Michal Hocko wrote: > On Thu 09-11-17 10:34:46, peter enderborg wrote: > > On 11/09/2017 09:52 AM, Michal Hocko wrote: > > > I am not sure. I would rather see a tracepoint to mark the allocator > > > entry. This would allow both 1) measuring the allocation latency (to > > > compare it to the trace_mm_page_alloc and 2) check for stalls with > > > arbitrary user defined timeout (just print all allocations which haven't > > > passed trace_mm_page_alloc for the given amount of time). > > > > Traces are not that expensive, but there are more than few in calls > > in this path. And Im trying to keep it as small that it can used for > > maintenance versions too. > > > > This is suggestion is a quick way of keeping the current solution for > > the ones that are interested the slow allocations. If we are going > > for a solution with a time-out parameter from the user what interface > > do you suggest to do this configuration. A filter parameter for the > > event? > > I meant to do all that in postprocessing. So no specific API is needed, > just parse the output. Anyway, it seems that the printk will be put in > shape in a forseeable future so we might preserve the stall warning > after all. It is the show_mem part which is interesting during that > warning. I don't know whether printk() will be put in shape in a foreseeable future. The rule that "do not try to printk() faster than the kernel can write to consoles" will remain no matter how printk() changes. Unless asynchronous approach like https://lwn.net/Articles/723447/ is used, I think we can't obtain useful information. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
