mm: alloc_pages_bulk: rename API

The previous commit removed the page_list argument from
alloc_pages_bulk_noprof() along with the alloc_pages_bulk_list() function.

Now that only the *_array() flavo

mm: alloc_pages_bulk: rename API

The previous commit removed the page_list argument from
alloc_pages_bulk_noprof() along with the alloc_pages_bulk_list() function.

Now that only the *_array() flavour of the API remains, we can do the
following renaming (along with the _noprof() ones):

alloc_pages_bulk_array -> alloc_pages_bulk
alloc_pages_bulk_array_mempolicy -> alloc_pages_bulk_mempolicy
alloc_pages_bulk_array_node -> alloc_pages_bulk_node

Link: https://lkml.kernel.org/r/275a3bbc0be20fbe9002297d60045e67ab3d4ada.1734991165.git.luizcap@redhat.com
Signed-off-by: Luiz Capitulino <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Yunsheng Lin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

lib/test_vmalloc.c: use unsigned long constant

Use an unsigned long constant instead of an int constant and a cast. This
fixes the checkpatch warning

WARNING: Unnecessary typecast of c90 int const

lib/test_vmalloc.c: use unsigned long constant

Use an unsigned long constant instead of an int constant and a cast. This
fixes the checkpatch warning

WARNING: Unnecessary typecast of c90 int constant - '(unsigned long) 1' could be '1UL'
+ align = ((unsigned long) 1) << i;

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Martin Kaiser <[email protected]>
Reviewed-by: Uladzislau Rezki (Sony) <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

lib/test_vmalloc.c: drop empty exit function

The module is never loaded successfully. Therefore, it'll never be
unloaded and we can remove the exit function.

Link: https://lkml.kernel.org/r/202402

lib/test_vmalloc.c: drop empty exit function

The module is never loaded successfully. Therefore, it'll never be
unloaded and we can remove the exit function.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Martin Kaiser <[email protected]>
Reviewed-by: Uladzislau Rezki (Sony) <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

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lib/test_vmalloc.c: fix typo in function name

Fix a typo and change the function name to init_test_configuration. Both
caller and definition have the same typo, so the current code already
works.

lib/test_vmalloc.c: fix typo in function name

Fix a typo and change the function name to init_test_configuration. Both
caller and definition have the same typo, so the current code already
works.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Martin Kaiser <[email protected]>
Reviewed-by: Uladzislau Rezki (Sony) <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

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lib/test_vmalloc.c: avoid garbage in page array

It turns out that alloc_pages_bulk_array() does not treat the page_array
parameter as an output parameter, but rather reads the array and skips any
en

lib/test_vmalloc.c: avoid garbage in page array

It turns out that alloc_pages_bulk_array() does not treat the page_array
parameter as an output parameter, but rather reads the array and skips any
entries that have already been allocated.

This is somewhat unexpected and breaks this test, as we allocate the pages
array uninitialised on the assumption it will be overwritten.

As a result, the test was referencing uninitialised data and causing the
PFN to not be valid and thus a WARN_ON() followed by a null pointer deref
and panic.

In addition, this is an array of pointers not of struct page objects, so we
need only allocate an array with elements of pointer size.

We solve both problems by simply using kcalloc() and referencing
sizeof(struct page *) rather than sizeof(struct page).

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 869cb29a61a1 ("lib/test_vmalloc.c: add vm_map_ram()/vm_unmap_ram() test case")
Signed-off-by: Lorenzo Stoakes <[email protected]>
Reviewed-by: Uladzislau Rezki (Sony) <[email protected]>
Reviewed-by: Baoquan He <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

lib/test_vmalloc.c: add vm_map_ram()/vm_unmap_ram() test case

Add vm_map_ram()/vm_unmap_ram() test case to our stress test-suite.

[[email protected]: fix whitespace, per Lorenzo]
Link: http

lib/test_vmalloc.c: add vm_map_ram()/vm_unmap_ram() test case

Add vm_map_ram()/vm_unmap_ram() test case to our stress test-suite.

