DAMOS filters supports allowing behavior, but the core layer's DAMOS
filters handling logic still assumes only rejecting (filtering-out)
behavior. Update the logic to aware of and respect the behavioral
decision by reading damos_filter->allow when making the decision to
exclude a region or not.
Link: https://lkml.kernel.org/r/20250109175126.57878-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
After "mm: move per-vma lock into vm_area_struct" we're hitting
mm/damon/tests/vaddr-kunit.h: In function 'damon_test_three_regions_in_vmas':
mm/damon/tests/vaddr-kunit.h:92:1: error: the frame size of 3280 bytes is larger than 2048 bytes [-Werror=frame-larger-than=]
Fix by moving all those vmas off the stack.
[akpm@linux-foundation.org: fix build]
Closes: https://lkml.kernel.org/r/20241209170829.11311e70@canb.auug.org.au
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/damon/vaddr: Fix issue in
damon_va_evenly_split_region()". v2.
According to the logic of damon_va_evenly_split_region(), currently
following split case would not meet the expectation:
Suppose DAMON_MIN_REGION=0x1000,
Case: Split [0x0, 0x3000) into 2 pieces, then the result would be
acutually 3 regions:
[0x0, 0x1000), [0x1000, 0x2000), [0x2000, 0x3000)
but NOT the expected 2 regions:
[0x0, 0x1000), [0x1000, 0x3000) !!!
The root cause is that when calculating size of each split piece in
damon_va_evenly_split_region():
`sz_piece = ALIGN_DOWN(sz_orig / nr_pieces, DAMON_MIN_REGION);`
both the dividing and the ALIGN_DOWN may cause loss of precision, then
each time split one piece of size 'sz_piece' from origin 'start' to 'end'
would cause more pieces are split out than expected!!!
To fix it, count for each piece split and make sure no more than
'nr_pieces'. In addition, add above case into damon_test_split_evenly().
And add 'nr_piece == 1' check in damon_va_evenly_split_region() for better
code readability and add a corresponding kunit testcase.
This patch (of 2):
According to the logic of damon_va_evenly_split_region(), currently
following split case would not meet the expectation:
Suppose DAMON_MIN_REGION=0x1000,
Case: Split [0x0, 0x3000) into 2 pieces, then the result would be
acutually 3 regions:
[0x0, 0x1000), [0x1000, 0x2000), [0x2000, 0x3000)
but NOT the expected 2 regions:
[0x0, 0x1000), [0x1000, 0x3000) !!!
The root cause is that when calculating size of each split piece in
damon_va_evenly_split_region():
`sz_piece = ALIGN_DOWN(sz_orig / nr_pieces, DAMON_MIN_REGION);`
both the dividing and the ALIGN_DOWN may cause loss of precision,
then each time split one piece of size 'sz_piece' from origin 'start' to
'end' would cause more pieces are split out than expected!!!
To fix it, count for each piece split and make sure no more than
'nr_pieces'. In addition, add above case into damon_test_split_evenly().
After this patch, damon-operations test passed:
# ./tools/testing/kunit/kunit.py run damon-operations
[...]
============== damon-operations (6 subtests) ===============
[PASSED] damon_test_three_regions_in_vmas
[PASSED] damon_test_apply_three_regions1
[PASSED] damon_test_apply_three_regions2
[PASSED] damon_test_apply_three_regions3
[PASSED] damon_test_apply_three_regions4
[PASSED] damon_test_split_evenly
================ [PASSED] damon-operations =================
Link: https://lkml.kernel.org/r/20241022083927.3592237-1-zhengyejian@huaweicloud.com
Link: https://lkml.kernel.org/r/20241022083927.3592237-2-zhengyejian@huaweicloud.com
Fixes: 3f49584b26 ("mm/damon: implement primitives for the virtual memory address spaces")
Signed-off-by: Zheng Yejian <zhengyejian@huaweicloud.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: Fernand Sieber <sieberf@amazon.com>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Ye Weihua <yeweihua4@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The aggregation interval of test purpose damon_attrs for
damon_test_nr_accesses_to_accesses_bp() becomes zero on 32 bit
architecture, since size of int and long types are same. As a result,
damon_nr_accesses_to_accesses_bp() call with the test data triggers
divide-by-zero exception. damon_nr_accesses_to_accesses_bp() shouldn't
be called with such data, and the non-test code avoids that by checking
the case on damon_update_monitoring_results(). Skip the test code in
the case, and add an explicit caution of the case on the comment for the
test target function.
Link: https://lkml.kernel.org/r/20240905162423.74053-1-sj@kernel.org
Fixes: 5e06ad5900 ("mm/damon/core-test: test max_nr_accesses overflow caused divide-by-zero")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Closes: https://lore.kernel.org/c771b962-a58f-435b-89e4-1211a9323181@roeck-us.net
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Gow <davidgow@google.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
damon_test_three_regions_in_vmas() initializes a maple tree with
MM_MT_FLAGS. The flags contains MT_FLAGS_LOCK_EXTERN, which means mt_lock
of the maple tree will not be used. And therefore the maple tree
initialization code skips initialization of the mt_lock. However,
__link_vmas(), which adds vmas for test to the maple tree, uses the
mt_lock. In other words, the uninitialized spinlock is used. The problem
becomes clear when spinlock debugging is turned on, since it reports
spinlock bad magic bug.
Fix the issue by excluding MT_FLAGS_LOCK_EXTERN from the maple tree
initialization flags. Note that we don't use empty flags to make it
further similar to the usage of mm maple tree, and to be prepared for
possible future changes, as suggested by Liam.
Link: https://lkml.kernel.org/r/20240904172931.1284-1-sj@kernel.org
Fixes: d0cf3dd47f ("damon: convert __damon_va_three_regions to use the VMA iterator")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Closes: https://lore.kernel.org/1453b2b2-6119-4082-ad9e-f3c5239bf87e@roeck-us.net
Suggested-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
