On Fri, Sep 04, 2015 at 12:44:59PM -0400, Rik van Riel wrote: > On 09/04/2015 12:07 PM, Vlastimil Babka wrote: > > On 09/03/2015 10:51 PM, Ebru Akagunduz wrote: > >> Using static tracepoints, data of functions is recorded. > >> It is good to automatize debugging without doing a lot > >> of changes in the source code. > >> > >> This patch adds tracepoint for khugepaged_scan_pmd, > >> collapse_huge_page and __collapse_huge_page_isolate. > >> > >> Signed-off-by: Ebru Akagunduz <ebru.akagunduz@xxxxxxxxx> > >> Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> > >> Acked-by: Rik van Riel <riel@xxxxxxxxxx> > >> --- > >> Changes in v2: > >> - Nothing changed > >> > >> Changes in v3: > >> - Print page address instead of vm_start (Vlastimil Babka) > >> - Define constants to specify exact tracepoint result (Vlastimil Babka) > >> > >> Changes in v4: > >> - Change the constant prefix with SCAN_ instead of MM_ (Vlastimil Babka) > >> - Move the constants into the enum (Vlastimil Babka) > >> - Move the constants from mm.h to huge_memory.c > >> (because only will be used in huge_memory.c) (Vlastimil Babka) > >> - Print pfn in tracepoints (Vlastimil Babka) > >> - Print scan result as string in tracepoint (Vlastimil Babka) > >> (I tried to make same things to print string like mm/compaction.c. > >> My patch does not print string, I skip something but could not see why) > > > > How do you print the trace? Do you cat /sys/kernel/debug/tracing/trace_pipe > > or use some tool such as trace-cmd? I have just recently realized that tools > > don't print strings in the compaction tracepoints, which lead to a patch [1]. > > You could convert this patch in the same way and then it should work with > > tracing tools. Sorry for previously suggesting a wrong example to follow. > > > > [1] https://lkml.org/lkml/2015/8/27/373 I use perf tool to test changes. > > Well that explains why doing the same thing as compaction.c > resulted in the strings not being printed! Ebru and I got > confused over that for quite a while :) > > Thanks for pointing us to the fix. > > Ebru, can you use tracepoint macros like in Vlastimil's patch > above, so your tracepoints work? > I did similar changes with Vlastimil's patch. It works! Thanks, Ebru -- 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>