[[email protected]: fix whitespace, per Lorenzo]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Uladzislau Rezki (Sony) <[email protected]>
Reviewed-by: Lorenzo Stoakes <[email protected]>
Reviewed-by: Baoquan He <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Dave Chinner <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Oleksiy Avramchenko <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

lib/test_vmalloc.c: Rename kvfree_rcu() to kvfree_rcu_mightsleep()

The kvfree_rcu() macro's single-argument form is deprecated. Therefore
switch to the new kvfree_rcu_mightsleep() variant. The goal

lib/test_vmalloc.c: Rename kvfree_rcu() to kvfree_rcu_mightsleep()

The kvfree_rcu() macro's single-argument form is deprecated. Therefore
switch to the new kvfree_rcu_mightsleep() variant. The goal is to
avoid accidental use of the single-argument forms, which can introduce
functionality bugs in atomic contexts and latency bugs in non-atomic
contexts.

Acked-by: Joel Fernandes (Google) <[email protected]>
Signed-off-by: Uladzislau Rezki (Sony) <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
Signed-off-by: Joel Fernandes (Google) <[email protected]>

show more ...

lib/test_vmalloc.c: add parameter use_huge for fix_size_alloc_test

Add a parameter `use_huge' for fix_size_alloc_test(), which can be used to
test allocation vie vmalloc_huge for both functionality

lib/test_vmalloc.c: add parameter use_huge for fix_size_alloc_test

Add a parameter `use_huge' for fix_size_alloc_test(), which can be used to
test allocation vie vmalloc_huge for both functionality and performance.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Qinglin Pan <[email protected]>
Cc: "Uladzislau Rezki (Sony)" <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

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treewide: use get_random_u32_inclusive() when possible

These cases were done with this Coccinelle:

@@
expression H;
expression L;
@@
- (get_random_u32_below(H) + L)
+ get_random_u32_inclusive(L, H

treewide: use get_random_u32_inclusive() when possible

These cases were done with this Coccinelle:

@@
expression H;
expression L;
@@
- (get_random_u32_below(H) + L)
+ get_random_u32_inclusive(L, H + L - 1)

@@
expression H;
expression L;
expression E;
@@
get_random_u32_inclusive(L,
H
- + E
- - E
)

@@
expression H;
expression L;
expression E;
@@
get_random_u32_inclusive(L,
H
- - E
- + E
)

@@
expression H;
expression L;
expression E;
expression F;
@@
get_random_u32_inclusive(L,
H
- - E
+ F
- + E
)

@@
expression H;
expression L;
expression E;
expression F;
@@
get_random_u32_inclusive(L,
H
- + E
+ F
- - E
)

And then subsequently cleaned up by hand, with several automatic cases
rejected if it didn't make sense contextually.

Reviewed-by: Kees Cook <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Reviewed-by: Jason Gunthorpe <[email protected]> # for infiniband
Signed-off-by: Jason A. Donenfeld <[email protected]>

show more ...

treewide: use get_random_u32_below() instead of deprecated function

This is a simple mechanical transformation done by:

@@
expression E;
@@
- prandom_u32_max
+ get_random_u32_below
(E)

Reviewed-

treewide: use get_random_u32_below() instead of deprecated function

This is a simple mechanical transformation done by:

@@
expression E;
@@
- prandom_u32_max
+ get_random_u32_below
(E)

Reviewed-by: Kees Cook <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Acked-by: Darrick J. Wong <[email protected]> # for xfs
Reviewed-by: SeongJae Park <[email protected]> # for damon
Reviewed-by: Jason Gunthorpe <[email protected]> # for infiniband
Reviewed-by: Russell King (Oracle) <[email protected]> # for arm
Acked-by: Ulf Hansson <[email protected]> # for mmc
Signed-off-by: Jason A. Donenfeld <[email protected]>

show more ...

treewide: use get_random_{u8,u16}() when possible, part 2

Rather than truncate a 32-bit value to a 16-bit value or an 8-bit value,
simply use the get_random_{u8,u16}() functions, which are faster th

treewide: use get_random_{u8,u16}() when possible, part 2

Rather than truncate a 32-bit value to a 16-bit value or an 8-bit value,
simply use the get_random_{u8,u16}() functions, which are faster than
wasting the additional bytes from a 32-bit value. This was done by hand,
identifying all of the places where one of the random integer functions
was used in a non-32-bit context.

