llvmpipe: Use an anonymous file for memory allocations

Preparation for sparse.

Reviewed-By: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29408>

src/gallium/drivers/llvmpipe/lp_screen.c

@@ -43,6 +43,7 @@
 #include "util/os_misc.h"
 #include "util/os_time.h"
 #include "util/u_helpers.h"
+#include "util/anon_file.h"
 #include "lp_texture.h"
 #include "lp_fence.h"
 #include "lp_jit.h"
@@ -929,6 +930,10 @@ llvmpipe_destroy_screen(struct pipe_screen *_screen)
    close(screen->udmabuf_fd);
 #endif
 
+   util_vma_heap_finish(&screen->mem_heap);
+
+   close(screen->fd_mem_alloc);
+   mtx_destroy(&screen->mem_mutex);
    mtx_destroy(&screen->rast_mutex);
    mtx_destroy(&screen->cs_mutex);
    FREE(screen);
@@ -1170,6 +1175,16 @@ llvmpipe_create_screen(struct sw_winsys *winsys)
    screen->udmabuf_fd = open("/dev/udmabuf", O_RDWR);
 #endif
 
+   screen->fd_mem_alloc = os_create_anonymous_file(0, "allocation fd");
+   (void) mtx_init(&screen->mem_mutex, mtx_plain);
+
+   uint64_t alignment;
+   if (!os_get_page_size(&alignment))
+      alignment = 256;
+
+   util_vma_heap_init(&screen->mem_heap, alignment, UINT64_MAX - alignment);
+   screen->mem_heap.alloc_high = false;
+
    snprintf(screen->renderer_string, sizeof(screen->renderer_string),
             "llvmpipe (LLVM " MESA_LLVM_VERSION_STRING ", %u bits)",
             lp_build_init_native_width() );

src/gallium/drivers/llvmpipe/lp_screen.h

@@ -38,6 +38,7 @@
 #include "pipe/p_defines.h"
 #include "util/u_thread.h"
 #include "util/list.h"
+#include "util/vma.h"
 #include "gallivm/lp_bld.h"
 #include "gallivm/lp_bld_misc.h"
 
@@ -77,6 +78,11 @@ struct llvmpipe_screen
 #ifdef HAVE_LIBDRM
    int udmabuf_fd;
 #endif
+
+   int fd_mem_alloc;
+   mtx_t mem_mutex;
+   uint64_t mem_file_size;
+   struct util_vma_heap mem_heap;
 };
 
 

src/gallium/drivers/llvmpipe/lp_texture.c

@@ -35,6 +35,7 @@
 #include "pipe/p_context.h"
 #include "pipe/p_defines.h"
 
+#include "util/detect_os.h"
 #include "util/simple_mtx.h"
 #include "util/u_inlines.h"
 #include "util/u_cpu_detect.h"
@@ -43,6 +44,10 @@
 #include "util/u_memory.h"
 #include "util/u_transfer.h"
 
+#if DETECT_OS_POSIX
+#include "util/os_mman.h"
+#endif
+
 #include "lp_context.h"
 #include "lp_flush.h"
 #include "lp_screen.h"
@@ -1101,22 +1106,60 @@ llvmpipe_memory_barrier(struct pipe_context *pipe,
 
 
 static struct pipe_memory_allocation *
-llvmpipe_allocate_memory(struct pipe_screen *screen, uint64_t size)
+llvmpipe_allocate_memory(struct pipe_screen *_screen, uint64_t size)
 {
+   struct llvmpipe_screen *screen = llvmpipe_screen(_screen);
    struct llvmpipe_memory_allocation *mem = CALLOC_STRUCT(llvmpipe_memory_allocation);
    uint64_t alignment;
    if (!os_get_page_size(&alignment))
       alignment = 256;
-   mem->cpu_addr = os_malloc_aligned(size, alignment);
+
+   mem->fd = screen->fd_mem_alloc;
+   mem->size = align64(size, alignment);
+
+#if DETECT_OS_LINUX
+   mem->cpu_addr = MAP_FAILED;
+
+   mtx_lock(&screen->mem_mutex);
+
+   mem->offset = util_vma_heap_alloc(&screen->mem_heap, mem->size, alignment);
+
+   if (mem->offset + mem->size > screen->mem_file_size) {
+      /* expand the anonymous file */
+      screen->mem_file_size = mem->offset + mem->size;
+      ftruncate(screen->fd_mem_alloc, screen->mem_file_size);
+   }
+
+   mtx_unlock(&screen->mem_mutex);
+#else
+   mem->cpu_addr = malloc(mem->size);
+#endif
+
    return (struct pipe_memory_allocation *)mem;
 }
 
 
 static void
-llvmpipe_free_memory(struct pipe_screen *screen,
+llvmpipe_free_memory(struct pipe_screen *pscreen,
                      struct pipe_memory_allocation *pmem)
 {
-   os_free_aligned(pmem);
+   struct llvmpipe_screen *screen = llvmpipe_screen(pscreen);
+   struct llvmpipe_memory_allocation *mem = (struct llvmpipe_memory_allocation *)pmem;
+
+   if (mem->fd) {
+      mtx_lock(&screen->mem_mutex);
+      util_vma_heap_free(&screen->mem_heap, mem->offset, mem->size);
+      mtx_unlock(&screen->mem_mutex);
+   }
+
+#if DETECT_OS_LINUX
+   if (mem->cpu_addr != MAP_FAILED)
+      munmap(mem->cpu_addr, mem->size);
+#else
+   free(mem->cpu_addr);
+#endif
+
+   FREE(mem);
 }
 
 
@@ -1300,6 +1343,17 @@ llvmpipe_map_memory(struct pipe_screen *screen,
                     struct pipe_memory_allocation *pmem)
 {
    struct llvmpipe_memory_allocation *mem = (struct llvmpipe_memory_allocation *)pmem;
+
+#if DETECT_OS_LINUX
+   if (mem->cpu_addr != MAP_FAILED)
+      return mem->cpu_addr;
+
+   /* create a "CPU" mapping */
+   mem->cpu_addr = mmap(NULL, mem->size, PROT_READ|PROT_WRITE, MAP_SHARED,
+                        mem->fd, mem->offset);
+   assert(mem->cpu_addr != MAP_FAILED);
+#endif
+
    return mem->cpu_addr;
 }
 

src/gallium/drivers/llvmpipe/lp_texture.h

@@ -126,6 +126,8 @@ struct llvmpipe_transfer
 
 struct llvmpipe_memory_allocation
 {
+   int fd;
+   uint64_t offset;
    void *cpu_addr;
    uint64_t size;
    enum llvmpipe_memory_fd_type type;