linux-kernel - Re: [PATCH v5 1/1] mm/memory-failure: disable unpoison once hw error happens

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Date:   Wed, 15 Jun 2022 08:43:45 +0000
From:   HORIGUCHI NAOYA(堀口　直也) 
        <naoya.horiguchi@....com>
To:     David Hildenbrand <david@...hat.com>
CC:     zhenwei pi <pizhenwei@...edance.com>,
        "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linmiaohe@...wei.com" <linmiaohe@...wei.com>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>
Subject: Re: [PATCH v5 1/1] mm/memory-failure: disable unpoison once hw error
 happens

On Wed, Jun 15, 2022 at 10:21:09AM +0200, David Hildenbrand wrote:
> On 15.06.22 10:15, HORIGUCHI NAOYA(堀口 直也) wrote:
> > On Wed, Jun 15, 2022 at 10:00:05AM +0800, zhenwei pi wrote:
...
> > 
> > ...
> > 
> >> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> >> index b85661cbdc4a..385b5e99bfc1 100644
> >> --- a/mm/memory-failure.c
> >> +++ b/mm/memory-failure.c
> >> @@ -69,6 +69,8 @@ int sysctl_memory_failure_recovery __read_mostly = 1;
> >>  
> >>  atomic_long_t num_poisoned_pages __read_mostly = ATOMIC_LONG_INIT(0);
> >>  
> >> +static bool hw_memory_failure;
> > 
> > Could you set the initial value explicitly?  Using a default value is good,
> > but doing as the surrounding code do is better for consistency.  And this
> > variable can be updated only once, so adding __read_mostly macro is also fine.
> 
> No strong opinion. __read_mostly makes sense, but I assume we don't
> really care about performance that much when dealing with HW errors.

That's right, mm/memory-failure.c should be mostly performance insensitive.

- Naoya Horiguchi