[Qemu-devel] [PATCH v7 0/4] ramblock: add hmp command "info ramblock"

[Qemu-devel] [PATCH v7 0/4] ramblock: add hmp command "info ramblock"

[Peter Xu]

v7:
- patch 1: removed Dave's r-b since the patch conflicted during rebase
- patch 2: add r-b for Markus, with the nice function comment that
  provided [Markus]
- patch 3: add r-b for Dave
- patch 4 (new): added new patch to remove assert in size_to_str(),
  assuming that would be better.

v6
- patch 2: instead of create a new size_to_str(), abstract the logic
  out from print_type_size(), refactor it, to make sure
  print_type_size() dumps exactly the same thing as before. (a simple
  test with info qtree is done)
- let suffixes be an array of strings [Markus]

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 (4):
  ramblock: add RAMBLOCK_FOREACH()
  utils: provide size_to_str()
  ramblock: add new hmp command "info ramblock"
  utils: remove assert in size_to_str()

 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              | 13 +++++++------
 qapi/string-output-visitor.c | 22 ++++++----------------
 util/cutils.c                | 31 +++++++++++++++++++++++++++++++
 9 files changed, 105 insertions(+), 33 deletions(-)

-- 
2.7.4

[Qemu-devel] [PATCH v7 1/4] ramblock: add RAMBLOCK_FOREACH()

[Peter Xu]

So that it can simplifies the iterators.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 exec.c                 | 22 +++++++++++-----------
 include/exec/ramlist.h |  5 +++++
 migration/ram.c        | 13 +++++++------
 3 files changed, 23 insertions(+), 17 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 293d27c..d88afea 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -648,7 +648,7 @@ 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;
     }
 
@@ -676,7 +676,7 @@ 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();
@@ -1408,8 +1408,9 @@ 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;
 }
@@ -1500,7 +1501,7 @@ void ram_postcopy_migrated_memory_release(MigrationState *ms)
 {
     struct RAMBlock *block;
 
-    QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
+    RAMBLOCK_FOREACH(block) {
         unsigned long *bitmap = block->bmap;
         unsigned long range = block->used_length >> TARGET_PAGE_BITS;
         unsigned long run_start = find_next_zero_bit(bitmap, range, 0);
@@ -1578,7 +1579,7 @@ 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) {
         PostcopyDiscardState *pds =
             postcopy_discard_send_init(ms, block->idstr);
 
@@ -1961,7 +1962,7 @@ 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 v7 2/4] utils: provide size_to_str()

[Peter Xu]

Moving the algorithm from print_type_size() into size_to_str() so that
other component can also leverage it. With that, refactor
print_type_size().

Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
---
 include/qemu-common.h        |  1 +
 qapi/string-output-visitor.c | 22 ++++++----------------
 util/cutils.c                | 26 ++++++++++++++++++++++++++
 3 files changed, 33 insertions(+), 16 deletions(-)

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/qapi/string-output-visitor.c b/qapi/string-output-visitor.c
index 94ac821..53c2175 100644
--- a/qapi/string-output-visitor.c
+++ b/qapi/string-output-visitor.c
@@ -211,10 +211,8 @@ static void print_type_size(Visitor *v, const char *name, uint64_t *obj,
                             Error **errp)
 {
     StringOutputVisitor *sov = to_sov(v);
-    static const char suffixes[] = { 'B', 'K', 'M', 'G', 'T', 'P', 'E' };
-    uint64_t div, val;
-    char *out;
-    int i;
+    uint64_t val;
+    char *out, *psize;
 
     if (!sov->human) {
         out = g_strdup_printf("%"PRIu64, *obj);
@@ -223,19 +221,11 @@ static void print_type_size(Visitor *v, const char *name, uint64_t *obj,
     }
 
     val = *obj;
-
-    /* The exponent (returned in i) minus one gives us
-     * floor(log2(val * 1024 / 1000).  The correction makes us
-     * switch to the higher power when the integer part is >= 1000.
-     */
-    frexp(val / (1000.0 / 1024.0), &i);
-    i = (i - 1) / 10;
-    assert(i < ARRAY_SIZE(suffixes));
-    div = 1ULL << (i * 10);
-
-    out = g_strdup_printf("%"PRIu64" (%0.3g %c%s)", val,
-                          (double)val/div, suffixes[i], i ? "iB" : "");
+    psize = size_to_str(val);
+    out = g_strdup_printf("%"PRIu64" (%s)", val, psize);
     string_output_set(sov, out);
+
+    g_free(psize);
 }
 
