Fix kmalloc slab creation sequence

This patch restores the slab creation sequence that was broken by commit
4066c33d0308f8 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: 4066c33d0308f8 ("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>

diff --git a/include/linux/slab.h b/include/linux/slab.h
index 9de2fdc8b5e4643b99c94176eb8dea6f1144852f..a99f0e5243e1e0d30feff453515ae40cc7247334 100644 (file)
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -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
 
 /*

diff --git a/mm/slab_common.c b/mm/slab_common.c
index 9f8d71f784041af8cafebb4751b39757f13f558e..983b78694c4637adcd617de8085498acecfbd288 100644 (file)
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -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 */