[Qemu-devel] [PATCH v5 0/3] ramblock: add hmp command "info ramblock"

[Qemu-devel] [PATCH v5 0/3] ramblock: add hmp command "info ramblock"

[Peter Xu]

v5
- add r-b for Dave on first patch (which I forgot in v4, so I got it
  again)
- add one more patch to introduce size_to_str() as patch 2 [Dave]
- let the last patch use the new interface

v4:
- move page_size_to_str() into util/cutil.c [Dave]

v3:
- cast the three PRIx64 addresses using (uint64_t) [Fam]
- add more comment in patch 2 to emphasize that this command is only
  suitable for HMP, not QMP [Markus]

v2:
- replace "lx" with "PRIx64" in three places

Sometimes I would like to know ramblock info for a VM. This command
would help. It provides a way to dump ramblock info. Currently the
list is by default sorted by size, though I think it's good enough.

Please review, thanks.

Peter Xu (3):
  ramblock: add RAMBLOCK_FOREACH()
  utils: provide size_to_str()
  ramblock: add new hmp command "info ramblock"

 exec.c                 | 44 +++++++++++++++++++++++++++++++++-----------
 hmp-commands-info.hx   | 14 ++++++++++++++
 hmp.c                  |  6 ++++++
 hmp.h                  |  1 +
 include/exec/ramlist.h |  6 ++++++
 include/qemu-common.h  |  1 +
 migration/ram.c        | 15 ++++++++-------
 util/cutils.c          | 26 ++++++++++++++++++++++++++
 8 files changed, 95 insertions(+), 18 deletions(-)

-- 
2.7.4

[Qemu-devel] [PATCH v5 1/3] ramblock: add RAMBLOCK_FOREACH()

[Peter Xu]

So that it can simplifies the iterators.

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
---
 exec.c                 | 22 +++++++++++-----------
 include/exec/ramlist.h |  5 +++++
 migration/ram.c        | 15 ++++++++-------
 3 files changed, 24 insertions(+), 18 deletions(-)

diff --git a/exec.c b/exec.c
index eac6085..50519ae 100644
--- a/exec.c
+++ b/exec.c
@@ -978,7 +978,7 @@ static RAMBlock *qemu_get_ram_block(ram_addr_t addr)
     if (block && addr - block->offset < block->max_length) {
         return block;
     }
-    QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
+    RAMBLOCK_FOREACH(block) {
         if (addr - block->offset < block->max_length) {
             goto found;
         }
@@ -1578,12 +1578,12 @@ static ram_addr_t find_ram_offset(ram_addr_t size)
         return 0;
     }
 
-    QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
+    RAMBLOCK_FOREACH(block) {
         ram_addr_t end, next = RAM_ADDR_MAX;
 
         end = block->offset + block->max_length;
 
-        QLIST_FOREACH_RCU(next_block, &ram_list.blocks, next) {
+        RAMBLOCK_FOREACH(next_block) {
             if (next_block->offset >= end) {
                 next = MIN(next, next_block->offset);
             }
@@ -1609,7 +1609,7 @@ unsigned long last_ram_page(void)
     ram_addr_t last = 0;
 
     rcu_read_lock();
-    QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
+    RAMBLOCK_FOREACH(block) {
         last = MAX(last, block->offset + block->max_length);
     }
     rcu_read_unlock();
@@ -1659,7 +1659,7 @@ void qemu_ram_set_idstr(RAMBlock *new_block, const char *name, DeviceState *dev)
     pstrcat(new_block->idstr, sizeof(new_block->idstr), name);
 
     rcu_read_lock();
-    QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
+    RAMBLOCK_FOREACH(block) {
         if (block != new_block &&
             !strcmp(block->idstr, new_block->idstr)) {
             fprintf(stderr, "RAMBlock \"%s\" already registered, abort!\n",
@@ -1693,7 +1693,7 @@ size_t qemu_ram_pagesize_largest(void)
     RAMBlock *block;
     size_t largest = 0;
 
