From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
To: Arnd Bergmann <arnd@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>,
David Laight <David.Laight@aculab.com>,
Linux FS-devel Mailing List <linux-fsdevel@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Al Viro <viro@zeniv.linux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>,
Soheil Hassas Yeganeh <soheil.kdev@gmail.com>,
Arnd Bergmann <arnd@arndb.de>, Shuo Chen <shuochen@google.com>,
linux-man <linux-man@vger.kernel.org>,
Willem de Bruijn <willemb@google.com>
Subject: Re: [PATCH v3 1/2] epoll: add nsec timeout support with epoll_pwait2
Date: Fri, 20 Nov 2020 17:28:12 -0500 [thread overview]
Message-ID: <CAF=yD-LdtCCY=Mg9CruZHdjBXV6VmEPydzwfcE2BHUC8z7Xgng@mail.gmail.com> (raw)
In-Reply-To: <CAK8P3a1cJf7+b5HCmFiLq+FdM+D+37rHYaftRgRYbhTyjwR6wg@mail.gmail.com>
On Fri, Nov 20, 2020 at 2:23 PM Arnd Bergmann <arnd@kernel.org> wrote:
>
> On Fri, Nov 20, 2020 at 5:01 PM Willem de Bruijn
> <willemdebruijn.kernel@gmail.com> wrote:
> >
> > On Fri, Nov 20, 2020 at 3:13 AM Arnd Bergmann <arnd@kernel.org> wrote:
> > >
> > > On Thu, Nov 19, 2020 at 9:13 PM Willem de Bruijn
> > > <willemdebruijn.kernel@gmail.com> wrote:
> > > > On Thu, Nov 19, 2020 at 10:45 AM Arnd Bergmann <arnd@kernel.org> wrote:
>
> > Thanks for the suggestion.
> >
> > I do have an initial patchset. As expected, it does involve quite a
> > bit of code churn to pass slack through the callers. I'll take a look
> > at your suggestion to simplify it.
> >
> > As is, the patchset is not ready to send to the list for possible
> > merge. In the meantime, I did push the patchset to github at
> > https://github.com/wdebruij/linux/commits/epoll-nstimeo-1 . I can send
> > a version marked RFC to the list if that's easier.
>
> Looks all good to me, just two small things I noticed that you can
> address before sending the new series:
>
> * The div_u64_rem() in ep_timeout_to_timespec() looks wrong, as
> you are actually dividing a 'long' that does not need it.
>
> * In "epoll: wire up syscall epoll_pwait2", the alpha syscall has the
> wrong number, it
> should be 110 higher than the others, not 109.
Thanks! I'll fix these up.
> > Btw, the other change, to convert epoll implementation to timespec64
> > before adding the syscall, equally adds some code churn compared to
> > patch v3. But perhaps the end state is cleaner and more consistent.
>
> Right, that's what I meant. If it causes too much churn, don't worry
> about it it.
I think it'll be better to split the patchsets:
epoll: convert internal api to timespec64
epoll: add syscall epoll_pwait2
epoll: wire up syscall epoll_pwait2
selftests/filesystems: expand epoll with epoll_pwait2
and
select: compute slack based on relative time
epoll: compute slack based on relative time
and judge the slack conversion on its own merit.
I also would rather not tie this up with the compat deduplication.
Happy to take a stab at that though. On that note, when combining
functions like
int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
fd_set __user *exp, struct timespec64 *end_time,
u64 slack)
and
static int compat_core_sys_select(int n, compat_ulong_t __user *inp,
compat_ulong_t __user *outp, compat_ulong_t __user *exp,
struct timespec64 *end_time, u64 slack)
by branching on in_compat_syscall() inside get_fd_set/set_fd_set and
deprecating their compat_.. counterparts, what would the argument
pointers look like? Or is that not the approach you have in mind?
next prev parent reply other threads:[~2020-11-20 22:28 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-18 14:46 [PATCH v3 0/2] add epoll_pwait2 syscall Willem de Bruijn
2020-11-18 14:46 ` [PATCH v3 1/2] epoll: add nsec timeout support with epoll_pwait2 Willem de Bruijn
2020-11-18 15:00 ` Matthew Wilcox
2020-11-18 15:10 ` Willem de Bruijn
2020-11-18 15:37 ` Arnd Bergmann
2020-11-18 15:59 ` David Laight
2020-11-19 14:19 ` Willem de Bruijn
2020-11-19 14:31 ` Matthew Wilcox
2020-11-19 15:37 ` Willem de Bruijn
2020-11-19 15:45 ` Arnd Bergmann
2020-11-19 20:13 ` Willem de Bruijn
2020-11-20 8:13 ` Arnd Bergmann
2020-11-20 16:01 ` Willem de Bruijn
2020-11-20 19:23 ` Arnd Bergmann
2020-11-20 22:28 ` Willem de Bruijn [this message]
2020-11-21 9:27 ` Arnd Bergmann
2020-12-10 17:33 ` Willem de Bruijn
2020-12-10 20:34 ` Arnd Bergmann
2020-12-10 22:59 ` Willem de Bruijn
2021-01-11 20:06 ` Willem de Bruijn
2020-11-18 16:21 ` Willem de Bruijn
2020-11-18 16:50 ` Arnd Bergmann
2020-11-19 3:22 ` Willem de Bruijn
2020-11-18 14:46 ` [PATCH manpages RFC] epoll_wait.2: add epoll_pwait2 Willem de Bruijn
2020-11-18 14:46 ` [PATCH v3 2/2] selftests/filesystems: expand epoll with epoll_pwait2 Willem de Bruijn
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