Re: [PATCH] zram: Avoid duplicate slots in batched writeback

[Sergey Senozhatsky]

On (26/11/10 14:18), raoxu wrote:
> The writeback interface accepts multiple page_index and page_indexes
> parameters in one operation. Their ranges can overlap, but
> scan_slots_for_writeback() only excludes slots that are already being
> written back or marked as same-filled.
> 
> A slot selected by an earlier range is placed on the post-processing list
> and marked with ZRAM_PP_SLOT. Without checking that flag, an overlapping
> range can enqueue the same slot again and submit it for writeback more
> than once.
> 
> Skip slots already marked ZRAM_PP_SLOT while holding the slot lock. This
> keeps each slot in a writeback scan session represented by at most one
> post-processing entry and leaves the existing release and reuse paths
> unchanged.
> 
> Signed-off-by: Xu Rao <raoxu@xxxxxxxxxxxxx>

LGTM.
Reviewed-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>

Jens, do you want to pick it up and route via block tree or should
we route via "more traditional" tree (Andrew's tree)?