linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: carver4lio@163.com
To: rppt@kernel.org
Cc: akpm@linux-foundation.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org,
	Hailong Liu <liu.hailong6@zte.com.cn>
Subject: [PATCH] mm/memblock:use a more appropriate order calculation when free memblock pages
Date: Thu,  3 Dec 2020 23:23:10 +0800	[thread overview]
Message-ID: <20201203152311.5272-1-carver4lio@163.com> (raw)

From: Hailong Liu <liu.hailong6@zte.com.cn>

When system in the booting stage, pages span from [start, end] of a memblock
are freed to buddy in a order as large as possible (less than MAX_ORDER) at
first, then decrease gradually to a proper order(less than end) in a loop.

However, *min(MAX_ORDER - 1UL, __ffs(start))* can not get the largest order
in some cases.
Instead, *__ffs(end - start)* may be more appropriate and meaningful.

Signed-off-by: Hailong Liu <liu.hailong6@zte.com.cn>
---
 mm/memblock.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/memblock.c b/mm/memblock.c
index b68ee8678..7c6d0dde7 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -1931,7 +1931,7 @@ static void __init __free_pages_memory(unsigned long start, unsigned long end)
 	int order;
 
 	while (start < end) {
-		order = min(MAX_ORDER - 1UL, __ffs(start));
+		order = min(MAX_ORDER - 1UL, __ffs(end - start));
 
 		while (start + (1UL << order) > end)
 			order--;
-- 
2.17.1



             reply	other threads:[~2020-12-03 23:27 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-03 15:23 carver4lio [this message]
2020-12-04 13:42 ` [PATCH] mm/memblock:use a more appropriate order calculation when free memblock pages Qian Cai
     [not found]   ` <CGME20201204160751eucas1p13cc7aad8c68dd2a495c4bbf422c4228c@eucas1p1.samsung.com>
2020-12-04 16:07     ` Marek Szyprowski
2020-12-04 17:43       ` Jon Hunter
2020-12-05 17:09         ` Anders Roxell
2020-12-05 17:12           ` Anders Roxell
2020-12-06 11:55 ` Mike Rapoport
2020-12-06 14:21   ` carver4lio

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=20201203152311.5272-1-carver4lio@163.com \
    --to=carver4lio@163.com \
    --cc=akpm@linux-foundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=liu.hailong6@zte.com.cn \
    --cc=rppt@kernel.org \
    /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).