Merge remote-tracking branch 'remotes/dgilbert/tags/pull-migration-20170213a' into staging

Migration

  Amit: migration: remove myself as maintainer
        MAINTAINERS: update my email address
  Ashijeet: migrate: Introduce zero RAM checks to skip RAM migration
  Pavel: Postcopy release RAM
  Halil: consolidate VMStateField.start
  Hailiang: COLO: fix setting checkpoint-delay not working properly
         COLO: Shutdown related socket fd while do failover
         COLO: Don't process failover request while loading VM's state
  Me:
     migration: Add VMSTATE_UNUSED_VARRAY_UINT32
     migration: Add VMSTATE_WITH_TMP
     tests/migration: Add test for VMSTATE_WITH_TMP
     virtio-net VMState conversion and new VMSTATE macros

# gpg: Signature made Mon 13 Feb 2017 17:36:39 GMT
# gpg:                using RSA key 0x0516331EBC5BFDE7
# gpg: Good signature from "Dr. David Alan Gilbert (RH2) <dgilbert@redhat.com>"
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 45F5 C71B 4A0C B7FB 977A  9FA9 0516 331E BC5B FDE7

* remotes/dgilbert/tags/pull-migration-20170213a:
  virtio/migration: Migrate virtio-net to VMState
  tests/migration: Add test for VMSTATE_WITH_TMP
  migration: Add VMSTATE_WITH_TMP
  migration: Add VMSTATE_UNUSED_VARRAY_UINT32
  COLO: Don't process failover request while loading VM's state
  COLO: Shutdown related socket fd while do failover
  COLO: fix setting checkpoint-delay not working properly
  migration: consolidate VMStateField.start
  migrate: Introduce zero RAM checks to skip RAM migration
  migration: discard non-dirty ram pages after the start of postcopy
  add 'release-ram' migrate capability
  migration: add MigrationState arg for ram_save_/compressed_/page()
  MAINTAINERS: update my email address
  migration: remove myself as maintainer

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 52 insertions, 7 deletions

diff --git a/migration/qemu-file.c b/migration/qemu-file.c
index e9fae31158..195fa94fcf 100644
--- a/migration/qemu-file.c
+++ b/migration/qemu-file.c
@@ -49,6 +49,7 @@ struct QEMUFile {
     int buf_size; /* 0 when writing */
     uint8_t buf[IO_BUF_SIZE];
 
+    DECLARE_BITMAP(may_free, MAX_IOV_SIZE);
     struct iovec iov[MAX_IOV_SIZE];
     unsigned int iovcnt;
 
@@ -132,6 +133,41 @@ bool qemu_file_is_writable(QEMUFile *f)
     return f->ops->writev_buffer;
 }
 
+static void qemu_iovec_release_ram(QEMUFile *f)
+{
+    struct iovec iov;
+    unsigned long idx;
+
+    /* Find and release all the contiguous memory ranges marked as may_free. */
+    idx = find_next_bit(f->may_free, f->iovcnt, 0);
+    if (idx >= f->iovcnt) {
+        return;
+    }
+    iov = f->iov[idx];
+
+    /* The madvise() in the loop is called for iov within a continuous range and
+     * then reinitialize the iov. And in the end, madvise() is called for the
+     * last iov.
+     */
+    while ((idx = find_next_bit(f->may_free, f->iovcnt, idx + 1)) < f->iovcnt) {
+        /* check for adjacent buffer and coalesce them */
+        if (iov.iov_base + iov.iov_len == f->iov[idx].iov_base) {
+            iov.iov_len += f->iov[idx].iov_len;
+            continue;
+        }
+        if (qemu_madvise(iov.iov_base, iov.iov_len, QEMU_MADV_DONTNEED) < 0) {
+            error_report("migrate: madvise DONTNEED failed %p %zd: %s",
+                         iov.iov_base, iov.iov_len, strerror(errno));
+        }
+        iov = f->iov[idx];
+    }
+    if (qemu_madvise(iov.iov_base, iov.iov_len, QEMU_MADV_DONTNEED) < 0) {
+            error_report("migrate: madvise DONTNEED failed %p %zd: %s",
+                         iov.iov_base, iov.iov_len, strerror(errno));
+    }
+    memset(f->may_free, 0, sizeof(f->may_free));
+}
+
 /**
  * Flushes QEMUFile buffer
  *
@@ -151,6 +187,8 @@ void qemu_fflush(QEMUFile *f)
     if (f->iovcnt > 0) {
         expect = iov_size(f->iov, f->iovcnt);
         ret = f->ops->writev_buffer(f->opaque, f->iov, f->iovcnt, f->pos);
+
+        qemu_iovec_release_ram(f);
     }
 
