Re: [PATCH 3/3 v2] move hugepage test examples totools/testing/selftests/vm

From: Andrew Morton
Date: Thu Feb 09 2012 - 18:03:32 EST


On Thu, 9 Feb 2012 09:46:22 +0800
Dave Young <dyoung@xxxxxxxxxx> wrote:

> Andrew, updated the patch as below, is it ok to you?
> ---
>
> hugepage-mmap.c, hugepage-shm.c and map_hugetlb.c in Documentation/vm are
> simple pass/fail tests, It's better to promote them to tools/testing/selftests
>
> Thanks suggestion of Andrew Morton about this. They all need firstly setting up
> proper nr_hugepages and hugepage-mmap need to mount hugetlbfs. So I add a shell
> script run_vmtests to do such work which will call the three test programs and
> check the return value of them.
>
> Changes to original code including below:
> a. add run_vmtests script
> b. return error when read_bytes mismatch with writed bytes.
> c. coding style fixes: do not use assignment in if condition
>
> [v1 -> v2]:
> 1. [akpm:] rebased on runing make run_tests from Makefile
> 2. [akpm:] rename test script from run_test ro run_vmtests
> 2. fix a bug about shell exit code checking
>

So I tried to run this, from tools/testing/selftests.

a) The testing failed because ./vm's run_test target requires root.

We need to make a policy decision here. Do we require that
selftests run as root? If not then the root-requiring selftests
should warn and bail out without declaring a failure, so that those
tests which can be run without root permissions can be successfully
used.

b) When I ran the vm test, my machine went paralytically comatose
for half a minute. That's a bit rude - if all the selftests do this
then the selftests become kinda useless.

c) I can run "make run_tests" in the top-lvel directory and all is
well: the tools in ./vm get compiled first. But when I do "make
clean ; cd vm ; make run-tests" it fails, because vm/Makefile
doesn't build the targets before trying to run them.

This can be fixed with

--- a/tools/testing/selftests/vm/Makefile~a
+++ a/tools/testing/selftests/vm/Makefile
@@ -7,7 +7,7 @@ all: hugepage-mmap hugepage-shm map_hug
%: %.c
$(CC) $(CFLAGS) -o $@ $^

-run_tests:
+run_tests: all
/bin/sh ./run_vmtests

clean:

But this is unpleasing: a top-level "make run_tests" will end up
trying to compile the targets twice.

We could change the top-level Makefile to a single-pass thing
which just descends into the subdirectories and runs "make
run_tests". But that gives us no way of compiling everything
without also running everything. That's a huge PITA if running
everything sends your machine comatose for half a minute!

So I think I'll go with the above patch.

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