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Fix kmalloc slab creation sequence

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This patch restores the slab creation sequence that was broken by commit
4066c33d03 and also reverts the portions that introduced the
KMALLOC_LOOP_XXX macros. Those can never really work since the slab creation
is much more complex than just going from a minimum to a maximum number.

The latest upstream kernel boots cleanly on my machine with a 64 bit x86
configuration under KVM using either SLAB or SLUB.

Fixes: 4066c33d03 ("support the slub_debug boot option")
Reported-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Christoph Lameter 2015-06-29 09:28:08 -05:00 committed by Linus Torvalds
parent 88793e5c77
commit a9730fca99
2 changed files with 16 additions and 38 deletions
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22
include/linux/slab.h
View File

@ -153,30 +153,8 @@ size_t ksize(const void *);
#define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
#define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN
#define KMALLOC_SHIFT_LOW ilog2(ARCH_DMA_MINALIGN)
/*
* The KMALLOC_LOOP_LOW is the definition for the for loop index start number
* to create the kmalloc_caches object in create_kmalloc_caches(). The first
* and the second are 96 and 192. You can see that in the kmalloc_index(), if
* the KMALLOC_MIN_SIZE <= 32, then return 1 (96). If KMALLOC_MIN_SIZE <= 64,
* then return 2 (192). If the KMALLOC_MIN_SIZE is bigger than 64, we don't
* need to initialize 96 and 192. Go directly to start the KMALLOC_SHIFT_LOW.
*/
#if KMALLOC_MIN_SIZE <= 32
#define KMALLOC_LOOP_LOW 1
#elif KMALLOC_MIN_SIZE <= 64
#define KMALLOC_LOOP_LOW 2
#else
#define KMALLOC_LOOP_LOW KMALLOC_SHIFT_LOW
#endif
#else
#define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
/*
* The KMALLOC_MIN_SIZE of slub/slab/slob is 2^3/2^5/2^3. So, even slab is used.
* The KMALLOC_MIN_SIZE <= 32. The kmalloc-96 and kmalloc-192 should also be
* initialized.
*/
#define KMALLOC_LOOP_LOW 1
#endif
/*

32
mm/slab_common.c
View File

@ -855,6 +855,12 @@ void __init setup_kmalloc_cache_index_table(void)
}
}
static void new_kmalloc_cache(int idx, unsigned long flags)
{
kmalloc_caches[idx] = create_kmalloc_cache(kmalloc_info[idx].name,
kmalloc_info[idx].size, flags);
}
/*
* Create the kmalloc array. Some of the regular kmalloc arrays
* may already have been created because they were needed to
@ -864,25 +870,19 @@ void __init create_kmalloc_caches(unsigned long flags)
{
int i;
for (i = KMALLOC_LOOP_LOW; i <= KMALLOC_SHIFT_HIGH; i++) {
if (!kmalloc_caches[i]) {
kmalloc_caches[i] = create_kmalloc_cache(
kmalloc_info[i].name,
kmalloc_info[i].size,
flags);
}
for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) {
if (!kmalloc_caches[i])
new_kmalloc_cache(i, flags);
/*
* "i == 2" is the "kmalloc-192" case which is the last special
* case for initialization and it's the point to jump to
* allocate the minimize size of the object. In slab allocator,
* the KMALLOC_SHIFT_LOW = 5. So, it needs to skip 2^3 and 2^4
* and go straight to allocate 2^5. If the ARCH_DMA_MINALIGN is
* defined, it may be larger than 2^5 and here is also the
* trick to skip the empty gap.
* Caches that are not of the two-to-the-power-of size.
* These have to be created immediately after the
* earlier power of two caches
*/
if (i == 2)
i = (KMALLOC_SHIFT_LOW - 1);
if (KMALLOC_MIN_SIZE <= 32 && !kmalloc_caches[1] && i == 6)
new_kmalloc_cache(1, flags);
if (KMALLOC_MIN_SIZE <= 64 && !kmalloc_caches[2] && i == 7)
new_kmalloc_cache(2, flags);
}
/* Kmalloc array is now usable */