Re: [Qemu-devel] [PATCH 03/10] Store block name in local blocks structure

["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>
> >
> >In a later patch the block name will be used to match up two views
> >of the block list.  Keep a copy of the block name with the local block
> >list.
> >
> >(At some point it could be argued that it would be best just to let
> >migration see the innards of RAMBlock and avoid the need to use
> >foreach).
> 
> Maybe a silly question, but is there anything to enforce that
> the string names are always unique?

Good question...hmm; exec.c's qemu_ram_set_idstr looks like it has
a check:

    QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
        if (block != new_block && !strcmp(block->idstr, new_block->idstr)) {
            fprintf(stderr, "RAMBlock \"%s\" already registered, abort!\n",
                    new_block->idstr);
            abort();
        }
    }

Dave

> 
> >Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> >---
> >  migration/rdma.c | 35 +++++++++++++++++++++--------------
> >  trace-events     |  2 +-
> >  2 files changed, 22 insertions(+), 15 deletions(-)
> >
> >diff --git a/migration/rdma.c b/migration/rdma.c
> >index 38e5f44..c3814c5 100644
> >--- a/migration/rdma.c
> >+++ b/migration/rdma.c
> >@@ -214,17 +214,18 @@ static void network_to_caps(RDMACapabilities *cap)
> >   * the information. It's small anyway, so a list is overkill.
> >   */
> >  typedef struct RDMALocalBlock {
> >-    uint8_t  *local_host_addr; /* local virtual address */
> >-    uint64_t remote_host_addr; /* remote virtual address */
> >-    uint64_t offset;
> >-    uint64_t length;
> >-    struct   ibv_mr **pmr;     /* MRs for chunk-level registration */
> >-    struct   ibv_mr *mr;       /* MR for non-chunk-level registration */
> >-    uint32_t *remote_keys;     /* rkeys for chunk-level registration */
> >-    uint32_t remote_rkey;      /* rkeys for non-chunk-level registration */
> >-    int      index;            /* which block are we */
> >-    bool     is_ram_block;
> >-    int      nb_chunks;
> >+    char          *block_name;
> >+    uint8_t       *local_host_addr; /* local virtual address */
> >+    uint64_t       remote_host_addr; /* remote virtual address */
> >+    uint64_t       offset;
> >+    uint64_t       length;
> >+    struct         ibv_mr **pmr;    /* MRs for chunk-level registration */
> >+    struct         ibv_mr *mr;      /* MR for non-chunk-level registration */
> >+    uint32_t      *remote_keys;     /* rkeys for chunk-level registration */
> >+    uint32_t       remote_rkey;     /* rkeys for non-chunk-level registration */
> >+    int            index;           /* which block are we */
> >+    bool           is_ram_block;
> >+    int            nb_chunks;
> >      unsigned long *transit_bitmap;
> >      unsigned long *unregister_bitmap;
> >  } RDMALocalBlock;
> >@@ -510,7 +511,8 @@ static inline uint8_t *ram_chunk_end(const RDMALocalBlock *rdma_ram_block,
> >      return result;
> >  }
> >
> >-static int rdma_add_block(RDMAContext *rdma, void *host_addr,
> >+static int rdma_add_block(RDMAContext *rdma, const char *block_name,
> >+                         void *host_addr,
> >                           ram_addr_t block_offset, uint64_t length)
> >  {
> >      RDMALocalBlocks *local = &rdma->local_ram_blocks;
> >@@ -538,6 +540,7 @@ static int rdma_add_block(RDMAContext *rdma, void *host_addr,
> >
> >      block = &local->block[local->nb_blocks];
> >
> >+    block->block_name = g_strdup(block_name);
> >      block->local_host_addr = host_addr;
> >      block->offset = block_offset;
> >      block->length = length;
> >@@ -553,7 +556,8 @@ static int rdma_add_block(RDMAContext *rdma, void *host_addr,
> >
> >      g_hash_table_insert(rdma->blockmap, (void *) block_offset, block);
> >
> >-    trace_rdma_add_block(local->nb_blocks, (uintptr_t) block->local_host_addr,
> >+    trace_rdma_add_block(block_name, local->nb_blocks,
> >+                         (uintptr_t) block->local_host_addr,
> >                           block->offset, block->length,
> >                           (uintptr_t) (block->local_host_addr + block->length),
> >                           BITS_TO_LONGS(block->nb_chunks) *
> >@@ -573,7 +577,7 @@ static int rdma_add_block(RDMAContext *rdma, void *host_addr,
> >  static int qemu_rdma_init_one_block(const char *block_name, void *host_addr,
> >      ram_addr_t block_offset, ram_addr_t length, void *opaque)
> >  {
> >-    return rdma_add_block(opaque, host_addr, block_offset, length);
> >+    return rdma_add_block(opaque, block_name, host_addr, block_offset, length);
> >  }
> >
> >  /*
> >@@ -639,6 +643,9 @@ static int rdma_delete_block(RDMAContext *rdma, ram_addr_t block_offset)
> >          g_hash_table_remove(rdma->blockmap, (void *)(uintptr_t)old[x].offset);
> >      }
> >
> >+    g_free(block->block_name);
> >+    block->block_name = NULL;
> >+
> >      if (local->nb_blocks > 1) {
> >
> >          local->block = g_malloc0(sizeof(RDMALocalBlock) *
> >diff --git a/trace-events b/trace-events
> >index 30eba92..07f15da 100644
> >--- a/trace-events
> >+++ b/trace-events
> >@@ -1435,7 +1435,7 @@ qemu_rdma_write_one_recvregres(int mykey, int theirkey, uint64_t chunk) "Receive
> >  qemu_rdma_write_one_sendreg(uint64_t chunk, int len, int index, int64_t offset) "Sending registration request chunk %" PRIu64 " for %d bytes, index: %d, offset: %" PRId64
> >  qemu_rdma_write_one_top(uint64_t chunks, uint64_t size) "Writing %" PRIu64 " chunks, (%" PRIu64 " MB)"
> >  qemu_rdma_write_one_zero(uint64_t chunk, int len, int index, int64_t offset) "Entire chunk is zero, sending compress: %" PRIu64 " for %d bytes, index: %d, offset: %" PRId64
> >-rdma_add_block(int block, uint64_t addr, uint64_t offset, uint64_t len, uint64_t end, uint64_t bits, int chunks) "Added Block: %d, addr: %" PRIu64 ", offset: %" PRIu64 " length: %" PRIu64 " end: %" PRIu64 " bits %" PRIu64 " chunks %d"
> >+rdma_add_block(const char *block_name, int block, uint64_t addr, uint64_t offset, uint64_t len, uint64_t end, uint64_t bits, int chunks) "Added Block: '%s':%d, addr: %" PRIu64 ", offset: %" PRIu64 " length: %" PRIu64 " end: %" PRIu64 " bits %" PRIu64 " chunks %d"
> >  rdma_delete_block(int block, uint64_t addr, uint64_t offset, uint64_t len, uint64_t end, uint64_t bits, int chunks) "Deleted Block: %d, addr: %" PRIu64 ", offset: %" PRIu64 " length: %" PRIu64 " end: %" PRIu64 " bits %" PRIu64 " chunks %d"
> >  rdma_start_incoming_migration(void) ""
> >  rdma_start_incoming_migration_after_dest_init(void) ""
> 
> Reviewed-by: Michael R. Hines <mrhines@us.ibm.com>
> 
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK