[PATCH v2 0/6] migration: misc cleanups

[PATCH v2 0/6] migration: misc cleanups

[Juan Quintela]

Hi

Changes since v1:
- Add reviewed tags for reviewed patches
- Change comment about last_stage (philmd)
- Change cast to 1ULL for ram_release_page()
- remove TARGET_PAGE_MASK mask.  It was used only for compression,
  and offset should be page aligned already

Please, review.

Thanks, Juan.

[v1]
This series do several cleanups:
- Dave found that I was using "%d" for unsigned, fix all uses.
- We pass last_stage left and right, but we only use it in two places
  Just move it to RAMState.
- do_compress_page() used a goto when not needed.
- ram_release_pages() was always used with one page
- And put it when we detect zero pages, instead of everywhere we have find a zero page.

Please, review.

Juan Quintela (6):
  migration: All this fields are unsigned
  migration: We only need last_stage in two places
  migration: ram_release_pages() always receive 1 page as argument
  migration: Remove masking for compression
  migration: simplify do_compress_ram_page
  migration: Move ram_release_pages() call to save_zero_page_to_file()

 migration/multifd-zlib.c | 20 +++++------
 migration/multifd-zstd.c | 24 +++++++-------
 migration/multifd.c      | 16 ++++-----
 migration/ram.c          | 71 +++++++++++++++++-----------------------
 migration/trace-events   | 26 +++++++--------
 5 files changed, 73 insertions(+), 84 deletions(-)

-- 
2.33.1

[PATCH v2 1/6] migration: All this fields are unsigned

[Juan Quintela]

So printing it as %d is wrong.  Notice that for the channel id, that
is an uint8_t, but I changed it anyways for consistency.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 migration/multifd-zlib.c | 20 ++++++++++----------
 migration/multifd-zstd.c | 24 ++++++++++++------------
 migration/multifd.c      | 16 ++++++++--------
 migration/trace-events   | 26 +++++++++++++-------------
 4 files changed, 43 insertions(+), 43 deletions(-)

diff --git a/migration/multifd-zlib.c b/migration/multifd-zlib.c
index da6201704c..9f6ebf1076 100644
--- a/migration/multifd-zlib.c
+++ b/migration/multifd-zlib.c
@@ -51,7 +51,7 @@ static int zlib_send_setup(MultiFDSendParams *p, Error **errp)
     zs->opaque = Z_NULL;
     if (deflateInit(zs, migrate_multifd_zlib_level()) != Z_OK) {
         g_free(z);
-        error_setg(errp, "multifd %d: deflate init failed", p->id);
+        error_setg(errp, "multifd %u: deflate init failed", p->id);
         return -1;
     }
     /* To be safe, we reserve twice the size of the packet */
@@ -60,7 +60,7 @@ static int zlib_send_setup(MultiFDSendParams *p, Error **errp)
     if (!z->zbuff) {
         deflateEnd(&z->zs);
         g_free(z);
-        error_setg(errp, "multifd %d: out of memory for zbuff", p->id);
+        error_setg(errp, "multifd %u: out of memory for zbuff", p->id);
         return -1;
     }
     p->data = z;
@@ -132,12 +132,12 @@ static int zlib_send_prepare(MultiFDSendParams *p, Error **errp)
             ret = deflate(zs, flush);
         } while (ret == Z_OK && zs->avail_in && zs->avail_out);
         if (ret == Z_OK && zs->avail_in) {
-            error_setg(errp, "multifd %d: deflate failed to compress all input",
+            error_setg(errp, "multifd %u: deflate failed to compress all input",
                        p->id);
             return -1;
         }
         if (ret != Z_OK) {
-            error_setg(errp, "multifd %d: deflate returned %d instead of Z_OK",
+            error_setg(errp, "multifd %u: deflate returned %d instead of Z_OK",
                        p->id, ret);
             return -1;
         }
@@ -190,7 +190,7 @@ static int zlib_recv_setup(MultiFDRecvParams *p, Error **errp)
     zs->avail_in = 0;
     zs->next_in = Z_NULL;
     if (inflateInit(zs) != Z_OK) {
-        error_setg(errp, "multifd %d: inflate init failed", p->id);
+        error_setg(errp, "multifd %u: inflate init failed", p->id);
         return -1;
     }
     /* To be safe, we reserve twice the size of the packet */
@@ -198,7 +198,7 @@ static int zlib_recv_setup(MultiFDRecvParams *p, Error **errp)
     z->zbuff = g_try_malloc(z->zbuff_len);
     if (!z->zbuff) {
         inflateEnd(zs);
-        error_setg(errp, "multifd %d: out of memory for zbuff", p->id);
+        error_setg(errp, "multifd %u: out of memory for zbuff", p->id);
         return -1;
     }
     return 0;
@@ -247,7 +247,7 @@ static int zlib_recv_pages(MultiFDRecvParams *p, Error **errp)
     int i;
 
