On 6/30/21 4:10 PM, Pavel Begunkov wrote: > On 6/30/21 10:56 PM, Jens Axboe wrote: >> On 6/30/21 3:45 PM, Jens Axboe wrote: >>> On 6/30/21 3:38 PM, Pavel Begunkov wrote: >>>> On 6/30/21 10:22 PM, Jens Axboe wrote: >>>>> On 6/30/21 3:19 PM, Pavel Begunkov wrote: >>>>>> On 6/30/21 10:17 PM, Jens Axboe wrote: >>>>>>> On 6/30/21 2:54 PM, Pavel Begunkov wrote: >>>>>>>> Whenever possible we don't want to fallback a request. task_work_add() >>>>>>>> will be fine if the task is exiting, so don't check for PF_EXITING, >>>>>>>> there is anyway only a relatively small gap between setting the flag >>>>>>>> and doing the final task_work_run(). >>>>>>>> >>>>>>>> Also add likely for the hot path. >>>>>>> >>>>>>> I'm not a huge fan of likely/unlikely, and in particular constructs like: >>>>>>> >>>>>>>> - if (test_bit(0, &tctx->task_state) || >>>>>>>> + if (likely(test_bit(0, &tctx->task_state)) || >>>>>>>> test_and_set_bit(0, &tctx->task_state)) >>>>>>>> return 0; >>>>>>> >>>>>>> where the state is combined. In any case, it should be a separate >>>>>>> change. If there's an "Also" paragraph in a patch, then that's also >>>>>>> usually a good clue that that particular change should've been >>>>>>> separate :-) >>>>>> >>>>>> Not sure what's wrong with likely above, but how about drop >>>>>> this one then? >>>>> >>>>> Yep I did - we can do the exiting change separately, the commit message >>>> >>>> I think 1-2 is good enough for 5.14, I'll just send it for-next >>>> >>>>> just needs to be clarified a bit on why it's ok to do now. And that >>>> >>>> It should have been ok to do before those 2 patches, but >>>> haven't tracked where it lost actuality. >>> >>> Right, I was thinking it was related to the swapping of the signal >>> exit and task work run ordering. But didn't look that far yet... >> >> BTW, in usual testing, even just the one hunk removing the exit check >> seems to result in quite a lot of memory leaks running >> test/poll-mshot-update. So something is funky with the patch. > > I guess you're positive that patches 1-2 have nothing to do > with that. Right? I double checked, and seems fine with those two alone. Ran the test twice, saw massive amounts of leaks with patches 1-3, and none with patches 1-2 only. -- Jens Axboe
