From 909a3f0e9d8b0d8001cf6e99808f88eca8e44328 Mon Sep 17 00:00:00 2001 From: Cheng Lingfei Date: Mon, 24 Aug 2026 20:45:46 +0800 Subject: docs: cgroup-v2: fix misc.events key format description MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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., ".max"). Update the documentation to clarify that the entry key is ".max". Suggested-by: Michal Koutný Signed-off-by: Cheng Lingfei Signed-off-by: Tejun Heo --- lib/memweight.c | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) create mode 100644 lib/memweight.c (limited to 'lib/memweight.c') diff --git a/lib/memweight.c b/lib/memweight.c new file mode 100644 index 000000000..94dd72cca --- /dev/null +++ b/lib/memweight.c @@ -0,0 +1,39 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include + +/** + * memweight - count the total number of bits set in memory area + * @ptr: pointer to the start of the area + * @bytes: the size of the area + */ +size_t memweight(const void *ptr, size_t bytes) +{ + size_t ret = 0; + size_t longs; + const unsigned char *bitmap = ptr; + + for (; bytes > 0 && ((unsigned long)bitmap) % sizeof(long); + bytes--, bitmap++) + ret += hweight8(*bitmap); + + longs = bytes / sizeof(long); + if (longs) { + BUG_ON(longs >= INT_MAX / BITS_PER_LONG); + ret += bitmap_weight((unsigned long *)bitmap, + longs * BITS_PER_LONG); + bytes -= longs * sizeof(long); + bitmap += longs * sizeof(long); + } + /* + * The reason that this last loop is distinct from the preceding + * bitmap_weight() call is to compute 1-bits in the last region smaller + * than sizeof(long) properly on big-endian systems. + */ + for (; bytes > 0; bytes--, bitmap++) + ret += hweight8(*bitmap); + + return ret; +} +EXPORT_SYMBOL(memweight); -- cgit v1.3.1