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* Re: [PATCH 5/6] mm: add selftests to split_huge_page() to verify unmap/zap of zero pages
@ 2024-07-31 23:07 kernel test robot
  0 siblings, 0 replies; 6+ messages in thread
From: kernel test robot @ 2024-07-31 23:07 UTC (permalink / raw)
  To: oe-kbuild; +Cc: lkp

:::::: 
:::::: Manual check reason: "low confidence bisect report"
:::::: 

BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
In-Reply-To: <20240730125346.1580150-6-usamaarif642@gmail.com>
References: <20240730125346.1580150-6-usamaarif642@gmail.com>
TO: Usama Arif <usamaarif642@gmail.com>
TO: akpm@linux-foundation.org
TO: linux-mm@kvack.org
CC: hannes@cmpxchg.org
CC: riel@surriel.com
CC: shakeel.butt@linux.dev
CC: roman.gushchin@linux.dev
CC: yuzhao@google.com
CC: david@redhat.com
CC: baohua@kernel.org
CC: ryan.roberts@arm.com
CC: rppt@kernel.org
CC: willy@infradead.org
CC: cerasuolodomenico@gmail.com
CC: corbet@lwn.net
CC: linux-kernel@vger.kernel.org
CC: linux-doc@vger.kernel.org
CC: kernel-team@meta.com
CC: Alexander Zhu <alexlzhu@fb.com>
CC: Usama Arif <usamaarif642@gmail.com>

Hi Usama,

kernel test robot noticed the following build warnings:

[auto build test WARNING on akpm-mm/mm-everything]

url:    https://github.com/intel-lab-lkp/linux/commits/Usama-Arif/Revert-memcg-remove-mem_cgroup_uncharge_list/20240730-223949
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20240730125346.1580150-6-usamaarif642%40gmail.com
patch subject: [PATCH 5/6] mm: add selftests to split_huge_page() to verify unmap/zap of zero pages
:::::: branch date: 32 hours ago
:::::: commit date: 32 hours ago
compiler: gcc-13 (Ubuntu 13.2.0-4ubuntu3) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240801/202408010618.lgnamdZd-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/r/202408010618.lgnamdZd-lkp@intel.com/

All warnings (new ones prefixed by >>):

   vm_util.c: In function 'rss_anon':
>> vm_util.c:188:41: warning: format '%ld' expects argument of type 'long int *', but argument 3 has type 'uint64_t *' {aka 'long long unsigned int *'} [-Wformat=]
     188 |         if (sscanf(buffer, "RssAnon:%10ld kB", &rss_anon) != 1)
         |                                     ~~~~^      ~~~~~~~~~
         |                                         |      |
         |                                         |      uint64_t * {aka long long unsigned int *}
         |                                         long int *
         |                                     %10lld


vim +188 tools/testing/selftests/mm/vm_util.c

642bc52aed9c99 tools/testing/selftests/vm/vm_util.c Muhammad Usama Anjum 2022-04-28  174  
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  175  uint64_t rss_anon(void)
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  176  {
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  177  	uint64_t rss_anon = 0;
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  178  	FILE *fp;
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  179  	char buffer[MAX_LINE_LENGTH];
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  180  
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  181  	fp = fopen(STATUS_FILE_PATH, "r");
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  182  	if (!fp)
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  183  		ksft_exit_fail_msg("%s: Failed to open file %s\n", __func__, STATUS_FILE_PATH);
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  184  
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  185  	if (!check_for_pattern(fp, "RssAnon:", buffer, sizeof(buffer)))
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  186  		goto err_out;
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  187  
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30 @188  	if (sscanf(buffer, "RssAnon:%10ld kB", &rss_anon) != 1)
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  189  		ksft_exit_fail_msg("Reading status error\n");
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  190  
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  191  err_out:
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  192  	fclose(fp);
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  193  	return rss_anon;
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  194  }
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  195  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: [PATCH 5/6] mm: add selftests to split_huge_page() to verify unmap/zap of zero pages
@ 2024-08-02  4:17 kernel test robot
  0 siblings, 0 replies; 6+ messages in thread
From: kernel test robot @ 2024-08-02  4:17 UTC (permalink / raw)
  To: oe-kbuild; +Cc: lkp

:::::: 
:::::: Manual check reason: "low confidence bisect report"
:::::: 

BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
In-Reply-To: <20240730125346.1580150-6-usamaarif642@gmail.com>
References: <20240730125346.1580150-6-usamaarif642@gmail.com>
TO: Usama Arif <usamaarif642@gmail.com>
TO: akpm@linux-foundation.org
TO: linux-mm@kvack.org
CC: hannes@cmpxchg.org
CC: riel@surriel.com
CC: shakeel.butt@linux.dev
CC: roman.gushchin@linux.dev
CC: yuzhao@google.com
CC: david@redhat.com
CC: baohua@kernel.org
CC: ryan.roberts@arm.com
CC: rppt@kernel.org
CC: willy@infradead.org
CC: cerasuolodomenico@gmail.com
CC: corbet@lwn.net
CC: linux-kernel@vger.kernel.org
CC: linux-doc@vger.kernel.org
CC: kernel-team@meta.com
CC: Alexander Zhu <alexlzhu@fb.com>
CC: Usama Arif <usamaarif642@gmail.com>

