[PATCH] [RFC] Checkpoint/restart eventfd

[Matt Helsley]

On Sun, Oct 25, 2009 at 02:07:00PM -0400, Oren Laadan wrote:
> 
> 
> Matt Helsley wrote:
> > Save/restore eventfd files. These are anon_inodes just like epoll
> > but instead of a set of files to poll they are a 64-bit counter
> > and a flag value. Used for AIO.
> > 
> > Signed-off-by: Matt Helsley <matthltc at us.ibm.com>
> 
> Looks fine to me, except a nit below. Unless there are negative
> comments I'll pull it in a couple of days (and fix the nits).
> 
> Oren.
> 
> > 
> > NOTE: Marked [RFC] because it strangely does not pass my adapted LTP
> > 	test cases unless it's running from a checkpointed image.
> > 	Seems to be a mistake in the test case adaptation.
> > ---
> >  checkpoint/files.c             |    7 +++++
> >  fs/eventfd.c                   |   51 ++++++++++++++++++++++++++++++++++++++++
> >  include/linux/checkpoint_hdr.h |    8 ++++++
> >  include/linux/eventfd.h        |   10 ++++++++
> >  4 files changed, 76 insertions(+), 0 deletions(-)
> > 
> > diff --git a/checkpoint/files.c b/checkpoint/files.c
> > index f6de07e..43b95cc 100644
> > --- a/checkpoint/files.c
> > +++ b/checkpoint/files.c
> > @@ -23,6 +23,7 @@
> >  #include <linux/checkpoint.h>
> >  #include <linux/checkpoint_hdr.h>
> >  #include <net/sock.h>
> > +#include <linux/eventfd.h>
> >  
> >  
> >  /**************************************************************************
> > @@ -607,6 +608,12 @@ static struct restore_file_ops restore_file_ops[] = {
> >  		.file_type = CKPT_FILE_TTY,
> >  		.restore = tty_file_restore,
> >  	},
> > +	/* eventfd */
> > +	{
> > +		.file_name = "EVENTFD",
> > +		.file_type = CKPT_FILE_EVENTFD,
> > +		.restore = eventfd_restore,
> > +	},
> >  };
> >  
> >  static struct file *do_restore_file(struct ckpt_ctx *ctx)
> > diff --git a/fs/eventfd.c b/fs/eventfd.c
> > index 31d12de..5d30cd5 100644
> > --- a/fs/eventfd.c
> > +++ b/fs/eventfd.c
> > @@ -18,6 +18,8 @@
> >  #include <linux/module.h>
> >  #include <linux/kref.h>
> >  #include <linux/eventfd.h>
> > +#include <linux/checkpoint.h>
> > +#include <linux/checkpoint_hdr.h>
> >  
> >  struct eventfd_ctx {
> >  	struct kref kref;
> > @@ -223,11 +225,34 @@ static ssize_t eventfd_write(struct file *file, const char __user *buf, size_t c
> >  	return res;
> >  }
> >  
> > +static int eventfd_checkpoint(struct ckpt_ctx *ckpt_ctx, struct file *file)
> > +{
> > +	struct eventfd_ctx *ctx;
> 
> Nit: everywhere else we use @ctx for ckpt_ctx, so to avoid
> confusion, I suggest:
> 	struct eventfd_ctx *efd_ctx;

No. The code in that file usually refers to "ctx" as an eventfd context. It
seems wrong to adopt a contradictory naming convention just for the
checkpoint portions of that code. I'd be happy to rename ckpt_ctx but
not to ctx.

Cheers,
	-Matt Helsley