Index: chromium-140.0.7339.41/base/allocator/dispatcher/tls.h
===================================================================
--- chromium-140.0.7339.41.orig/base/allocator/dispatcher/tls.h
+++ chromium-140.0.7339.41/base/allocator/dispatcher/tls.h
@@ -88,6 +88,8 @@ struct BASE_EXPORT MMapAllocator {
   constexpr static size_t AllocationChunkSize = 16384;
 #elif BUILDFLAG(IS_LINUX) && defined(ARCH_CPU_ARM64)
   constexpr static size_t AllocationChunkSize = 16384;
+#elif BUILDFLAG(IS_LINUX) && defined(ARCH_CPU_PPC64)
+  constexpr static size_t AllocationChunkSize = 16384;
 #else
   constexpr static size_t AllocationChunkSize = 4096;
 #endif
Index: chromium-140.0.7339.41/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_constants.h
===================================================================
--- chromium-140.0.7339.41.orig/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_constants.h
+++ chromium-140.0.7339.41/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_constants.h
@@ -397,7 +397,7 @@ PA_ALWAYS_INLINE constexpr size_t MaxDir
 // TODO(casey.smalley@arm.com): under 64k pages we can end up in a situation
 // where a normal slot span will be large enough to contain multiple items,
 // but the address will go over the final partition page after being aligned.
-#if PA_BUILDFLAG(IS_LINUX) && PA_BUILDFLAG(PA_ARCH_CPU_ARM64)
+#if PA_BUILDFLAG(IS_LINUX) && (PA_BUILDFLAG(PA_ARCH_CPU_ARM64) || PA_BUILDFLAG(PA_ARCH_CPU_PPC64))
 constexpr size_t kMaxSupportedAlignment = kSuperPageSize / 4;
 #else
 constexpr size_t kMaxSupportedAlignment = kSuperPageSize / 2;