From: Nhat Pham <nphamcs@gmail.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Johannes Weiner <hannes@cmpxchg.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
bfoster@redhat.com, Matthew Wilcox <willy@infradead.org>,
linux-api@vger.kernel.org, kernel-team@meta.com
Subject: Re: [PATCH v13 2/3] cachestat: implement cachestat syscall
Date: Wed, 10 May 2023 16:20:53 -0700 [thread overview]
Message-ID: <CAKEwX=NW=sHAkQQw3TPA5tK9O+MC9AwX05=Wp8DRFbRZ4w-JAg@mail.gmail.com> (raw)
In-Reply-To: <315e7ec2-169c-4c4b-93df-485380bc0852@app.fastmail.com>
On Sat, May 6, 2023 at 10:35 AM Arnd Bergmann <arnd@arndb.de> wrote:
>
> On Fri, May 5, 2023, at 22:34, Andrew Morton wrote:
> > On Thu, 4 May 2023 19:26:11 +0200 Geert Uytterhoeven
> > <geert@linux-m68k.org> wrote:
> >
> >> > arch/x86/entry/syscalls/syscall_32.tbl | 1 +
> >> > arch/x86/entry/syscalls/syscall_64.tbl | 1 +
> >>
> >> This should be wired up on each and every architecture.
> >> Currently we're getting
> >>
> >> <stdin>:1567:2: warning: #warning syscall cachestat not implemented [-Wcpp]
> >>
> >> in linux-next for all the missing architectures.
> >
> > Is that wise? We risk adding a syscall to an architecture without the
> > arch maintainers and testers even knowing about it.
> >
> > The compile-time nag is there to inform the arch maintainers that a new
> > syscall is available and that they should wire it up, run the selftest
> > and then ship the code if they're happy with the result.
>
> The usual approach is for the author of a new syscall to
> include a patch with all the architecture specific changes
> and Cc the architecture maintainers for that.
>
> Note that half the architectures get the entry from
> include/uapi/asm-generic/unistd.h, so adding it there
> does not necessarily trigger adding each maintainer
> from scripts/get_maintainer.pl.
>
> The only real risk in adding a new syscall is passing __u64
> register arguments that behave differently across
> architectures, or using pointers to data structures that
> require a compat handler on some architectures. I watch out
> for those as they get sent to me or the linux-arch list,
> and this one is fine.
>
> Arnd
I took a stab at wiring the new syscall in this follow-up patch:
https://lore.kernel.org/lkml/20230510195806.2902878-1-nphamcs@gmail.com/
Let me know if I missed something! Review and/or suggestion
is very much appreciated.
next prev parent reply other threads:[~2023-05-10 23:21 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-03 1:36 [PATCH v13 0/3] cachestat: a new syscall for page cache state of files Nhat Pham
2023-05-03 1:36 ` [PATCH v13 1/3] workingset: refactor LRU refault to expose refault recency check Nhat Pham
2023-05-03 14:31 ` Johannes Weiner
2023-05-03 1:36 ` [PATCH v13 2/3] cachestat: implement cachestat syscall Nhat Pham
2023-05-03 15:04 ` Johannes Weiner
2023-05-04 2:25 ` Nhat Pham
2023-05-04 17:26 ` Geert Uytterhoeven
2023-05-04 18:06 ` Nhat Pham
2023-05-05 20:34 ` Andrew Morton
2023-05-06 17:35 ` Arnd Bergmann
2023-05-10 23:20 ` Nhat Pham [this message]
2023-05-03 1:36 ` [PATCH v13 3/3] selftests: Add selftests for cachestat Nhat Pham
2023-05-03 15:22 ` Johannes Weiner
2023-05-11 3:21 ` Michael Ellerman
2023-05-11 19:33 ` Nhat Pham
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