From: Dave Jiang <dave.jiang@intel.com>
To: dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org,
vkoul@kernel.org
Cc: dan.j.williams@intel.com, tony.luck@intel.com,
jing.lin@intel.com, ashok.raj@intel.com,
sanjay.k.kumar@intel.com, megha.dey@intel.com,
jacob.jun.pan@intel.com, yi.l.liu@intel.com, axboe@kernel.dk,
akpm@linux-foundation.org, tglx@linutronix.de, mingo@redhat.com,
bp@alien8.de, fenghua.yu@intel.com, hpa@zytor.com
Subject: [PATCH RFC v2 12/14] dmaengine: request submit optimization
Date: Thu, 12 Dec 2019 11:25:22 -0700 [thread overview]
Message-ID: <157617512234.42350.12520827545570294790.stgit@djiang5-desk3.ch.intel.com> (raw)
In-Reply-To: <157617487798.42350.4471714981643413895.stgit@djiang5-desk3.ch.intel.com>
Adding dsa direct call to dmaengine for optimization. Spectre-v2 makes
indirect branches expensive. Adding direct call to the driver in order
to mitigate that and reduce cycles to initiate a descriptor submit.
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
drivers/dma/idxd/dma.c | 5 +++--
include/linux/dmaengine.h | 6 +++++-
include/linux/idxd.h | 20 ++++++++++++++++++++
usr/include/Makefile | 1 +
4 files changed, 29 insertions(+), 3 deletions(-)
create mode 100644 include/linux/idxd.h
diff --git a/drivers/dma/idxd/dma.c b/drivers/dma/idxd/dma.c
index 07fbc98668ae..b9b4621e504a 100644
--- a/drivers/dma/idxd/dma.c
+++ b/drivers/dma/idxd/dma.c
@@ -8,6 +8,7 @@
#include <linux/io-64-nonatomic-lo-hi.h>
#include <linux/dmaengine.h>
#include <uapi/linux/idxd.h>
+#include <linux/idxd.h>
#include "../dmaengine.h"
#include "registers.h"
#include "idxd.h"
@@ -29,8 +30,7 @@ void idxd_parse_completion_status(u8 status, enum dmaengine_tx_result *res)
}
}
-static int idxd_dma_submit_request(struct dma_chan *chan,
- struct dma_request *req)
+int idxd_dma_submit_request(struct dma_chan *chan, struct dma_request *req)
{
struct idxd_wq *wq = container_of(chan, struct idxd_wq, dma_chan);
@@ -39,6 +39,7 @@ static int idxd_dma_submit_request(struct dma_chan *chan,
return -EINVAL;
}
+EXPORT_SYMBOL_GPL(idxd_dma_submit_request);
static int idxd_dma_alloc_chan_resources(struct dma_chan *chan)
{
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 220d241d71ed..cebfa8db60a0 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -1395,6 +1395,7 @@ static inline int dma_get_slave_caps(struct dma_chan *chan,
}
#endif
+#include <linux/idxd.h>
/* dmaengine_submit_request - helper routine for caller to submit
* a DMA request.
* @chan: dma channel context
@@ -1412,7 +1413,10 @@ static inline int dmaengine_submit_request(struct dma_chan *chan,
if (!ddev->device_submit_request)
return -EINVAL;
- return ddev->device_submit_request(chan, req);
+ if (ddev->device_submit_request == idxd_dma_submit_request)
+ return idxd_dma_submit_request(chan, req);
+ else
+ return ddev->device_submit_request(chan, req);
}
/* dmaengine_submit_request_and_wait - helper routine for caller to submit
diff --git a/include/linux/idxd.h b/include/linux/idxd.h
new file mode 100644
index 000000000000..4fb26d41a684
--- /dev/null
+++ b/include/linux/idxd.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright(c) 2019 Intel Corporation. All rights rsvd. */
+#ifndef _LINUX_IDXD_H_
+#define _LINUX_IDXD_H_
+
+struct dmaengine_result;
+struct dma_request;
+struct dma_chan;
+
+#if IS_ENABLED(CONFIG_INTEL_IDXD)
+int idxd_dma_submit_request(struct dma_chan *chan, struct dma_request *req);
+#else
+static inline int idxd_dma_submit_request(struct dma_chan *chan,
+ struct dma_request *req)
+{
+ return -EOPNOTSUPP;
+}
+#endif
+
+#endif
diff --git a/usr/include/Makefile b/usr/include/Makefile
index 4a753a48767b..8bfd68bbc777 100644
--- a/usr/include/Makefile
+++ b/usr/include/Makefile
@@ -24,6 +24,7 @@ header-test- += linux/am437x-vpfe.h
header-test- += linux/android/binder.h
header-test- += linux/android/binderfs.h
header-test- += linux/coda.h
+header-test- += linux/iadx.h
header-test- += linux/elfcore.h
header-test- += linux/errqueue.h
header-test- += linux/fsmap.h
next prev parent reply other threads:[~2019-12-12 18:25 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-12 18:24 [PATCH RFC v2 00/14] idxd driver for Intel Data Streaming Accelerator Dave Jiang
2019-12-12 18:24 ` [PATCH RFC v2 01/14] x86/asm: add iosubmit_cmds512() based on movdir64b CPU instruction Dave Jiang
2019-12-12 18:24 ` [PATCH RFC v2 02/14] dmaengine: break out channel registration Dave Jiang
2019-12-12 18:24 ` [PATCH RFC v2 03/14] dmaengine: add new dma device registration Dave Jiang
2019-12-12 18:24 ` [PATCH RFC v2 04/14] mm: create common code from request allocation based from blk-mq code Dave Jiang
2019-12-13 0:43 ` Andrew Morton
2019-12-13 22:06 ` Dave Jiang
2019-12-12 18:24 ` [PATCH RFC v2 05/14] dmaengine: add dma_request support functions Dave Jiang
2019-12-12 18:24 ` [PATCH RFC v2 06/14] dmaengine: add dma request submit and completion path support Dave Jiang
2019-12-12 18:24 ` [PATCH RFC v2 07/14] dmaengine: update dmatest to support dma request Dave Jiang
2019-12-12 18:24 ` [PATCH RFC v2 08/14] dmaengine: idxd: Init and probe for Intel data accelerators Dave Jiang
2019-12-12 18:25 ` [PATCH RFC v2 09/14] dmaengine: idxd: add configuration component of driver Dave Jiang
2019-12-12 18:25 ` [PATCH RFC v2 10/14] dmaengine: idxd: add descriptor manipulation routines Dave Jiang
2019-12-12 18:25 ` [PATCH RFC v2 11/14] dmaengine: idxd: connect idxd to dmaengine subsystem Dave Jiang
2019-12-12 18:25 ` Dave Jiang [this message]
2019-12-12 18:25 ` [PATCH RFC v2 13/14] dmaengine: idxd: add char driver to expose submission portal to userland Dave Jiang
2019-12-12 18:25 ` [PATCH RFC v2 14/14] dmaengine: idxd: add sysfs ABI for idxd driver Dave Jiang
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