From d3f0cb2bbea928854c0e05fcc43f9447a01c71c6 Mon Sep 17 00:00:00 2001
From: notaz <notasas@gmail.com>
Date: Mon, 2 Oct 2023 01:24:50 +0300
Subject: [PATCH] add a thp-based huge page alloc fallback

---
 frontend/libpicofe   |  2 +-
 libpcsxcore/psxmem.c | 21 +++++++++++++++++----
 2 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/frontend/libpicofe b/frontend/libpicofe
index 5dd225ec..b0ce6fa8 160000
--- a/frontend/libpicofe
+++ b/frontend/libpicofe
@@ -1 +1 @@
-Subproject commit 5dd225ecd6d5a04fd8e6f16c8f8ee65ee88c6fed
+Subproject commit b0ce6fa8bd3c171debd5589f3ee8a95e26b1d61b
diff --git a/libpcsxcore/psxmem.c b/libpcsxcore/psxmem.c
index 42755e52..389bdba5 100644
--- a/libpcsxcore/psxmem.c
+++ b/libpcsxcore/psxmem.c
@@ -44,16 +44,29 @@
 static void * psxMapDefault(unsigned long addr, size_t size,
 			    int is_fixed, enum psxMapTag tag)
 {
-#if !P_HAVE_MMAP
 	void *ptr;
-
-	ptr = malloc(size);
+#if !P_HAVE_MMAP
+	ptr = calloc(1, size);
 	return ptr ? ptr : MAP_FAILED;
 #else
 	int flags = MAP_PRIVATE | MAP_ANONYMOUS;
 
-	return mmap((void *)(uintptr_t)addr, size,
+	ptr = mmap((void *)(uintptr_t)addr, size,
 		    PROT_READ | PROT_WRITE, flags, -1, 0);
+#ifdef MADV_HUGEPAGE
+	if (size >= 2*1024*1024) {
+		if (ptr != MAP_FAILED && ((uintptr_t)ptr & (2*1024*1024 - 1))) {
+			// try to manually realign assuming bottom-to-top alloc
+			munmap(ptr, size);
+			addr = (uintptr_t)ptr & ~(2*1024*1024 - 1);
+			ptr = mmap((void *)(uintptr_t)addr, size,
+				PROT_READ | PROT_WRITE, flags, -1, 0);
+		}
+		if (ptr != MAP_FAILED)
+			madvise(ptr, size, MADV_HUGEPAGE);
+	}
+#endif
+	return ptr;
 #endif
 }
 
-- 
2.39.5