diff mbox series

[4/3] xfs: set WQ_SYSFS on all workqueues in debug mode

Message ID 20210126050619.GT7698@magnolia (mailing list archive)
State Superseded
Headers show
Series xfs: speed up parallel workqueues | expand

Commit Message

Darrick J. Wong Jan. 26, 2021, 5:06 a.m. UTC 
From: Darrick J. Wong <djwong@kernel.org>

When CONFIG_XFS_DEBUG=y, set WQ_SYSFS on all workqueues that we create
so that we (developers) have a means to monitor cpu affinity and whatnot
for background workers.  In the next patchset we'll expose knobs for
some of the workqueues publicly and document it, but not now.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
 fs/xfs/xfs_log.c       |    5 +++--
 fs/xfs/xfs_mru_cache.c |    2 +-
 fs/xfs/xfs_super.c     |   23 ++++++++++++++---------
 fs/xfs/xfs_super.h     |    6 ++++++
 4 files changed, 24 insertions(+), 12 deletions(-)

Comments

Christoph Hellwig Jan. 27, 2021, 5:03 p.m. UTC | #1 
On Mon, Jan 25, 2021 at 09:06:19PM -0800, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@kernel.org>
> 
> When CONFIG_XFS_DEBUG=y, set WQ_SYSFS on all workqueues that we create
> so that we (developers) have a means to monitor cpu affinity and whatnot
> for background workers.  In the next patchset we'll expose knobs for
> some of the workqueues publicly and document it, but not now.

I don't really think this is a very good idea.  If we want something like
this it should be kernel-wide and coordinated with the workqueue 
maintainer, but I'm a little doubtful about the use case.
Dave Chinner Jan. 27, 2021, 11:29 p.m. UTC | #2 
On Wed, Jan 27, 2021 at 05:03:06PM +0000, Christoph Hellwig wrote:
> On Mon, Jan 25, 2021 at 09:06:19PM -0800, Darrick J. Wong wrote:
> > From: Darrick J. Wong <djwong@kernel.org>
> > 
> > When CONFIG_XFS_DEBUG=y, set WQ_SYSFS on all workqueues that we create
> > so that we (developers) have a means to monitor cpu affinity and whatnot
> > for background workers.  In the next patchset we'll expose knobs for
> > some of the workqueues publicly and document it, but not now.
> 
> I don't really think this is a very good idea.  If we want something like
> this it should be kernel-wide and coordinated with the workqueue 
> maintainer, but I'm a little doubtful about the use case.

I don't think it is particular useful kernel wide. If it was, the
maintainer wouldn't have introduced a per-workqueue flag for this
functionality.

The reality is that very few workqueues in the system can expand out
into running thousands of kworker threads like the XFS workqueues
often do. And, really, there's nothing useful a typical user can do
at this point with the workqueue knobs to "tune" the behaviour - the
visibility/control the workqueue sysfs knobs provide at this point
is really only useful to XFS developers running tests in controlled
conditions...

Cheers,

Dave.
diff mbox series

Patch

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index 58699881c100..0da019a4a7f9 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -1493,8 +1493,9 @@  xlog_alloc_log(
 	log->l_iclog->ic_prev = prev_iclog;	/* re-write 1st prev ptr */
 
 	log->l_ioend_workqueue = alloc_workqueue("xfs-log/%s",
-			WQ_MEM_RECLAIM | WQ_FREEZABLE | WQ_HIGHPRI, 0,
-			mp->m_super->s_id);
+			XFS_WQFLAGS(WQ_FREEZABLE | WQ_MEM_RECLAIM |
+				    WQ_HIGHPRI),
+			0, mp->m_super->s_id);
 	if (!log->l_ioend_workqueue)
 		goto out_free_iclog;
 
diff --git a/fs/xfs/xfs_mru_cache.c b/fs/xfs/xfs_mru_cache.c
index a06661dac5be..34c3b16f834f 100644
--- a/fs/xfs/xfs_mru_cache.c
+++ b/fs/xfs/xfs_mru_cache.c
@@ -294,7 +294,7 @@  int
 xfs_mru_cache_init(void)
 {
 	xfs_mru_reap_wq = alloc_workqueue("xfs_mru_cache",
-				WQ_MEM_RECLAIM|WQ_FREEZABLE, 1);
+			XFS_WQFLAGS(WQ_MEM_RECLAIM | WQ_FREEZABLE), 1);
 	if (!xfs_mru_reap_wq)
 		return -ENOMEM;
 	return 0;
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index aed74a3fc787..8959561351ca 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -495,33 +495,37 @@  xfs_init_mount_workqueues(
 	struct xfs_mount	*mp)
 {
 	mp->m_buf_workqueue = alloc_workqueue("xfs-buf/%s",
-			WQ_MEM_RECLAIM|WQ_FREEZABLE, 1, mp->m_super->s_id);
+			XFS_WQFLAGS(WQ_FREEZABLE | WQ_MEM_RECLAIM),
+			1, mp->m_super->s_id);
 	if (!mp->m_buf_workqueue)
 		goto out;
 