-    QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
+    RAMBLOCK_FOREACH(block) {
         largest = MAX(largest, qemu_ram_pagesize(block));
     }
 
@@ -1839,7 +1839,7 @@ static void ram_block_add(RAMBlock *new_block, Error **errp)
      * QLIST (which has an RCU-friendly variant) does not have insertion at
      * tail, so save the last element in last_block.
      */
-    QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
+    RAMBLOCK_FOREACH(block) {
         last_block = block;
         if (block->max_length < new_block->max_length) {
             break;
@@ -2021,7 +2021,7 @@ void qemu_ram_remap(ram_addr_t addr, ram_addr_t length)
     int flags;
     void *area, *vaddr;
 
-    QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
+    RAMBLOCK_FOREACH(block) {
         offset = addr - block->offset;
         if (offset < block->max_length) {
             vaddr = ramblock_ptr(block, offset);
@@ -2167,7 +2167,7 @@ RAMBlock *qemu_ram_block_from_host(void *ptr, bool round_offset,
         goto found;
     }
 
-    QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
+    RAMBLOCK_FOREACH(block) {
         /* This case append when the block is not mapped. */
         if (block->host == NULL) {
             continue;
@@ -2200,7 +2200,7 @@ RAMBlock *qemu_ram_block_by_name(const char *name)
 {
     RAMBlock *block;
 
-    QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
+    RAMBLOCK_FOREACH(block) {
         if (!strcmp(name, block->idstr)) {
             return block;
         }
@@ -3424,7 +3424,7 @@ int qemu_ram_foreach_block(RAMBlockIterFunc func, void *opaque)
     int ret = 0;
 
     rcu_read_lock();
-    QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
+    RAMBLOCK_FOREACH(block) {
         ret = func(block->idstr, block->host, block->offset,
                    block->used_length, opaque);
         if (ret) {
diff --git a/include/exec/ramlist.h b/include/exec/ramlist.h
index c59880d..f1c6b45 100644
--- a/include/exec/ramlist.h
+++ b/include/exec/ramlist.h
@@ -4,6 +4,7 @@
 #include "qemu/queue.h"
 #include "qemu/thread.h"
 #include "qemu/rcu.h"
+#include "qemu/rcu_queue.h"
 
 typedef struct RAMBlockNotifier RAMBlockNotifier;
 
@@ -54,6 +55,10 @@ typedef struct RAMList {
 } RAMList;
 extern RAMList ram_list;
 
+/* Should be holding either ram_list.mutex, or the RCU lock. */
+#define  RAMBLOCK_FOREACH(block)  \
+    QLIST_FOREACH_RCU(block, &ram_list.blocks, next)
+
 void qemu_mutex_lock_ramlist(void);
 void qemu_mutex_unlock_ramlist(void);
 
diff --git a/migration/ram.c b/migration/ram.c
index f48664e..7ba5d7e 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -672,7 +672,7 @@ uint64_t ram_pagesize_summary(void)
     RAMBlock *block;
     uint64_t summary = 0;
 
-    QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
+    RAMBLOCK_FOREACH(block) {
         summary |= block->page_size;
     }
 
@@ -700,7 +700,7 @@ static void migration_bitmap_sync(RAMState *rs)
 
     qemu_mutex_lock(&rs->bitmap_mutex);
     rcu_read_lock();
-    QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
+    RAMBLOCK_FOREACH(block) {
         migration_bitmap_sync_range(rs, block, 0, block->used_length);
     }
     rcu_read_unlock();
@@ -1439,8 +1439,9 @@ uint64_t ram_bytes_total(void)
     uint64_t total = 0;
 
     rcu_read_lock();
-    QLIST_FOREACH_RCU(block, &ram_list.blocks, next)
+    RAMBLOCK_FOREACH(block) {
         total += block->used_length;
+    }
     rcu_read_unlock();
     return total;
 }
@@ -1543,7 +1544,7 @@ void ram_postcopy_migrated_memory_release(MigrationState *ms)
     struct RAMBlock *block;
     unsigned long *bitmap = atomic_rcu_read(&rs->ram_bitmap)->bmap;
 
