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authorCheng Lingfei <chenglingfei@foxmail.com>2026-08-24 20:45:46 +0800
committerTejun Heo <tj@kernel.org>2026-08-24 06:55:59 -1000
commit909a3f0e9d8b0d8001cf6e99808f88eca8e44328 (patch)
treebe05d18bd5619b55ff3b30f28a292907021768ee /include/asm-generic/bitops/fls64.h
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docs: cgroup-v2: fix misc.events key format descriptiongrafted
In misc cgroup, misc.events does not output a simple "max" key. Instead, each registered misc resource outputs a separate key suffixed with ".max" (i.e., "<res>.max"). Update the documentation to clarify that the entry key is "<res>.max". Suggested-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Cheng Lingfei <chenglingfei@foxmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'include/asm-generic/bitops/fls64.h')
-rw-r--r--include/asm-generic/bitops/fls64.h37
1 files changed, 37 insertions, 0 deletions
diff --git a/include/asm-generic/bitops/fls64.h b/include/asm-generic/bitops/fls64.h
new file mode 100644
index 000000000..b5f58dd26
--- /dev/null
+++ b/include/asm-generic/bitops/fls64.h
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_GENERIC_BITOPS_FLS64_H_
+#define _ASM_GENERIC_BITOPS_FLS64_H_
+
+#include <asm/types.h>
+
+/**
+ * fls64 - find last set bit in a 64-bit word
+ * @x: the word to search
+ *
+ * This is defined in a similar way as the libc and compiler builtin
+ * ffsll, but returns the position of the most significant set bit.
+ *
+ * fls64(value) returns 0 if value is 0 or the position of the last
+ * set bit if value is nonzero. The last (most significant) bit is
+ * at position 64.
+ */
+#if BITS_PER_LONG == 32
+static __always_inline __attribute_const__ int fls64(__u64 x)
+{
+ __u32 h = x >> 32;
+ if (h)
+ return fls(h) + 32;
+ return fls(x);
+}
+#elif BITS_PER_LONG == 64
+static __always_inline __attribute_const__ int fls64(__u64 x)
+{
+ if (x == 0)
+ return 0;
+ return __fls(x) + 1;
+}
+#else
+#error BITS_PER_LONG not 32 or 64
+#endif
+
+#endif /* _ASM_GENERIC_BITOPS_FLS64_H_ */