mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-07-27 14:29:59 -04:00
95f44886af
Commit77baa5bafc("sched/cputime: Fix mul_u64_u64_div_u64() precision for cputime") added a clamp in cputime_adjust(): if (unlikely(stime > rtime)) stime = rtime; The justification was that mul_u64_u64_div_u64() could over-approximate on some architectures (notably arm64 and the old 32-bit fallback), so the mathematically impossible stime > rtime was nevertheless reachable and would underflow utime = rtime - stime. That premise no longer holds. Commitb29a62d87c("mul_u64_u64_div_u64: make it precise always") replaced the fallback implementation with an exact 128-bit long division, and the x86_64 inline asm already produced exact results. The helper now returns the mathematically correct floor(a*b/d) on every architecture, so stime <= rtime is guaranteed by stime <= stime + utime and the clamp is dead code. Remove it along with its stale comment. Signed-off-by: Nicolas Pitre <nico@fluxnic.net> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://patch.msgid.link/20260514202629.673539-1-nico@fluxnic.net