Hi Usama,

kernel test robot noticed the following build warnings:

[auto build test WARNING on akpm-mm/mm-everything]

url:    https://github.com/intel-lab-lkp/linux/commits/Usama-Arif/Revert-memcg-remove-mem_cgroup_uncharge_list/20240730-223949
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20240730125346.1580150-6-usamaarif642%40gmail.com
patch subject: [PATCH 5/6] mm: add selftests to split_huge_page() to verify unmap/zap of zero pages
:::::: branch date: 3 days ago
:::::: commit date: 3 days ago
compiler: clang version 18.1.5 (https://github.com/llvm/llvm-project 617a15a9eac96088ae5e9134248d8236e34b91b1)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240802/202408021131.OcDZmjjR-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/r/202408021131.OcDZmjjR-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> vm_util.c:188:41: warning: format specifies type 'long *' but the argument has type 'uint64_t *' (aka 'unsigned long long *') [-Wformat]
     188 |         if (sscanf(buffer, "RssAnon:%10ld kB", &rss_anon) != 1)
         |                                     ~~~~~      ^~~~~~~~~
         |                                     %10lld
   1 warning generated.


vim +188 tools/testing/selftests/mm/vm_util.c

642bc52aed9c99 tools/testing/selftests/vm/vm_util.c Muhammad Usama Anjum 2022-04-28  174  
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  175  uint64_t rss_anon(void)
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  176  {
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  177  	uint64_t rss_anon = 0;
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  178  	FILE *fp;
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  179  	char buffer[MAX_LINE_LENGTH];
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  180  
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  181  	fp = fopen(STATUS_FILE_PATH, "r");
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  182  	if (!fp)
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  183  		ksft_exit_fail_msg("%s: Failed to open file %s\n", __func__, STATUS_FILE_PATH);
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  184  
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  185  	if (!check_for_pattern(fp, "RssAnon:", buffer, sizeof(buffer)))
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  186  		goto err_out;
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  187  
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30 @188  	if (sscanf(buffer, "RssAnon:%10ld kB", &rss_anon) != 1)
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  189  		ksft_exit_fail_msg("Reading status error\n");
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  190  
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  191  err_out:
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  192  	fclose(fp);
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  193  	return rss_anon;
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  194  }
15bd39f288be91 tools/testing/selftests/mm/vm_util.c Alexander Zhu        2024-07-30  195  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

^ permalink raw reply	[flat|nested] 6+ messages in thread
* [PATCH 0/6] mm: split underutilized THPs
@ 2024-07-30 12:45 Usama Arif
  2024-07-30 12:46 ` [PATCH 5/6] mm: add selftests to split_huge_page() to verify unmap/zap of zero pages Usama Arif
  0 siblings, 1 reply; 6+ messages in thread
From: Usama Arif @ 2024-07-30 12:45 UTC (permalink / raw)
  To: akpm, linux-mm
  Cc: hannes, riel, shakeel.butt, roman.gushchin, yuzhao, david, baohua,
	ryan.roberts, rppt, willy, cerasuolodomenico, corbet,
	linux-kernel, linux-doc, kernel-team, Usama Arif

The current upstream default policy for THP is always. However, Meta
uses madvise in production as the current THP=always policy vastly
overprovisions THPs in sparsely accessed memory areas, resulting in
excessive memory pressure and premature OOM killing.
Using madvise + relying on khugepaged has certain drawbacks over
THP=always. Using madvise hints mean THPs aren't "transparent" and
require userspace changes. Waiting for khugepaged to scan memory and
collapse pages into THP can be slow and unpredictable in terms of performance
(i.e. you dont know when the collapse will happen), while production
environments require predictable performance. If there is enough memory
available, its better for both performance and predictability to have
a THP from fault time, i.e. THP=always rather than wait for khugepaged
to collapse it, and deal with sparsely populated THPs when the system is
running out of memory.

This patch-series is an attempt to mitigate the issue of running out of
memory when THP is always enabled. During runtime whenever a THP is being
faulted in or collapsed by khugepaged, the THP is added to a list.
Whenever memory reclaim happens, the kernel runs the deferred_split
shrinker which goes through the list and checks if the THP was underutilized,
i.e. how many of the base 4K pages of the entire THP were zero-filled.
If this number goes above a certain threshold, the shrinker will attempt
to split that THP. Then at remap time, the pages that were zero-filled are
not remapped, hence saving memory. This method avoids the downside of
wasting memory in areas where THP is sparsely filled when THP is always
enabled, while still providing the upside THPs like reduced TLB misses without
having to use madvise.

