On 2019-08-15 8:54 p.m., Jason Gunthorpe wrote: > On Thu, Aug 15, 2019 at 08:52:56PM +0000, Yang, Philip wrote: >> hmm_range_fault may return NULL pages because some of pfns are equal to >> HMM_PFN_NONE. This happens randomly under memory pressure. The reason is >> for swapped out page pte path, hmm_vma_handle_pte doesn't update fault >> variable from cpu_flags, so it failed to call hmm_vam_do_fault to swap >> the page in. >> >> The fix is to call hmm_pte_need_fault to update fault variable. > >> Change-Id: I2e8611485563d11d938881c18b7935fa1e7c91ee > > I'll fix it for you but please be careful not to send Change-id's to > the public lists. > Thanks, the change-id was added by our Gerrit hook, I need generate patch files, remove change-id line and then send out modified patch files in future. > Also what is the Fixes line for this? > This fixes the issue found by the internal rocrtst, the rocrtstFunc.Memory_Max_Mem evicted some user buffers, and then following test restore those user buffers failed because the buffers are swapped out and application doesn't touch the buffers to swap it in. >> Signed-off-by: Philip Yang <Philip.Yang@xxxxxxx> >> mm/hmm.c | 3 +++ >> 1 file changed, 3 insertions(+) > > Ralph has also been looking at this area also so I'll give him a bit > to chime in, otherwise with Jerome's review this looks OK to go to > linux-next > Ok, thanks for helping push this to hmm branch at https://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma.git > Thanks, > Jason >
