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        Ingo Molnar <mingo@kernel.org>,
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        "Arnaldo Carvalho de Melo" <acme@redhat.com>,
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        Thomas Gleixner <tglx@linutronix.de>,
        <wanghaibin.wang@huawei.com>, <yezengruan@huawei.com>,
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Subject: [RFC PATCH v3 2/8] tools headers: Add a macro to get HUGETLB page sizes for mmap
Date:   Mon, 1 Mar 2021 14:59:10 +0800
Message-ID: <20210301065916.11484-3-wangyanan55@huawei.com>
In-Reply-To: <20210301065916.11484-1-wangyanan55@huawei.com>
References: <20210301065916.11484-1-wangyanan55@huawei.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

We know that if a system supports multiple hugetlb page sizes,
the desired hugetlb page size can be specified in bits [26:31]
of the flag arguments. The value in these 6 bits will be the
shift of each hugetlb page size.

So add a macro to get the page size shift and then calculate the
corresponding hugetlb page size, using flag x.

Cc: Ben Gardon <bgardon@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Suggested-by: Ben Gardon <bgardon@google.com>
Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
---
 include/uapi/linux/mman.h       | 2 ++
 tools/include/uapi/linux/mman.h | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/include/uapi/linux/mman.h b/include/uapi/linux/mman.h
index f55bc680b5b0..8bd41128a0ee 100644
--- a/include/uapi/linux/mman.h
+++ b/include/uapi/linux/mman.h
@@ -41,4 +41,6 @@
 #define MAP_HUGE_2GB	HUGETLB_FLAG_ENCODE_2GB
 #define MAP_HUGE_16GB	HUGETLB_FLAG_ENCODE_16GB
 
+#define MAP_HUGE_PAGE_SIZE(x) (1 << ((x >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK))
+
 #endif /* _UAPI_LINUX_MMAN_H */
diff --git a/tools/include/uapi/linux/mman.h b/tools/include/uapi/linux/mman.h
index f55bc680b5b0..8bd41128a0ee 100644
--- a/tools/include/uapi/linux/mman.h
+++ b/tools/include/uapi/linux/mman.h
@@ -41,4 +41,6 @@
 #define MAP_HUGE_2GB	HUGETLB_FLAG_ENCODE_2GB
 #define MAP_HUGE_16GB	HUGETLB_FLAG_ENCODE_16GB
 
+#define MAP_HUGE_PAGE_SIZE(x) (1 << ((x >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK))
+
 #endif /* _UAPI_LINUX_MMAN_H */
-- 
2.23.0