     if (flags != MULTIFD_FLAG_ZLIB) {
-        error_setg(errp, "multifd %d: flags received %x flags expected %x",
+        error_setg(errp, "multifd %u: flags received %x flags expected %x",
                    p->id, flags, MULTIFD_FLAG_ZLIB);
         return -1;
     }
@@ -284,19 +284,19 @@ static int zlib_recv_pages(MultiFDRecvParams *p, Error **errp)
         } while (ret == Z_OK && zs->avail_in
                              && (zs->total_out - start) < page_size);
         if (ret == Z_OK && (zs->total_out - start) < page_size) {
-            error_setg(errp, "multifd %d: inflate generated too few output",
+            error_setg(errp, "multifd %u: inflate generated too few output",
                        p->id);
             return -1;
         }
         if (ret != Z_OK) {
-            error_setg(errp, "multifd %d: inflate returned %d instead of Z_OK",
+            error_setg(errp, "multifd %u: inflate returned %d instead of Z_OK",
                        p->id, ret);
             return -1;
         }
     }
     out_size = zs->total_out - out_size;
     if (out_size != expected_size) {
-        error_setg(errp, "multifd %d: packet size received %d size expected %d",
+        error_setg(errp, "multifd %u: packet size received %u size expected %u",
                    p->id, out_size, expected_size);
         return -1;
     }
diff --git a/migration/multifd-zstd.c b/migration/multifd-zstd.c
index 2d5b61106c..cc4e991724 100644
--- a/migration/multifd-zstd.c
+++ b/migration/multifd-zstd.c
@@ -55,7 +55,7 @@ static int zstd_send_setup(MultiFDSendParams *p, Error **errp)
     z->zcs = ZSTD_createCStream();
     if (!z->zcs) {
         g_free(z);
-        error_setg(errp, "multifd %d: zstd createCStream failed", p->id);
+        error_setg(errp, "multifd %u: zstd createCStream failed", p->id);
         return -1;
     }
 
@@ -63,7 +63,7 @@ static int zstd_send_setup(MultiFDSendParams *p, Error **errp)
     if (ZSTD_isError(res)) {
         ZSTD_freeCStream(z->zcs);
         g_free(z);
-        error_setg(errp, "multifd %d: initCStream failed with error %s",
+        error_setg(errp, "multifd %u: initCStream failed with error %s",
                    p->id, ZSTD_getErrorName(res));
         return -1;
     }
@@ -73,7 +73,7 @@ static int zstd_send_setup(MultiFDSendParams *p, Error **errp)
     if (!z->zbuff) {
         ZSTD_freeCStream(z->zcs);
         g_free(z);
-        error_setg(errp, "multifd %d: out of memory for zbuff", p->id);
+        error_setg(errp, "multifd %u: out of memory for zbuff", p->id);
         return -1;
     }
     return 0;
@@ -144,12 +144,12 @@ static int zstd_send_prepare(MultiFDSendParams *p, Error **errp)
         } while (ret > 0 && (z->in.size - z->in.pos > 0)
                          && (z->out.size - z->out.pos > 0));
         if (ret > 0 && (z->in.size - z->in.pos > 0)) {
-            error_setg(errp, "multifd %d: compressStream buffer too small",
+            error_setg(errp, "multifd %u: compressStream buffer too small",
                        p->id);
             return -1;
         }
         if (ZSTD_isError(ret)) {
-            error_setg(errp, "multifd %d: compressStream error %s",
+            error_setg(errp, "multifd %u: compressStream error %s",
                        p->id, ZSTD_getErrorName(ret));
             return -1;
         }
@@ -198,7 +198,7 @@ static int zstd_recv_setup(MultiFDRecvParams *p, Error **errp)
     z->zds = ZSTD_createDStream();
     if (!z->zds) {
         g_free(z);
-        error_setg(errp, "multifd %d: zstd createDStream failed", p->id);
+        error_setg(errp, "multifd %u: zstd createDStream failed", p->id);
         return -1;
     }
 
@@ -206,7 +206,7 @@ static int zstd_recv_setup(MultiFDRecvParams *p, Error **errp)
     if (ZSTD_isError(ret)) {
         ZSTD_freeDStream(z->zds);
         g_free(z);
-        error_setg(errp, "multifd %d: initDStream failed with error %s",
+        error_setg(errp, "multifd %u: initDStream failed with error %s",
                    p->id, ZSTD_getErrorName(ret));
         return -1;
     }
@@ -217,7 +217,7 @@ static int zstd_recv_setup(MultiFDRecvParams *p, Error **errp)
     if (!z->zbuff) {
         ZSTD_freeDStream(z->zds);
         g_free(z);
-        error_setg(errp, "multifd %d: out of memory for zbuff", p->id);
+        error_setg(errp, "multifd %u: out of memory for zbuff", p->id);
         return -1;
     }
     return 0;
@@ -265,7 +265,7 @@ static int zstd_recv_pages(MultiFDRecvParams *p, Error **errp)
     int i;
 
