From e7af1dd2e0d8203a4d498a18bdd153a82da22227 Mon Sep 17 00:00:00 2001
From: Augustin Cavalier <waddlesplash@gmail.com>
Date: Fri, 13 Dec 2024 14:25:40 -0500
Subject: [PATCH] kernel/vm: Introduce VMCache::CanOvercommit().

Allows the Anonymous caches to report overcommitting status.
---
 headers/private/kernel/vm/VMCache.h             | 1 +
 src/system/kernel/vm/VMAnonymousCache.cpp       | 7 +++++++
 src/system/kernel/vm/VMAnonymousCache.h         | 1 +
 src/system/kernel/vm/VMAnonymousNoSwapCache.cpp | 7 +++++++
 src/system/kernel/vm/VMAnonymousNoSwapCache.h   | 1 +
 src/system/kernel/vm/VMCache.cpp                | 7 +++++++
 6 files changed, 24 insertions(+)

diff --git a/headers/private/kernel/vm/VMCache.h b/headers/private/kernel/vm/VMCache.h
index 504f4f655f..8bfc57e323 100644
--- a/headers/private/kernel/vm/VMCache.h
+++ b/headers/private/kernel/vm/VMCache.h
@@ -149,6 +149,7 @@ public:
 									{ return fRefCount; }
 
 	// backing store operations
+	virtual	bool				CanOvercommit();
 	virtual	status_t			Commit(off_t size, int priority);
 	virtual	bool				HasPage(off_t offset);
 
diff --git a/src/system/kernel/vm/VMAnonymousCache.cpp b/src/system/kernel/vm/VMAnonymousCache.cpp
index 6247423a61..b77f825e75 100644
--- a/src/system/kernel/vm/VMAnonymousCache.cpp
+++ b/src/system/kernel/vm/VMAnonymousCache.cpp
@@ -738,6 +738,13 @@ VMAnonymousCache::Commit(off_t size, int priority)
 }
 
 
+bool
+VMAnonymousCache::CanOvercommit()
+{
+	return fCanOvercommit;
+}
+
+
 bool
 VMAnonymousCache::HasPage(off_t offset)
 {
diff --git a/src/system/kernel/vm/VMAnonymousCache.h b/src/system/kernel/vm/VMAnonymousCache.h
index 741d2a283a..b312e52df0 100644
--- a/src/system/kernel/vm/VMAnonymousCache.h
+++ b/src/system/kernel/vm/VMAnonymousCache.h
@@ -49,6 +49,7 @@ public:
 
 	virtual	status_t			Discard(off_t offset, off_t size);
 
+	virtual	bool				CanOvercommit();
 	virtual	status_t			Commit(off_t size, int priority);
 	virtual	bool				HasPage(off_t offset);
 	virtual	bool				DebugHasPage(off_t offset);
diff --git a/src/system/kernel/vm/VMAnonymousNoSwapCache.cpp b/src/system/kernel/vm/VMAnonymousNoSwapCache.cpp
index cd402fde25..09bc70f082 100644
--- a/src/system/kernel/vm/VMAnonymousNoSwapCache.cpp
+++ b/src/system/kernel/vm/VMAnonymousNoSwapCache.cpp
@@ -94,6 +94,13 @@ VMAnonymousNoSwapCache::Commit(off_t size, int priority)
 }
 
 
+bool
+VMAnonymousNoSwapCache::CanOvercommit()
+{
+	return fCanOvercommit;
+}
+
+
 bool
 VMAnonymousNoSwapCache::HasPage(off_t offset)
 {
diff --git a/src/system/kernel/vm/VMAnonymousNoSwapCache.h b/src/system/kernel/vm/VMAnonymousNoSwapCache.h
index 762717e4db..615f20f026 100644
--- a/src/system/kernel/vm/VMAnonymousNoSwapCache.h
+++ b/src/system/kernel/vm/VMAnonymousNoSwapCache.h
@@ -22,6 +22,7 @@ public:
 									int32 numGuardPages,
 									uint32 allocationFlags);
 
+	virtual	bool				CanOvercommit();
 	virtual	status_t			Commit(off_t size, int priority);
 	virtual	bool				HasPage(off_t offset);
 
diff --git a/src/system/kernel/vm/VMCache.cpp b/src/system/kernel/vm/VMCache.cpp
index ae86c643ba..d152ad47bc 100644
--- a/src/system/kernel/vm/VMCache.cpp
+++ b/src/system/kernel/vm/VMCache.cpp
@@ -1298,6 +1298,13 @@ VMCache::FlushAndRemoveAllPages()
 }
 
 
+bool
+VMCache::CanOvercommit()
+{
+	return false;
+}
+
+
 status_t
 VMCache::Commit(off_t size, int priority)
 {