On Wed, Mar 17, 2021 at 06:59:59PM -0700, Shakeel Butt wrote: > The function swap_readpage() (and other functions it call) extracts swap > entry from page->private. However for SWP_SYNCHRONOUS_IO, the kernel > skips the swapcache and thus we need to manually set the page->private > with the swap entry before calling swap_readpage(). > > Signed-off-by: Shakeel Butt <shakeelb@xxxxxxxxxx> > Reported-by: Heiko Carstens <hca@xxxxxxxxxxxxx> > --- > > Andrew, please squash this into "memcg: charge before adding to > swapcache on swapin" patch. > > mm/memory.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/mm/memory.c b/mm/memory.c > index aefd158ae1ea..b6f3410b5902 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -3324,7 +3324,11 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) > workingset_refault(page, shadow); > > lru_cache_add(page); > + > + /* To provide entry to swap_readpage() */ > + set_page_private(page, entry.val); > swap_readpage(page, true); > + set_page_private(page, 0); Yes, this seems to fix it. Thanks a lot! Tested-by: Heiko Carstens <hca@xxxxxxxxxxxxx>