 	mp->m_unwritten_workqueue = alloc_workqueue("xfs-conv/%s",
-			WQ_MEM_RECLAIM|WQ_FREEZABLE, 0, mp->m_super->s_id);
+			XFS_WQFLAGS(WQ_FREEZABLE | WQ_MEM_RECLAIM),
+			0, mp->m_super->s_id);
 	if (!mp->m_unwritten_workqueue)
 		goto out_destroy_buf;
 
 	mp->m_cil_workqueue = alloc_workqueue("xfs-cil/%s",
-			WQ_MEM_RECLAIM | WQ_FREEZABLE | WQ_UNBOUND,
+			XFS_WQFLAGS(WQ_FREEZABLE | WQ_MEM_RECLAIM | WQ_UNBOUND),
 			0, mp->m_super->s_id);
 	if (!mp->m_cil_workqueue)
 		goto out_destroy_unwritten;
 
 	mp->m_reclaim_workqueue = alloc_workqueue("xfs-reclaim/%s",
-			WQ_MEM_RECLAIM|WQ_FREEZABLE, 0, mp->m_super->s_id);
+			XFS_WQFLAGS(WQ_FREEZABLE | WQ_MEM_RECLAIM),
+			0, mp->m_super->s_id);
 	if (!mp->m_reclaim_workqueue)
 		goto out_destroy_cil;
 
 	mp->m_eofblocks_workqueue = alloc_workqueue("xfs-eofblocks/%s",
-			WQ_MEM_RECLAIM|WQ_FREEZABLE, 0, mp->m_super->s_id);
+			XFS_WQFLAGS(WQ_FREEZABLE | WQ_MEM_RECLAIM),
+			0, mp->m_super->s_id);
 	if (!mp->m_eofblocks_workqueue)
 		goto out_destroy_reclaim;
 
-	mp->m_sync_workqueue = alloc_workqueue("xfs-sync/%s", WQ_FREEZABLE, 0,
-					       mp->m_super->s_id);
+	mp->m_sync_workqueue = alloc_workqueue("xfs-sync/%s",
+			XFS_WQFLAGS(WQ_FREEZABLE), 0, mp->m_super->s_id);
 	if (!mp->m_sync_workqueue)
 		goto out_destroy_eofb;
 
@@ -2085,11 +2089,12 @@  xfs_init_workqueues(void)
 	 * max_active value for this workqueue.
 	 */
 	xfs_alloc_wq = alloc_workqueue("xfsalloc",
-			WQ_MEM_RECLAIM|WQ_FREEZABLE, 0);
+			XFS_WQFLAGS(WQ_MEM_RECLAIM | WQ_FREEZABLE), 0);
 	if (!xfs_alloc_wq)
 		return -ENOMEM;
 
-	xfs_discard_wq = alloc_workqueue("xfsdiscard", WQ_UNBOUND, 0);
+	xfs_discard_wq = alloc_workqueue("xfsdiscard", XFS_WQFLAGS(WQ_UNBOUND),
+			0);
 	if (!xfs_discard_wq)
 		goto out_free_alloc_wq;
 
diff --git a/fs/xfs/xfs_super.h b/fs/xfs/xfs_super.h
index b552cf6d3379..1ca484b8357f 100644
--- a/fs/xfs/xfs_super.h
+++ b/fs/xfs/xfs_super.h
@@ -75,6 +75,12 @@  extern void xfs_qm_exit(void);
 				XFS_ASSERT_FATAL_STRING \
 				XFS_DBG_STRING /* DBG must be last */
 
+#ifdef DEBUG
+# define XFS_WQFLAGS(wqflags)	(WQ_SYSFS | (wqflags))
+#else
+# define XFS_WQFLAGS(wqflags)	(wqflags)
+#endif
+
 struct xfs_inode;
 struct xfs_mount;
 struct xfs_buftarg;