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From: Yunsheng Lin <linyunsheng@huawei.com>
To: <davem@davemloft.net>, <kuba@kernel.org>, <mst@redhat.com>,
	<jasowang@redhat.com>
Cc: <nickhu@andestech.com>, <green.hu@gmail.com>,
	<deanbo422@gmail.com>, <akpm@linux-foundation.org>,
	<yury.norov@gmail.com>, <andriy.shevchenko@linux.intel.com>,
	<ojeda@kernel.org>, <ndesaulniers@gooogle.com>, <joe@perches.com>,
	<linux-kernel@vger.kernel.org>,
	<virtualization@lists.linux-foundation.org>,
	<netdev@vger.kernel.org>, <linuxarm@openeuler.org>
Subject: [PATCH v2 1/4] tools headers UAPI: add cache aligning related macro
Date: Tue, 20 Jul 2021 10:21:46 +0800	[thread overview]
Message-ID: <1626747709-34013-2-git-send-email-linyunsheng@huawei.com> (raw)
In-Reply-To: <1626747709-34013-1-git-send-email-linyunsheng@huawei.com>

____cacheline_aligned_in_smp macro is needed to avoid
cache bouncing in SMP system, which is used in ptr_ring
lib.

So add the related macro in order to bulid ptr_ring from
user space.

As SMP_CACHE_BYTES is 64 bytes for arm64 and most of x86
system, so use 64 bytes as the default SMP_CACHE_BYTES if
SMP_CACHE_BYTES is not defined.

Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
---
 tools/include/linux/cache.h | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)
 create mode 100644 tools/include/linux/cache.h

diff --git a/tools/include/linux/cache.h b/tools/include/linux/cache.h
new file mode 100644
index 0000000..df04307
--- /dev/null
+++ b/tools/include/linux/cache.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __TOOLS_LINUX__CACHE_H
+#define __TOOLS_LINUX__CACHE_H
+
+#ifndef CONFIG_SMP
+#define CONFIG_SMP	1
+#endif
+
+#ifndef SMP_CACHE_BYTES
+#define SMP_CACHE_BYTES	64
+#endif
+
+#ifndef ____cacheline_aligned
+#define ____cacheline_aligned __attribute__((__aligned__(SMP_CACHE_BYTES)))
+#endif
+
+#ifndef ____cacheline_aligned_in_smp
+#ifdef CONFIG_SMP
+#define ____cacheline_aligned_in_smp ____cacheline_aligned
+#else
+#define ____cacheline_aligned_in_smp
+#endif /* CONFIG_SMP */
+#endif
+
+#endif /* __LINUX_CACHE_H */
-- 
2.7.4


  reply	other threads:[~2021-07-20  2:38 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-20  2:21 [PATCH v2 0/4] refactor the ringtest testing for ptr_ring Yunsheng Lin
2021-07-20  2:21 ` Yunsheng Lin [this message]
2021-07-20  2:21 ` [PATCH v2 2/4] tools headers UAPI: add kmalloc/vmalloc related interface Yunsheng Lin
2021-07-20  2:21 ` [PATCH v2 3/4] tools headers UAPI: add cpu_relax() implementation for x86 and arm64 Yunsheng Lin
2021-07-21 20:53   ` David Laight
2021-07-22  8:18     ` Yunsheng Lin
2021-07-22  8:45       ` David Laight
2021-07-20  2:21 ` [PATCH v2 4/4] tools/virtio: use common infrastructure to build ptr_ring.h Yunsheng Lin

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