On 11/27/2023 12:38 PM, Christoph Hellwig wrote: > On Tue, Nov 14, 2023 at 01:40:56PM -0800, Bart Van Assche wrote: >> - case WRITE_LIFE_SHORT: >> + case WRITE_LIFE_2: >> return CURSEG_HOT_DATA; >> - case WRITE_LIFE_EXTREME: >> + case WRITE_LIFE_5: >> return CURSEG_COLD_DATA; >> default: >> return CURSEG_WARM_DATA; > > A WRITE_LIFE_2 constant is strictly more confusing than just using 2, > so this patch makes no sense whatsoever. > > More importantly these constant have been around forever, so we'd better > have a really good argument for changing them. How about this argument (assuming you may not have seen) from previous iteration [1]- "Does it make sense to do away with these, and have temperature-neutral names instead e.g., WRITE_LIFE_1, WRITE_LIFE_2? With the current choice: - If the count goes up (beyond 5 hints), infra can scale fine but these names do not. Imagine ULTRA_EXTREME after EXTREME. - Applications or in-kernel users can specify LONG hint with data that actually has a SHORT lifetime. Nothing really ensures that LONG is really LONG. Temperature-neutral names seem more generic/scalable and do not present the unnecessary need to be accurate with relative temperatures." [1] https://lore.kernel.org/linux-block/b3058ce6-e297-b4c3-71d4-4b76f76439ba@xxxxxxxxxxx/
