From: Afzal Mohammed <afzal.mohd.ma@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Afzal Mohammed <afzal.mohd.ma@gmail.com>
Subject: [PATCH v2] sched,fair: Remove > u32 weight handling for delta
Date: Mon, 6 Jul 2015 23:49:15 +0530 [thread overview]
Message-ID: <1436206755-2540-1-git-send-email-afzal.mohd.ma@gmail.com> (raw)
In-Reply-To: <20150706133407.GA5861@afzalpc>
scaled down weight 'fact' would not be > u32 rather than unlikely as the
weight being passed in __calc_delta() is either 'se->load.weight' or
NICE_O_LOAD. 'se->load.weight' would be one of the values of
prio_to_weight[] in the case of task, while in the case of task group it
would be capped to MAX_SHARES. All those possible values can fit in u32.
Hence remove the initial > u32 handling on 'fact'.
Signed-off-by: Afzal Mohammed <afzal.mohd.ma@gmail.com>
---
v2: expand change log on why weight can fit in u32, remove incorrect
comments.
kernel/sched/fair.c | 7 -------
1 file changed, 7 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 65c8f3ebdc3c..22cf3958bbac 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -218,13 +218,6 @@ static u64 __calc_delta(u64 delta_exec, unsigned long weight, struct load_weight
__update_inv_weight(lw);
- if (unlikely(fact >> 32)) {
- while (fact >> 32) {
- fact >>= 1;
- shift--;
- }
- }
-
/* hint to use a 32x32->64 mul */
fact = (u64)(u32)fact * lw->inv_weight;
--
2.1.4
next prev parent reply other threads:[~2015-07-06 18:19 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-06 2:44 [PATCH] " Afzal Mohammed
2015-07-06 11:44 ` Peter Zijlstra
2015-07-06 13:34 ` Afzal Mohammed
2015-07-06 14:39 ` Afzal Mohammed
2015-07-06 18:19 ` Afzal Mohammed [this message]
2015-08-12 11:12 ` [PATCH v2] " Afzal Mohammed
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=1436206755-2540-1-git-send-email-afzal.mohd.ma@gmail.com \
--to=afzal.mohd.ma@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.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
all inboxes | Powered by JetHome®