(struct page_pool *pool)
>> return page;
>> }
>>
>> -static void page_pool_dma_sync_for_device(const struct page_pool *pool,
>> - const struct page *page,
>> - unsigned int dma_sync_size)
>> +static void __page_pool_dma_sync_for_device(const struct page_pool *pool,
>> + const struct page *page,
>> + u32 dma_sync_size)
>> {
>> dma_addr_t dma_addr = page_pool_get_dma_addr(page);
>>
>> dma_sync_size = min(dma_sync_size, pool->p.max_len);
>> - dma_sync_single_range_for_device(pool->p.dev, dma_addr,
>> - pool->p.offset, dma_sync_size,
>> - pool->p.dma_dir);
>> + __dma_sync_single_for_device(pool->p.dev, dma_addr + pool->p.offset,
>> + dma_sync_size, pool->p.dma_dir);
>
> Breh, this breaks builds on !DMA_NEED_SYNC systems, as this function
> isn't defined there, and my CI didn't catch it in time... I'll ifdef
> this in the next spin after some reviews for this one.
Hmm, the way things have ended up, do we even need this change? (Other
than factoring out the pool->dma_sync check, which is clearly nice)
Since __page_pool_dma_sync_for_device() is never called directly, the
flow we always get is:
page_pool_dma_sync_for_device()
dma_dev_need_sync()
__page_pool_dma_sync_for_device()
... // a handful of trivial arithmetic
__dma_sync_single_for_device()
i.e. still effectively the same order of
"if (dma_dev_need_sync()) __dma_sync()" invocations as if we'd just used
the standard dma_sync(), so referencing the unwrapped internals only
spreads it out a bit more for no real benefit. As an experiment I tried
the diff below on top, effectively undoing this problematic part, and it
doesn't seem to make any appreciable difference in a before-and-after
comparison of the object code, at least for my arm64 build.
Thanks,
Robin.
----->8-----
diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index 27f3b6db800e..b8ab7d4ca229 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c
@@ -398,24 +398,20 @@ static struct page *__page_pool_get_cached(struct page_pool *pool)
return page;
}
-static void __page_pool_dma_sync_for_device(const struct page_pool *pool,
- const struct page *page,
- u32 dma_sync_size)
-{
- dma_addr_t dma_addr = page_pool_get_dma_addr(page);
-
- dma_sync_size = min(dma_sync_size, pool->p.max_len);
- __dma_sync_single_for_device(pool->p.dev, dma_addr + pool->p.offset,
- dma_sync_size, pool->p.dma_dir);
-}
-
static __always_inline void
page_pool_dma_sync_for_device(const struct page_pool *pool,
const struct page *page,
u32 dma_sync_size)
{
- if (pool->dma_sync && dma_dev_need_sync(pool->p.dev))
- __page_pool_dma_sync_for_device(pool, page, dma_sync_size);
+ dma_addr_t dma_addr = page_pool_get_dma_addr(page);
+
+ if (!pool->dma_sync)
+ return;
+
+ dma_sync_size = min(dma_sync_size, pool->p.max_len);
+ dma_sync_single_range_for_device(pool->p.dev, dma_addr,
+ pool->p.offset, dma_sync_size,
+ pool->p.dma_dir);
}
static bool page_pool_dma_map(struct page_pool *pool, struct page *page)
^ permalink raw reply related [flat|nested] 15+ messages in thread
* Re: [PATCH net-next v4 6/7] page_pool: check for DMA sync shortcut earlier
2024-05-02 5:58 ` Christoph Hellwig
@ 2024-05-06 9:38 ` Alexander Lobakin
2024-05-06 9:43 ` Christoph Hellwig
0 siblings, 1 reply; 15+ messages in thread
From: Alexander Lobakin @ 2024-05-06 9:38 UTC (permalink / raw)
To: Christoph Hellwig
Cc: David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni,
Marek Szyprowski, Robin Murphy, Joerg Roedel, Will Deacon,
Rafael J. Wysocki, Magnus Karlsson,
nex.sw.ncis.osdt.itp.upstreaming, bpf, netdev, iommu,
linux-kernel
From: Christoph Hellwig <hch@lst.de>
Date: Thu, 2 May 2024 07:58:55 +0200
> Hi Alexander,
>
> do you have time to resend the series? I'd love to merge it for
> 6.10 if I can get the updated version ASAP.
Hi!
Sorry, I was on a small vacation.