     if (flags != MULTIFD_FLAG_ZSTD) {
-        error_setg(errp, "multifd %d: flags received %x flags expected %x",
+        error_setg(errp, "multifd %u: flags received %x flags expected %x",
                    p->id, flags, MULTIFD_FLAG_ZSTD);
         return -1;
     }
@@ -297,19 +297,19 @@ static int zstd_recv_pages(MultiFDRecvParams *p, Error **errp)
         } while (ret > 0 && (z->in.size - z->in.pos > 0)
                          && (z->out.pos < page_size));
         if (ret > 0 && (z->out.pos < page_size)) {
-            error_setg(errp, "multifd %d: decompressStream buffer too small",
+            error_setg(errp, "multifd %u: decompressStream buffer too small",
                        p->id);
             return -1;
         }
         if (ZSTD_isError(ret)) {
-            error_setg(errp, "multifd %d: decompressStream returned %s",
+            error_setg(errp, "multifd %u: decompressStream returned %s",
                        p->id, ZSTD_getErrorName(ret));
             return ret;
         }
         out_size += z->out.pos;
     }
     if (out_size != expected_size) {
-        error_setg(errp, "multifd %d: packet size received %d size expected %d",
+        error_setg(errp, "multifd %u: packet size received %u size expected %u",
                    p->id, out_size, expected_size);
         return -1;
     }
diff --git a/migration/multifd.c b/migration/multifd.c
index 3242f688e5..4d62850258 100644
--- a/migration/multifd.c
+++ b/migration/multifd.c
@@ -148,7 +148,7 @@ static int nocomp_recv_pages(MultiFDRecvParams *p, Error **errp)
     uint32_t flags = p->flags & MULTIFD_FLAG_COMPRESSION_MASK;
 
     if (flags != MULTIFD_FLAG_NOCOMP) {
-        error_setg(errp, "multifd %d: flags received %x flags expected %x",
+        error_setg(errp, "multifd %u: flags received %x flags expected %x",
                    p->id, flags, MULTIFD_FLAG_NOCOMP);
         return -1;
     }
@@ -212,8 +212,8 @@ static int multifd_recv_initial_packet(QIOChannel *c, Error **errp)
     }
 
     if (msg.version != MULTIFD_VERSION) {
-        error_setg(errp, "multifd: received packet version %d "
-                   "expected %d", msg.version, MULTIFD_VERSION);
+        error_setg(errp, "multifd: received packet version %u "
+                   "expected %u", msg.version, MULTIFD_VERSION);
         return -1;
     }
 
@@ -229,8 +229,8 @@ static int multifd_recv_initial_packet(QIOChannel *c, Error **errp)
     }
 
     if (msg.id > migrate_multifd_channels()) {
-        error_setg(errp, "multifd: received channel version %d "
-                   "expected %d", msg.version, MULTIFD_VERSION);
+        error_setg(errp, "multifd: received channel version %u "
+                   "expected %u", msg.version, MULTIFD_VERSION);
         return -1;
     }
 
@@ -303,7 +303,7 @@ static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp)
     packet->version = be32_to_cpu(packet->version);
     if (packet->version != MULTIFD_VERSION) {
         error_setg(errp, "multifd: received packet "
-                   "version %d and expected version %d",
+                   "version %u and expected version %u",
                    packet->version, MULTIFD_VERSION);
         return -1;
     }
@@ -317,7 +317,7 @@ static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp)
      */
     if (packet->pages_alloc > pages_max * 100) {
         error_setg(errp, "multifd: received packet "
-                   "with size %d and expected a maximum size of %d",
+                   "with size %u and expected a maximum size of %u",
                    packet->pages_alloc, pages_max * 100) ;
         return -1;
     }
@@ -333,7 +333,7 @@ static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp)
     p->pages->num = be32_to_cpu(packet->pages_used);
     if (p->pages->num > packet->pages_alloc) {
         error_setg(errp, "multifd: received packet "
-                   "with %d pages and expected maximum pages are %d",
+                   "with %u pages and expected maximum pages are %u",
                    p->pages->num, packet->pages_alloc) ;
         return -1;
     }
diff --git a/migration/trace-events b/migration/trace-events
index b48d873b8a..5172cb3b3d 100644
--- a/migration/trace-events
+++ b/migration/trace-events
@@ -115,23 +115,23 @@ ram_write_tracking_ramblock_start(const char *block_id, size_t page_size, void *
 ram_write_tracking_ramblock_stop(const char *block_id, size_t page_size, void *addr, size_t length) "%s: page_size: %zu addr: %p length: %zu"
 
