From aeb709c767aeca996e6011133e4f7bdb2a4af652 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Wed, 30 Sep 2026 09:59:20 +0000 Subject: selftests/bpf: Add a test for objects stuck in free_by_rcu_ttrace Delete all elements of BPF_F_NO_PREALLOC hash map in one batch. The first free_bulk() starts RCU tasks trace GP and the rest of the elements are freed while it's in flight. Wait for call_rcu_ttrace_in_progress to clear in bpf_mem_cache of every cpu and check that free_by_rcu_ttrace and waiting_for_gp_ttrace lists are empty. Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20260930095920.601738-4-alexei.starovoitov@gmail.com Signed-off-by: Kumar Kartikeya Dwivedi --- tools/lib/hweight.c | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 63 insertions(+) create mode 100644 tools/lib/hweight.c (limited to 'tools/lib/hweight.c') diff --git a/tools/lib/hweight.c b/tools/lib/hweight.c new file mode 100644 index 000000000..a16ebf515 --- /dev/null +++ b/tools/lib/hweight.c @@ -0,0 +1,63 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include + +/** + * hweightN - returns the hamming weight of a N-bit word + * @x: the word to weigh + * + * The Hamming Weight of a number is the total number of bits set in it. + */ + +unsigned int __sw_hweight32(unsigned int w) +{ +#ifdef CONFIG_ARCH_HAS_FAST_MULTIPLIER + w -= (w >> 1) & 0x55555555; + w = (w & 0x33333333) + ((w >> 2) & 0x33333333); + w = (w + (w >> 4)) & 0x0f0f0f0f; + return (w * 0x01010101) >> 24; +#else + unsigned int res = w - ((w >> 1) & 0x55555555); + res = (res & 0x33333333) + ((res >> 2) & 0x33333333); + res = (res + (res >> 4)) & 0x0F0F0F0F; + res = res + (res >> 8); + return (res + (res >> 16)) & 0x000000FF; +#endif +} + +unsigned int __sw_hweight16(unsigned int w) +{ + unsigned int res = w - ((w >> 1) & 0x5555); + res = (res & 0x3333) + ((res >> 2) & 0x3333); + res = (res + (res >> 4)) & 0x0F0F; + return (res + (res >> 8)) & 0x00FF; +} + +unsigned int __sw_hweight8(unsigned int w) +{ + unsigned int res = w - ((w >> 1) & 0x55); + res = (res & 0x33) + ((res >> 2) & 0x33); + return (res + (res >> 4)) & 0x0F; +} + +unsigned long __sw_hweight64(__u64 w) +{ +#if BITS_PER_LONG == 32 + return __sw_hweight32((unsigned int)(w >> 32)) + + __sw_hweight32((unsigned int)w); +#elif BITS_PER_LONG == 64 +#ifdef CONFIG_ARCH_HAS_FAST_MULTIPLIER + w -= (w >> 1) & 0x5555555555555555ul; + w = (w & 0x3333333333333333ul) + ((w >> 2) & 0x3333333333333333ul); + w = (w + (w >> 4)) & 0x0f0f0f0f0f0f0f0ful; + return (w * 0x0101010101010101ul) >> 56; +#else + __u64 res = w - ((w >> 1) & 0x5555555555555555ul); + res = (res & 0x3333333333333333ul) + ((res >> 2) & 0x3333333333333333ul); + res = (res + (res >> 4)) & 0x0F0F0F0F0F0F0F0Ful; + res = res + (res >> 8); + res = res + (res >> 16); + return (res + (res >> 32)) & 0x00000000000000FFul; +#endif +#endif +} -- cgit v1.3.1