[Qemu-devel] [RFC PATCH 12/13] split MRU ram list

[Paolo Bonzini <pbonzini@redhat.com>]

Outside the execution threads the normal, non-MRU-ized order of
the RAM blocks should always be enough.  So manage two separate
lists, which will have separate locking rules.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 cpu-all.h |    4 +++-
 exec.c    |   16 +++++++++++-----
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/cpu-all.h b/cpu-all.h
index f5c82cd..083d9e6 100644
--- a/cpu-all.h
+++ b/cpu-all.h
@@ -479,8 +479,9 @@ typedef struct RAMBlock {
     ram_addr_t offset;
     ram_addr_t length;
     uint32_t flags;
-    char idstr[256];
     QLIST_ENTRY(RAMBlock) next;
+    QLIST_ENTRY(RAMBlock) next_mru;
+    char idstr[256];
 #if defined(__linux__) && !defined(TARGET_S390X)
     int fd;
 #endif
@@ -489,6 +490,7 @@ typedef struct RAMBlock {
 typedef struct RAMList {
     uint8_t *phys_dirty;
     QLIST_HEAD(, RAMBlock) blocks;
+    QLIST_HEAD(, RAMBlock) blocks_mru;
 } RAMList;
 extern RAMList ram_list;
 
diff --git a/exec.c b/exec.c
index 63adb18..d25e3cc 100644
--- a/exec.c
+++ b/exec.c
@@ -110,7 +110,10 @@ static uint8_t *code_gen_ptr;
 int phys_ram_fd;
 static int in_migration;
 
-RAMList ram_list = { .blocks = QLIST_HEAD_INITIALIZER(ram_list.blocks) };
+RAMList ram_list = {
+    .blocks = QLIST_HEAD_INITIALIZER(ram_list.blocks),
+    .blocks_mru = QLIST_HEAD_INITIALIZER(ram_list.blocks_mru)
+};
 
 static MemoryRegion *system_memory;
 static MemoryRegion *system_io;
@@ -2983,6 +2986,7 @@ ram_addr_t qemu_ram_alloc_from_ptr(DeviceState *dev, const char *name,
     new_block->length = size;
 
     QLIST_INSERT_HEAD(&ram_list.blocks, new_block, next);
+    QLIST_INSERT_HEAD(&ram_list.blocks_mru, new_block, next_mru);
 
     ram_list.phys_dirty = qemu_realloc(ram_list.phys_dirty,
                                        last_ram_offset() >> TARGET_PAGE_BITS);
@@ -3007,6 +3011,7 @@ void qemu_ram_free_from_ptr(ram_addr_t addr)
     QLIST_FOREACH(block, &ram_list.blocks, next) {
         if (addr == block->offset) {
             QLIST_REMOVE(block, next);
+            QLIST_REMOVE(block, next_mru);
             qemu_free(block);
             return;
         }
@@ -3020,6 +3025,7 @@ void qemu_ram_free(ram_addr_t addr)
     QLIST_FOREACH(block, &ram_list.blocks, next) {
         if (addr == block->offset) {
             QLIST_REMOVE(block, next);
+            QLIST_REMOVE(block, next_mru);
             if (block->flags & RAM_PREALLOC_MASK) {
                 ;
             } else if (mem_path) {
@@ -3124,12 +3130,12 @@ void *qemu_get_ram_ptr(ram_addr_t addr)
 {
     RAMBlock *block;
 
-    QLIST_FOREACH(block, &ram_list.blocks, next) {
+    QLIST_FOREACH(block, &ram_list.blocks_mru, next_mru) {
         if (addr - block->offset < block->length) {
             /* Move this entry to to start of the list.  */
             if (block != QLIST_FIRST(&ram_list.blocks)) {
-                QLIST_REMOVE(block, next);
-                QLIST_INSERT_HEAD(&ram_list.blocks, block, next);
+                QLIST_REMOVE(block, next_mru);
+                QLIST_INSERT_HEAD(&ram_list.blocks_mru, block, next_mru);
             }
             if (xen_enabled()) {
                 /* We need to check if the requested address is in the RAM
@@ -3224,7 +3230,7 @@ int qemu_ram_addr_from_host(void *ptr, ram_addr_t *ram_addr)
         return 0;
     }
 
-    QLIST_FOREACH(block, &ram_list.blocks, next) {
+    QLIST_FOREACH(block, &ram_list.blocks_mru, next_mru) {
         /* This case append when the block is not mapped. */
         if (block->host == NULL) {
             continue;
-- 
1.7.6