 static void print_type_bool(Visitor *v, const char *name, bool *obj,
diff --git a/util/cutils.c b/util/cutils.c
index 50ad179..fa5ddec 100644
--- a/util/cutils.c
+++ b/util/cutils.c
@@ -619,3 +619,29 @@ const char *qemu_ether_ntoa(const MACAddr *mac)
 
     return ret;
 }
+
+/*
+ * Return human readable string for size @val.
+ * @val must be between (-1000Eib, 1000EiB), exclusively.
+ * Use IEC binary units like KiB, MiB, and so forth.
+ * Caller is responsible for passing it to g_free().
+ */
+char *size_to_str(double val)
+{
+    static const char *suffixes[] = { "", "Ki", "Mi", "Gi", "Ti", "Pi", "Ei" };
+    unsigned long div;
+    int i;
+
+    /*
+     * The exponent (returned in i) minus one gives us
+     * floor(log2(val * 1024 / 1000).  The correction makes us
+     * switch to the higher power when the integer part is >= 1000.
+     * (see e41b509d68afb1f for more info)
+     */
+    frexp(val / (1000.0 / 1024.0), &i);
+    i = (i - 1) / 10;
+    assert(i < ARRAY_SIZE(suffixes));
+    div = 1ULL << (i * 10);
+
+    return g_strdup_printf("%0.3g %sB", val / div, suffixes[i]);
+}
-- 
2.7.4

[Qemu-devel] [PATCH v7 3/4] 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 MiB  0x0000000000000000 0x0000000080000000 0x0000000080000000
                vga.vram    4 KiB  0x0000000080060000 0x0000000001000000 0x0000000001000000
    /rom@etc/acpi/tables    4 KiB  0x00000000810b0000 0x0000000000020000 0x0000000000200000
                 pc.bios    4 KiB  0x0000000080000000 0x0000000000040000 0x0000000000040000
  0000:00:03.0/e1000.rom    4 KiB  0x0000000081070000 0x0000000000040000 0x0000000000040000
                  pc.rom    4 KiB  0x0000000080040000 0x0000000000020000 0x0000000000020000
    0000:00:02.0/vga.rom    4 KiB  0x0000000081060000 0x0000000000010000 0x0000000000010000
   /rom@etc/table-loader    4 KiB  0x00000000812b0000 0x0000000000001000 0x0000000000001000
      /rom@etc/acpi/rsdp    4 KiB  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.

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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 bd7b1ca..45a5686 100644
--- a/hmp.c
+++ b/hmp.c
@@ -38,6 +38,7 @@
 #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
@@ -2737,6 +2738,11 @@ 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 37bb65a..d8b94ce 100644
--- a/hmp.h
+++ b/hmp.h
@@ -140,6 +140,7 @@ 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

[Qemu-devel] [PATCH v7 4/4] utils: remove assert in size_to_str()

[Peter Xu]

It's not very safe to assert in size_to_str(). Let's be inclusive.

It naturally allows negative values. Now it won't even limit on the
size, as long as double would allow.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 util/cutils.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/util/cutils.c b/util/cutils.c
index fa5ddec..8df0963 100644
--- a/util/cutils.c
+++ b/util/cutils.c
@@ -622,7 +622,7 @@ const char *qemu_ether_ntoa(const MACAddr *mac)
 
 /*
  * Return human readable string for size @val.
- * @val must be between (-1000Eib, 1000EiB), exclusively.
+ * @val can be any value.
  * Use IEC binary units like KiB, MiB, and so forth.
  * Caller is responsible for passing it to g_free().
  */
@@ -640,7 +640,12 @@ char *size_to_str(double val)
      */
     frexp(val / (1000.0 / 1024.0), &i);
     i = (i - 1) / 10;
-    assert(i < ARRAY_SIZE(suffixes));
+
+    /* Use the biggest possible suffix */
+    if (i > ARRAY_SIZE(suffixes) - 1) {
+        i = ARRAY_SIZE(suffixes) - 1;
+    }
+
     div = 1ULL << (i * 10);
 
     return g_strdup_printf("%0.3g %sB", val / div, suffixes[i]);
-- 
2.7.4

Re: [Qemu-devel] [PATCH v7 1/4] ramblock: add RAMBLOCK_FOREACH()