Reviewed-by: Greg Kroah-Hartman <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Reviewed-by: Yury Norov <[email protected]>
Acked-by: Jakub Kicinski <[email protected]>
Acked-by: Heiko Carstens <[email protected]> # for s390
Signed-off-by: Jason A. Donenfeld <[email protected]>

show more ...

treewide: use prandom_u32_max() when possible, part 2

Rather than incurring a division or requesting too many random bytes for
the given range, use the prandom_u32_max() function, which only takes
t

treewide: use prandom_u32_max() when possible, part 2

Rather than incurring a division or requesting too many random bytes for
the given range, use the prandom_u32_max() function, which only takes
the minimum required bytes from the RNG and avoids divisions. This was
done by hand, covering things that coccinelle could not do on its own.

Reviewed-by: Greg Kroah-Hartman <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Reviewed-by: Yury Norov <[email protected]>
Reviewed-by: Jan Kara <[email protected]> # for ext2, ext4, and sbitmap
Acked-by: Jakub Kicinski <[email protected]>
Signed-off-by: Jason A. Donenfeld <[email protected]>

show more ...

lib/test_vmalloc: switch to prandom_u32()

A get_random_bytes() function can cause a high contention if it is called
across CPUs simultaneously. Because it shares one lock per all CPUs:

<snip>
c

lib/test_vmalloc: switch to prandom_u32()

A get_random_bytes() function can cause a high contention if it is called
across CPUs simultaneously. Because it shares one lock per all CPUs:

<snip>
class name con-bounces contentions waittime-min waittime-max waittime-total waittime-avg acq-bounces acquisitions holdtime-min holdtime-max holdtime-total holdtime-avg
&crng->lock: 663145 665886 0.05 8.85 261966.66 0.39 7188152 13731279 0.04 11.89 2181582.30 0.16
-----------
&crng->lock 307835 [<00000000acba59cd>] _extract_crng+0x48/0x90
&crng->lock 358051 [<00000000f0075abc>] _crng_backtrack_protect+0x32/0x90
-----------
&crng->lock 234241 [<00000000f0075abc>] _crng_backtrack_protect+0x32/0x90
&crng->lock 431645 [<00000000acba59cd>] _extract_crng+0x48/0x90
<snip>

Switch from the get_random_bytes() to prandom_u32() that does not have any
internal contention when a random value is needed for the tests.

The reason is to minimize CPU cycles introduced by the test-suite itself
from the vmalloc performance metrics.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Uladzislau Rezki (Sony) <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Oleksiy Avramchenko <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

lib/test_vmalloc.c: use swap() to make code cleaner

Use swap() in order to make code cleaner. Issue found by coccinelle.

Link: https://lkml.kernel.org/r/20211028111443.15744-1-deng.changcheng@zte.

lib/test_vmalloc.c: use swap() to make code cleaner

Use swap() in order to make code cleaner. Issue found by coccinelle.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Changcheng Deng <[email protected]>
Reported-by: Zeal Robot <[email protected]>
Reviewed-by: Uladzislau Rezki (Sony) <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

lib/test_vmalloc.c: add a new 'nr_pages' parameter

In order to simulate different fixed sizes for vmalloc allocation
introduce a new parameter that sets number of pages to be allocated for
the "fix_

lib/test_vmalloc.c: add a new 'nr_pages' parameter

In order to simulate different fixed sizes for vmalloc allocation
introduce a new parameter that sets number of pages to be allocated for
the "fix_size_alloc_test" test.

By default 1 page is used unless a different number is specified over the
new parameter.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Uladzislau Rezki (Sony) <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Hillf Danton <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Oleksiy Avramchenko <[email protected]>
Cc: Steven Rostedt <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

lib/test_vmalloc.c: add a new 'nr_threads' parameter

By using this parameter we can specify how many workers are created to
perform vmalloc tests. By default it is one CPU. The maximum value is
se

lib/test_vmalloc.c: add a new 'nr_threads' parameter

By using this parameter we can specify how many workers are created to
perform vmalloc tests. By default it is one CPU. The maximum value is
set to 1024.

