Re: [PATCH 2/4] powerpc/64s: Remove unneeded #ifdef CONFIG_DEBUG_PAGEALLOC in hash_utils
From: Daniel Axtens <hidden>
Date: 2021-06-18 07:49:41
Hi Jordan and Christophe,
quoted hunk ↗ jump to hunk
--- a/arch/powerpc/mm/book3s64/hash_utils.c +++ b/arch/powerpc/mm/book3s64/hash_utils.c@@ -126,11 +126,8 @@ EXPORT_SYMBOL_GPL(mmu_slb_size); #ifdef CONFIG_PPC_64K_PAGES int mmu_ci_restrictions; #endif -#ifdef CONFIG_DEBUG_PAGEALLOC static u8 *linear_map_hash_slots; static unsigned long linear_map_hash_count; -static DEFINE_SPINLOCK(linear_map_hash_lock); -#endif /* CONFIG_DEBUG_PAGEALLOC */ struct mmu_hash_ops mmu_hash_ops; EXPORT_SYMBOL(mmu_hash_ops);
quoted hunk ↗ jump to hunk
@@ -1944,6 +1937,8 @@ long hpte_insert_repeating(unsigned long hash, unsigned long vpn, } #ifdef CONFIG_DEBUG_PAGEALLOC +static DEFINE_SPINLOCK(linear_map_hash_lock); +
I had some trouble figuring out why the spinlock has to be in the ifdef. A bit of investigation suggests that it's only used in functions that are only defined under CONFIG_DEBUG_PAGEALLOC - unlike the other variables. So that makes sense. While I was poking around, I noticed that linear_map_hash_slots is manipulated under linear_map_hash_lock in kernel_(un)map_linear_page but is manipulated outside the lock in htab_bolt_mapping(). Is that OK? (I don't know when htab_bolt_mapping is called, it's possible it's only called at times where nothing else could be happing to that array.) Kind regards, Daniel
static void kernel_map_linear_page(unsigned long vaddr, unsigned long lmi)
{
unsigned long hash;
--
2.25.1