| Message ID | 20240420062954.6816-1-hyunminlr@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm/slub: create kmalloc 96 and 192 caches regardless cache size order | expand |
On Sat, 20 Apr 2024, Hyunmin Lee wrote: > diff --git a/mm/slab_common.c b/mm/slab_common.c > index 3179a6aeffc5..c3271b17eb76 100644 > --- a/mm/slab_common.c > +++ b/mm/slab_common.c > @@ -919,19 +919,12 @@ void __init create_kmalloc_caches(void) > for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) { > if (!kmalloc_caches[type][i]) > new_kmalloc_cache(i, type); > - > - /* > - * 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 (KMALLOC_MIN_SIZE <= 32 && i == 6 && > - !kmalloc_caches[type][1]) > - new_kmalloc_cache(1, type); > - if (KMALLOC_MIN_SIZE <= 64 && i == 7 && > - !kmalloc_caches[type][2]) > - new_kmalloc_cache(2, type); > } > + > + if (KMALLOC_MIN_SIZE <= 32 && !kmalloc_caches[type][1]) > + new_kmalloc_cache(1, type); > + if (KMALLOC_MIN_SIZE <= 64 && !kmalloc_caches[type][2]) > + new_kmalloc_cache(2, type); > } > #ifdef CONFIG_RANDOM_KMALLOC_CACHES > random_kmalloc_seed = get_random_u64(); No objection to this, but it would be nice to continue to have a comment about why these slab caches are special. Another thought: can we move the check for NULL kmalloc_caches to new_kmalloc_cache() instead of handling it in the caller?
On Sat, 20 Apr 2024, Hyunmin Lee wrote: > For SLAB the kmalloc caches needed to be created in ascending sizes in > order. However, the constraint is not necessary anymore because SLAB has > been deprecated and SLUB doesn't need to comply with the constraint. Thus, > kmalloc 96 and 192 caches can be created after the other size kmalloc > caches are created instead of checking every time to find their order to > be created. Also, this change could prevent engineers from being confused > by the deprecated constraint. Ok but you are creating index 1 2 after going through KMALLOC_SHIFT_LOW to KMALLOC_SHIFT_HIGH. 1 and 2 should come before the loop in order to make it easily readable. At that point you can also skip the check for the kmalloc caches already being present I think.
diff --git a/mm/slab_common.c b/mm/slab_common.c index 3179a6aeffc5..c3271b17eb76 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -919,19 +919,12 @@ void __init create_kmalloc_caches(void) for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) { if (!kmalloc_caches[type][i]) new_kmalloc_cache(i, type); - - /* - * 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 (KMALLOC_MIN_SIZE <= 32 && i == 6 && - !kmalloc_caches[type][1]) - new_kmalloc_cache(1, type); - if (KMALLOC_MIN_SIZE <= 64 && i == 7 && - !kmalloc_caches[type][2]) - new_kmalloc_cache(2, type); } + + if (KMALLOC_MIN_SIZE <= 32 && !kmalloc_caches[type][1]) + new_kmalloc_cache(1, type); + if (KMALLOC_MIN_SIZE <= 64 && !kmalloc_caches[type][2]) + new_kmalloc_cache(2, type); } #ifdef CONFIG_RANDOM_KMALLOC_CACHES random_kmalloc_seed = get_random_u64();