Re: [Qemu-devel] [PATCH v2] ram_blocks: Convert to a QLIST

[Anthony Liguori <anthony@codemonkey.ws>]

On 06/11/2010 12:11 PM, Alex Williamson wrote:
> This makes the RAM block list easier to manipulate.  Also incorporate
> relevant variables into the RAMList struct.
>
> Signed-off-by: Alex Williamson<alex.williamson@redhat.com>
> Acked-by: Chris Wright<chrisw@redhat.com>
>    

Applied.  Thanks.

Regards,

Anthony Liguori
> ---
>
> v2: For qemu.git this time
>
>   arch_init.c |   14 +++++------
>   cpu-all.h   |   28 +++++++++++++++------
>   exec.c      |   78 ++++++++++++++++++++---------------------------------------
>   3 files changed, 54 insertions(+), 66 deletions(-)
>
> diff --git a/arch_init.c b/arch_init.c
> index 8e849a8..eb5b67c 100644
> --- a/arch_init.c
> +++ b/arch_init.c
> @@ -110,7 +110,7 @@ static int ram_save_block(QEMUFile *f)
>       ram_addr_t addr = 0;
>       int bytes_sent = 0;
>
> -    while (addr<  last_ram_offset) {
> +    while (addr<  ram_list.last_offset) {
>           if (cpu_physical_memory_get_dirty(current_addr, MIGRATION_DIRTY_FLAG)) {
>               uint8_t *p;
>
> @@ -133,7 +133,7 @@ static int ram_save_block(QEMUFile *f)
>               break;
>           }
>           addr += TARGET_PAGE_SIZE;
> -        current_addr = (saved_addr + addr) % last_ram_offset;
> +        current_addr = (saved_addr + addr) % ram_list.last_offset;
>       }
>
>       return bytes_sent;
> @@ -146,7 +146,7 @@ static ram_addr_t ram_save_remaining(void)
>       ram_addr_t addr;
>       ram_addr_t count = 0;
>
> -    for (addr = 0; addr<  last_ram_offset; addr += TARGET_PAGE_SIZE) {
> +    for (addr = 0; addr<  ram_list.last_offset; addr += TARGET_PAGE_SIZE) {
>           if (cpu_physical_memory_get_dirty(addr, MIGRATION_DIRTY_FLAG)) {
>               count++;
>           }
> @@ -167,7 +167,7 @@ uint64_t ram_bytes_transferred(void)
>
>   uint64_t ram_bytes_total(void)
>   {
> -    return last_ram_offset;
> +    return ram_list.last_offset;
>   }
>
>   int ram_save_live(Monitor *mon, QEMUFile *f, int stage, void *opaque)
> @@ -191,7 +191,7 @@ int ram_save_live(Monitor *mon, QEMUFile *f, int stage, void *opaque)
>           bytes_transferred = 0;
>
>           /* Make sure all dirty bits are set */
> -        for (addr = 0; addr<  last_ram_offset; addr += TARGET_PAGE_SIZE) {
> +        for (addr = 0; addr<  ram_list.last_offset; addr += TARGET_PAGE_SIZE) {
>               if (!cpu_physical_memory_get_dirty(addr, MIGRATION_DIRTY_FLAG)) {
>                   cpu_physical_memory_set_dirty(addr);
>               }
> @@ -200,7 +200,7 @@ int ram_save_live(Monitor *mon, QEMUFile *f, int stage, void *opaque)
>           /* Enable dirty memory tracking */
>           cpu_physical_memory_set_dirty_tracking(1);
>
> -        qemu_put_be64(f, last_ram_offset | RAM_SAVE_FLAG_MEM_SIZE);
> +        qemu_put_be64(f, ram_list.last_offset | RAM_SAVE_FLAG_MEM_SIZE);
>       }
>
>       bytes_transferred_last = bytes_transferred;
> @@ -259,7 +259,7 @@ int ram_load(QEMUFile *f, void *opaque, int version_id)
>           addr&= TARGET_PAGE_MASK;
>
>           if (flags&  RAM_SAVE_FLAG_MEM_SIZE) {
> -            if (addr != last_ram_offset) {
> +            if (addr != ram_list.last_offset) {
>                   return -EINVAL;
