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b=KvI/3slLTixTWJPuy8wRgOO7cNbeRJ12UJMkkQu4o6PX9jqH5pgpLj1u5hXria7XV HA16d7/8v+ycDnzUleKLRhdztkVi/mjdmyPnLBmjWEi9T71/8P7MsOb1KqA5fxX3jF 9ec4n7LyCq2DJI882zt8zstCfyRmShCocp7SmfjWy0DGW6OALxOqk3gE7Gu5dUlLyF wVLV2AAlFe39YCEm+TfNs8eK9QrS3DTNi7tkoPoy0yJYvUdjyoX1qjL+m9kubIV5Dw Fd4kfCQ7zKWBNMvGhR4a7tuGEhVi8occ9UK4G4IKK+7sYwmE9EgQSowLHpSXTvxC0V H9FLAC4L+lVrQ== From: SeongJae Park To: Andrew Morton Cc: SeongJae Park , damon@lists.linux.dev, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 1/7] mm/damon/core: use mult_frac() Date: Sat, 7 Mar 2026 11:53:49 -0800 Message-ID: <20260307195356.203753-2-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260307195356.203753-1-sj@kernel.org> References: <20260307195356.203753-1-sj@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 4B395180002 X-Stat-Signature: b8rrg5rcjstgxs8h4nrz95jr6qunhmrn X-Rspam-User: X-HE-Tag: 1772913248-408388 X-HE-Meta: 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 oHyoQ6bf rtfAcXLg5hOLPdw+Eee9EETZusGpbyadpuYzW+WGSWsmvPMirvJ+GGqzcmAozzOCQ4S8B89l0ADroD0x3v41t4j6lxVZaKENiFswkKDy3WMGC4TTOvb048M2LRZD3MNq/ynLuqU+zARF5JwWo9RJqnrfkpSVXYdXc+g28HFuFZzu2dm9N3GxstOhUSt2NgK/6P5835JqIPX+8lHhraZBEfKS72orBVmuirmFkRcrxXxnOgtK+Os3TfKvU30D+W+F9pf8KxrRe7yFJpiQiZvaagr7p4e8XWM2BATxxBtyCo2ewNaH4obOJVsoLk8WabqhCCbhn Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: There are multiple places in core code that do open-code rate calculations. Use mult_frac(), which is developed for doing that in a way more safe from overflow and precision loss. Signed-off-by: SeongJae Park --- mm/damon/core.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/mm/damon/core.c b/mm/damon/core.c index cd2d7a8e3fe92..4e931f7380477 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -665,7 +665,7 @@ static unsigned int damon_accesses_bp_to_nr_accesses( static unsigned int damon_nr_accesses_to_accesses_bp( unsigned int nr_accesses, struct damon_attrs *attrs) { - return nr_accesses * 10000 / damon_max_nr_accesses(attrs); + return mult_frac(nr_accesses, 10000, damon_max_nr_accesses(attrs)); } static unsigned int damon_nr_accesses_for_new_attrs(unsigned int nr_accesses, @@ -1722,7 +1722,7 @@ static unsigned long damon_get_intervals_score(struct damon_ctx *c) } target_access_events = max_access_events * goal_bp / 10000; target_access_events = target_access_events ? : 1; - return access_events * 10000 / target_access_events; + return mult_frac(access_events, 10000, target_access_events); } static unsigned long damon_feed_loop_next_input(unsigned long last_input, @@ -2202,7 +2202,7 @@ static __kernel_ulong_t damos_get_node_mem_bp( numerator = i.totalram - i.freeram; else /* DAMOS_QUOTA_NODE_MEM_FREE_BP */ numerator = i.freeram; - return numerator * 10000 / i.totalram; + return mult_frac(numerator, 10000, i.totalram); } static unsigned long damos_get_node_memcg_used_bp( @@ -2235,7 +2235,7 @@ static unsigned long damos_get_node_memcg_used_bp( numerator = used_pages; else /* DAMOS_QUOTA_NODE_MEMCG_FREE_BP */ numerator = i.totalram - used_pages; - return numerator * 10000 / i.totalram; + return mult_frac(numerator, 10000, i.totalram); } #else static __kernel_ulong_t damos_get_node_mem_bp( @@ -2265,8 +2265,8 @@ static unsigned int damos_get_in_active_mem_bp(bool active_ratio) global_node_page_state(NR_LRU_BASE + LRU_INACTIVE_FILE); total = active + inactive; if (active_ratio) - return active * 10000 / total; - return inactive * 10000 / total; + return mult_frac(active, 10000, total); + return mult_frac(inactive, 10000, total); } static void damos_set_quota_goal_current_value(struct damos_quota_goal *goal) @@ -2309,8 +2309,8 @@ static unsigned long damos_quota_score(struct damos_quota *quota) damos_for_each_quota_goal(goal, quota) { damos_set_quota_goal_current_value(goal); highest_score = max(highest_score, - goal->current_value * 10000 / - goal->target_value); + mult_frac(goal->current_value, 10000, + goal->target_value)); } return highest_score; @@ -2340,8 +2340,8 @@ static void damos_set_effective_quota(struct damos_quota *quota) if (quota->ms) { if (quota->total_charged_ns) - throughput = mult_frac(quota->total_charged_sz, 1000000, - quota->total_charged_ns); + throughput = mult_frac(quota->total_charged_sz, + 1000000, quota->total_charged_ns); else throughput = PAGE_SIZE * 1024; esz = min(throughput * quota->ms, esz); -- 2.47.3