On 3/2/22 13:12, Olivier Langlois wrote:
On Wed, 2022-03-02 at 02:31 +0800, Hao Xu wrote:+static void io_blocking_napi_busy_loop(struct list_head *napi_list, + struct io_wait_queue *iowq) +{ + unsigned long start_time = + list_is_singular(napi_list) ? 0 : + busy_loop_current_time(); + + do { + if (list_is_singular(napi_list)) { + struct napi_entry *ne = + list_first_entry(napi_list, + struct napi_entry, list); + + napi_busy_loop(ne->napi_id, io_busy_loop_end, iowq, + true, BUSY_POLL_BUDGET); + io_check_napi_entry_timeout(ne); + break; + } + } while (io_napi_busy_loop(napi_list) && + !io_busy_loop_end(iowq, start_time)); +} +How about: if (list is singular) { do something; return; } while (!io_busy_loop_end() && io_napi_busy_loop()) ; Btw, start_time seems not used in singular branch.Hao, it takes me few readings before being able to figure out the idea behind your suggestions. Sorry about that! So, if I get it correctly, you are proposing extract out the singular block out of the while loop... IMHO, this is not a good idea because you could start iterating the do/while loop with a multiple entries list that ends up becoming a singular list after one or few iterations.
My bad, I get your point now.
Check what io_napi_busy_loop() is doing... It does not look like that but a lot thoughts have been put into writing io_blocking_napi_busy_loop()...
True.