>               }
>           }
> diff --git a/cpu-all.h b/cpu-all.h
> index 77eaf85..e31c2de 100644
> --- a/cpu-all.h
> +++ b/cpu-all.h
> @@ -859,9 +859,21 @@ target_phys_addr_t cpu_get_phys_page_debug(CPUState *env, target_ulong addr);
>   /* memory API */
>
>   extern int phys_ram_fd;
> -extern uint8_t *phys_ram_dirty;
>   extern ram_addr_t ram_size;
> -extern ram_addr_t last_ram_offset;
> +
> +typedef struct RAMBlock {
> +    uint8_t *host;
> +    ram_addr_t offset;
> +    ram_addr_t length;
> +    QLIST_ENTRY(RAMBlock) next;
> +} RAMBlock;
> +
> +typedef struct RAMList {
> +    uint8_t *phys_dirty;
> +    ram_addr_t last_offset;
> +    QLIST_HEAD(ram, RAMBlock) blocks;
> +} RAMList;
> +extern RAMList ram_list;
>
>   extern const char *mem_path;
>   extern int mem_prealloc;
> @@ -891,29 +903,29 @@ extern int mem_prealloc;
>   /* read dirty bit (return 0 or 1) */
>   static inline int cpu_physical_memory_is_dirty(ram_addr_t addr)
>   {
> -    return phys_ram_dirty[addr>>  TARGET_PAGE_BITS] == 0xff;
> +    return ram_list.phys_dirty[addr>>  TARGET_PAGE_BITS] == 0xff;
>   }
>
>   static inline int cpu_physical_memory_get_dirty_flags(ram_addr_t addr)
>   {
> -    return phys_ram_dirty[addr>>  TARGET_PAGE_BITS];
> +    return ram_list.phys_dirty[addr>>  TARGET_PAGE_BITS];
>   }
>
>   static inline int cpu_physical_memory_get_dirty(ram_addr_t addr,
>                                                   int dirty_flags)
>   {
> -    return phys_ram_dirty[addr>>  TARGET_PAGE_BITS]&  dirty_flags;
> +    return ram_list.phys_dirty[addr>>  TARGET_PAGE_BITS]&  dirty_flags;
>   }
>
>   static inline void cpu_physical_memory_set_dirty(ram_addr_t addr)
>   {
> -    phys_ram_dirty[addr>>  TARGET_PAGE_BITS] = 0xff;
> +    ram_list.phys_dirty[addr>>  TARGET_PAGE_BITS] = 0xff;
>   }
>
>   static inline int cpu_physical_memory_set_dirty_flags(ram_addr_t addr,
>                                                         int dirty_flags)
>   {
> -    return phys_ram_dirty[addr>>  TARGET_PAGE_BITS] |= dirty_flags;
> +    return ram_list.phys_dirty[addr>>  TARGET_PAGE_BITS] |= dirty_flags;
>   }
>
>   static inline void cpu_physical_memory_mask_dirty_range(ram_addr_t start,
> @@ -925,7 +937,7 @@ static inline void cpu_physical_memory_mask_dirty_range(ram_addr_t start,
>
>       len = length>>  TARGET_PAGE_BITS;
>       mask = ~dirty_flags;
> -    p = phys_ram_dirty + (start>>  TARGET_PAGE_BITS);
> +    p = ram_list.phys_dirty + (start>>  TARGET_PAGE_BITS);
>       for (i = 0; i<  len; i++) {
>           p[i]&= mask;
>       }
> diff --git a/exec.c b/exec.c
> index 4273797..7f64384 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -110,21 +110,9 @@ uint8_t *code_gen_ptr;
>
>   #if !defined(CONFIG_USER_ONLY)
>   int phys_ram_fd;
> -uint8_t *phys_ram_dirty;
>   static int in_migration;
>
> -typedef struct RAMBlock {
> -    uint8_t *host;
> -    ram_addr_t offset;
> -    ram_addr_t length;
> -    struct RAMBlock *next;
> -} RAMBlock;
> -
> -static RAMBlock *ram_blocks;
> -/* TODO: When we implement (and use) ram deallocation (e.g. for hotplug)
> -   then we can no longer assume contiguous ram offsets, and external uses
> -   of this variable will break.  */
> -ram_addr_t last_ram_offset;
