[lttng-dev] [PATCH lttng-modules] RFC: Always build vmscan probe

[Jonathan Rajotte Julien]

Hi,

On 2017-04-10 03:03 PM, Michael Jeanson wrote:
> The mm/vmscan.c compile unit is a obj-y, even on an old 2.6.36 kernel,
> always build the vmscan probe regardless of kernel configuration.
> 
> Closes: #143

Probably the incorrect number since the #143 of bugs.lttng.org point to an internal project issue that date back to 5 years ago.

> 

I tested build and runtime on a 4.4.14 kernel with !CONFIG_SWAP & !CONFIG_MEMCG. Everything seems fine, events get hits correctly on a memory stress with "stress" with 90% memory usage scenario.

Tested-by: Jonathan Rajotte <jonathan.rajotte-julien at efficios.com>

> Signed-off-by: Michael Jeanson <mjeanson at efficios.com>
> ---
>  probes/Kbuild | 10 +---------
>  1 file changed, 1 insertion(+), 9 deletions(-)
> 
> diff --git a/probes/Kbuild b/probes/Kbuild
> index 2afb6dd..bf14c75 100644
> --- a/probes/Kbuild
> +++ b/probes/Kbuild
> @@ -143,19 +143,11 @@ ifneq ($(CONFIG_SCSI),)
>        echo "lttng-probe-scsi.o" ; fi;)
>  endif # CONFIG_SCSI
>  
> -vmscan = $(shell \
> +obj-$(CONFIG_LTTNG) += $(shell \
>    if [ $(VERSION) -ge 3 \
>      -o \( $(VERSION) -eq 2 -a $(PATCHLEVEL) -eq 6 -a $(SUBLEVEL) -ge 36 \) ] ; then \
>      echo "lttng-probe-vmscan.o" ; fi;)

We might want to move this closer to similar statements (e.g. closer to lttng-probe-signal.o).

Cheers

>  
> -ifneq ($(CONFIG_SWAP),)
> -  obj-$(CONFIG_LTTNG) += $(vmscan)
> -else
> -  ifneq ($(CONFIG_CGROUP_MEM_RES_CTLR),)
> -    obj-$(CONFIG_LTTNG) += $(vmscan)
> -  endif # CONFIG_CGROUP_MEM_RES_CTLR
> -endif # CONFIG_SWAP
> -
>  # lock probe does not work, so disabling it for now
>  #ifneq ($(CONFIG_LOCKDEP),)
>  #  obj-$(CONFIG_LTTNG) += lttng-probe-lock.o
> 

-- 
Jonathan R. Julien
Efficios