Re: [PATCH v3 05/13] epoll: offload polling to a work in case of epfd polled from userspace

[Roman Penyaev]

On 2019-05-21 09:51, Eric Wong wrote:
> Roman Penyaev <rpenyaev@xxxxxxx> wrote:
> > diff --git a/fs/eventpoll.c b/fs/eventpoll.c
> > index 81da4571f1e0..9d3905c0afbf 100644
> > --- a/fs/eventpoll.c
> > +++ b/fs/eventpoll.c
> > @@ -44,6 +44,7 @@
> >  #include <linux/seq_file.h>
> >  #include <linux/compat.h>
> >  #include <linux/rculist.h>
> > +#include <linux/workqueue.h>
> >  #include <net/busy_poll.h>
> >
> >  /*
> > @@ -185,6 +186,9 @@ struct epitem {
> >
> >  	/* The structure that describe the interested events and the source 
> > fd */
> >  	struct epoll_event event;
> > +
> > +	/* Work for offloading event callback */
> > +	struct work_struct work;
> >  };
> >
> >  /*
>
> Can we avoid the size regression for existing epoll users?

Yeah, ->next, ->rdllink, ->ws are not used for user polling, so can hold 
work
struct and co (or pointer on container which holds work struct, if work 
struct
is huge).

--
Roman