Do I still have a chance to get this into 6.10?
Thanks,
Olek
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH net-next v4 6/7] page_pool: check for DMA sync shortcut earlier
2024-05-02 15:49 ` Robin Murphy
@ 2024-05-06 9:40 ` Alexander Lobakin
0 siblings, 0 replies; 15+ messages in thread
From: Alexander Lobakin @ 2024-05-06 9:40 UTC (permalink / raw)
To: Robin Murphy
Cc: David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni,
Christoph Hellwig, Marek Szyprowski, Joerg Roedel, Will Deacon,
Rafael J. Wysocki, Magnus Karlsson,
nex.sw.ncis.osdt.itp.upstreaming, bpf, netdev, iommu,
linux-kernel
From: Robin Murphy <robin.murphy@arm.com>
Date: Thu, 2 May 2024 16:49:48 +0100
> On 24/04/2024 9:52 am, Alexander Lobakin wrote:
>> From: Alexander Lobakin <aleksander.lobakin@intel.com>
>> Date: Tue, 23 Apr 2024 15:58:31 +0200
>>
>>> We can save a couple more function calls in the Page Pool code if we
>>> check for dma_need_sync() earlier, just when we test pp->p.dma_sync.
>>> Move both these checks into an inline wrapper and call the PP wrapper
>>> over the generic DMA sync function only when both are true.
>>> You can't cache the result of dma_need_sync() in &page_pool, as it may
>>> change anytime if an SWIOTLB buffer is allocated or mapped.
>>>
>>> Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
>>> ---
>>> net/core/page_pool.c | 31 +++++++++++++++++--------------
>>> 1 file changed, 17 insertions(+), 14 deletions(-)
>>>
>>> diff --git a/net/core/page_pool.c b/net/core/page_pool.c
>>> index 6cf26a68fa91..87319c6365e0 100644
>>> --- a/net/core/page_pool.c
>>> +++ b/net/core/page_pool.c
>>> @@ -398,16 +398,24 @@ static struct page
>>> *__page_pool_get_cached(struct page_pool *pool)
>>> return page;
>>> }
>>> -static void page_pool_dma_sync_for_device(const struct page_pool
>>> *pool,
>>> - const struct page *page,
>>> - unsigned int dma_sync_size)
>>> +static void __page_pool_dma_sync_for_device(const struct page_pool
>>> *pool,
>>> + const struct page *page,
>>> + u32 dma_sync_size)
>>> {
>>> dma_addr_t dma_addr = page_pool_get_dma_addr(page);
>>> dma_sync_size = min(dma_sync_size, pool->p.max_len);
>>> - dma_sync_single_range_for_device(pool->p.dev, dma_addr,
>>> - pool->p.offset, dma_sync_size,
>>> - pool->p.dma_dir);
>>> + __dma_sync_single_for_device(pool->p.dev, dma_addr +
>>> pool->p.offset,
>>> + dma_sync_size, pool->p.dma_dir);
>>
>> Breh, this breaks builds on !DMA_NEED_SYNC systems, as this function
>> isn't defined there, and my CI didn't catch it in time... I'll ifdef
>> this in the next spin after some reviews for this one.
>
> Hmm, the way things have ended up, do we even need this change? (Other
> than factoring out the pool->dma_sync check, which is clearly nice)
>
> Since __page_pool_dma_sync_for_device() is never called directly, the
> flow we always get is:
>
> page_pool_dma_sync_for_device()
> dma_dev_need_sync()
> __page_pool_dma_sync_for_device()
> ... // a handful of trivial arithmetic
> __dma_sync_single_for_device()
>
> i.e. still effectively the same order of
> "if (dma_dev_need_sync()) __dma_sync()" invocations as if we'd just used
> the standard dma_sync(), so referencing the unwrapped internals only
> spreads it out a bit more for no real benefit. As an experiment I tried
> the diff below on top, effectively undoing this problematic part, and it
> doesn't seem to make any appreciable difference in a before-and-after
> comparison of the object code, at least for my arm64 build.
>
> Thanks,
> Robin.