 # multifd.c
-multifd_new_send_channel_async(uint8_t id) "channel %d"
-multifd_recv(uint8_t id, uint64_t packet_num, uint32_t used, uint32_t flags, uint32_t next_packet_size) "channel %d packet_num %" PRIu64 " pages %d flags 0x%x next packet size %d"
-multifd_recv_new_channel(uint8_t id) "channel %d"
+multifd_new_send_channel_async(uint8_t id) "channel %u"
+multifd_recv(uint8_t id, uint64_t packet_num, uint32_t used, uint32_t flags, uint32_t next_packet_size) "channel %u packet_num %" PRIu64 " pages %u flags 0x%x next packet size %u"
+multifd_recv_new_channel(uint8_t id) "channel %u"
 multifd_recv_sync_main(long packet_num) "packet num %ld"
-multifd_recv_sync_main_signal(uint8_t id) "channel %d"
-multifd_recv_sync_main_wait(uint8_t id) "channel %d"
+multifd_recv_sync_main_signal(uint8_t id) "channel %u"
+multifd_recv_sync_main_wait(uint8_t id) "channel %u"
 multifd_recv_terminate_threads(bool error) "error %d"
-multifd_recv_thread_end(uint8_t id, uint64_t packets, uint64_t pages) "channel %d packets %" PRIu64 " pages %" PRIu64
-multifd_recv_thread_start(uint8_t id) "%d"
-multifd_send(uint8_t id, uint64_t packet_num, uint32_t used, uint32_t flags, uint32_t next_packet_size) "channel %d packet_num %" PRIu64 " pages %d flags 0x%x next packet size %d"
-multifd_send_error(uint8_t id) "channel %d"
+multifd_recv_thread_end(uint8_t id, uint64_t packets, uint64_t pages) "channel %u packets %" PRIu64 " pages %" PRIu64
+multifd_recv_thread_start(uint8_t id) "%u"
+multifd_send(uint8_t id, uint64_t packet_num, uint32_t used, uint32_t flags, uint32_t next_packet_size) "channel %u packet_num %" PRIu64 " pages %u flags 0x%x next packet size %u"
+multifd_send_error(uint8_t id) "channel %u"
 multifd_send_sync_main(long packet_num) "packet num %ld"
-multifd_send_sync_main_signal(uint8_t id) "channel %d"
-multifd_send_sync_main_wait(uint8_t id) "channel %d"
+multifd_send_sync_main_signal(uint8_t id) "channel %u"
+multifd_send_sync_main_wait(uint8_t id) "channel %u"
 multifd_send_terminate_threads(bool error) "error %d"
-multifd_send_thread_end(uint8_t id, uint64_t packets, uint64_t pages) "channel %d packets %" PRIu64 " pages %"  PRIu64
-multifd_send_thread_start(uint8_t id) "%d"
+multifd_send_thread_end(uint8_t id, uint64_t packets, uint64_t pages) "channel %u packets %" PRIu64 " pages %"  PRIu64
+multifd_send_thread_start(uint8_t id) "%u"
 multifd_tls_outgoing_handshake_start(void *ioc, void *tioc, const char *hostname) "ioc=%p tioc=%p hostname=%s"
 multifd_tls_outgoing_handshake_error(void *ioc, const char *err) "ioc=%p err=%s"
 multifd_tls_outgoing_handshake_complete(void *ioc) "ioc=%p"
-- 
2.33.1

Re: [PATCH v2 1/6] migration: All this fields are unsigned

[Peter Xu]

On Tue, Dec 21, 2021 at 01:52:30PM +0100, Juan Quintela wrote:
> So printing it as %d is wrong.  Notice that for the channel id, that
> is an uint8_t, but I changed it anyways for consistency.

Just curious: uint_8 can always correctly converted to a int, so the patch
shouldn't have a functional change, right?

> 
> Signed-off-by: Juan Quintela <quintela@redhat.com>
> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

Reviewed-by: Peter Xu <peterx@redhat.com>

-- 
Peter Xu

Re: [PATCH v2 1/6] migration: All this fields are unsigned

[Juan Quintela]

Peter Xu <peterx@redhat.com> wrote:
> On Tue, Dec 21, 2021 at 01:52:30PM +0100, Juan Quintela wrote:
>> So printing it as %d is wrong.  Notice that for the channel id, that
>> is an uint8_t, but I changed it anyways for consistency.
>
> Just curious: uint_8 can always correctly converted to a int, so the patch
> shouldn't have a functional change, right?

Yeap.  My understanding of C promotion rules is that everything is
promoted to int by default, if the size is smaller than positive part of
it, that is ok.

But once there, I reviewed all "%d", and if it was unsigned, I change it
to "%u".

>> Signed-off-by: Juan Quintela <quintela@redhat.com>
>> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>
> Reviewed-by: Peter Xu <peterx@redhat.com>

Thanks, Juan.

[PATCH v2 2/6] migration: We only need last_stage in two places

[Juan Quintela]

We only need last_stage in two places and we are passing it all
around.  Just add a field to RAMState that passes it.