-    QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
+    RAMBLOCK_FOREACH(block) {
         unsigned long first = block->offset >> TARGET_PAGE_BITS;
         unsigned long range = first + (block->used_length >> TARGET_PAGE_BITS);
         unsigned long run_start = find_next_zero_bit(bitmap, range, first);
@@ -1624,7 +1625,7 @@ static int postcopy_each_ram_send_discard(MigrationState *ms)
     struct RAMBlock *block;
     int ret;
 
-    QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
+    RAMBLOCK_FOREACH(block) {
         unsigned long first = block->offset >> TARGET_PAGE_BITS;
         PostcopyDiscardState *pds = postcopy_discard_send_init(ms,
                                                                first,
@@ -1802,7 +1803,7 @@ static int postcopy_chunk_hostpages(MigrationState *ms)
     rs->last_sent_block = NULL;
     rs->last_page = 0;
 
-    QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
+    RAMBLOCK_FOREACH(block) {
         unsigned long first = block->offset >> TARGET_PAGE_BITS;
 
         PostcopyDiscardState *pds =
@@ -2021,7 +2022,7 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
 
     qemu_put_be64(f, ram_bytes_total() | RAM_SAVE_FLAG_MEM_SIZE);
 
-    QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
+    RAMBLOCK_FOREACH(block) {
         qemu_put_byte(f, strlen(block->idstr));
         qemu_put_buffer(f, (uint8_t *)block->idstr, strlen(block->idstr));
         qemu_put_be64(f, block->used_length);
-- 
2.7.4

[Qemu-devel] [PATCH v5 2/3] utils: provide size_to_str()

[Peter Xu]

I stole the algorithm from print_type_size(). I didn't generalize it
since that's using [KM...]iB while here we need [KM...]B to finally
be able to stands for page sizes (and even more general).

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 include/qemu-common.h |  1 +
 util/cutils.c         | 26 ++++++++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/include/qemu-common.h b/include/qemu-common.h
index d218821..d7d0448 100644
--- a/include/qemu-common.h
+++ b/include/qemu-common.h
@@ -145,6 +145,7 @@ void qemu_hexdump(const char *buf, FILE *fp, const char *prefix, size_t size);
 int parse_debug_env(const char *name, int max, int initial);
 
 const char *qemu_ether_ntoa(const MACAddr *mac);
+char *size_to_str(double val);
 void page_size_init(void);
 
 /* returns non-zero if dump is in progress, otherwise zero is
diff --git a/util/cutils.c b/util/cutils.c
index 50ad179..5aaf370 100644
--- a/util/cutils.c
+++ b/util/cutils.c
@@ -619,3 +619,29 @@ const char *qemu_ether_ntoa(const MACAddr *mac)
 
     return ret;
 }
+
+/*
+ * Sample output:
+ *
+ * 1          -> "1 B"
+ * 528        -> "0.516 KB"
+ * 4096       -> "4 KB"
+ * 2402958    -> "2.29 MB"
+ * 1073741824 -> "1 GB"
+ *
+ * Please free the buffer after use.
+ */
+char *size_to_str(double val)
+{
+    static const char suffixes[] = { 'B', 'K', 'M', 'G', 'T', 'P', 'E' };
+    unsigned long div;
+    int i;
+
+    frexp(val, &i);
+    i /= 10;
+    assert(i < sizeof(suffixes));
+    div = 1ULL << (i * 10);
+
+    return g_strdup_printf("%0.3g %c%s", val / div,
+                           suffixes[i], i ? "B" : "");
+}
-- 
2.7.4

[Qemu-devel] [PATCH v5 3/3] ramblock: add new hmp command "info ramblock"

[Peter Xu]

To dump information about ramblocks. It looks like:

