On Thu, Jan 08, 2015 at 09:46:27AM +0100, Vlastimil Babka wrote: > 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. Okay. > > >> 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. Ah... now I see your point and found my mistake. My intention is also to print terminated pfn rather than end_pfn of pageblock. :/ I will change it to print pfn where we terminate scanning. 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>