linux-toradex.git/drivers/xen/tmem.c, branch v3.10.15

xen/tmem: Don't over-write tmem_frontswap_poolid after tmem_frontswap_init set it.

2013-06-10T14:14:33+00:00

Commit 10a7a0771399a57a297fca9615450dbb3f88081a ("xen: tmem: enable Xen
tmem shim to be built/loaded as a module") allows the tmem module
to be loaded any time. For this work the frontswap API had to
be able to asynchronously to call tmem_frontswap_init before
or after the swap image had been set. That was added in git
commit 905cd0e1bf9ffe82d6906a01fd974ea0f70be97a
("mm: frontswap: lazy initialization to allow tmem backends to build/run as modules").

Which means we could do this (The common case):

 modprobe tmem		[so calls frontswap_register_ops, no ->init]
			 modifies tmem_frontswap_poolid = -1
 swapon /dev/xvda1	[__frontswap_init, calls -> init, tmem_frontswap_poolid is
			 < 0 so tmem hypercall done]

Or the failing one:

 swapon /dev/xvda1	[calls __frontswap_init, sets the need_init bitmap]
 modprobe tmem		[calls frontswap_register_ops, -->init calls, finds out
			tmem_frontswap_poolid is 0, does not make a hypercall.
			Later in the module_init, sets tmem_frontswap_poolid=-1]

Which meant that in the failing case we would not call the hypercall
to initialize the pool and never be able to make any frontswap
backend calls.

Moving the frontswap_register_ops after setting the tmem_frontswap_poolid
fixes it.

Signed-off-by: Konrad Rzeszutek Wilk 
Reviewed-by: Bob Liu

xmem/tmem: fix 'undefined variable' build error.

2013-05-28T13:54:48+00:00

In the (not so useful) kernel configuration where CONFIG_SWAP
is undefined and CONFIG_XEN_SELFBALLOONING is defined,
xen_tmem_init would use undefined variable 'static bool frontswap'.

Added #else to have #define frontswap (0) in the case where
CONFIG_FRONTSWAP is not defined.

Signed-off-by: Frederico Cadete 
Signed-off-by: Konrad Rzeszutek Wilk

xen/tmem: Don't use self[ballooning|shrinking] if frontswap is off.

2013-05-15T14:27:50+00:00

There is no point. We would just squeeze the guest to put more and
more pages in the swap disk without any purpose.

The only time it makes sense to use the selfballooning and shrinking
is when frontswap is being utilized.

Signed-off-by: Konrad Rzeszutek Wilk

xen/tmem: Remove the boot options and fold them in the tmem.X parameters.

2013-05-15T14:27:47+00:00

If tmem is built-in or a module, the user has the option on
the command line to influence it by doing: tmem.
instead of having a variety of "nocleancache", and
"nofrontswap". The others: "noselfballooning" and "selfballooning";
and "noselfshrink" are in a different driver xen-selfballoon.c
and the patches:

 xen/tmem: Remove the usage of 'noselfshrink' and use 'tmem.selfshrink' bool instead.
 xen/tmem: Remove the usage of 'noselfballoon','selfballoon' and use 'tmem.selfballon' bool instead.

remove them.

Also add documentation.

Signed-off-by: Konrad Rzeszutek Wilk

xen/tmem: s/disable_// and change the logic.

2013-05-15T14:27:46+00:00

The variety of disable_[cleancache|frontswap|selfshrinking] are
making this a bit complex. Just remove the "disable_" part and
change the logic around for the "nofrontswap" and "nocleancache"
parameters.

Signed-off-by: Konrad Rzeszutek Wilk

xen/tmem: Fix compile warning.

2013-05-15T14:27:45+00:00

We keep on getting:
drivers/xen/tmem.c:65:13: warning: ‘disable_frontswap_selfshrinking’ defined but not used [-Wunused-variable]

if CONFIG_FRONTSWAP=y and # CONFIG_CLEANCACHE is not set

Found by 0 day test project

Reported-by: Fengguang Wu 
Signed-off-by: Konrad Rzeszutek Wilk

xen/tmem: Split out the different module/boot options.

2013-05-15T14:27:44+00:00

There are three options - depending on what combination of
CONFIG_FRONTSWAP, CONFIG_CLEANCACHE and CONFIG_XEN_SELFBALLOONING
is used. Lets split them out nicely out in three groups to
make it easier to clean up.

Signed-off-by: Konrad Rzeszutek Wilk

xen/tmem: Move all of the boot and module parameters to the top of the file.

2013-05-15T14:27:43+00:00

Just code movement to see the different boot or module parameters.

Signed-off-by: Konrad Rzeszutek Wilk

xen/tmem: Cleanup. Remove the parts that say temporary.

2013-05-15T14:27:43+00:00

Frontswap is upstream, no need to having this #ifdef.

Signed-off-by: Konrad Rzeszutek Wilk

zcache/tmem: Better error checking on frontswap_register_ops return value.

2013-05-01T00:04:01+00:00

In the past it either used to be NULL or the "older" backend. Now we
also return -Exx error codes.

Signed-off-by: Konrad Rzeszutek Wilk 
Signed-off-by: Bob Liu 
Cc: Wanpeng Li 
Cc: Andor Daam 
Cc: Dan Magenheimer 
Cc: Florian Schmaus 
Cc: Minchan Kim 
Cc: Stefan Hengelein 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds