[PATCH 0/1] MR11742: krnl386: Don't free DISCARDABLE resources in FreeResource16.

[Alex Henrie (＠alexhenrie)]

If a resource is marked DISCARDABLE, it is not actually freed when its
refcount reaches 0. In theory the resource's memory is freed when the
system is low on memory, but its global handle remains valid to allow
the resource to be resurrected with the same handle later. In practice,
16-bit programs can't run out of memory on modern hardware, and the game
Tetris Jr. depends on its discardable resources never being discarded.

See https://devblogs.microsoft.com/oldnewthing/20040202-00/?p=40783

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=23364

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/11742

[PATCH 1/1] krnl386: Don't free DISCARDABLE resources in FreeResource16.

[Alex Henrie]

From: Alex Henrie <[e-mail]>

If a resource is marked DISCARDABLE, it is not actually freed when its
refcount reaches 0. In theory the resource's memory is freed when the
system is low on memory, but its global handle remains valid to allow
the resource to be resurrected with the same handle later. In practice,
16-bit programs can't run out of memory on modern hardware, and the game
Tetris Jr. depends on its discardable resources never being discarded.

See https://devblogs.microsoft.com/oldnewthing/20040202-00/?p=40783

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=23364
---
 dlls/krnl386.exe16/resource.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/dlls/krnl386.exe16/resource.c b/dlls/krnl386.exe16/resource.c
index bcdb01a3b30..52d24dc67ba 100644
--- a/dlls/krnl386.exe16/resource.c
+++ b/dlls/krnl386.exe16/resource.c
@@ -1125,7 +1125,7 @@ BOOL16 WINAPI FreeResource16( HGLOBAL16 handle )
                 if (pNameInfo->handle == handle)
                 {
                     if (pNameInfo->usage > 0) pNameInfo->usage--;
-                    if (pNameInfo->usage == 0)
+                    if (pNameInfo->usage == 0 && !(pNameInfo->flags & NE_SEGFLAGS_DISCARDABLE))
                     {
                         GlobalFree16( pNameInfo->handle );
                         pNameInfo->handle = 0;
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/11742

[Jinoh Kang (＠iamahuman)]

Jinoh Kang (@iamahuman) commented about dlls/krnl386.exe16/resource.c:
> if (pNameInfo->handle == handle)
>                  {
>                      if (pNameInfo->usage > 0) pNameInfo->usage--;
> -                    if (pNameInfo->usage == 0)
> +                    if (pNameInfo->usage == 0 && !(pNameInfo->flags & NE_SEGFLAGS_DISCARDABLE))

https://devblogs.microsoft.com/oldnewthing/20040202-00/?p=40783 says you're supposed to mark the segment discardable, not ignore the request entirely.
> 16-bit programs can't run out of memory on modern hardware

Are you sure? That 16-bit programs can utilize all memory of modern hardware?

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/11742#note_149668