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From: Nathaniel Yazdani <n1ght.4nd.d4y@gmail.com>
To: Eric Wong <normalperson@yhbt.net>
Cc: viro@zeniv.linux.org.uk, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH for-next 2/4] epoll: epoll() syscall declaration
Date: Tue, 25 Feb 2014 15:44:16 -0800
Message-ID: <1393371856.2886.2.camel@linux-whg8.site> (raw)
In-Reply-To: <20140225103013.GB9963@dcvr.yhbt.net>

On Tue, 2014-02-25 at 10:30 +0000, Eric Wong wrote:
> Nathaniel Yazdani <n1ght.4nd.d4y@gmail.com> wrote:
> > On Sun, Feb 23, 2014 at 9:32 PM, Eric Wong <normalperson@yhbt.net> wrote:
> > > Nathaniel Yazdani <n1ght.4nd.d4y@gmail.com> wrote:
> > >> +asmlinkage long sys_epoll(int ep, struct epoll __user *in,
> > >> +                       unsigned int inc, struct epoll __user *out,
> > >> +                       unsigned int outc, int timeout);
> > >
> > > I can understand using the new struct for 'in', but 'out' could just be
> > > "struct epoll_event *" like sys_epoll_wait, right?
> > >
> > >>  asmlinkage long sys_epoll_wait(int epfd, struct epoll_event __user *events,
> > 
> > Yeah and I went back and forth on that, it just seemed to me that the
> > inconsistency could be confusing to others... maybe instead of defining a new
> > struct to begin with it might make me sense to just have an 'infd' array of file
> > descriptors in addition to an 'in' array of epoll_event struct
> > (obviously the length
> > of these would be identical).
> 
> I don't think a separate array for in is a good idea, too error prone
> and you lose locality.
> 
> For output, some users either end up allocating more memory/retrieve
> fewer items with the larger struct for *out.
Well having a different struct for input and output would be just as
error prone too, plus the file descriptor of a triggered event is
highly relevant information.


  reply index

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-24  1:42 [RFC PATCH for-next 0/4] epoll: combined control/wait syscall Nathaniel Yazdani
2014-02-24  1:42 ` [RFC PATCH for-next 1/4] epoll: struct epoll userspace definiton Nathaniel Yazdani
2014-02-24  5:29   ` Eric Wong
     [not found]     ` <CAJ3m7Bq1y+MLn=HFY3AADnVc2HK31+WANahiYLUcdBw=hh_2pg@mail.gmail.com>
     [not found]       ` <20140225101527.GA9963@dcvr.yhbt.net>
2014-02-26  0:13         ` Nathaniel Yazdani
2014-02-24  1:42 ` [RFC PATCH for-next 2/4] epoll: epoll() syscall declaration Nathaniel Yazdani
2014-02-24  5:32   ` Eric Wong
2014-02-24  5:44     ` Nathaniel Yazdani
2014-02-25 10:30       ` Eric Wong
2014-02-25 23:44         ` Nathaniel Yazdani [this message]
2014-02-24  1:42 ` [RFC PATCH for-next 3/4] epoll: struct epoll support Nathaniel Yazdani
2014-02-24 18:59   ` Jonathan Corbet
2014-02-24 19:24     ` Nathaniel Yazdani
2014-02-24  1:42 ` [RFC PATCH for-next 4/4] epoll: epoll() syscall definition Nathaniel Yazdani
2014-02-25 10:21   ` Eric Wong
2014-02-25 23:46     ` Nathaniel Yazdani

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