linux-kernel - Re: [PATCH v8 2/4] uprobe: use original page when all uprobes are removed

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Message-ID: <58E13FCB-FE49-454F-995F-832870D314F1@fb.com>
Date:   Wed, 24 Jul 2019 09:20:22 +0000
From:   Song Liu <songliubraving@...com>
To:     Oleg Nesterov <oleg@...hat.com>
CC:     lkml <linux-kernel@...r.kernel.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
        "matthew.wilcox@...cle.com" <matthew.wilcox@...cle.com>,
        "kirill.shutemov@...ux.intel.com" <kirill.shutemov@...ux.intel.com>,
        "peterz@...radead.org" <peterz@...radead.org>,
        "rostedt@...dmis.org" <rostedt@...dmis.org>,
        "Kernel Team" <Kernel-team@...com>,
        "william.kucharski@...cle.com" <william.kucharski@...cle.com>
Subject: Re: [PATCH v8 2/4] uprobe: use original page when all uprobes are
 removed



> On Jul 24, 2019, at 2:17 AM, Oleg Nesterov <oleg@...hat.com> wrote:
> 
> On 07/24, Oleg Nesterov wrote:
>> 
>> On 07/24, Song Liu wrote:
>>> 
>>> This patch allows uprobe to use original page when possible (all uprobes
>>> on the page are already removed).
>> 
>> and only if the original page is already in the page cache and uptodate,
>> right?
>> 
>> another reason why I think unmap makes more sense... but I won't argue.
> 
> but somehow I forgot we need to read the original page anyway to check
> pages_identical(), so unmap is not really better, please forget.
> 

Yeah, I was trying to explain this. :)

Thanks for your feedbacks. 
Song