On 01/08/2015 09:18 AM, Joonsoo Kim wrote: > On Tue, Jan 06, 2015 at 10:05:39AM +0100, Vlastimil Babka wrote: >> On 12/03/2014 08:52 AM, Joonsoo Kim wrote: >> > It'd be useful to know where the both scanner is start. And, it also be >> > useful to know current range where compaction work. It will help to find >> > odd behaviour or problem on compaction. >> >> Overall it looks good, just two questions: >> 1) Why change the pfn output to hexadecimal with different printf layout and >> change the variable names and? Is it that better to warrant people having to >> potentially modify their scripts parsing the old output? > > Deciaml output has really bad readability since we manage all pages by order > of 2 which is well represented by hexadecimal. With hex output, we can > easily notice whether we move out from one pageblock to another one. OK. I don't have any strong objection, maybe Mel should comment on this as the author of most of the tracepoints? But if it happens, I think converting the old tracepoints to new hexadecimal format should be a separate patch from adding the new ones. >> 2) Would it be useful to also print in the mm_compaction_isolate_template based >> tracepoints, pfn of where the particular scanner left off a block prematurely? >> It doesn't always match start_pfn + nr_scanned. > > With start_pfn and end_pfn, detailed analysis is possible. We can know pageblock > where we actually scan and isolate and how much pages we try in that > pageblock and can guess why it doesn't become freepage with pageblock > order roughly. > > nr_scanned is just different metric. end_pfn don't need to match with > start_pfn + nr_scanned. Well that's part of my point. end_pfn is the end of the pageblock. nr_scanned might be lower than end_pfn - start_pfn, because we terminate in the middle of the pageblock. But it might be also lower, because we e.g. skip higher-order free pages. So we don't recognize where we terminated early. > Thanks. > > -- > 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> > -- 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>