Hi,
I reproduced the build failure according to lkp report and made a patch
as below to fix it.
>From dae7dd9705015ce36db757e88c78802584f949b1 Mon Sep 17 00:00:00 2001
From: Baoquan He <bhe@xxxxxxxxxx>
Date: Sun, 13 Nov 2022 18:08:27 +0800
Subject: [PATCH] percpu: adjust the value of PERCPU_DYNAMIC_EARLY_SIZE
Content-type: text/plain
LKP reported a build failure as below on the patch "mm/slub, percpu:
correct the calculation of early percpu allocation size"
~~~~~~
In file included from <command-line>:
In function 'alloc_kmem_cache_cpus',
inlined from 'kmem_cache_open' at mm/slub.c:4340:6:
>> include/linux/compiler_types.h:357:45: error: call to '__compiletime_assert_474' declared with attribute error:
BUILD_BUG_ON failed: PERCPU_DYNAMIC_EARLY_SIZE < NR_KMALLOC_TYPES * KMALLOC_SHIFT_HIGH * sizeof(struct kmem_cache_cpu)
357 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
~~~~~~
>From the kernel config file provided by LKP, the building was made on
arm64 with below Kconfig item enabled:
CONFIG_ZONE_DMA=y
CONFIG_SLUB_CPU_PARTIAL=y
CONFIG_DEBUG_LOCK_ALLOC=y
CONFIG_SLUB_STATS=y
CONFIG_ARM64_PAGE_SHIFT=16
CONFIG_ARM64_64K_PAGES=y
Then we will have:
NR_KMALLOC_TYPES:4
KMALLOC_SHIFT_HIGH:17
sizeof(struct kmem_cache_cpu):184
The product of them is 12512, which is bigger than PERCPU_DYNAMIC_EARLY_SIZE,
12K. Hence, the BUILD_BUG_ON in alloc_kmem_cache_cpus() is triggered.
Earlier, in commit 099a19d91ca4 ("percpu: allow limited allocation
before slab is online"), PERCPU_DYNAMIC_EARLY_SIZE was introduced and
set to 12K which is equal to the then PERPCU_DYNAMIC_RESERVE.
Later, in commit 1a4d76076cda ("percpu: implement asynchronous chunk
population"), PERPCU_DYNAMIC_RESERVE was increased by 8K, while
PERCPU_DYNAMIC_EARLY_SIZE was kept unchanged.
So, here increase PERCPU_DYNAMIC_EARLY_SIZE by 8K too to accommodate to
the slub's requirement.
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
---
include/linux/percpu.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/percpu.h b/include/linux/percpu.h
index 70bc17db00a6..1338ea2aa720 100644
--- a/include/linux/percpu.h
+++ b/include/linux/percpu.h
@@ -41,7 +41,7 @@
* for this. Keep PERCPU_DYNAMIC_RESERVE equal to or larger than
* PERCPU_DYNAMIC_EARLY_SIZE.
*/
-#define PERCPU_DYNAMIC_EARLY_SIZE (12 << 10)
+#define PERCPU_DYNAMIC_EARLY_SIZE (20 << 10)
/*
* PERCPU_DYNAMIC_RESERVE indicates the amount of free area to piggy
--
2.34.1
