Messages in this thread | | | Date | Sun, 8 Oct 2023 13:36:03 +0200 | From | Oleg Nesterov <> | Subject | Re: [PATCH] blk-throttle: Calculate allowed value only when the throttle is enabled |
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On 10/08, Yu Kuai wrote: > > >> static u64 calculate_bytes_allowed(u64 bps_limit, unsigned long > >>jiffy_elapsed) > >> { > >>+ if (jiffy_elapsed > HZ && > >>+ bps_limit > mul_u64_u64_div_u64(U64_MAX, (u64)HZ, > >>(u64)jiffy_elapsed); > >>+ return U64_MAX; > >>+ > > > >I can't suggest anything better... > > > >but I do not know if it is possible that HZ > jiffy_elapsed. If yes, then > >mul_u64_u64_div_u64() above is not safe too. > > Well, 'jiffy_elapsed > HZ' is judged before mul_u64_u64_div_u64().
Yes, sorry, somehow I didn't notice this check.
Oleg.
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