(qemu) info ramblock
              Block Name    PSize              Offset               Used              Total
            /objects/mem     2 MB  0x0000000000000000 0x0000000080000000 0x0000000080000000
                vga.vram     4 KB  0x0000000080060000 0x0000000001000000 0x0000000001000000
    /rom@etc/acpi/tables     4 KB  0x00000000810b0000 0x0000000000020000 0x0000000000200000
                 pc.bios     4 KB  0x0000000080000000 0x0000000000040000 0x0000000000040000
  0000:00:03.0/e1000.rom     4 KB  0x0000000081070000 0x0000000000040000 0x0000000000040000
                  pc.rom     4 KB  0x0000000080040000 0x0000000000020000 0x0000000000020000
    0000:00:02.0/vga.rom     4 KB  0x0000000081060000 0x0000000000010000 0x0000000000010000
   /rom@etc/table-loader     4 KB  0x00000000812b0000 0x0000000000001000 0x0000000000001000
      /rom@etc/acpi/rsdp     4 KB  0x00000000812b1000 0x0000000000001000 0x0000000000001000

Ramblock is something hidden internally in QEMU implementation, and this
command should only be used by mostly QEMU developers on RAM stuff. It
is not a command suitable for QMP interface. So only HMP interface is
provided for it.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 exec.c                 | 22 ++++++++++++++++++++++
 hmp-commands-info.hx   | 14 ++++++++++++++
 hmp.c                  |  6 ++++++
 hmp.h                  |  1 +
 include/exec/ramlist.h |  1 +
 5 files changed, 44 insertions(+)

diff --git a/exec.c b/exec.c
index 50519ae..821bef3 100644
--- a/exec.c
+++ b/exec.c
@@ -71,6 +71,8 @@
 #include "qemu/mmap-alloc.h"
 #endif
 
+#include "monitor/monitor.h"
+
 //#define DEBUG_SUBPAGE
 
 #if !defined(CONFIG_USER_ONLY)
@@ -1333,6 +1335,26 @@ void qemu_mutex_unlock_ramlist(void)
     qemu_mutex_unlock(&ram_list.mutex);
 }
 
+void ram_block_dump(Monitor *mon)
+{
+    RAMBlock *block;
+    char *psize;
+
+    rcu_read_lock();
+    monitor_printf(mon, "%24s %8s  %18s %18s %18s\n",
+                   "Block Name", "PSize", "Offset", "Used", "Total");
+    RAMBLOCK_FOREACH(block) {
+        psize = size_to_str(block->page_size);
+        monitor_printf(mon, "%24s %8s  0x%016" PRIx64 " 0x%016" PRIx64
+                       " 0x%016" PRIx64 "\n", block->idstr, psize,
+                       (uint64_t)block->offset,
+                       (uint64_t)block->used_length,
+                       (uint64_t)block->max_length);
+        g_free(psize);
+    }
+    rcu_read_unlock();
+}
+
 #ifdef __linux__
 /*
  * FIXME TOCTTOU: this iterates over memory backends' mem-path, which
diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx
index a53f105..ae16901 100644
--- a/hmp-commands-info.hx
+++ b/hmp-commands-info.hx
@@ -788,6 +788,20 @@ Display the latest dump status.
 ETEXI
 
     {
+        .name       = "ramblock",
+        .args_type  = "",
+        .params     = "",
+        .help       = "Display system ramblock information",
+        .cmd        = hmp_info_ramblock,
+    },
+
+STEXI
+@item info ramblock
+@findex ramblock
+Dump all the ramblocks of the system.
+ETEXI
+
+    {
         .name       = "hotpluggable-cpus",
         .args_type  = "",
         .params     = "",
diff --git a/hmp.c b/hmp.c
index ab407d6..8369388 100644
--- a/hmp.c
+++ b/hmp.c
@@ -37,6 +37,7 @@
 #include "qemu-io.h"
 #include "qemu/cutils.h"
 #include "qemu/error-report.h"
+#include "exec/ramlist.h"
 #include "hw/intc/intc.h"
 
