From: Jason Gunthorpe <jgg@ziepe.ca>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Matthew Wilcox <willy@infradead.org>,
linux-mm@kvack.org, kirill.shutemov@linux.intel.com,
pasha.tatashin@soleen.com
Subject: Re: [PATCH 1/5] mm: Constify a lot of struct page arguments
Date: Thu, 9 Apr 2020 14:12:10 -0300 [thread overview]
Message-ID: <20200409171210.GJ11886@ziepe.ca> (raw)
In-Reply-To: <20200409144744.25bloz245hmtr5rm@box>
On Thu, Apr 09, 2020 at 05:47:44PM +0300, Kirill A. Shutemov wrote:
> On Thu, Apr 09, 2020 at 07:32:38AM -0700, Matthew Wilcox wrote:
> > On Thu, Apr 09, 2020 at 05:28:51PM +0300, Kirill A. Shutemov wrote:
> > > > We have a few places that do things like
> > > >
> > > > mm/filemap.c: if (unlikely(compound_head(page)->mapping != mapping)) {
> > >
> > > Good point.
> > >
> > > Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> >
> > Darn, I hoped you'd have a better idea. I feel quite ashamed of this patch.
>
> I had two ideas. Both awful.
>
> - Rename compound_head() to __compound_head() or something and make it
> return void *. Then wrap it into a macro that would cast return type to
> type of the argument. It would allow to regain *some* type safety.
>
> - Provide two implementations and use C11 _Generic() :P
> (bump GCC version requirements first)
I saw people using static_assert stuff in the kernel, maybe C11 is
feasible now? It is 9 years old..
Jason
next prev parent reply other threads:[~2020-04-09 17:12 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-08 15:01 [PATCH 0/5] Improve page poisoning implementation Matthew Wilcox
2020-04-08 15:01 ` [PATCH 1/5] mm: Constify a lot of struct page arguments Matthew Wilcox
2020-04-08 15:14 ` Pavel Tatashin
2020-04-09 14:09 ` Kirill A. Shutemov
2020-04-09 14:15 ` Matthew Wilcox
2020-04-09 14:28 ` Kirill A. Shutemov
2020-04-09 14:32 ` Matthew Wilcox
2020-04-09 14:47 ` Kirill A. Shutemov
2020-04-09 15:00 ` Kirill A. Shutemov
2020-04-09 17:12 ` Jason Gunthorpe [this message]
2020-04-09 20:47 ` John Hubbard
2020-04-08 15:01 ` [PATCH 2/5] mm: Rename PF_POISONED_PAGE to page_poison_check Matthew Wilcox
2020-04-08 15:21 ` Pavel Tatashin
2020-04-09 14:14 ` Kirill A. Shutemov
2020-04-08 15:01 ` [PATCH 3/5] mm: Remove casting away of constness Matthew Wilcox
2020-04-08 15:23 ` Pavel Tatashin
2020-04-09 14:19 ` Kirill A. Shutemov
2020-04-08 15:01 ` [PATCH 4/5] mm: Check for page poison in both page_to_nid implementations Matthew Wilcox
2020-04-08 15:24 ` Pavel Tatashin
2020-04-09 14:21 ` Kirill A. Shutemov
2020-04-08 15:01 ` [PATCH 5/5] mm: Check page poison before finding a head page Matthew Wilcox
2020-04-08 15:32 ` Pavel Tatashin
2020-04-09 14:25 ` Kirill A. Shutemov
2020-04-08 15:11 ` [PATCH 0/5] Improve page poisoning implementation Pavel Tatashin
2020-04-09 20:55 ` John Hubbard
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