Signed-off-by: Juan Quintela <quintela@redhat.com>

---

Repeat subject (philmd suggestion)
---
 migration/ram.c | 41 ++++++++++++++++++-----------------------
 1 file changed, 18 insertions(+), 23 deletions(-)

diff --git a/migration/ram.c b/migration/ram.c
index 57efa67f20..7223b0d8ca 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -325,7 +325,8 @@ struct RAMState {
     uint64_t xbzrle_bytes_prev;
     /* Start using XBZRLE (e.g., after the first round). */
     bool xbzrle_enabled;
-
+    /* Are we on the last stage of migration */
+    bool last_stage;
     /* compression statistics since the beginning of the period */
     /* amount of count that no free thread to compress data */
     uint64_t compress_thread_busy_prev;
@@ -683,11 +684,10 @@ static void xbzrle_cache_zero_page(RAMState *rs, ram_addr_t current_addr)
  * @current_addr: addr of the page
  * @block: block that contains the page we want to send
  * @offset: offset inside the block for the page
- * @last_stage: if we are at the completion stage
  */
 static int save_xbzrle_page(RAMState *rs, uint8_t **current_data,
                             ram_addr_t current_addr, RAMBlock *block,
-                            ram_addr_t offset, bool last_stage)
+                            ram_addr_t offset)
 {
     int encoded_len = 0, bytes_xbzrle;
     uint8_t *prev_cached_page;
@@ -695,7 +695,7 @@ static int save_xbzrle_page(RAMState *rs, uint8_t **current_data,
     if (!cache_is_cached(XBZRLE.cache, current_addr,
                          ram_counters.dirty_sync_count)) {
         xbzrle_counters.cache_miss++;
-        if (!last_stage) {
+        if (!rs->last_stage) {
             if (cache_insert(XBZRLE.cache, current_addr, *current_data,
                              ram_counters.dirty_sync_count) == -1) {
                 return -1;
@@ -734,7 +734,7 @@ static int save_xbzrle_page(RAMState *rs, uint8_t **current_data,
      * Update the cache contents, so that it corresponds to the data
      * sent, in all cases except where we skip the page.
      */
-    if (!last_stage && encoded_len != 0) {
+    if (!rs->last_stage && encoded_len != 0) {
         memcpy(prev_cached_page, XBZRLE.current_buf, TARGET_PAGE_SIZE);
         /*
          * In the case where we couldn't compress, ensure that the caller
@@ -1290,9 +1290,8 @@ static int save_normal_page(RAMState *rs, RAMBlock *block, ram_addr_t offset,
  * @rs: current RAM state
  * @block: block that contains the page we want to send
  * @offset: offset inside the block for the page
- * @last_stage: if we are at the completion stage
  */
-static int ram_save_page(RAMState *rs, PageSearchStatus *pss, bool last_stage)
+static int ram_save_page(RAMState *rs, PageSearchStatus *pss)
 {
     int pages = -1;
     uint8_t *p;
@@ -1307,8 +1306,8 @@ static int ram_save_page(RAMState *rs, PageSearchStatus *pss, bool last_stage)
     XBZRLE_cache_lock();
     if (rs->xbzrle_enabled && !migration_in_postcopy()) {
         pages = save_xbzrle_page(rs, &p, current_addr, block,
-                                 offset, last_stage);
-        if (!last_stage) {
+                                 offset);
+        if (!rs->last_stage) {
             /* Can't send this cached data async, since the cache page
              * might get updated before it gets to the wire
              */
@@ -2129,10 +2128,8 @@ static bool save_compress_page(RAMState *rs, RAMBlock *block, ram_addr_t offset)
  *
  * @rs: current RAM state
  * @pss: data about the page we want to send
- * @last_stage: if we are at the completion stage
  */
-static int ram_save_target_page(RAMState *rs, PageSearchStatus *pss,
-                                bool last_stage)
+static int ram_save_target_page(RAMState *rs, PageSearchStatus *pss)
 {
     RAMBlock *block = pss->block;
     ram_addr_t offset = ((ram_addr_t)pss->page) << TARGET_PAGE_BITS;
@@ -2171,7 +2168,7 @@ static int ram_save_target_page(RAMState *rs, PageSearchStatus *pss,
         return ram_save_multifd_page(rs, block, offset);
     }
 
-    return ram_save_page(rs, pss, last_stage);
+    return ram_save_page(rs, pss);
 }
 
