> wait_for_scan() gives every case the same three seconds, whatever the huge > page costs to build. collapse_full asks for four of them: 8M at a 2M PMD,
collapse_full() please > but 2G at a 512M PMD -- arm64 with 64K base pages. > > Three seconds is thin at that size rather than generous. Across 80 runs of > collapse_full on arm64 with 64K pages the wait was half a second in 73 of > them, with a tail to two seconds, and the case has timed out in a full > matrix run, reporting a failure for a collapse that was still going. > > Keep three seconds as the floor and add a second per 128M to collapse. A > 2M PMD is unchanged. A 512M PMD gets 19 seconds, which is headroom over > the observed tail rather than a measured requirement. The budget bounds > how long a real failure takes to report, not how long a passing case > waits: wait_for_scan() returns as soon as the collapse turns up. > > arm64/64K: khugepaged all:anon 21 pass/1 fail -> 22 pass/0 fail. x86-64 is > unchanged. > > Assisted-by: Claude-Code:claude-opus-5 > Tested-by: Muhammad Usama Anjum <[email protected]> > Signed-off-by: Kiryl Shutsemau (Meta) <[email protected]> > > diff --git a/tools/testing/selftests/mm/khugepaged.c > b/tools/testing/selftests/mm/khugepaged.c > index 48eb74c255f6..a5ada78d90ee 100644 > --- a/tools/testing/selftests/mm/khugepaged.c > +++ b/tools/testing/selftests/mm/khugepaged.c > @@ -583,8 +583,10 @@ static bool wait_for_scan(const char *msg, char *p, > size_t len, > int nr_hpages, int collap_order, struct mem_ops *ops) > { > unsigned long hpage_size = page_size << collap_order; > + /* Three seconds as a floor, plus a second per 128M to collapse */ > + const unsigned long bytes = (unsigned long)nr_hpages * hpage_size; > + int timeout = 6 + 2 * (bytes / (128UL << 20)); > int full_scans; > - int timeout = 6; /* 3 seconds */ It's a pity we lost the comment explainging that timeout is seconds x2 > > /* Sanity check */ > if (!ops->check_huge(p, len, 0, hpage_size)) Reviewed-by: Mike Rapoport (Microsoft) <[email protected]> -- Sincerely yours, Mike.