> +RAMList ram_list = { .blocks = QLIST_HEAD_INITIALIZER(ram_list) };
>   #endif
>
>   CPUState *first_cpu;
> @@ -2810,18 +2798,17 @@ ram_addr_t qemu_ram_alloc(ram_addr_t size)
>           madvise(new_block->host, size, MADV_MERGEABLE);
>   #endif
>       }
> -    new_block->offset = last_ram_offset;
> +    new_block->offset = ram_list.last_offset;
>       new_block->length = size;
>
> -    new_block->next = ram_blocks;
> -    ram_blocks = new_block;
> +    QLIST_INSERT_HEAD(&ram_list.blocks, new_block, next);
>
> -    phys_ram_dirty = qemu_realloc(phys_ram_dirty,
> -        (last_ram_offset + size)>>  TARGET_PAGE_BITS);
> -    memset(phys_ram_dirty + (last_ram_offset>>  TARGET_PAGE_BITS),
> +    ram_list.phys_dirty = qemu_realloc(ram_list.phys_dirty,
> +        (ram_list.last_offset + size)>>  TARGET_PAGE_BITS);
> +    memset(ram_list.phys_dirty + (ram_list.last_offset>>  TARGET_PAGE_BITS),
>              0xff, size>>  TARGET_PAGE_BITS);
>
> -    last_ram_offset += size;
> +    ram_list.last_offset += size;
>
>       if (kvm_enabled())
>           kvm_setup_guest_memory(new_block->host, size);
> @@ -2844,31 +2831,20 @@ void qemu_ram_free(ram_addr_t addr)
>    */
>   void *qemu_get_ram_ptr(ram_addr_t addr)
>   {
> -    RAMBlock *prev;
> -    RAMBlock **prevp;
>       RAMBlock *block;
>
> -    prev = NULL;
> -    prevp =&ram_blocks;
> -    block = ram_blocks;
> -    while (block&&  (block->offset>  addr
> -                     || block->offset + block->length<= addr)) {
> -        if (prev)
> -          prevp =&prev->next;
> -        prev = block;
> -        block = block->next;
> -    }
> -    if (!block) {
> -        fprintf(stderr, "Bad ram offset %" PRIx64 "\n", (uint64_t)addr);
> -        abort();
> -    }
> -    /* Move this entry to to start of the list.  */
> -    if (prev) {
> -        prev->next = block->next;
> -        block->next = *prevp;
> -        *prevp = block;
> +    QLIST_FOREACH(block,&ram_list.blocks, next) {
> +        if (addr - block->offset<  block->length) {
> +            QLIST_REMOVE(block, next);
> +            QLIST_INSERT_HEAD(&ram_list.blocks, block, next);
> +            return block->host + (addr - block->offset);
> +        }
>       }
> -    return block->host + (addr - block->offset);
> +
> +    fprintf(stderr, "Bad ram offset %" PRIx64 "\n", (uint64_t)addr);
> +    abort();
> +
> +    return NULL;
>   }
>
>   /* Some of the softmmu routines need to translate from a host pointer
> @@ -2878,16 +2854,16 @@ ram_addr_t qemu_ram_addr_from_host(void *ptr)
>       RAMBlock *block;
>       uint8_t *host = ptr;
>
> -    block = ram_blocks;
> -    while (block&&  (block->host>  host
> -                     || block->host + block->length<= host)) {
> -        block = block->next;
> -    }
> -    if (!block) {
> -        fprintf(stderr, "Bad ram pointer %p\n", ptr);
> -        abort();
> +    QLIST_FOREACH(block,&ram_list.blocks, next) {
> +        if (host - block->host<  block->length) {
> +            return block->offset + (host - block->host);
> +        }
>       }
> -    return block->offset + (host - block->host);
> +
> +    fprintf(stderr, "Bad ram pointer %p\n", ptr);
> +    abort();
> +
> +    return 0;
>   }
>
>   static uint32_t unassigned_mem_readb(void *opaque, target_phys_addr_t addr)
>
>
>
>