As a result of this change a 'single_cpu_test' one becomes obsolete,
therefore it is no longer needed.

[[email protected]: extend max value of nr_threads parameter]
Link: https://lkml.kernel.org/r/[email protected]

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Uladzislau Rezki (Sony) <[email protected]>
Cc: Hillf Danton <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Oleksiy Avramchenko <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Steven Rostedt <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

lib/test_vmalloc.c: remove two kvfree_rcu() tests

Remove two test cases related to kvfree_rcu() and SLAB. Those are
considered as redundant now, because similar test functionality has
recently been

lib/test_vmalloc.c: remove two kvfree_rcu() tests

Remove two test cases related to kvfree_rcu() and SLAB. Those are
considered as redundant now, because similar test functionality has
recently been introduced in the "rcuscale" RCU test-suite.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Uladzislau Rezki (Sony) <[email protected]>
Cc: Hillf Danton <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Oleksiy Avramchenko <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Shuah Khan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

lib/test_vmalloc.c: Add test cases for kvfree_rcu()

Introduce four new test cases for testing the kvfree_rcu()
interface. Two of them belong to single argument functionality
and another two for 2-ar

lib/test_vmalloc.c: Add test cases for kvfree_rcu()

Introduce four new test cases for testing the kvfree_rcu()
interface. Two of them belong to single argument functionality
and another two for 2-argument functionality.

The aim is to stress and check how kvfree_rcu() behaves under
different load and memory conditions and analyze its performance
throughput.

Reviewed-by: Joel Fernandes (Google) <[email protected]>
Signed-off-by: Uladzislau Rezki (Sony) <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>

show more ...

mm: switch the test_vmalloc module to use __vmalloc_node

No need to export the very low-level __vmalloc_node_range when the test
module can use a slightly higher level variant.

[akpm@linux-foundati

mm: switch the test_vmalloc module to use __vmalloc_node

No need to export the very low-level __vmalloc_node_range when the test
module can use a slightly higher level variant.

[[email protected]: add missing `node' arg]
[[email protected]: fix riscv nommu build]
Signed-off-by: Christoph Hellwig <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: David Airlie <[email protected]>
Cc: Gao Xiang <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Haiyang Zhang <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: "K. Y. Srinivasan" <[email protected]>
Cc: Laura Abbott <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Michael Kelley <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: Nitin Gupta <[email protected]>
Cc: Robin Murphy <[email protected]>
Cc: Sakari Ailus <[email protected]>
Cc: Stephen Hemminger <[email protected]>
Cc: Sumit Semwal <[email protected]>
Cc: Wei Liu <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Will Deacon <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

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lib/test_vmalloc.c:test_func(): eliminate local `ret'

Local 'ret' is unneeded and was poorly named: the variable `ret'
generally means the "the value which this function will return".

Cc: Roman Gus

lib/test_vmalloc.c:test_func(): eliminate local `ret'

Local 'ret' is unneeded and was poorly named: the variable `ret'
generally means the "the value which this function will return".

Cc: Roman Gushchin <[email protected]>
Cc: Uladzislau Rezki <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Thomas Garnier <[email protected]>
Cc: Oleksiy Avramchenko <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Joel Fernandes <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Tejun Heo <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

lib/test_vmalloc.c: do not create cpumask_t variable on stack

On my "Intel(R) Xeon(R) W-2135 CPU @ 3.70GHz" system(12 CPUs) i get the
warning from the compiler about frame size:

warning: the fra

lib/test_vmalloc.c: do not create cpumask_t variable on stack

On my "Intel(R) Xeon(R) W-2135 CPU @ 3.70GHz" system(12 CPUs) i get the
warning from the compiler about frame size:

warning: the frame size of 1096 bytes is larger than 1024 bytes [-Wframe-larger-than=]

the size of cpumask_t depends on number of CPUs, therefore just make use
of cpumask_of() in set_cpus_allowed_ptr() as a second argument.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Uladzislau Rezki (Sony) <[email protected]>
Reviewed-by: Andrew Morton <[email protected]>
Reviewed-by: Roman Gushchin <[email protected]>
Cc: Uladzislau Rezki <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Thomas Garnier <[email protected]>
Cc: Oleksiy Avramchenko <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Joel Fernandes <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Tejun Heo <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

vmalloc: add test driver to analyse vmalloc allocator

This adds a new kernel module for analysis of vmalloc allocator. It is
only enabled as a module. There are two main reasons this module should

vmalloc: add test driver to analyse vmalloc allocator

This adds a new kernel module for analysis of vmalloc allocator. It is
only enabled as a module. There are two main reasons this module should
be used for: performance evaluation and stressing of vmalloc subsystem.

