Messages in this thread | | | Date | Fri, 22 Jul 2022 10:31:24 +0800 | Subject | Re: [PATCH] USB: HCD: Fix URB giveback issue in tasklet function | From | "" <> |
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On 2022/7/21 21:50, Alan Stern wrote: > On Thu, Jul 21, 2022 at 02:08:33PM +0800, Weitao Wang wrote: >> Usb core introduce the mechanism of giveback of URB in tasklet context to >> reduce hardware interrupt handling time. On some test situation(such as >> FIO with 4KB block size), when tasklet callback function called to >> giveback URB, interrupt handler add URB node to the bh->head list also. >> If check bh->head list again after finish all URB giveback of local_list, >> then it may introduce a "dynamic balance" between giveback URB and add URB >> to bh->head list. This tasklet callback function may not exit for a long >> time, which will cause other tasklet function calls to be delayed. Some >> real-time applications(such as KB and Mouse) will see noticeable lag. >> >> Fix this issue by taking new URBs giveback in next tasklet function call. > > The patch also replaces the local high_prio_bh variable with a new > bh->high_prio structure member. This should be mentioned in the patch > description. > > Alan Stern > . Okay,I will take your suggestion and submit a revised version.
Thanks weitao
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