From: Andrew Morton <akpm@linux-foundation.org>
To: tj@kernel.org, cai@lca.pw, axboe@kernel.dk,
wenyang@linux.alibaba.com, akpm@linux-foundation.org,
linux-mm@kvack.org, mm-commits@vger.kernel.org,
torvalds@linux-foundation.org
Subject: [patch 09/11] mm/page-writeback.c: improve arithmetic divisions
Date: Mon, 13 Jan 2020 16:29:29 -0800 [thread overview]
Message-ID: <20200114002929.P5URA%akpm@linux-foundation.org> (raw)
In-Reply-To: <20200113162831.f7d69e11e9e673c40005c9b0@linux-foundation.org>
From: Wen Yang <wenyang@linux.alibaba.com>
Subject: mm/page-writeback.c: improve arithmetic divisions
Use div64_ul() instead of do_div() if the divisor is unsigned long, to
avoid truncation to 32-bit on 64-bit platforms.
Link: http://lkml.kernel.org/r/20200102081442.8273-4-wenyang@linux.alibaba.com
Signed-off-by: Wen Yang <wenyang@linux.alibaba.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Qian Cai <cai@lca.pw>
Cc: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/page-writeback.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/page-writeback.c~mm-page-writebackc-improve-arithmetic-divisions
+++ a/mm/page-writeback.c
@@ -1102,7 +1102,7 @@ static void wb_update_write_bandwidth(st
bw = written - min(written, wb->written_stamp);
bw *= HZ;
if (unlikely(elapsed > period)) {
- do_div(bw, elapsed);
+ bw = div64_ul(bw, elapsed);
avg = bw;
goto out;
}
_
next prev parent reply other threads:[~2020-01-14 0:29 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-14 0:28 incoming Andrew Morton
2020-01-14 0:29 ` [patch 01/11] mm, thp: tweak reclaim/compaction effort of local-only and all-node allocations Andrew Morton
2020-01-14 0:29 ` [patch 02/11] mm/memory_hotplug: don't free usage map when removing a re-added early section Andrew Morton
2020-01-14 0:29 ` [patch 03/11] mm/huge_memory.c: thp: fix conflict of above-47bit hint address and PMD alignment Andrew Morton
2020-01-14 0:29 ` [patch 04/11] mm/shmem.c: thp, shmem: " Andrew Morton
2020-01-14 0:29 ` [patch 05/11] mm: memcg/slab: fix percpu slab vmstats flushing Andrew Morton
2020-01-14 0:29 ` [patch 06/11] mm, debug_pagealloc: don't rely on static keys too early Andrew Morton
2020-01-14 0:29 ` [patch 07/11] mm/page-writeback.c: avoid potential division by zero in wb_min_max_ratio() Andrew Morton
2020-01-14 0:29 ` [patch 08/11] mm/page-writeback.c: use div64_ul() for u64-by-unsigned-long divide Andrew Morton
2020-01-14 0:29 ` Andrew Morton [this message]
2020-01-14 0:29 ` [patch 10/11] mm: memcg/slab: call flush_memcg_workqueue() only if memcg workqueue is valid Andrew Morton
2020-01-14 0:29 ` [patch 11/11] mm: khugepaged: add trace status description for SCAN_PAGE_HAS_PRIVATE Andrew Morton
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=20200114002929.P5URA%akpm@linux-foundation.org \
--to=akpm@linux-foundation.org \
--cc=axboe@kernel.dk \
--cc=cai@lca.pw \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mm-commits@vger.kernel.org \
--cc=tj@kernel.org \
--cc=torvalds@linux-foundation.org \
--cc=wenyang@linux.alibaba.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;
as well as URLs for NNTP newsgroup(s).