>
> ----->8-----
> diff --git a/net/core/page_pool.c b/net/core/page_pool.c
> index 27f3b6db800e..b8ab7d4ca229 100644
> --- a/net/core/page_pool.c
> +++ b/net/core/page_pool.c
> @@ -398,24 +398,20 @@ static struct page *__page_pool_get_cached(struct
> page_pool *pool)
> return page;
> }
>
> -static void __page_pool_dma_sync_for_device(const struct page_pool *pool,
> - const struct page *page,
> - u32 dma_sync_size)
> -{
> - dma_addr_t dma_addr = page_pool_get_dma_addr(page);
> -
> - dma_sync_size = min(dma_sync_size, pool->p.max_len);
> - __dma_sync_single_for_device(pool->p.dev, dma_addr + pool->p.offset,
> - dma_sync_size, pool->p.dma_dir);
> -}
> -
> static __always_inline void
So this would unconditionally inline the whole sync code into the call
sites, while I wanted to give a chance for the compilers to uninline
__page_pool_dma_sync_for_device().
> page_pool_dma_sync_for_device(const struct page_pool *pool,
> const struct page *page,
> u32 dma_sync_size)
> {
> - if (pool->dma_sync && dma_dev_need_sync(pool->p.dev))
> - __page_pool_dma_sync_for_device(pool, page, dma_sync_size);
> + dma_addr_t dma_addr = page_pool_get_dma_addr(page);
> +
> + if (!pool->dma_sync)
> + return;
> +
> + dma_sync_size = min(dma_sync_size, pool->p.max_len);
> + dma_sync_single_range_for_device(pool->p.dev, dma_addr,
> + pool->p.offset, dma_sync_size,
> + pool->p.dma_dir);
> }
>
> static bool page_pool_dma_map(struct page_pool *pool, struct page *page)
Thanks,
Olek
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH net-next v4 6/7] page_pool: check for DMA sync shortcut earlier
2024-05-06 9:38 ` Alexander Lobakin
@ 2024-05-06 9:43 ` Christoph Hellwig
0 siblings, 0 replies; 15+ messages in thread
From: Christoph Hellwig @ 2024-05-06 9:43 UTC (permalink / raw)
To: Alexander Lobakin
Cc: Christoph Hellwig, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Marek Szyprowski, Robin Murphy, Joerg Roedel,
Will Deacon, Rafael J. Wysocki, Magnus Karlsson,
nex.sw.ncis.osdt.itp.upstreaming, bpf, netdev, iommu,
linux-kernel
On Mon, May 06, 2024 at 11:38:17AM +0200, Alexander Lobakin wrote:
> From: Christoph Hellwig <hch@lst.de>
> Date: Thu, 2 May 2024 07:58:55 +0200
>
> > Hi Alexander,
> >
> > do you have time to resend the series? I'd love to merge it for
> > 6.10 if I can get the updated version ASAP.
>
> Hi!
>
> Sorry, I was on a small vacation.
> Do I still have a chance to get this into 6.10?
If I can get it merged by tomorrow, yes.
^ permalink raw reply [flat|nested] 15+ messages in thread
end of thread, other threads:[~2024-05-06 9:43 UTC | newest]
Thread overview: 15+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2024-04-23 13:58 [PATCH net-next v4 0/7] dma: skip calling no-op sync ops when possible Alexander Lobakin
2024-04-23 13:58 ` [PATCH net-next v4 1/7] dma: compile-out DMA sync op calls when not used Alexander Lobakin
2024-04-23 13:58 ` [PATCH net-next v4 2/7] dma: avoid redundant calls for sync operations Alexander Lobakin
2024-04-23 13:58 ` [PATCH net-next v4 3/7] iommu/dma: avoid expensive indirect " Alexander Lobakin
2024-04-23 13:58 ` [PATCH net-next v4 4/7] page_pool: make sure frag API fields don't span between cachelines Alexander Lobakin
2024-04-23 13:58 ` [PATCH net-next v4 5/7] page_pool: don't use driver-set flags field directly Alexander Lobakin
2024-04-23 13:58 ` [PATCH net-next v4 6/7] page_pool: check for DMA sync shortcut earlier Alexander Lobakin
2024-04-24 8:52 ` Alexander Lobakin
2024-04-26 5:02 ` Christoph Hellwig
2024-05-02 5:58 ` Christoph Hellwig
2024-05-06 9:38 ` Alexander Lobakin
2024-05-06 9:43 ` Christoph Hellwig
2024-05-02 15:49 ` Robin Murphy
2024-05-06 9:40 ` Alexander Lobakin
2024-04-23 13:58 ` [PATCH net-next v4 7/7] xsk: use generic DMA sync shortcut instead of a custom one Alexander Lobakin
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