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From: Matthew Wilcox <willy@infradead.org>
To: Aneesh Kumar K V <aneesh.kumar@linux.ibm.com>
Cc: linux-mm@kvack.org, akpm@linux-foundation.org,
	Yu Zhao <yuzhao@google.com>,
	"T . J . Alumbaugh" <talumbau@google.com>
Subject: Re: [PATCH 3/3] mm/lru_gen: Don't build multi-gen LRU page table walk code on architecture not supported
Date: Tue, 13 Jun 2023 14:36:06 +0100	[thread overview]
Message-ID: <ZIhwxspMuQGGKaX/@casper.infradead.org> (raw)
In-Reply-To: <e53c2e4d-71c7-74fd-0019-5f36b13861f3@linux.ibm.com>

On Tue, Jun 13, 2023 at 06:58:41PM +0530, Aneesh Kumar K V wrote:
> On 6/13/23 5:53 PM, Matthew Wilcox wrote:
> > On Tue, Jun 13, 2023 at 05:30:47PM +0530, Aneesh Kumar K.V wrote:
> >> @@ -4498,7 +4533,7 @@ static bool try_to_inc_max_seq(struct lruvec *lruvec, unsigned long max_seq,
> >>  		goto done;
> >>  	}
> >>  
> >> -	walk = set_mm_walk(NULL, true);
> >> +	walk = (struct lru_gen_mm_walk *)set_mm_walk(NULL, true);
> > 
> > This isn't C++.
> > 
> 
> We have similar pattern for things like kmalloc()?

No.  No, we don't.  Nobody does that.  Perhaps some really crappy code
in staging.  DO NOT USE CASTS.

> I understand the desire to have functions return
> the correct type. But the amount of code that we are able to avoid with this patch for certain architecture is
> really large. 

There's probably a better way to do what you're trying to do, but the
simple fact remains that the cast you added is needed in C++ and not in C.
Linux is not written in C++.  Do not add the cast.


  reply	other threads:[~2023-06-13 13:28 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-06-13 12:00 [PATCH 1/3] mm/lru_gen: Move some code around so that next patch is simpler Aneesh Kumar K.V
2023-06-13 12:00 ` [PATCH 2/3] mm/lru_gen: lru_gen_look_around simplification Aneesh Kumar K.V
2023-06-13 12:00 ` [PATCH 3/3] mm/lru_gen: Don't build multi-gen LRU page table walk code on architecture not supported Aneesh Kumar K.V
2023-06-13 12:23   ` Matthew Wilcox
2023-06-13 13:28     ` Aneesh Kumar K V
2023-06-13 13:36       ` Matthew Wilcox [this message]
2023-06-13 13:47         ` Aneesh Kumar K V
2023-06-21  2:27   ` kernel test robot
2023-06-24 14:53   ` Aneesh Kumar K.V
2023-06-25 19:34     ` Yu Zhao
2023-06-26 10:52       ` Aneesh Kumar K V
2023-06-26 17:04         ` Yu Zhao
2023-06-27 11:48           ` Aneesh Kumar K V
2023-06-27 19:10             ` Yu Zhao

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