[Dr. David Alan Gilbert]

* Peter Xu (peterx@redhat.com) wrote:
> So that it can simplifies the iterators.
> 
> Signed-off-by: Peter Xu <peterx@redhat.com>

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

> ---
>  exec.c                 | 22 +++++++++++-----------
>  include/exec/ramlist.h |  5 +++++
>  migration/ram.c        | 13 +++++++------
>  3 files changed, 23 insertions(+), 17 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 293d27c..d88afea 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -648,7 +648,7 @@ 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;
>      }
>  
> @@ -676,7 +676,7 @@ 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();
> @@ -1408,8 +1408,9 @@ 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;
>  }
> @@ -1500,7 +1501,7 @@ void ram_postcopy_migrated_memory_release(MigrationState *ms)
>  {
>      struct RAMBlock *block;
>  
> -    QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
> +    RAMBLOCK_FOREACH(block) {
>          unsigned long *bitmap = block->bmap;
>          unsigned long range = block->used_length >> TARGET_PAGE_BITS;
>          unsigned long run_start = find_next_zero_bit(bitmap, range, 0);
> @@ -1578,7 +1579,7 @@ 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) {
>          PostcopyDiscardState *pds =
>              postcopy_discard_send_init(ms, block->idstr);
>  
> @@ -1961,7 +1962,7 @@ 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
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK

Re: [Qemu-devel] [PATCH v7 2/4] utils: provide size_to_str()

[Dr. David Alan Gilbert]

* Peter Xu (peterx@redhat.com) wrote:
> Moving the algorithm from print_type_size() into size_to_str() so that
> other component can also leverage it. With that, refactor
> print_type_size().
> 
> Reviewed-by: Markus Armbruster <armbru@redhat.com>
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>  include/qemu-common.h        |  1 +
>  qapi/string-output-visitor.c | 22 ++++++----------------
>  util/cutils.c                | 26 ++++++++++++++++++++++++++
>  3 files changed, 33 insertions(+), 16 deletions(-)
> 
> 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/qapi/string-output-visitor.c b/qapi/string-output-visitor.c
> index 94ac821..53c2175 100644
> --- a/qapi/string-output-visitor.c
> +++ b/qapi/string-output-visitor.c
> @@ -211,10 +211,8 @@ static void print_type_size(Visitor *v, const char *name, uint64_t *obj,
>                              Error **errp)
>  {
>      StringOutputVisitor *sov = to_sov(v);
> -    static const char suffixes[] = { 'B', 'K', 'M', 'G', 'T', 'P', 'E' };
> -    uint64_t div, val;
> -    char *out;
> -    int i;
> +    uint64_t val;
> +    char *out, *psize;
>  
>      if (!sov->human) {
>          out = g_strdup_printf("%"PRIu64, *obj);
> @@ -223,19 +221,11 @@ static void print_type_size(Visitor *v, const char *name, uint64_t *obj,
>      }
>  
>      val = *obj;
> -
> -    /* The exponent (returned in i) minus one gives us
> -     * floor(log2(val * 1024 / 1000).  The correction makes us
> -     * switch to the higher power when the integer part is >= 1000.
> -     */
> -    frexp(val / (1000.0 / 1024.0), &i);
> -    i = (i - 1) / 10;
> -    assert(i < ARRAY_SIZE(suffixes));
> -    div = 1ULL << (i * 10);
> -
> -    out = g_strdup_printf("%"PRIu64" (%0.3g %c%s)", val,
> -                          (double)val/div, suffixes[i], i ? "iB" : "");
> +    psize = size_to_str(val);
> +    out = g_strdup_printf("%"PRIu64" (%s)", val, psize);
>      string_output_set(sov, out);
> +
> +    g_free(psize);
>  }
>  
>  static void print_type_bool(Visitor *v, const char *name, bool *obj,
> diff --git a/util/cutils.c b/util/cutils.c
> index 50ad179..fa5ddec 100644
> --- a/util/cutils.c
> +++ b/util/cutils.c
> @@ -619,3 +619,29 @@ const char *qemu_ether_ntoa(const MACAddr *mac)
>  
>      return ret;
>  }
> +
> +/*
> + * Return human readable string for size @val.
> + * @val must be between (-1000Eib, 1000EiB), exclusively.
> + * Use IEC binary units like KiB, MiB, and so forth.
> + * Caller is responsible for passing it to g_free().
> + */
> +char *size_to_str(double val)
> +{
> +    static const char *suffixes[] = { "", "Ki", "Mi", "Gi", "Ti", "Pi", "Ei" };
> +    unsigned long div;
> +    int i;
> +
> +    /*
> +     * The exponent (returned in i) minus one gives us
> +     * floor(log2(val * 1024 / 1000).  The correction makes us
> +     * switch to the higher power when the integer part is >= 1000.
> +     * (see e41b509d68afb1f for more info)
> +     */
> +    frexp(val / (1000.0 / 1024.0), &i);
> +    i = (i - 1) / 10;
> +    assert(i < ARRAY_SIZE(suffixes));