It consists of several test cases. As of now there are 8. The module
has five parameters we can specify to change its the behaviour.

1) run_test_mask - set of tests to be run

id: 1, name: fix_size_alloc_test
id: 2, name: full_fit_alloc_test
id: 4, name: long_busy_list_alloc_test
id: 8, name: random_size_alloc_test
id: 16, name: fix_align_alloc_test
id: 32, name: random_size_align_alloc_test
id: 64, name: align_shift_alloc_test
id: 128, name: pcpu_alloc_test

By default all tests are in run test mask. If you want to select some
specific tests it is possible to pass the mask. For example for first,
second and fourth tests we go 11 value.

2) test_repeat_count - how many times each test should be repeated
By default it is one time per test. It is possible to pass any number.
As high the value is the test duration gets increased.

3) test_loop_count - internal test loop counter. By default it is set
to 1000000.

4) single_cpu_test - use one CPU to run the tests
By default this parameter is set to false. It means that all online
CPUs execute tests. By setting it to 1, the tests are executed by
first online CPU only.

5) sequential_test_order - run tests in sequential order
By default this parameter is set to false. It means that before running
tests the order is shuffled. It is possible to make it sequential, just
set it to 1.

Performance analysis:
In order to evaluate performance of vmalloc allocations, usually it
makes sense to use only one CPU that runs tests, use sequential order,
number of repeat tests can be different as well as set of test mask.

For example if we want to run all tests, to use one CPU and repeat each
test 3 times. Insert the module passing following parameters:

single_cpu_test=1 sequential_test_order=1 test_repeat_count=3

with following output:

<snip>
Summary: fix_size_alloc_test passed: 3 failed: 0 repeat: 3 loops: 1000000 avg: 901177 usec
Summary: full_fit_alloc_test passed: 3 failed: 0 repeat: 3 loops: 1000000 avg: 1039341 usec
Summary: long_busy_list_alloc_test passed: 3 failed: 0 repeat: 3 loops: 1000000 avg: 11775763 usec
Summary: random_size_alloc_test passed 3: failed: 0 repeat: 3 loops: 1000000 avg: 6081992 usec
Summary: fix_align_alloc_test passed: 3 failed: 0 repeat: 3, loops: 1000000 avg: 2003712 usec
Summary: random_size_align_alloc_test passed: 3 failed: 0 repeat: 3 loops: 1000000 avg: 2895689 usec
Summary: align_shift_alloc_test passed: 0 failed: 3 repeat: 3 loops: 1000000 avg: 573 usec
Summary: pcpu_alloc_test passed: 3 failed: 0 repeat: 3 loops: 1000000 avg: 95802 usec
All test took CPU0=192945605995 cycles
<snip>

The align_shift_alloc_test is expected to be failed.

Stressing:
In order to stress the vmalloc subsystem we run all available test cases
on all available CPUs simultaneously. In order to prevent constant behaviour
pattern, the test cases array is shuffled by default to randomize the order
of test execution.

For example if we want to run all tests(default), use all online CPUs(default)
with shuffled order(default) and to repeat each test 30 times. The command
would be like:

modprobe vmalloc_test test_repeat_count=30

Expected results are the system is alive, there are no any BUG_ONs or Kernel
Panics the tests are completed, no memory leaks.

[[email protected]: fix 32-bit builds]
Link: http://lkml.kernel.org/r/20190106214839.ffvjvmrn52uqog7k@pc636
[[email protected]: make CONFIG_TEST_VMALLOC depend on CONFIG_MMU]
Link: http://lkml.kernel.org/r/20190219085441.s6bg2gpy4esny5vw@pc636
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Uladzislau Rezki (Sony) <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Oleksiy Avramchenko <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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