Re: [Qemu-devel] [PATCH 05/10] Rework ram_control_load_hook to hook during block load

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Michael R. Hines (mrhines@linux.vnet.ibm.com) wrote:
> On 04/20/2015 10:57 AM, Dr. David Alan Gilbert (git) wrote:
> >From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> >
> >We need the names of RAMBlocks as they're loaded for RDMA,
> >reuse an existing QEMUFile hook with some small mods.
> >
> >Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> >---
> >  arch_init.c                   |  4 +++-
> >  include/migration/migration.h |  2 +-
> >  include/migration/qemu-file.h | 14 +++++++++-----
> >  migration/qemu-file.c         |  8 ++++----
> >  migration/rdma.c              | 28 ++++++++++++++++++++++------
> >  trace-events                  |  2 +-
> >  6 files changed, 40 insertions(+), 18 deletions(-)
> >
> >diff --git a/arch_init.c b/arch_init.c
> >index 4c8fcee..6c0b355 100644
> >--- a/arch_init.c
> >+++ b/arch_init.c
> >@@ -1164,6 +1164,8 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id)
> >                                  error_report_err(local_err);
> >                              }
> >                          }
> >+                        ram_control_load_hook(f, RAM_CONTROL_BLOCK_REG,
> >+                                              block->idstr);
> >                          break;
> >                      }
> >                  }
> >@@ -1215,7 +1217,7 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id)
> >              break;
> >          default:
> >              if (flags & RAM_SAVE_FLAG_HOOK) {
> >-                ram_control_load_hook(f, flags);
> >+                ram_control_load_hook(f, RAM_CONTROL_HOOK, NULL);
> >              } else {
> >                  error_report("Unknown combination of migration flags: %#x",
> >                               flags);
> >diff --git a/include/migration/migration.h b/include/migration/migration.h
> >index bf09968..3c2f91a 100644
> >--- a/include/migration/migration.h
> >+++ b/include/migration/migration.h
> >@@ -154,7 +154,7 @@ int64_t xbzrle_cache_resize(int64_t new_size);
> >
> >  void ram_control_before_iterate(QEMUFile *f, uint64_t flags);
> >  void ram_control_after_iterate(QEMUFile *f, uint64_t flags);
> >-void ram_control_load_hook(QEMUFile *f, uint64_t flags);
> >+void ram_control_load_hook(QEMUFile *f, uint64_t flags, void *data);
> >
> >  /* Whenever this is found in the data stream, the flags
> >   * will be passed to ram_control_load_hook in the incoming-migration
> >diff --git a/include/migration/qemu-file.h b/include/migration/qemu-file.h
> >index 745a850..a3ceb3b 100644
> >--- a/include/migration/qemu-file.h
> >+++ b/include/migration/qemu-file.h
> >@@ -63,16 +63,20 @@ typedef ssize_t (QEMUFileWritevBufferFunc)(void *opaque, struct iovec *iov,
> >  /*
> >   * This function provides hooks around different
> >   * stages of RAM migration.
> >+ * 'opaque' is the backend specific data in QEMUFile
> >+ * 'data' is call specific data associated with the 'flags' value
> >   */
> 
> What data is this exactly?

In the case of the RAM_CONTROL_BLOCK_REG case we're passing the name of the block.

