From: Quanmin Yan <yanquanmin1@huawei.com>
To: <sj@kernel.org>
Cc: <akpm@linux-foundation.org>, <damon@lists.linux.dev>,
<linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>,
<yanquanmin1@huawei.com>, <wangkefeng.wang@huawei.com>,
<zuoze1@huawei.com>
Subject: [RFC PATCH mm-next v2 12/12] mm/damon/core: prevent unnecessary overflow in damos_set_effective_quota()
Date: Wed, 20 Aug 2025 16:06:22 +0800 [thread overview]
Message-ID: <20250820080623.3799131-13-yanquanmin1@huawei.com> (raw)
In-Reply-To: <20250820080623.3799131-1-yanquanmin1@huawei.com>
On 32-bit systems, the throughput calculation in function
damos_set_effective_quota() is prone to unnecessary
multiplication overflow. Using mult_frac() to fix it.
Signed-off-by: Quanmin Yan <yanquanmin1@huawei.com>
---
mm/damon/core.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/damon/core.c b/mm/damon/core.c
index 980e271e42e9..38b5f842ef30 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -2102,8 +2102,8 @@ static void damos_set_effective_quota(struct damos_quota *quota)
if (quota->ms) {
if (quota->total_charged_ns)
- throughput = 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);
--
2.43.0
next prev parent reply other threads:[~2025-08-20 8:20 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-20 8:06 [RFC PATCH mm-next v2 00/12] mm/damon: support ARM32 with LPAE Quanmin Yan
2025-08-20 8:06 ` [RFC PATCH mm-next v2 01/12] mm/damon/core: add damon_ctx->addr_unit Quanmin Yan
2025-08-20 8:06 ` [RFC PATCH mm-next v2 02/12] mm/damon/paddr: support addr_unit for access monitoring Quanmin Yan
2025-08-20 8:06 ` [RFC PATCH mm-next v2 03/12] mm/damon/paddr: support addr_unit for DAMOS_PAGEOUT Quanmin Yan
2025-08-20 8:06 ` [RFC PATCH mm-next v2 04/12] mm/damon/paddr: support addr_unit for DAMOS_LRU_[DE]PRIO Quanmin Yan
2025-08-20 8:06 ` [RFC PATCH mm-next v2 05/12] mm/damon/paddr: support addr_unit for MIGRATE_{HOT,COLD} Quanmin Yan
2025-08-20 8:06 ` [RFC PATCH mm-next v2 06/12] mm/damon/paddr: support addr_unit for DAMOS_STAT Quanmin Yan
2025-08-20 8:06 ` [RFC PATCH mm-next v2 07/12] mm/damon/sysfs: implement addr_unit file under context dir Quanmin Yan
2025-08-20 8:06 ` [RFC PATCH mm-next v2 08/12] Docs/mm/damon/design: document 'address unit' parameter Quanmin Yan
2025-08-20 8:06 ` [RFC PATCH mm-next v2 09/12] Docs/admin-guide/mm/damon/usage: document addr_unit file Quanmin Yan
2025-08-20 8:06 ` [RFC PATCH mm-next v2 10/12] Docs/ABI/damon: " Quanmin Yan
2025-08-20 21:37 ` SeongJae Park
2025-08-20 8:06 ` [RFC PATCH mm-next v2 11/12] mm/damon: add damon_ctx->min_region Quanmin Yan
2025-08-20 21:56 ` SeongJae Park
2025-08-20 8:06 ` Quanmin Yan [this message]
2025-08-20 22:16 ` [RFC PATCH mm-next v2 12/12] mm/damon/core: prevent unnecessary overflow in damos_set_effective_quota() SeongJae Park
2025-08-20 22:23 ` [RFC PATCH mm-next v2 00/12] mm/damon: support ARM32 with LPAE SeongJae Park
2025-08-21 11:19 ` Quanmin Yan
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20250820080623.3799131-13-yanquanmin1@huawei.com \
--to=yanquanmin1@huawei.com \
--cc=akpm@linux-foundation.org \
--cc=damon@lists.linux.dev \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=sj@kernel.org \
--cc=wangkefeng.wang@huawei.com \
--cc=zuoze1@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox