On Thu, 26 May 2011, Andrea Arcangeli wrote: > On Thu, May 26, 2011 at 01:13:58PM -0400, Eric B Munson wrote: > > +#define YES "yes" > > +#define NO "no" > > Upstream 2.6.39 was changed to 0/1, that differs from 2.6.38 :(. It's > probably better to support only 0/1 and let it fail on 2.6.38.
Sounds good.
>
> > +#define TRANS_ENABLE "/sys/kernel/mm/transparent_hugepage/enabled"
>
> This sounds ok if you want hugeadm to be able to tweak everything
> (maybe set madvise mode and then use THP only in a few apps with
> madvise through --trans-madvise).
>
> > +#define TRANS_DEFRAG "/sys/kernel/mm/transparent_hugepage/defrag"
> > +#define KHUGE_DEFRAG
> > "/sys/kernel/mm/transparent_hugepage/khugepaged/defrag"
>
> I'd drop these two, they're too much for debugging, in libhugetlbfs
> context especially I can't see anybody using THP with defrag off that
> turns off compaction and reclaim entirely and just polls the buddy
> allocator. This is more for debugging only, not useful to tweak.
I will remove these two options then.
>
> > +#define KHUGE_SCAN_PAGES
> > "/sys/kernel/mm/transparent_hugepage/khugepaged/pages_to_scan"
> > +#define KHUGE_SCAN_SLEEP
> > "/sys/kernel/mm/transparent_hugepage/khugepaged/scan_sleep_millisecs"
> > +#define KHUGE_ALLOC_SLEEP
> > "/sys/kernel/mm/transparent_hugepage/khugepaged/alloc_sleep_millisecs"
>
> This is useful too. These three plus the "/enabled" are the only 4 I'd
> consider worth tweaking not only for debugging.
>
> > @@ -97,6 +109,20 @@ void print_usage()
> > CONT("Adjust pool 'size' lower bound");
> > OPTION("--obey-mempolicy", "Obey the NUMA memory policy when");
> > CONT("adjusting the pool 'size' lower bound");
> > + OPTION("--trans-always", "Enable transparent huge pages always");
> > + OPTION("--trans-madvise", "Enable transparent huge pages with madvise");
> > + OPTION("--trans-never", "Disable transparent huge pages");
> > + OPTION("--trans-defrag-always", "Don't limit THP defrag");
> > + OPTION("--trans-defrag-madvise", "Limit THP defrag to madvise areas
> > only");
> > + OPTION("--trans-defrag-never", "Disable defrag during THP allocation");
> > + OPTION("--khugepaged-defrag-off", "Disable defrag during THP
> > promotion");
> > + OPTION("--khugepaged-defrag-on", "Enable defrag during THP promotion");
> > + OPTION("--khugepaged-pages <pages to scan>", "Number of pages that
> > khugepaged");
> > + CONT("should scan on each pass");
> > + OPTION("--khugepaged-scan-sleep <milliseconds>", "Time in ms to sleep
> > between");
> > + CONT("khugepaged passes");
> > + OPTION("--khugepages-alloc-sleep <milliseconds>", "Time in ms for
> > khugepaged");
> > + CONT("to wait if there was a huge page allocation failure");
>
> Wouldn't it be cleaner to use a "thp" prefix instead of "trans". And
> add the thp prefix to thp-khugepaged too? (but the latter is ok also
> keeping it khugepaged I guess, I'd still s/trans/thp/)
Sure, I will move to the thp leader in all the options.
>
> > +.B --khugepaged-pages <pages to scan>
> > +
> > +Configure the number of pages that khugepaged should scan on each pass
> > +
> > +.TP
> > +.B --khugepaged-scan-sleep <milliseconds>
> > +
> > +Configure how many milliseconds khugepaged should wait between passes
> > +
> > +.TP
> > +.B --khugepages-alloc-sleep <milliseconds>
> > +
> > +Configure how many milliseconds khugepaged should wait after failing to
> > +allocate a huge page to throttle the next attempt.
> > +
> > +.PP
> > The following options affect the verbosity of libhugetlbfs.
>
> Good description.
Thanks, they came straight out of your transhuge.txt ;)
>
> Thanks,
> Andrea
>
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