     if (ret >= 0) {
@@ -304,13 +342,19 @@ int qemu_fclose(QEMUFile *f)
     return ret;
 }
 
-static void add_to_iovec(QEMUFile *f, const uint8_t *buf, size_t size)
+static void add_to_iovec(QEMUFile *f, const uint8_t *buf, size_t size,
+                         bool may_free)
 {
     /* check for adjacent buffer and coalesce them */
     if (f->iovcnt > 0 && buf == f->iov[f->iovcnt - 1].iov_base +
-        f->iov[f->iovcnt - 1].iov_len) {
+        f->iov[f->iovcnt - 1].iov_len &&
+        may_free == test_bit(f->iovcnt - 1, f->may_free))
+    {
         f->iov[f->iovcnt - 1].iov_len += size;
     } else {
+        if (may_free) {
+            set_bit(f->iovcnt, f->may_free);
+        }
         f->iov[f->iovcnt].iov_base = (uint8_t *)buf;
         f->iov[f->iovcnt++].iov_len = size;
     }
@@ -320,14 +364,15 @@ static void add_to_iovec(QEMUFile *f, const uint8_t *buf, size_t size)
     }
 }
 
-void qemu_put_buffer_async(QEMUFile *f, const uint8_t *buf, size_t size)
+void qemu_put_buffer_async(QEMUFile *f, const uint8_t *buf, size_t size,
+                           bool may_free)
 {
     if (f->last_error) {
         return;
     }
 
     f->bytes_xfer += size;
-    add_to_iovec(f, buf, size);
+    add_to_iovec(f, buf, size, may_free);
 }
 
 void qemu_put_buffer(QEMUFile *f, const uint8_t *buf, size_t size)
@@ -345,7 +390,7 @@ void qemu_put_buffer(QEMUFile *f, const uint8_t *buf, size_t size)
         }
         memcpy(f->buf + f->buf_index, buf, l);
         f->bytes_xfer += l;
-        add_to_iovec(f, f->buf + f->buf_index, l);
+        add_to_iovec(f, f->buf + f->buf_index, l, false);
         f->buf_index += l;
         if (f->buf_index == IO_BUF_SIZE) {
             qemu_fflush(f);
@@ -366,7 +411,7 @@ void qemu_put_byte(QEMUFile *f, int v)
 
     f->buf[f->buf_index] = v;
     f->bytes_xfer++;
-    add_to_iovec(f, f->buf + f->buf_index, 1);
+    add_to_iovec(f, f->buf + f->buf_index, 1, false);
     f->buf_index++;
     if (f->buf_index == IO_BUF_SIZE) {
         qemu_fflush(f);
@@ -647,7 +692,7 @@ ssize_t qemu_put_compression_data(QEMUFile *f, const uint8_t *p, size_t size,
     }
     qemu_put_be32(f, blen);
     if (f->ops->writev_buffer) {
-        add_to_iovec(f, f->buf + f->buf_index, blen);
+        add_to_iovec(f, f->buf + f->buf_index, blen, false);
     }
     f->buf_index += blen;
     if (f->buf_index == IO_BUF_SIZE) {