 /**
@@ -2190,10 +2187,8 @@ static int ram_save_target_page(RAMState *rs, PageSearchStatus *pss,
  * @rs: current RAM state
  * @ms: current migration state
  * @pss: data about the page we want to send
- * @last_stage: if we are at the completion stage
  */
-static int ram_save_host_page(RAMState *rs, PageSearchStatus *pss,
-                              bool last_stage)
+static int ram_save_host_page(RAMState *rs, PageSearchStatus *pss)
 {
     int tmppages, pages = 0;
     size_t pagesize_bits =
@@ -2211,7 +2206,7 @@ static int ram_save_host_page(RAMState *rs, PageSearchStatus *pss,
     do {
         /* Check the pages is dirty and if it is send it */
         if (migration_bitmap_clear_dirty(rs, pss->block, pss->page)) {
-            tmppages = ram_save_target_page(rs, pss, last_stage);
+            tmppages = ram_save_target_page(rs, pss);
             if (tmppages < 0) {
                 return tmppages;
             }
@@ -2245,13 +2240,11 @@ static int ram_save_host_page(RAMState *rs, PageSearchStatus *pss,
  * or negative on error
  *
  * @rs: current RAM state
- * @last_stage: if we are at the completion stage
  *
  * On systems where host-page-size > target-page-size it will send all the
  * pages in a host page that are dirty.
  */
-
-static int ram_find_and_save_block(RAMState *rs, bool last_stage)
+static int ram_find_and_save_block(RAMState *rs)
 {
     PageSearchStatus pss;
     int pages = 0;
@@ -2280,7 +2273,7 @@ static int ram_find_and_save_block(RAMState *rs, bool last_stage)
         }
 
         if (found) {
-            pages = ram_save_host_page(rs, &pss, last_stage);
+            pages = ram_save_host_page(rs, &pss);
         }
     } while (!pages && again);
 
@@ -3080,7 +3073,7 @@ static int ram_save_iterate(QEMUFile *f, void *opaque)
                 break;
             }
 
-            pages = ram_find_and_save_block(rs, false);
+            pages = ram_find_and_save_block(rs);
             /* no more pages to sent */
             if (pages == 0) {
                 done = 1;
@@ -3160,6 +3153,8 @@ static int ram_save_complete(QEMUFile *f, void *opaque)
     RAMState *rs = *temp;
     int ret = 0;
 
+    rs->last_stage = !migration_in_colo_state();
+
     WITH_RCU_READ_LOCK_GUARD() {
         if (!migration_in_postcopy()) {
             migration_bitmap_sync_precopy(rs);
@@ -3173,7 +3168,7 @@ static int ram_save_complete(QEMUFile *f, void *opaque)
         while (true) {
             int pages;
 
-            pages = ram_find_and_save_block(rs, !migration_in_colo_state());
+            pages = ram_find_and_save_block(rs);
             /* no more blocks to sent */
             if (pages == 0) {
                 break;
-- 
2.33.1

Re: [PATCH v2 2/6] migration: We only need last_stage in two places

[Peter Xu]

On Tue, Dec 21, 2021 at 01:52:31PM +0100, Juan Quintela wrote:
> We only need last_stage in two places and we are passing it all
> around.  Just add a field to RAMState that passes it.
> 
> Signed-off-by: Juan Quintela <quintela@redhat.com>

Reviewed-by: Peter Xu <peterx@redhat.com>

-- 
Peter Xu

[PATCH v2 3/6] migration: ram_release_pages() always receive 1 page as argument

[Juan Quintela]

Remove the pages argument. And s/pages/page/

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

--

Use 1LL instead of casts

Signed-off-by: Juan Quintela <quintela@redhat.com>
---
 migration/ram.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/migration/ram.c b/migration/ram.c
index 7223b0d8ca..0b98862b9e 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -1204,13 +1204,13 @@ static int save_zero_page(RAMState *rs, RAMBlock *block, ram_addr_t offset)
     return -1;
 }
 
-static void ram_release_pages(const char *rbname, uint64_t offset, int pages)
+static void ram_release_page(const char *rbname, uint64_t offset)
 {
     if (!migrate_release_ram() || !migration_in_postcopy()) {
         return;
     }
 
-    ram_discard_range(rbname, offset, ((ram_addr_t)pages) << TARGET_PAGE_BITS);
+    ram_discard_range(rbname, offset, 1ULL << TARGET_PAGE_BITS);
 }
 
 /*
@@ -1365,7 +1365,7 @@ static bool do_compress_ram_page(QEMUFile *f, z_stream *stream, RAMBlock *block,
     }
 
 exit:
-    ram_release_pages(block->idstr, offset & TARGET_PAGE_MASK, 1);
+    ram_release_page(block->idstr, offset & TARGET_PAGE_MASK);
     return zero_page;
 }
 
@@ -2153,7 +2153,7 @@ static int ram_save_target_page(RAMState *rs, PageSearchStatus *pss)
             xbzrle_cache_zero_page(rs, block->offset + offset);
             XBZRLE_cache_unlock();
         }
-        ram_release_pages(block->idstr, offset, res);
+        ram_release_page(block->idstr, offset);
         return res;
     }
 
-- 
2.33.1

Re: [PATCH v2 3/6] migration: ram_release_pages() always receive 1 page as argument

[Peter Xu]

