[dm-devel] Patch "dm cache: add cond_resched() to various workqueue loops" has been added to the 5.4-stable tree

[Sasha Levin]

This is a note to let you know that I've just added the patch titled

    dm cache: add cond_resched() to various workqueue loops

to the 5.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     dm-cache-add-cond_resched-to-various-workqueue-loops.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable at vger.kernel.org> know about it.



commit eecd73d287dc78cae35bff1d642ee7e726d15da8
Author: Mike Snitzer <snitzer at kernel.org>
Date:   Thu Feb 16 15:31:08 2023 -0500

    dm cache: add cond_resched() to various workqueue loops
    
    [ Upstream commit 76227f6dc805e9e960128bcc6276647361e0827c ]
    
    Otherwise on resource constrained systems these workqueues may be too
    greedy.
    
    Signed-off-by: Mike Snitzer <snitzer at kernel.org>
    Signed-off-by: Sasha Levin <sashal at kernel.org>

diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index 10b2a4e10a46b..08b5e44df3248 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -1910,6 +1910,7 @@ static void process_deferred_bios(struct work_struct *ws)
 
 		else
 			commit_needed = process_bio(cache, bio) || commit_needed;
+		cond_resched();
 	}
 
 	if (commit_needed)
@@ -1932,6 +1933,7 @@ static void requeue_deferred_bios(struct cache *cache)
 	while ((bio = bio_list_pop(&bios))) {
 		bio->bi_status = BLK_STS_DM_REQUEUE;
 		bio_endio(bio);
+		cond_resched();
 	}
 }
 
@@ -1972,6 +1974,8 @@ static void check_migrations(struct work_struct *ws)
 		r = mg_start(cache, op, NULL);
 		if (r)
 			break;
+
+		cond_resched();
 	}
 }