 #ifdef CONFIG_SPICE
@@ -2563,6 +2564,11 @@ void hmp_info_dump(Monitor *mon, const QDict *qdict)
     qapi_free_DumpQueryResult(result);
 }
 
+void hmp_info_ramblock(Monitor *mon, const QDict *qdict)
+{
+    ram_block_dump(mon);
+}
+
 void hmp_hotpluggable_cpus(Monitor *mon, const QDict *qdict)
 {
     Error *err = NULL;
diff --git a/hmp.h b/hmp.h
index 799fd37..7353b67 100644
--- a/hmp.h
+++ b/hmp.h
@@ -136,6 +136,7 @@ void hmp_rocker_ports(Monitor *mon, const QDict *qdict);
 void hmp_rocker_of_dpa_flows(Monitor *mon, const QDict *qdict);
 void hmp_rocker_of_dpa_groups(Monitor *mon, const QDict *qdict);
 void hmp_info_dump(Monitor *mon, const QDict *qdict);
+void hmp_info_ramblock(Monitor *mon, const QDict *qdict);
 void hmp_hotpluggable_cpus(Monitor *mon, const QDict *qdict);
 void hmp_info_vm_generation_id(Monitor *mon, const QDict *qdict);
 
diff --git a/include/exec/ramlist.h b/include/exec/ramlist.h
index f1c6b45..2e2ac6c 100644
--- a/include/exec/ramlist.h
+++ b/include/exec/ramlist.h
@@ -73,5 +73,6 @@ void ram_block_notifier_remove(RAMBlockNotifier *n);
 void ram_block_notify_add(void *host, size_t size);
 void ram_block_notify_remove(void *host, size_t size);
 
+void ram_block_dump(Monitor *mon);
 
 #endif /* RAMLIST_H */
-- 
2.7.4

Re: [Qemu-devel] [PATCH v5 2/3] utils: provide size_to_str()

[Markus Armbruster]

Peter Xu <peterx@redhat.com> writes:

> I stole the algorithm from print_type_size(). I didn't generalize it
> since that's using [KM...]iB while here we need [KM...]B to finally
> be able to stands for page sizes (and even more general).

Can you explain why we need units without the 'i' here?

>
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>  include/qemu-common.h |  1 +
>  util/cutils.c         | 26 ++++++++++++++++++++++++++
>  2 files changed, 27 insertions(+)
>
> diff --git a/include/qemu-common.h b/include/qemu-common.h
> index d218821..d7d0448 100644
> --- a/include/qemu-common.h
> +++ b/include/qemu-common.h
> @@ -145,6 +145,7 @@ void qemu_hexdump(const char *buf, FILE *fp, const char *prefix, size_t size);
>  int parse_debug_env(const char *name, int max, int initial);
>  
>  const char *qemu_ether_ntoa(const MACAddr *mac);
> +char *size_to_str(double val);
>  void page_size_init(void);
>  
>  /* returns non-zero if dump is in progress, otherwise zero is
> diff --git a/util/cutils.c b/util/cutils.c
> index 50ad179..5aaf370 100644
> --- a/util/cutils.c
> +++ b/util/cutils.c
> @@ -619,3 +619,29 @@ const char *qemu_ether_ntoa(const MACAddr *mac)
>  
>      return ret;
>  }
> +
> +/*
> + * Sample output:
> + *
> + * 1          -> "1 B"
> + * 528        -> "0.516 KB"
> + * 4096       -> "4 KB"
> + * 2402958    -> "2.29 MB"
> + * 1073741824 -> "1 GB"
> + *
> + * Please free the buffer after use.
> + */
> +char *size_to_str(double val)
> +{
> +    static const char suffixes[] = { 'B', 'K', 'M', 'G', 'T', 'P', 'E' };
> +    unsigned long div;
> +    int i;
> +
> +    frexp(val, &i);

The ignored return value is in [0.5,1), and multiplying it by 2^i yields
val.  i is close to the binary logarithm.