> >-typedef int (QEMURamHookFunc)(QEMUFile *f, void *opaque, uint64_t flags);
> >+typedef int (QEMURamHookFunc)(QEMUFile *f, void *opaque, uint64_t flags,
> >+                              void *data);
> >
> >  /*
> >   * Constants used by ram_control_* hooks
> >   */
> >-#define RAM_CONTROL_SETUP    0
> >-#define RAM_CONTROL_ROUND    1
> >-#define RAM_CONTROL_HOOK     2
> >-#define RAM_CONTROL_FINISH   3
> >+#define RAM_CONTROL_SETUP     0
> >+#define RAM_CONTROL_ROUND     1
> >+#define RAM_CONTROL_HOOK      2
> >+#define RAM_CONTROL_FINISH    3
> >+#define RAM_CONTROL_BLOCK_REG 4
> >
> >  /*
> >   * This function allows override of where the RAM page
> >diff --git a/migration/qemu-file.c b/migration/qemu-file.c
> >index 1a4f986..4986e05 100644
> >--- a/migration/qemu-file.c
> >+++ b/migration/qemu-file.c
> >@@ -127,7 +127,7 @@ void ram_control_before_iterate(QEMUFile *f, uint64_t flags)
> >      int ret = 0;
> >
> >      if (f->ops->before_ram_iterate) {
> >-        ret = f->ops->before_ram_iterate(f, f->opaque, flags);
> >+        ret = f->ops->before_ram_iterate(f, f->opaque, flags, NULL);
> >          if (ret < 0) {
> >              qemu_file_set_error(f, ret);
> >          }
> >@@ -139,19 +139,19 @@ void ram_control_after_iterate(QEMUFile *f, uint64_t flags)
> >      int ret = 0;
> >
> >      if (f->ops->after_ram_iterate) {
> >-        ret = f->ops->after_ram_iterate(f, f->opaque, flags);
> >+        ret = f->ops->after_ram_iterate(f, f->opaque, flags, NULL);
> >          if (ret < 0) {
> >              qemu_file_set_error(f, ret);
> >          }
> >      }
> >  }
> >
> >-void ram_control_load_hook(QEMUFile *f, uint64_t flags)
> >+void ram_control_load_hook(QEMUFile *f, uint64_t flags, void *data)
> >  {
> >      int ret = -EINVAL;
> >
> >      if (f->ops->hook_ram_load) {
> >-        ret = f->ops->hook_ram_load(f, f->opaque, flags);
> >+        ret = f->ops->hook_ram_load(f, f->opaque, flags, data);
> >          if (ret < 0) {
> >              qemu_file_set_error(f, ret);
> >          }
> >diff --git a/migration/rdma.c b/migration/rdma.c
> >index 2c0d11b..e43fae4 100644
> >--- a/migration/rdma.c
> >+++ b/migration/rdma.c
> >@@ -2906,8 +2906,7 @@ err_rdma_dest_wait:
> >   *
> >   * Keep doing this until the source tells us to stop.
> >   */
> >-static int qemu_rdma_registration_handle(QEMUFile *f, void *opaque,
> >-                                         uint64_t flags)
> >+static int qemu_rdma_registration_handle(QEMUFile *f, void *opaque)
> >  {
> >      RDMAControlHeader reg_resp = { .len = sizeof(RDMARegisterResult),
> >                                 .type = RDMA_CONTROL_REGISTER_RESULT,
> >@@ -2937,7 +2936,7 @@ static int qemu_rdma_registration_handle(QEMUFile *f, void *opaque,
> >      CHECK_ERROR_STATE();
> >
> >      do {
> >-        trace_qemu_rdma_registration_handle_wait(flags);
> >+        trace_qemu_rdma_registration_handle_wait();
> >
> >          ret = qemu_rdma_exchange_recv(rdma, &head, RDMA_CONTROL_NONE);
> >
> >@@ -3125,8 +3124,25 @@ out:
> >      return ret;
> >  }
> >
> >+static int rdma_load_hook(QEMUFile *f, void *opaque, uint64_t flags, void *data)
> >+{
> >+    switch (flags) {
> >+    case RAM_CONTROL_BLOCK_REG:
> >+        /* TODO A later patch */
> >+        return -1;
> >+        break;
> >+
> >+    case RAM_CONTROL_HOOK:
> >+        return qemu_rdma_registration_handle(f, opaque);
> >+
> >+    default:
> >+        /* Shouldn't be called with any other values */
> >+        abort();
> >+    }
> >+}
> >+
> 
> Rename this to qemu_rdma_load_hook()

I've been trying to remove the qemu_'s generally on static
functions - there's no need to uniqueify the names if they're static.

Dave

> >  static int qemu_rdma_registration_start(QEMUFile *f, void *opaque,
> >-                                        uint64_t flags)
> >+                                        uint64_t flags, void *data)
> >  {
> >      QEMUFileRDMA *rfile = opaque;
> >      RDMAContext *rdma = rfile->rdma;
> >@@ -3145,7 +3161,7 @@ static int qemu_rdma_registration_start(QEMUFile *f, void *opaque,
> >   * First, flush writes, if any.
> >   */
> >  static int qemu_rdma_registration_stop(QEMUFile *f, void *opaque,
> >-                                       uint64_t flags)
> >+                                       uint64_t flags, void *data)
> >  {
> >      Error *local_err = NULL, **errp = &local_err;
> >      QEMUFileRDMA *rfile = opaque;
> >@@ -3267,7 +3283,7 @@ static const QEMUFileOps rdma_read_ops = {
> >      .get_buffer    = qemu_rdma_get_buffer,
> >      .get_fd        = qemu_rdma_get_fd,
> >      .close         = qemu_rdma_close,
> >-    .hook_ram_load = qemu_rdma_registration_handle,
> >+    .hook_ram_load = rdma_load_hook,
> >  };
> >
> >  static const QEMUFileOps rdma_write_ops = {
> >diff --git a/trace-events b/trace-events
> >index 07f15da..baf8647 100644
> >--- a/trace-events
> >+++ b/trace-events
> >@@ -1416,7 +1416,7 @@ qemu_rdma_registration_handle_register_rkey(int rkey) "%x"
> >  qemu_rdma_registration_handle_unregister(int requests) "%d requests"
> >  qemu_rdma_registration_handle_unregister_loop(int count, int index, uint64_t chunk) "Unregistration request (%d): index %d, chunk %" PRIu64
> >  qemu_rdma_registration_handle_unregister_success(uint64_t chunk) "%" PRIu64
> >-qemu_rdma_registration_handle_wait(uint64_t flags) "Waiting for next request %" PRIu64
> >+qemu_rdma_registration_handle_wait(void) ""
> >  qemu_rdma_registration_start(uint64_t flags) "%" PRIu64
> >  qemu_rdma_registration_stop(uint64_t flags) "%" PRIu64
> >  qemu_rdma_registration_stop_ram(void) ""
> 
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK