[Qemu-devel] [PATCH 01/18] split MRU ram list

[Juan Quintela <quintela@redhat.com>]

From: 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>

Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
---
 arch_init.c |  1 +
 cpu-all.h   |  6 +++++-
 exec.c      | 17 ++++++++++++-----
 3 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/arch_init.c b/arch_init.c
index e6effe8..4293557 100644
--- a/arch_init.c
+++ b/arch_init.c
@@ -48,6 +48,7 @@
 #include "qemu/page_cache.h"
 #include "qmp-commands.h"
 #include "trace.h"
+#include "cpu-all.h"

 #ifdef DEBUG_ARCH_INIT
 #define DPRINTF(fmt, ...) \
diff --git a/cpu-all.h b/cpu-all.h
index 6606432..cc9f164 100644
--- a/cpu-all.h
+++ b/cpu-all.h
@@ -490,8 +490,9 @@ typedef struct RAMBlock {
     ram_addr_t offset;
     ram_addr_t length;
     uint32_t flags;
-    char idstr[256];
+    QLIST_ENTRY(RAMBlock) next_mru;
     QLIST_ENTRY(RAMBlock) next;
+    char idstr[256];
 #if defined(__linux__) && !defined(TARGET_S390X)
     int fd;
 #endif
@@ -499,6 +500,9 @@ typedef struct RAMBlock {

 typedef struct RAMList {
     uint8_t *phys_dirty;
+    /* memory blocks are sorted in most recently used order */
+    QLIST_HEAD(, RAMBlock) blocks_mru;
+    /* memory blocks sorted by address */
     QLIST_HEAD(, RAMBlock) blocks;
 } RAMList;
 extern RAMList ram_list;
diff --git a/exec.c b/exec.c
index b0ed593..85399da 100644
--- a/exec.c
+++ b/exec.c
@@ -56,6 +56,7 @@
 #include "xen-mapcache.h"
 #include "trace.h"
 #endif
+#include "cpu-all.h"

 #include "cputlb.h"

@@ -96,7 +97,10 @@ 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;
@@ -2563,6 +2567,7 @@ ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,
     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 = g_realloc(ram_list.phys_dirty,
                                        last_ram_offset() >> TARGET_PAGE_BITS);
@@ -2591,6 +2596,7 @@ 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);
             g_free(block);
             return;
         }
@@ -2604,6 +2610,7 @@ 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) {
@@ -2709,12 +2716,12 @@ 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
@@ -2809,7 +2816,7 @@ 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;
-- 
1.7.11.7