On Thu, Sep 13, 2018 at 07:32:24PM +0800, Christian König wrote:
> Am 13.09.2018 um 10:31 schrieb Huang Rui:
> > On Wed, Sep 12, 2018 at 09:23:55PM +0200, Christian König wrote:
> >> While cutting the lists we sometimes accidentally added a list_head from
> >> the stack to the LRUs, effectively corrupting the list.
> >>
> >> Remove the list cutting and use explicit list manipulation instead.
> > This patch actually fixes the corruption bug. Was it a defect of
> > list_cut_position or list_splice handlers?
>
> We somehow did something illegal with list_cut_position. I haven't
> narrowed it down till the end, but we ended up with list_heads from the
> stack to the lru.
>
I am confused, in theory, even we do any manipulation with list helper, it
should not trigger the list corruption. The usage of those helpers should
ensure the list operation safely...
> Anyway adding a specialized list bulk move function is much simpler and
> avoids the issue.
>
> I've just split that up as Michel suggested and send it out to the
> mailing lists, please review that version once more.
>
Sure, already reviewed.
> Thanks,
> Christian.
>
> >
> > Reviewed-and-Tested: Huang Rui <ray.huang at amd.com>
> >
> >> Signed-off-by: Christian König <christian.koenig at amd.com>
> >> ---
> >> drivers/gpu/drm/ttm/ttm_bo.c | 51 ++++++++++++++++++++++++++------------------
> >> 1 file changed, 30 insertions(+), 21 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
> >> index 138c98902033..b2a33bf1ef10 100644
> >> --- a/drivers/gpu/drm/ttm/ttm_bo.c
> >> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> >> @@ -247,23 +247,18 @@ void ttm_bo_move_to_lru_tail(struct ttm_buffer_object *bo,
> >> }
> >> EXPORT_SYMBOL(ttm_bo_move_to_lru_tail);
> >>
> >> -static void ttm_bo_bulk_move_helper(struct ttm_lru_bulk_move_pos *pos,
> >> - struct list_head *lru, bool is_swap)
> >> +static void ttm_list_move_bulk_tail(struct list_head *list,
> >> + struct list_head *first,
> >> + struct list_head *last)
> >> {
> >> - struct list_head *list;
> >> - LIST_HEAD(entries);
> >> - LIST_HEAD(before);
> >> + first->prev->next = last->next;
> >> + last->next->prev = first->prev;
> >>
> >> - reservation_object_assert_held(pos->last->resv);
> >> - list = is_swap ? &pos->last->swap : &pos->last->lru;
> >> - list_cut_position(&entries, lru, list);
> >> + list->prev->next = first;
> >> + first->prev = list->prev;
> >>
> >> - reservation_object_assert_held(pos->first->resv);
> >> - list = is_swap ? pos->first->swap.prev : pos->first->lru.prev;
> >> - list_cut_position(&before, &entries, list);
> >> -
> >> - list_splice(&before, lru);
> >> - list_splice_tail(&entries, lru);
> >> + last->next = list;
> >> + list->prev = last;
> >> }
> >>
> >> void ttm_bo_bulk_move_lru_tail(struct ttm_lru_bulk_move *bulk)
> >> @@ -271,23 +266,33 @@ void ttm_bo_bulk_move_lru_tail(struct ttm_lru_bulk_move *bulk)
> >> unsigned i;
> >>
> >> for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
> >> + struct ttm_lru_bulk_move_pos *pos = &bulk->tt[i];
> >> struct ttm_mem_type_manager *man;
> >>
> >> - if (!bulk->tt[i].first)
> >> + if (!pos->first)
> >> continue;
> >>
> >> - man = &bulk->tt[i].first->bdev->man[TTM_PL_TT];
> >> - ttm_bo_bulk_move_helper(&bulk->tt[i], &man->lru[i], false);
> >> + reservation_object_assert_held(pos->first->resv);
> >> + reservation_object_assert_held(pos->last->resv);
> >> +
> >> + man = &pos->first->bdev->man[TTM_PL_TT];
> >> + ttm_list_move_bulk_tail(&man->lru[i], &pos->first->lru,
> >> + &pos->last->lru);
> >> }
> >>
> >> for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
> >> + struct ttm_lru_bulk_move_pos *pos = &bulk->vram[i];
> >> struct ttm_mem_type_manager *man;
> >>
> >> - if (!bulk->vram[i].first)
> >> + if (!pos->first)
> >> continue;
> >>
> >> - man = &bulk->vram[i].first->bdev->man[TTM_PL_VRAM];
> >> - ttm_bo_bulk_move_helper(&bulk->vram[i], &man->lru[i], false);
> >> + reservation_object_assert_held(pos->first->resv);
> >> + reservation_object_assert_held(pos->last->resv);
> >> +
> >> + man = &pos->first->bdev->man[TTM_PL_VRAM];
> >> + ttm_list_move_bulk_tail(&man->lru[i], &pos->first->lru,
> >> + &pos->last->lru);
> >> }
> >>
> >> for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
> >> @@ -297,8 +302,12 @@ void ttm_bo_bulk_move_lru_tail(struct ttm_lru_bulk_move *bulk)
> >> if (!pos->first)
> >> continue;
> >>
> >> + reservation_object_assert_held(pos->first->resv);
> >> + reservation_object_assert_held(pos->last->resv);
> >> +
> >> lru = &pos->first->bdev->glob->swap_lru[i];
> >> - ttm_bo_bulk_move_helper(&bulk->swap[i], lru, true);
> >> + ttm_list_move_bulk_tail(lru, &pos->first->swap,
> >> + &pos->last->swap);
> >> }
> >> }
> >> EXPORT_SYMBOL(ttm_bo_bulk_move_lru_tail);
> >> --
> >> 2.14.1
> >>
> >> _______________________________________________
> >> amd-gfx mailing list
> >> amd-gfx at lists.freedesktop.org
> >> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
>
