From: Song Liu <songliubraving@fb.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: lkml <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>,
"Andrew Morton" <akpm@linux-foundation.org>,
"matthew.wilcox@oracle.com" <matthew.wilcox@oracle.com>,
"kirill.shutemov@linux.intel.com"
<kirill.shutemov@linux.intel.com>,
"peterz@infradead.org" <peterz@infradead.org>,
"rostedt@goodmis.org" <rostedt@goodmis.org>,
"Kernel Team" <Kernel-team@fb.com>,
"william.kucharski@oracle.com" <william.kucharski@oracle.com>
Subject: Re: [PATCH v8 2/4] uprobe: use original page when all uprobes are removed
Date: Fri, 26 Jul 2019 21:19:54 +0000 [thread overview]
Message-ID: <4398BBD5-31AB-4342-9572-32763B016175@fb.com> (raw)
In-Reply-To: <20190726084423.GA16112@redhat.com>
> On Jul 26, 2019, at 1:44 AM, Oleg Nesterov <oleg@redhat.com> wrote:
>
> On 07/25, Song Liu wrote:
>>
>> I guess I know the case now. We can probably avoid this with an simp\x10le
>> check for old_page == new_page?
>
> better yet, I think we can check PageAnon(old_page) and avoid the unnecessary
> __replace_page() in this case. See the patch below.
I added PageAnon(old_page) check in v9 of the patch.
>
> Anyway, why __replace_page() needs to lock both pages? This doesn't look nice
> even if it were correct. I think it can do lock_page(old_page) later.
>
Agreed. I have changed the v9 to only unmap old_page. So it should be cleaner.
Thanks again for these good suggestions,
Song
next prev parent reply other threads:[~2019-07-26 21:20 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-24 8:35 [PATCH v8 0/4] THP aware uprobe Song Liu
2019-07-24 8:35 ` [PATCH v8 1/4] mm: move memcmp_pages() and pages_identical() Song Liu
2019-07-24 8:35 ` [PATCH v8 2/4] uprobe: use original page when all uprobes are removed Song Liu
2019-07-24 9:07 ` Oleg Nesterov
2019-07-24 9:17 ` Oleg Nesterov
2019-07-24 9:20 ` Song Liu
2019-07-24 11:37 ` Oleg Nesterov
2019-07-24 18:52 ` Song Liu
2019-07-25 8:14 ` Oleg Nesterov
2019-07-25 18:17 ` Song Liu
2019-07-26 6:07 ` Song Liu
2019-07-26 8:44 ` Oleg Nesterov
2019-07-26 21:19 ` Song Liu [this message]
2019-07-24 8:35 ` [PATCH v8 3/4] mm, thp: introduce FOLL_SPLIT_PMD Song Liu
2019-07-24 8:36 ` [PATCH v8 4/4] uprobe: use FOLL_SPLIT_PMD instead of FOLL_SPLIT Song Liu
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