All of lore.kernel.org
 help / color / mirror / Atom feed
From: Sasha Levin <sasha.levin@oracle.com>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>,
	akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
	riel@redhat.com, peterz@infradead.org, linux-mm@kvack.org
Subject: Re: [PATCH] mm: initialize variable for mem_cgroup_end_page_stat
Date: Thu, 30 Oct 2014 12:02:52 -0400	[thread overview]
Message-ID: <5452612C.5090609@oracle.com> (raw)
In-Reply-To: <20141030150624.GA24818@phnom.home.cmpxchg.org>

On 10/30/2014 11:06 AM, Johannes Weiner wrote:
>> You're using that value as soon as you are passing it to a function, it
>> > doesn't matter what happens inside that function.
> It's copied as part of the pass-by-value protocol, but we really don't
> do anything with it.  So why does it matter?

Because it's undefined behaviour, which gives your compiler a license to
do whatever it wants?


Thanks,
Sasha

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

WARNING: multiple messages have this Message-ID (diff)
From: Sasha Levin <sasha.levin@oracle.com>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>,
	akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
	riel@redhat.com, peterz@infradead.org, linux-mm@kvack.org
Subject: Re: [PATCH] mm: initialize variable for mem_cgroup_end_page_stat
Date: Thu, 30 Oct 2014 12:02:52 -0400	[thread overview]
Message-ID: <5452612C.5090609@oracle.com> (raw)
In-Reply-To: <20141030150624.GA24818@phnom.home.cmpxchg.org>

On 10/30/2014 11:06 AM, Johannes Weiner wrote:
>> You're using that value as soon as you are passing it to a function, it
>> > doesn't matter what happens inside that function.
> It's copied as part of the pass-by-value protocol, but we really don't
> do anything with it.  So why does it matter?

Because it's undefined behaviour, which gives your compiler a license to
do whatever it wants?


Thanks,
Sasha


  reply	other threads:[~2014-10-30 16:03 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-30  1:44 [PATCH] mm: initialize variable for mem_cgroup_end_page_stat Sasha Levin
2014-10-30  1:44 ` Sasha Levin
2014-10-30  8:27 ` Michal Hocko
2014-10-30  8:27   ` Michal Hocko
2014-10-30 13:32   ` Sasha Levin
2014-10-30 13:32     ` Sasha Levin
2014-10-30 14:14     ` Johannes Weiner
2014-10-30 14:14       ` Johannes Weiner
2014-10-30 14:24       ` Sasha Levin
2014-10-30 14:24         ` Sasha Levin
2014-10-30 15:06         ` Johannes Weiner
2014-10-30 15:06           ` Johannes Weiner
2014-10-30 16:02           ` Sasha Levin [this message]
2014-10-30 16:02             ` Sasha Levin
2014-10-30 15:31         ` Michal Hocko
2014-10-30 15:31           ` Michal Hocko
2014-10-30 17:26           ` Johannes Weiner
2014-10-30 17:26             ` Johannes Weiner
2014-10-30 17:42             ` Michal Hocko
2014-10-30 17:42               ` Michal Hocko
2014-10-30 19:30               ` Peter Zijlstra
2014-10-30 19:30                 ` Peter Zijlstra
2014-10-31 18:17               ` Johannes Weiner
2014-10-31 18:17                 ` Johannes Weiner

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=5452612C.5090609@oracle.com \
    --to=sasha.levin@oracle.com \
    --cc=akpm@linux-foundation.org \
    --cc=hannes@cmpxchg.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mhocko@suse.cz \
    --cc=peterz@infradead.org \
    --cc=riel@redhat.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.