Commit e68cba36 authored by Peter Maydell's avatar Peter Maydell
Browse files

Merge remote-tracking branch 'remotes/amit-migration/tags/mig-2.3-1' into staging 



A set of patches collected over the holidays.  Mix of optimizations and
fixes.

# gpg: Signature made Fri 16 Jan 2015 07:42:00 GMT using RSA key ID 854083B6
# gpg: Good signature from "Amit Shah <amit@amitshah.net>"
# gpg:                 aka "Amit Shah <amit@kernel.org>"
# gpg:                 aka "Amit Shah <amitshah@gmx.net>"

* remotes/amit-migration/tags/mig-2.3-1:
  vmstate: type-check sub-arrays
  migration_cancel: shutdown migration socket
  Handle bi-directional communication for fd migration
  socket shutdown
  Tests: QEMUSizedBuffer/QEMUBuffer
  QEMUSizedBuffer: only free qsb that qemu_bufopen allocated
  xbzrle: rebuild the cache_is_cached function
  xbzrle: optimize XBZRLE to decrease the cache misses

Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
parents df58887b ea987c2c

arch_init.c

+5 −3
Original line number Diff line number Diff line
@@ -346,7 +346,8 @@ static void xbzrle_cache_zero_page(ram_addr_t current_addr) 


    /* We don't care if this fails to allocate a new cache page

     * as long as it updated an old one */

    cache_insert(XBZRLE.cache, current_addr, ZERO_TARGET_PAGE);

    cache_insert(XBZRLE.cache, current_addr, ZERO_TARGET_PAGE,

                 bitmap_sync_count);

}



#define ENCODING_FLAG_XBZRLE 0x1
@@ -358,10 +359,11 @@ static int save_xbzrle_page(QEMUFile *f, uint8_t **current_data, 
    int encoded_len = 0, bytes_sent = -1;

    uint8_t *prev_cached_page;



    if (!cache_is_cached(XBZRLE.cache, current_addr)) {

    if (!cache_is_cached(XBZRLE.cache, current_addr, bitmap_sync_count)) {

        acct_info.xbzrle_cache_miss++;

        if (!last_stage) {

            if (cache_insert(XBZRLE.cache, current_addr, *current_data) == -1) {

            if (cache_insert(XBZRLE.cache, current_addr, *current_data,

                             bitmap_sync_count) == -1) {

                return -1;

            } else {

                /* update *current_data when the page has been

docs/xbzrle.txt

+8 −0
Original line number Diff line number Diff line
@@ -71,6 +71,14 @@ encoded buffer: 
encoded length 24

e9 07 0f 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f 03 01 67 01 01 69



Cache update strategy

=====================

Keeping the hot pages in the cache is effective for decreased cache

misses. XBZRLE uses a counter as the age of each page. The counter will

increase after each ram dirty bitmap sync. When a cache conflict is

detected, XBZRLE will only evict pages in the cache that are older than

a threshold.



Usage

======================

1. Verify the destination QEMU version is able to decode the new format.

include/migration/page_cache.h

+7 −3
Original line number Diff line number Diff line
@@ -43,8 +43,10 @@ void cache_fini(PageCache *cache); 
 *

 * @cache pointer to the PageCache struct

 * @addr: page addr

 * @current_age: current bitmap generation

 */

bool cache_is_cached(const PageCache *cache, uint64_t addr);

bool cache_is_cached(const PageCache *cache, uint64_t addr,

                     uint64_t current_age);



/**

 * get_cached_data: Get the data cached for an addr
@@ -60,13 +62,15 @@ uint8_t *get_cached_data(const PageCache *cache, uint64_t addr); 
 * cache_insert: insert the page into the cache. the page cache

 * will dup the data on insert. the previous value will be overwritten

 *

 * Returns -1 on error

 * Returns -1 when the page isn't inserted into cache

 *

 * @cache pointer to the PageCache struct

 * @addr: page address

 * @pdata: pointer to the page

 * @current_age: current bitmap generation

 */

int cache_insert(PageCache *cache, uint64_t addr, const uint8_t *pdata);

int cache_insert(PageCache *cache, uint64_t addr, const uint8_t *pdata,

                 uint64_t current_age);



/**

 * cache_resize: resize the page cache. In case of size reduction the extra

include/migration/qemu-file.h

+10 −0
Original line number Diff line number Diff line
@@ -84,6 +84,14 @@ typedef size_t (QEMURamSaveFunc)(QEMUFile *f, void *opaque, 
                               size_t size,

                               int *bytes_sent);



/*

 * Stop any read or write (depending on flags) on the underlying

 * transport on the QEMUFile.

 * Existing blocking reads/writes must be woken

 * Returns 0 on success, -err on error

 */

typedef int (QEMUFileShutdownFunc)(void *opaque, bool rd, bool wr);



typedef struct QEMUFileOps {

    QEMUFilePutBufferFunc *put_buffer;

    QEMUFileGetBufferFunc *get_buffer;
@@ -94,6 +102,7 @@ typedef struct QEMUFileOps { 
    QEMURamHookFunc *after_ram_iterate;

    QEMURamHookFunc *hook_ram_load;

    QEMURamSaveFunc *save_page;

    QEMUFileShutdownFunc *shut_down;

} QEMUFileOps;



struct QEMUSizedBuffer {
@@ -177,6 +186,7 @@ void qemu_file_set_rate_limit(QEMUFile *f, int64_t new_rate); 
int64_t qemu_file_get_rate_limit(QEMUFile *f);

int qemu_file_get_error(QEMUFile *f);

void qemu_file_set_error(QEMUFile *f, int ret);

int qemu_file_shutdown(QEMUFile *f);

void qemu_fflush(QEMUFile *f);



static inline void qemu_put_be64s(QEMUFile *f, const uint64_t *pv)

include/migration/vmstate.h

+1 −1
Original line number Diff line number Diff line
@@ -189,7 +189,7 @@ extern const VMStateInfo vmstate_info_bitmap; 
     type_check_2darray(_type, typeof_field(_state, _field), _n1, _n2))



#define vmstate_offset_sub_array(_state, _field, _type, _start)      \

    (offsetof(_state, _field[_start]))

    vmstate_offset_value(_state, _field[_start], _type)



#define vmstate_offset_buffer(_state, _field)                        \

    vmstate_offset_array(_state, _field, uint8_t,                    \