Meta production workloads that were CPU bound (>99% CPU utilzation) were
tested with THP shrinker. The results after 2 hours are as follows:

                            | THP=madvise |  THP=always   | THP=always
                            |             |               | + shrinker series
                            |             |               | + max_ptes_none=409
-----------------------------------------------------------------------------
Performance improvement     |      -      |    +1.8%      |     +1.7%
(over THP=madvise)          |             |               |
-----------------------------------------------------------------------------
Memory usage                |    54.6G    | 58.8G (+7.7%) |   55.9G (+2.4%)
-----------------------------------------------------------------------------
max_ptes_none=409 means that any THP that has more than 409 out of 512
(80%) zero filled filled pages will be split.

To test out the patches, the below commands without the shrinker will
invoke OOM killer immediately and kill stress, but will not fail with
the shrinker:

echo 450 > /sys/kernel/mm/transparent_hugepage/khugepaged/max_ptes_none
mkdir /sys/fs/cgroup/test
echo $$ > /sys/fs/cgroup/test/cgroup.procs
echo 20M > /sys/fs/cgroup/test/memory.max
echo 0 > /sys/fs/cgroup/test/memory.swap.max
# allocate twice memory.max for each stress worker and touch 40/512 of
# each THP, i.e. vm-stride 50K.
# With the shrinker, max_ptes_none of 470 and below won't invoke OOM
# killer.
# Without the shrinker, OOM killer is invoked immediately irrespective
# of max_ptes_none value and kill stress.
stress --vm 1 --vm-bytes 40M --vm-stride 50K

Patches 1-2 add back helper functions that were previously removed
to operate on page lists (needed by patch 3).
Patch 3 is an optimization to free zapped tail pages rather than
waiting for page reclaim or migration.
Patch 4 is a prerequisite for THP shrinker to not remap zero-filled
subpages when splitting THP.
Patches 6 adds support for THP shrinker.

(This patch-series restarts the work on having a THP shrinker in kernel
originally done in
https://lore.kernel.org/all/cover.1667454613.git.alexlzhu@fb.com/.
The THP shrinker in this series is significantly different than the
original one, hence its labelled v1 (although the prerequisite to not
remap clean subpages is the same).)

Alexander Zhu (1):
  mm: add selftests to split_huge_page() to verify unmap/zap of zero
    pages

Usama Arif (3):
  Revert "memcg: remove mem_cgroup_uncharge_list()"
  Revert "mm: remove free_unref_page_list()"
  mm: split underutilized THPs

Yu Zhao (2):
  mm: free zapped tail pages when splitting isolated thp
  mm: don't remap unused subpages when splitting isolated thp

 Documentation/admin-guide/mm/transhuge.rst    |   6 +
 include/linux/huge_mm.h                       |   4 +-
 include/linux/khugepaged.h                    |   1 +
 include/linux/memcontrol.h                    |  12 ++
 include/linux/mm_types.h                      |   2 +
 include/linux/rmap.h                          |   2 +-
 include/linux/vm_event_item.h                 |   1 +
 mm/huge_memory.c                              | 152 +++++++++++++++---
 mm/hugetlb.c                                  |   1 +
 mm/internal.h                                 |   5 +-
 mm/khugepaged.c                               |   3 +-
 mm/memcontrol.c                               |  22 ++-
 mm/migrate.c                                  |  76 +++++++--
 mm/migrate_device.c                           |   4 +-
 mm/page_alloc.c                               |  18 +++
 mm/rmap.c                                     |   2 +-
 mm/vmscan.c                                   |   3 +-
 mm/vmstat.c                                   |   1 +
 .../selftests/mm/split_huge_page_test.c       | 113 +++++++++++++
 tools/testing/selftests/mm/vm_util.c          |  22 +++
 tools/testing/selftests/mm/vm_util.h          |   1 +
 21 files changed, 414 insertions(+), 37 deletions(-)

-- 
2.43.0


^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2024-08-06 22:02 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2024-07-31 23:07 [PATCH 5/6] mm: add selftests to split_huge_page() to verify unmap/zap of zero pages kernel test robot
  -- strict thread matches above, loose matches on Subject: below --
2024-08-02  4:17 kernel test robot
2024-07-30 12:45 [PATCH 0/6] mm: split underutilized THPs Usama Arif
2024-07-30 12:46 ` [PATCH 5/6] mm: add selftests to split_huge_page() to verify unmap/zap of zero pages Usama Arif
2024-07-30 18:10   ` Rik van Riel
2024-08-01  4:45   ` kernel test robot
2024-08-06 22:02     ` Usama Arif

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