On Tue, Dec 21, 2021 at 01:52:32PM +0100, Juan Quintela wrote:
> -static void ram_release_pages(const char *rbname, uint64_t offset, int pages)
> +static void ram_release_page(const char *rbname, uint64_t offset)
>  {
>      if (!migrate_release_ram() || !migration_in_postcopy()) {
>          return;
>      }
>  
> -    ram_discard_range(rbname, offset, ((ram_addr_t)pages) << TARGET_PAGE_BITS);
> +    ram_discard_range(rbname, offset, 1ULL << TARGET_PAGE_BITS);

This is TARGET_PAGE_SIZE, afaict.. anyway,

Reviewed-by: Peter Xu <peterx@redhat.com>

-- 
Peter Xu

[PATCH v2 4/6] migration: Remove masking for compression

[Juan Quintela]

Remove the mask in the call to ram_release_pages().  Nothing else does
it, and if the offset has that bits set, we have a lot of trouble.

Signed-off-by: Juan Quintela <quintela@redhat.com>
---
 migration/ram.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/migration/ram.c b/migration/ram.c
index 0b98862b9e..4ee0369d6f 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -1365,7 +1365,7 @@ static bool do_compress_ram_page(QEMUFile *f, z_stream *stream, RAMBlock *block,
     }
 
 exit:
-    ram_release_page(block->idstr, offset & TARGET_PAGE_MASK);
+    ram_release_page(block->idstr, offset);
     return zero_page;
 }
 
-- 
2.33.1

[PATCH v2 5/6] migration: simplify do_compress_ram_page

[Juan Quintela]

The goto is not needed at all.

Signed-off-by: Juan Quintela <quintela@redhat.com>
---
 migration/ram.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/migration/ram.c b/migration/ram.c
index 4ee0369d6f..eddc85ffb0 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -1341,12 +1341,11 @@ static bool do_compress_ram_page(QEMUFile *f, z_stream *stream, RAMBlock *block,
 {
     RAMState *rs = ram_state;
     uint8_t *p = block->host + (offset & TARGET_PAGE_MASK);
-    bool zero_page = false;
     int ret;
 
     if (save_zero_page_to_file(rs, f, block, offset)) {
-        zero_page = true;
-        goto exit;
+        ram_release_page(block->idstr, offset & TARGET_PAGE_MASK);
+        return true;
     }
 
     save_page_header(rs, f, block, offset | RAM_SAVE_FLAG_COMPRESS_PAGE);
@@ -1361,12 +1360,8 @@ static bool do_compress_ram_page(QEMUFile *f, z_stream *stream, RAMBlock *block,
     if (ret < 0) {
         qemu_file_set_error(migrate_get_current()->to_dst_file, ret);
         error_report("compressed data failed!");
-        return false;
     }
-
-exit:
-    ram_release_page(block->idstr, offset);
-    return zero_page;
+    return false;
 }
 
 static void
-- 
2.33.1

Re: [PATCH v2 5/6] migration: simplify do_compress_ram_page

[Philippe Mathieu-Daudé]

On 12/21/21 13:52, Juan Quintela wrote:
> The goto is not needed at all.
> 
> Signed-off-by: Juan Quintela <quintela@redhat.com>
> ---
>  migration/ram.c | 11 +++--------
>  1 file changed, 3 insertions(+), 8 deletions(-)
> 
> diff --git a/migration/ram.c b/migration/ram.c
> index 4ee0369d6f..eddc85ffb0 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -1341,12 +1341,11 @@ static bool do_compress_ram_page(QEMUFile *f, z_stream *stream, RAMBlock *block,
>  {
>      RAMState *rs = ram_state;
>      uint8_t *p = block->host + (offset & TARGET_PAGE_MASK);
> -    bool zero_page = false;
>      int ret;
>  
>      if (save_zero_page_to_file(rs, f, block, offset)) {
> -        zero_page = true;
> -        goto exit;
> +        ram_release_page(block->idstr, offset & TARGET_PAGE_MASK);

We don't want TARGET_PAGE_MASK anymore here, right?

> +        return true;
>      }
>  
>      save_page_header(rs, f, block, offset | RAM_SAVE_FLAG_COMPRESS_PAGE);
> @@ -1361,12 +1360,8 @@ static bool do_compress_ram_page(QEMUFile *f, z_stream *stream, RAMBlock *block,
>      if (ret < 0) {
>          qemu_file_set_error(migrate_get_current()->to_dst_file, ret);
>          error_report("compressed data failed!");
> -        return false;
>      }
> -
> -exit:
> -    ram_release_page(block->idstr, offset);
> -    return zero_page;
> +    return false;
>  }
>  
>  static void

Re: [PATCH v2 5/6] migration: simplify do_compress_ram_page

[Peter Xu]

