Add some extra vmemmap pr_debug message that will indicate the type of vmemmap allocations. For ex: with DAX vmemmap optimization we can find the below details: [ 187.166580] radix-mmu: PAGE_SIZE vmemmap mapping [ 187.166587] radix-mmu: PAGE_SIZE vmemmap mapping [ 187.166591] radix-mmu: Tail page reuse vmemmap mapping [ 187.166594] radix-mmu: Tail page reuse vmemmap mapping [ 187.166598] radix-mmu: Tail page reuse vmemmap mapping [ 187.166601] radix-mmu: Tail page reuse vmemmap mapping [ 187.166604] radix-mmu: Tail page reuse vmemmap mapping [ 187.166608] radix-mmu: Tail page reuse vmemmap mapping [ 187.166611] radix-mmu: Tail page reuse vmemmap mapping [ 187.166614] radix-mmu: Tail page reuse vmemmap mapping [ 187.166617] radix-mmu: Tail page reuse vmemmap mapping [ 187.166620] radix-mmu: Tail page reuse vmemmap mapping [ 187.166623] radix-mmu: Tail page reuse vmemmap mapping [ 187.166626] radix-mmu: Tail page reuse vmemmap mapping [ 187.166629] radix-mmu: Tail page reuse vmemmap mapping [ 187.166632] radix-mmu: Tail page reuse vmemmap mapping And without vmemmap optimization [ 293.549931] radix-mmu: PMD_SIZE vmemmap mapping [ 293.549984] radix-mmu: PMD_SIZE vmemmap mapping [ 293.550032] radix-mmu: PMD_SIZE vmemmap mapping [ 293.550076] radix-mmu: PMD_SIZE vmemmap mapping [ 293.550117] radix-mmu: PMD_SIZE vmemmap mapping Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx> --- arch/powerpc/mm/book3s64/radix_pgtable.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c index 73d0987369ff..2828e7e0802c 100644 --- a/arch/powerpc/mm/book3s64/radix_pgtable.c +++ b/arch/powerpc/mm/book3s64/radix_pgtable.c @@ -1034,6 +1034,7 @@ static pte_t * __meminit radix__vmemmap_pte_populate(pmd_t *pmdp, unsigned long p = vmemmap_alloc_block_buf(PAGE_SIZE, node, NULL); if (!p) return NULL; + pr_debug("PAGE_SIZE vmemmap mapping\n"); } else { /* * When a PTE/PMD entry is freed from the init_mm @@ -1046,6 +1047,7 @@ static pte_t * __meminit radix__vmemmap_pte_populate(pmd_t *pmdp, unsigned long */ get_page(reuse); p = page_to_virt(reuse); + pr_debug("Tail page reuse vmemmap mapping\n"); } VM_BUG_ON(!PAGE_ALIGNED(addr)); @@ -1155,6 +1157,7 @@ int __meminit radix__vmemmap_populate(unsigned long start, unsigned long end, in p = vmemmap_alloc_block_buf(PMD_SIZE, node, altmap); if (p) { vmemmap_set_pmd(pmd, p, node, addr, next); + pr_debug("PMD_SIZE vmemmap mapping\n"); continue; } else if (altmap) { /* -- 2.41.0