On Tue, May 16, 2023 at 01:28:00PM +0100, Matthew Wilcox wrote: > Plain 6.4.0-rc2 with a relatively minor change to the futex code that > I cannot believe was in any way responsible for this. > > kworkers blocked all over the place. Some on XFS_ILOCK_EXCL. Some on > xfs_buf_lock. One in xfs_btree_split() calling wait_for_completion. > > This was an overnight test run that is now dead, so I can't get any > more info from the locked up kernel. I have the vmlinux if some > decoding of offsets is useful. This is likely the same AGF try-lock bug that was discovered in this thread: https://lore.kernel.org/linux-xfs/202305090905.aff4e0e6-oliver.sang@xxxxxxxxx/ The fact that the try-lock was ignored means that out of order AGF locking can be attempted, and the try-lock prevents deadlocks from occurring. Can you try the patch below - I was going to send it for review anyway this morning so it can't hurt to see if it also fixes this issue. -Dave. -- Dave Chinner david@xxxxxxxxxxxxx xfs: restore allocation trylock iteration From: Dave Chinner <dchinner@xxxxxxxxxx> It was accidentally dropped when refactoring the allocation code, resulting in the AG iteration always doing blocking AG iteration. This results in a small performance regression for a specific fsmark test that runs more user data writer threads than there are AGs. Reported-by: kernel test robot <oliver.sang@xxxxxxxxx> Fixes: 2edf06a50f5b ("xfs: factor xfs_alloc_vextent_this_ag() for _iterate_ags()") Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx> --- fs/xfs/libxfs/xfs_alloc.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c index fdfa08cbf4db..61eb65be17f3 100644 --- a/fs/xfs/libxfs/xfs_alloc.c +++ b/fs/xfs/libxfs/xfs_alloc.c @@ -3187,7 +3187,8 @@ xfs_alloc_vextent_check_args( */ static int xfs_alloc_vextent_prepare_ag( - struct xfs_alloc_arg *args) + struct xfs_alloc_arg *args, + uint32_t flags) { bool need_pag = !args->pag; int error; @@ -3196,7 +3197,7 @@ xfs_alloc_vextent_prepare_ag( args->pag = xfs_perag_get(args->mp, args->agno); args->agbp = NULL; - error = xfs_alloc_fix_freelist(args, 0); + error = xfs_alloc_fix_freelist(args, flags); if (error) { trace_xfs_alloc_vextent_nofix(args); if (need_pag) @@ -3336,7 +3337,7 @@ xfs_alloc_vextent_this_ag( return error; } - error = xfs_alloc_vextent_prepare_ag(args); + error = xfs_alloc_vextent_prepare_ag(args, 0); if (!error && args->agbp) error = xfs_alloc_ag_vextent_size(args); @@ -3380,7 +3381,7 @@ xfs_alloc_vextent_iterate_ags( for_each_perag_wrap_range(mp, start_agno, restart_agno, mp->m_sb.sb_agcount, agno, args->pag) { args->agno = agno; - error = xfs_alloc_vextent_prepare_ag(args); + error = xfs_alloc_vextent_prepare_ag(args, flags); if (error) break; if (!args->agbp) { @@ -3546,7 +3547,7 @@ xfs_alloc_vextent_exact_bno( return error; } - error = xfs_alloc_vextent_prepare_ag(args); + error = xfs_alloc_vextent_prepare_ag(args, 0); if (!error && args->agbp) error = xfs_alloc_ag_vextent_exact(args); @@ -3587,7 +3588,7 @@ xfs_alloc_vextent_near_bno( if (needs_perag) args->pag = xfs_perag_grab(mp, args->agno); - error = xfs_alloc_vextent_prepare_ag(args); + error = xfs_alloc_vextent_prepare_ag(args, 0); if (!error && args->agbp) error = xfs_alloc_ag_vextent_near(args);