On Tue, Dec 21, 2021 at 02:29:13PM +0100, Philippe Mathieu-Daudé wrote:
> On 12/21/21 13:52, Juan Quintela wrote:
> > The goto is not needed at all.
> > 
> > Signed-off-by: Juan Quintela <quintela@redhat.com>
> > ---
> >  migration/ram.c | 11 +++--------
> >  1 file changed, 3 insertions(+), 8 deletions(-)
> > 
> > diff --git a/migration/ram.c b/migration/ram.c
> > index 4ee0369d6f..eddc85ffb0 100644
> > --- a/migration/ram.c
> > +++ b/migration/ram.c
> > @@ -1341,12 +1341,11 @@ static bool do_compress_ram_page(QEMUFile *f, z_stream *stream, RAMBlock *block,
> >  {
> >      RAMState *rs = ram_state;
> >      uint8_t *p = block->host + (offset & TARGET_PAGE_MASK);
> > -    bool zero_page = false;
> >      int ret;
> >  
> >      if (save_zero_page_to_file(rs, f, block, offset)) {
> > -        zero_page = true;
> > -        goto exit;
> > +        ram_release_page(block->idstr, offset & TARGET_PAGE_MASK);
> 
> We don't want TARGET_PAGE_MASK anymore here, right?

I suggest we simply do:

  offset &= TARGET_PAGE_MASK;

At the entry, then yes here. Meanwhile squash previous patch into this one;
that one smells half-done anyway..

Thanks,

> 
> > +        return true;
> >      }
> >  
> >      save_page_header(rs, f, block, offset | RAM_SAVE_FLAG_COMPRESS_PAGE);
> > @@ -1361,12 +1360,8 @@ static bool do_compress_ram_page(QEMUFile *f, z_stream *stream, RAMBlock *block,
> >      if (ret < 0) {
> >          qemu_file_set_error(migrate_get_current()->to_dst_file, ret);
> >          error_report("compressed data failed!");
> > -        return false;
> >      }
> > -
> > -exit:
> > -    ram_release_page(block->idstr, offset);
> > -    return zero_page;
> > +    return false;
> >  }
> >  
> >  static void
> 

-- 
Peter Xu

[PATCH v2 6/6] migration: Move ram_release_pages() call to save_zero_page_to_file()

[Juan Quintela]

We always need to call it when we find a zero page, so put it in a
single place.

Signed-off-by: Juan Quintela <quintela@redhat.com>
---
 migration/ram.c | 21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/migration/ram.c b/migration/ram.c
index eddc85ffb0..3cd98e19d5 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -1158,6 +1158,15 @@ static void migration_bitmap_sync_precopy(RAMState *rs)
     }
 }
 
+static void ram_release_page(const char *rbname, uint64_t offset)
+{
+    if (!migrate_release_ram() || !migration_in_postcopy()) {
+        return;
+    }
+
+    ram_discard_range(rbname, offset, 1ULL << TARGET_PAGE_BITS);
+}
+
 /**
  * save_zero_page_to_file: send the zero page to the file
  *
@@ -1179,6 +1188,7 @@ static int save_zero_page_to_file(RAMState *rs, QEMUFile *file,
         len += save_page_header(rs, file, block, offset | RAM_SAVE_FLAG_ZERO);
         qemu_put_byte(file, 0);
         len += 1;
+        ram_release_page(block->idstr, offset);
     }
     return len;
 }
@@ -1204,15 +1214,6 @@ static int save_zero_page(RAMState *rs, RAMBlock *block, ram_addr_t offset)
     return -1;
 }
 
-static void ram_release_page(const char *rbname, uint64_t offset)
-{
-    if (!migrate_release_ram() || !migration_in_postcopy()) {
-        return;
-    }
-
-    ram_discard_range(rbname, offset, 1ULL << TARGET_PAGE_BITS);
-}
-
 /*
  * @pages: the number of pages written by the control path,
  *        < 0 - error
@@ -1344,7 +1345,6 @@ static bool do_compress_ram_page(QEMUFile *f, z_stream *stream, RAMBlock *block,
     int ret;
 
     if (save_zero_page_to_file(rs, f, block, offset)) {
-        ram_release_page(block->idstr, offset & TARGET_PAGE_MASK);
         return true;
     }
 
@@ -2148,7 +2148,6 @@ static int ram_save_target_page(RAMState *rs, PageSearchStatus *pss)
             xbzrle_cache_zero_page(rs, block->offset + offset);
             XBZRLE_cache_unlock();
         }
-        ram_release_page(block->idstr, offset);
         return res;
     }
 
-- 
2.33.1

Re: [PATCH v2 6/6] migration: Move ram_release_pages() call to save_zero_page_to_file()

[Peter Xu]

On Tue, Dec 21, 2021 at 01:52:35PM +0100, Juan Quintela wrote:
> We always need to call it when we find a zero page, so put it in a
> single place.
> 
> Signed-off-by: Juan Quintela <quintela@redhat.com>

Reviewed-by: Peter Xu <peterx@redhat.com>

-- 
Peter Xu