Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   xiakaixu1987@gmail.com
To:     sj@kernel.org, akpm@linux-foundation.org
Cc:     damon@lists.linux.dev, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, Kaixu Xia <kaixuxia@tencent.com>
Subject: [PATCH 3/4] mm/damon/core: simplify the kdamond stop mechanism by removing 'done'
Date:   Tue, 13 Sep 2022 17:11:26 +0800
Message-Id: <1663060287-30201-4-git-send-email-kaixuxia@tencent.com>
In-Reply-To: <1663060287-30201-1-git-send-email-kaixuxia@tencent.com>
References: <1663060287-30201-1-git-send-email-kaixuxia@tencent.com>
Precedence: bulk

From: Kaixu Xia <kaixuxia@tencent.com>

When the 'kdamond_wait_activation()' function or 'after_sampling()'
or 'after_aggregation()' DAMON callbacks return an error, it is
unnecessary to use bool 'done' to check if kdamond should be
finished. This commit simplifies the kdamond stop mechanism by
removing 'done' and break the while loop directly in the cases.

Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>
---
 mm/damon/core.c | 24 +++++++++---------------
 1 file changed, 9 insertions(+), 15 deletions(-)

diff --git a/mm/damon/core.c b/mm/damon/core.c
index 0b1eb945c68a..4ce860af70ec 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -1165,30 +1165,25 @@ static int kdamond_fn(void *data)
 	struct damon_region *r, *next;
 	unsigned int max_nr_accesses = 0;
 	unsigned long sz_limit = 0;
-	bool done = false;
 
 	pr_debug("kdamond (%d) starts\n", current->pid);
 
 	if (ctx->ops.init)
 		ctx->ops.init(ctx);
 	if (ctx->callback.before_start && ctx->callback.before_start(ctx))
-		done = true;
+		goto done;
 
 	sz_limit = damon_region_sz_limit(ctx);
 
-	while (!kdamond_need_stop(ctx) && !done) {
-		if (kdamond_wait_activation(ctx)) {
-			done = true;
-			continue;
-		}
+	while (!kdamond_need_stop(ctx)) {
+		if (kdamond_wait_activation(ctx))
+			break;
 
 		if (ctx->ops.prepare_access_checks)
 			ctx->ops.prepare_access_checks(ctx);
 		if (ctx->callback.after_sampling &&
-				ctx->callback.after_sampling(ctx)) {
-			done = true;
-			continue;
-		}
+				ctx->callback.after_sampling(ctx))
+			break;
 
 		kdamond_usleep(ctx->sample_interval);
 
@@ -1200,10 +1195,8 @@ static int kdamond_fn(void *data)
 					max_nr_accesses / 10,
 					sz_limit);
 			if (ctx->callback.after_aggregation &&
-					ctx->callback.after_aggregation(ctx)) {
-				done = true;
-				continue;
-			}
+					ctx->callback.after_aggregation(ctx))
+				break;
 			kdamond_apply_schemes(ctx);
 			kdamond_reset_aggregated(ctx);
 			kdamond_split_regions(ctx);
@@ -1217,6 +1210,7 @@ static int kdamond_fn(void *data)
 			sz_limit = damon_region_sz_limit(ctx);
 		}
 	}
+done:
 	damon_for_each_target(t, ctx) {
 		damon_for_each_region_safe(r, next, t)
 			damon_destroy_region(r, t);
-- 
2.27.0