> +    i /= 10;

Now it's close to base-1024 logarithm.

Figuring this out requires too much thought for comfort.  Recommend
steal the comment from print_type_size(), too.

> +    assert(i < sizeof(suffixes));
> +    div = 1ULL << (i * 10);
> +
> +    return g_strdup_printf("%0.3g %c%s", val / div,
> +                           suffixes[i], i ? "B" : "");

The conditional is a bit confusing.  To avoid it, we could make
suffixes[] an array of strings, with suffixes[0] = "".

> +}

Re: [Qemu-devel] [PATCH v5 2/3] utils: provide size_to_str()

[Peter Xu]

On Tue, May 09, 2017 at 04:50:26PM +0200, Markus Armbruster wrote:
> Peter Xu <peterx@redhat.com> writes:
> 
> > I stole the algorithm from print_type_size(). I didn't generalize it
> > since that's using [KM...]iB while here we need [KM...]B to finally
> > be able to stands for page sizes (and even more general).
> 
> Can you explain why we need units without the 'i' here?

Oops. I misunderstood XiB... My fault. Page sizes needs exactly "i".

> 
> >
> > Signed-off-by: Peter Xu <peterx@redhat.com>
> > ---
> >  include/qemu-common.h |  1 +
> >  util/cutils.c         | 26 ++++++++++++++++++++++++++
> >  2 files changed, 27 insertions(+)
> >
> > diff --git a/include/qemu-common.h b/include/qemu-common.h
> > index d218821..d7d0448 100644
> > --- a/include/qemu-common.h
> > +++ b/include/qemu-common.h
> > @@ -145,6 +145,7 @@ void qemu_hexdump(const char *buf, FILE *fp, const char *prefix, size_t size);
> >  int parse_debug_env(const char *name, int max, int initial);
> >  
> >  const char *qemu_ether_ntoa(const MACAddr *mac);
> > +char *size_to_str(double val);
> >  void page_size_init(void);
> >  
> >  /* returns non-zero if dump is in progress, otherwise zero is
> > diff --git a/util/cutils.c b/util/cutils.c
> > index 50ad179..5aaf370 100644
> > --- a/util/cutils.c
> > +++ b/util/cutils.c
> > @@ -619,3 +619,29 @@ const char *qemu_ether_ntoa(const MACAddr *mac)
> >  
> >      return ret;
> >  }
> > +
> > +/*
> > + * Sample output:
> > + *
> > + * 1          -> "1 B"
> > + * 528        -> "0.516 KB"
> > + * 4096       -> "4 KB"
> > + * 2402958    -> "2.29 MB"
> > + * 1073741824 -> "1 GB"
> > + *
> > + * Please free the buffer after use.
> > + */
> > +char *size_to_str(double val)
> > +{
> > +    static const char suffixes[] = { 'B', 'K', 'M', 'G', 'T', 'P', 'E' };
> > +    unsigned long div;
> > +    int i;
> > +
> > +    frexp(val, &i);
> 
> The ignored return value is in [0.5,1), and multiplying it by 2^i yields
> val.  i is close to the binary logarithm.
> 
> > +    i /= 10;
> 
> Now it's close to base-1024 logarithm.
> 
> Figuring this out requires too much thought for comfort.  Recommend
> steal the comment from print_type_size(), too.

Let me do it even simpler - I'll just move the whole logic in
print_type_size() into size_to_str(), then I'll refactor
print_type_size().

> 
> > +    assert(i < sizeof(suffixes));
> > +    div = 1ULL << (i * 10);
> > +
> > +    return g_strdup_printf("%0.3g %c%s", val / div,
> > +                           suffixes[i], i ? "B" : "");
> 
> The conditional is a bit confusing.  To avoid it, we could make
> suffixes[] an array of strings, with suffixes[0] = "".

I can fix this. Thanks reviewing!

-- 
Peter Xu