From: Oleg Nesterov <oleg@redhat.com>
To: Chen Gang <xili_gchen_5257@hotmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
"kirill.shutemov@linux.intel.com"
<kirill.shutemov@linux.intel.com>,
"riel@redhat.com" <riel@redhat.com>,
Michal Hocko <mhocko@suse.cz>,
"sasha.levin@oracle.com" <sasha.levin@oracle.com>,
"pfeiner@google.com" <pfeiner@google.com>,
"aarcange@redhat.com" <aarcange@redhat.com>,
"vishnu.ps@samsung.com" <vishnu.ps@samsung.com>,
Linux Memory <linux-mm@kvack.org>,
kernel mailing list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm/mmap.c: Remove useless statement "vma = NULL" in find_vma()
Date: Thu, 10 Sep 2015 20:19:35 +0200 [thread overview]
Message-ID: <20150910181935.GB21456@redhat.com> (raw)
In-Reply-To: <COL130-W43C0C45AA4E2A7AA6361D0B9520@phx.gbl>
On 09/10, Chen Gang wrote:
>
> On 9/10/15 00:26, Oleg Nesterov wrote:
> >
> > The implementation looks correct. Why do you think it can be not 1st vma?
> >
>
> It is in while (rb_node) {...}.
>
> - When we set "vma = tmp", it is alreay match "addr < vm_end".
Yes,
> - If "addr>= vm_start", we return this vma (else continue searching).
This is optimization, we can stop the search because in this case
vma == tmp is obviously the 1st vma with "addr < vm_end".
I simply can't understand your concerns. Perhaps you can make a
patch, then it will be more clear what me-or-you have missed.
Oleg.
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WARNING: multiple messages have this Message-ID (diff)
From: Oleg Nesterov <oleg@redhat.com>
To: Chen Gang <xili_gchen_5257@hotmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
"kirill.shutemov@linux.intel.com"
<kirill.shutemov@linux.intel.com>,
"riel@redhat.com" <riel@redhat.com>,
Michal Hocko <mhocko@suse.cz>,
"sasha.levin@oracle.com" <sasha.levin@oracle.com>,
"pfeiner@google.com" <pfeiner@google.com>,
"aarcange@redhat.com" <aarcange@redhat.com>,
"vishnu.ps@samsung.com" <vishnu.ps@samsung.com>,
Linux Memory <linux-mm@kvack.org>,
kernel mailing list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm/mmap.c: Remove useless statement "vma = NULL" in find_vma()
Date: Thu, 10 Sep 2015 20:19:35 +0200 [thread overview]
Message-ID: <20150910181935.GB21456@redhat.com> (raw)
In-Reply-To: <COL130-W43C0C45AA4E2A7AA6361D0B9520@phx.gbl>
On 09/10, Chen Gang wrote:
>
> On 9/10/15 00:26, Oleg Nesterov wrote:
> >
> > The implementation looks correct. Why do you think it can be not 1st vma?
> >
>
> It is in while (rb_node) {...}.
>
> - When we set "vma = tmp", it is alreay match "addr < vm_end".
Yes,
> - If "addr>= vm_start", we return this vma (else continue searching).
This is optimization, we can stop the search because in this case
vma == tmp is obviously the 1st vma with "addr < vm_end".
I simply can't understand your concerns. Perhaps you can make a
patch, then it will be more clear what me-or-you have missed.
Oleg.
next prev parent reply other threads:[~2015-09-10 18:22 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-05 14:03 [PATCH] mm/mmap.c: Remove useless statement "vma = NULL" in find_vma() Chen Gang
2015-09-07 12:36 ` Oleg Nesterov
2015-09-07 12:36 ` Oleg Nesterov
[not found] ` <55EEED66.6090509@hotmail.com>
2015-09-08 14:14 ` Chen Gang
2015-09-08 14:14 ` Chen Gang
2015-09-09 16:26 ` Oleg Nesterov
2015-09-09 16:26 ` Oleg Nesterov
[not found] ` <55F0B6C2.2000706@hotmail.com>
2015-09-09 22:44 ` Chen Gang
2015-09-09 22:44 ` Chen Gang
2015-09-10 18:19 ` Oleg Nesterov [this message]
2015-09-10 18:19 ` Oleg Nesterov
2015-09-10 22:20 ` Chen Gang
2015-09-10 22:20 ` Chen Gang
2015-09-08 23:14 ` David Rientjes
2015-09-08 23:14 ` David Rientjes
-- strict thread matches above, loose matches on Subject: below --
2015-09-03 3:52 gang.chen.5i5j
2015-09-03 4:02 ` Chen Gang
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