Commit 8846d968 authored by Ritesh Harjani (IBM)'s avatar Ritesh Harjani (IBM) Committed by Michael Ellerman
Browse files

book3s64/hash: Early detect debug_pagealloc size requirement 



Add hash_supports_debug_pagealloc() helper to detect whether
debug_pagealloc can be supported on hash or not. This checks for both,
whether debug_pagealloc config is enabled and the linear map should
fit within rma_size/4 region size.

This can then be used early during htab_init_page_sizes() to decide
linear map pagesize if hash supports either debug_pagealloc or
kfence.

Signed-off-by: default avatarRitesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://patch.msgid.link/c33c6691b2a2cf619cc74ac100118ca4dbf21a48.1729271995.git.ritesh.list@gmail.com
parent 76b7d646

arch/powerpc/mm/book3s64/hash_utils.c

+13 −12
Original line number Diff line number Diff line
@@ -329,25 +329,26 @@ static void kernel_unmap_linear_page(unsigned long vaddr, unsigned long idx, 
}

#endif



static inline bool hash_supports_debug_pagealloc(void)

{

	unsigned long max_hash_count = ppc64_rma_size / 4;

	unsigned long linear_map_count = memblock_end_of_DRAM() >> PAGE_SHIFT;



	if (!debug_pagealloc_enabled() || linear_map_count > max_hash_count)

		return false;

	return true;

}



#ifdef CONFIG_DEBUG_PAGEALLOC

static u8 *linear_map_hash_slots;

static unsigned long linear_map_hash_count;

static DEFINE_RAW_SPINLOCK(linear_map_hash_lock);

static void hash_debug_pagealloc_alloc_slots(void)

{

	unsigned long max_hash_count = ppc64_rma_size / 4;



	if (!debug_pagealloc_enabled())

		return;

	linear_map_hash_count = memblock_end_of_DRAM() >> PAGE_SHIFT;

	if (unlikely(linear_map_hash_count > max_hash_count)) {

		pr_info("linear map size (%llu) greater than 4 times RMA region (%llu). Disabling debug_pagealloc\n",

			((u64)linear_map_hash_count << PAGE_SHIFT),

			ppc64_rma_size);

		linear_map_hash_count = 0;

	if (!hash_supports_debug_pagealloc())

		return;

	}



	linear_map_hash_count = memblock_end_of_DRAM() >> PAGE_SHIFT;

	linear_map_hash_slots = memblock_alloc_try_nid(

			linear_map_hash_count, 1, MEMBLOCK_LOW_LIMIT,

			ppc64_rma_size,	NUMA_NO_NODE);
@@ -1076,7 +1077,7 @@ static void __init htab_init_page_sizes(void) 
	bool aligned = true;

	init_hpte_page_sizes();



	if (!debug_pagealloc_enabled() && !kfence_early_init_enabled()) {

	if (!hash_supports_debug_pagealloc() && !kfence_early_init_enabled()) {

		/*

		 * Pick a size for the linear mapping. Currently, we only

		 * support 16M, 1M and 4K which is the default