On Wed, Jan 27, 2016 at 02:59:11PM +0100, Vlastimil Babka wrote: > [CC += linux-api, linux-man] > > On 01/22/2016 09:27 AM, Naoya Horiguchi wrote: > > Currently the return value of memory_failure() is not passed to userspace, > > which > > is inconvenient for test programs that want to know the result of error > > handling. > > So let's return it to the caller as we already do in MADV_SOFT_OFFLINE case. > > > > Signed-off-by: Naoya Horiguchi <n-horigu...@ah.jp.nec.com> > > --- > > mm/madvise.c | 5 +++-- > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > diff --git v4.4-mmotm-2016-01-20-16-10/mm/madvise.c > > v4.4-mmotm-2016-01-20-16-10_patched/mm/madvise.c > > index f56825b..6a77114 100644 > > --- v4.4-mmotm-2016-01-20-16-10/mm/madvise.c > > +++ v4.4-mmotm-2016-01-20-16-10_patched/mm/madvise.c > > @@ -555,8 +555,9 @@ static int madvise_hwpoison(int bhv, unsigned long > > start, unsigned long end) > > } > > pr_info("Injecting memory failure for page %#lx at %#lx\n", > > page_to_pfn(p), start); > > - /* Ignore return value for now */ > > - memory_failure(page_to_pfn(p), 0, MF_COUNT_INCREASED); > > + ret = memory_failure(page_to_pfn(p), 0, MF_COUNT_INCREASED); > > + if (ret) > > + return ret; > > Can you explain what madvise can newly return for MADV_HWPOISON in which > situations, for the purposes of updated man page?
OK, this patch newly allows madvise(MADV_HWPOISON) to return EBUSY when error handling failed due to 2 major reasons: - the target page is a page type which memory error handler doesn't support (like slab pages, kernel-reserved pages) - the memory error handler failed to isolate the target page (for example, due to failure in unmapping) And for man page purpose, errnos of MADV_SOFT_OFFLINE is not documented either. So let me refer to 2 possible error code from madvise(MADV_SOFT_OFFLINE): - EBUSY: failed to isolate from lru list, - EIO: failed to migrate the target page to another page. Thanks, Naoya Horiguchi