On Tue, Jul 16, 2024 at 2:20 PM Gao Xiang <hsiang...@linux.alibaba.com> wrote: > > > > On 2024/7/16 14:14, Zhaoyang Huang wrote: > > On Tue, Jul 16, 2024 at 1:50 PM Gao Xiang <hsiang...@linux.alibaba.com> > > wrote: > >> > >> > >> > >> On 2024/7/16 13:44, zhaoyang.huang wrote: > >>> From: Zhaoyang Huang <zhaoyang.hu...@unisoc.com> > >>> > >>> scheduling while atomic was reported as below where the schedule_timeout > >>> comes from too_many_isolated when doing direct_reclaim. Fix this by > >>> masking GFP_DIRECT_RECLAIM from gfp. > >>> > >>> [ 175.610416][ T618] BUG: scheduling while atomic: > >>> kworker/u16:6/618/0x00000000 > >>> [ 175.643480][ T618] CPU: 2 PID: 618 Comm: kworker/u16:6 Tainted: G > >>> [ 175.645791][ T618] Workqueue: loop20 loop_workfn > >>> [ 175.646394][ T618] Call trace: > >>> [ 175.646785][ T618] dump_backtrace+0xf4/0x140 > >>> [ 175.647345][ T618] show_stack+0x20/0x2c > >>> [ 175.647846][ T618] dump_stack_lvl+0x60/0x84 > >>> [ 175.648394][ T618] dump_stack+0x18/0x24 > >>> [ 175.648895][ T618] __schedule_bug+0x64/0x90 > >>> [ 175.649445][ T618] __schedule+0x680/0x9b8 > >>> [ 175.649970][ T618] schedule+0x130/0x1b0 > >>> [ 175.650470][ T618] schedule_timeout+0xac/0x1d0 > >>> [ 175.651050][ T618] schedule_timeout_uninterruptible+0x24/0x34 > >>> [ 175.651789][ T618] __alloc_pages_slowpath+0x8dc/0x121c > >>> [ 175.652455][ T618] __alloc_pages+0x294/0x2fc > >>> [ 175.653011][ T618] erofs_allocpage+0x48/0x58 > >>> [ 175.653572][ T618] z_erofs_runqueue+0x314/0x8a4 > >>> [ 175.654161][ T618] z_erofs_readahead+0x258/0x318 > >>> [ 175.654761][ T618] read_pages+0x88/0x394 > >>> [ 175.655275][ T618] page_cache_ra_unbounded+0x1cc/0x23c > >>> [ 175.655939][ T618] page_cache_ra_order+0x27c/0x33c > >>> [ 175.656559][ T618] ondemand_readahead+0x224/0x334 > >>> [ 175.657169][ T618] page_cache_async_ra+0x60/0x9c > >>> [ 175.657767][ T618] filemap_get_pages+0x19c/0x7cc > >>> [ 175.658367][ T618] filemap_read+0xf0/0x484 > >>> [ 175.658901][ T618] generic_file_read_iter+0x4c/0x15c > >>> [ 175.659543][ T618] do_iter_read+0x224/0x348 > >>> [ 175.660100][ T618] vfs_iter_read+0x24/0x38 > >>> [ 175.660635][ T618] loop_process_work+0x408/0xa68 > >>> [ 175.661236][ T618] loop_workfn+0x28/0x34 > >>> [ 175.661751][ T618] process_scheduled_works+0x254/0x4e8 > >>> [ 175.662417][ T618] worker_thread+0x24c/0x33c > >>> [ 175.662974][ T618] kthread+0x110/0x1b8 > >>> [ 175.663465][ T618] ret_from_fork+0x10/0x20 > >>> > >>> Signed-off-by: Zhaoyang Huang <zhaoyang.hu...@unisoc.com> > >> > >> I don't see why it's an atomic context, > >> so this patch is incorrect. > > Sorry, I should provide more details. page_cache_ra_unbounded() will > > call filemap_invalidate_lock_shared(mapping) to ensure the integrity > > of page cache during readahead, which will disable preempt. > > Why a rwsem sleepable lock disable preemption? emm, that's the original design of down_read()
> context should be always non-atomic context, which is applied > to all kernel filesystems. AFAICT, filemap_fault/read have added the folios of readahead to page cache which means the aops->readahead basically just need to map the block to this folios and then launch the bio. The erofs is a little bit different to others as it has to alloc_pages for decompression when doing this. > > Thanks, > Gao Xiang > > >> > >> Thanks, > >> Gao Xiang
