Received-SPF: pass (google.com: domain of linux-kernel+bounces-27422-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) client-ip=147.75.80.249;
From: Ronald Monthero <debug.penguin32@gmail.com>
To: nphamcs@gmail.com
Cc: sjenning@redhat.com,
	ddstreet@ieee.org,
	vitaly.wool@konsulko.com,
	akpm@linux-foundation.org,
	chrisl@kernel.org,
	linux-mm@kvack.org,
	linux-kernel@vger.kernel.org,
	Ronald Monthero <debug.penguin32@gmail.com>
Subject: [PATCH] mm/zswap: Improve with alloc_workqueue() call
Date: Tue, 16 Jan 2024 23:31:45 +1000
Message-Id: <20240116133145.12454-1-debug.penguin32@gmail.com>
In-Reply-To: <CAKEwX=NLe-N6dLvOVErPSL3Vfw6wqHgcUBQoNRLeWkN6chdvLQ@mail.gmail.com>
References: <CAKEwX=NLe-N6dLvOVErPSL3Vfw6wqHgcUBQoNRLeWkN6chdvLQ@mail.gmail.com>
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit

The core-api create_workqueue is deprecated, this patch replaces
the create_workqueue with alloc_workqueue. The previous
implementation workqueue of zswap was a bounded workqueue, this
patch uses alloc_workqueue() to create an unbounded workqueue.
The WQ_UNBOUND attribute is desirable making the workqueue
not localized to a specific cpu so that the scheduler is free
to exercise improvisations in any demanding scenarios for
offloading cpu time slices for workqueues.
For example if any other workqueues of the same primary cpu
had to be served which are WQ_HIGHPRI and WQ_CPU_INTENSIVE.
Also Unbound workqueue happens to be more efficient
in a system during memory pressure scenarios in comparison
 to a bounded workqueue.

shrink_wq = alloc_workqueue("zswap-shrink",
                     WQ_UNBOUND|WQ_MEM_RECLAIM, 1);

Overall the change suggested in this patch should be
seamless and does not alter the existing behavior,
other than the improvisation to be an unbounded workqueue.

Signed-off-by: Ronald Monthero <debug.penguin32@gmail.com>
---
 mm/zswap.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/zswap.c b/mm/zswap.c
index 74411dfdad92..64dbe3e944a2 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -1620,7 +1620,8 @@ static int zswap_setup(void)
 		zswap_enabled = false;
 	}
 
-	shrink_wq = create_workqueue("zswap-shrink");
+	shrink_wq = alloc_workqueue("zswap-shrink",
+			WQ_UNBOUND|WQ_MEM_RECLAIM, 1);
 	if (!shrink_wq)
 		goto fallback_fail;
 
-- 
2.34.1