Because your code takes a double, where as Paolo's only takes uint's,
I think you have to be careful to check that i >= 0  as well,  for
example, what would happen if someone did size_to_str(1.0/100.0) ?

Dave

> +    div = 1ULL << (i * 10);
> +
> +    return g_strdup_printf("%0.3g %sB", val / div, suffixes[i]);
> +}
> -- 
> 2.7.4
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK

Re: [Qemu-devel] [PATCH v7 4/4] utils: remove assert in size_to_str()

[Eric Blake]

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On 05/11/2017 07:22 AM, Peter Xu wrote:
> It's not very safe to assert in size_to_str(). Let's be inclusive.
> 
> It naturally allows negative values. Now it won't even limit on the
> size, as long as double would allow.
> 
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>  util/cutils.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)

Since you just introduced this in 2/4, I'd rather see the two squashed
together if we decide this is the interface we want to support.


-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org


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Re: [Qemu-devel] [PATCH v7 4/4] utils: remove assert in size_to_str()

[Markus Armbruster]

Eric Blake <eblake@redhat.com> writes:

> On 05/11/2017 07:22 AM, Peter Xu wrote:
>> It's not very safe to assert in size_to_str(). Let's be inclusive.
>> 
>> It naturally allows negative values. Now it won't even limit on the
>> size, as long as double would allow.
>> 
>> Signed-off-by: Peter Xu <peterx@redhat.com>
>> ---
>>  util/cutils.c | 9 +++++++--
>>  1 file changed, 7 insertions(+), 2 deletions(-)
>
> Since you just introduced this in 2/4, I'd rather see the two squashed
> together if we decide this is the interface we want to support.

PATCH 2 factors it out of print_type_size().  Doing just that and
improving only on top makes some sense.

Re: [Qemu-devel] [PATCH v7 4/4] utils: remove assert in size_to_str()

[Eric Blake]

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On 05/11/2017 01:22 PM, Markus Armbruster wrote:
> Eric Blake <eblake@redhat.com> writes:
> 
>> On 05/11/2017 07:22 AM, Peter Xu wrote:
>>> It's not very safe to assert in size_to_str(). Let's be inclusive.
>>>
>>> It naturally allows negative values. Now it won't even limit on the
>>> size, as long as double would allow.
>>>
>>> Signed-off-by: Peter Xu <peterx@redhat.com>
>>> ---
>>>  util/cutils.c | 9 +++++++--
>>>  1 file changed, 7 insertions(+), 2 deletions(-)
>>
>> Since you just introduced this in 2/4, I'd rather see the two squashed
>> together if we decide this is the interface we want to support.
> 
> PATCH 2 factors it out of print_type_size().  Doing just that and
> improving only on top makes some sense.

Okay. (Moral of the story: I should have done more than just glance at 2
before commenting on 4)

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org


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Re: [Qemu-devel] [PATCH v7 2/4] utils: provide size_to_str()

[Peter Xu]

On Thu, May 11, 2017 at 02:05:26PM +0100, Dr. David Alan Gilbert wrote:
> * Peter Xu (peterx@redhat.com) wrote:
> > Moving the algorithm from print_type_size() into size_to_str() so that
> > other component can also leverage it. With that, refactor
> > print_type_size().
> > 
> > Reviewed-by: Markus Armbruster <armbru@redhat.com>
> > Signed-off-by: Peter Xu <peterx@redhat.com>
> > ---
> >  include/qemu-common.h        |  1 +
> >  qapi/string-output-visitor.c | 22 ++++++----------------
> >  util/cutils.c                | 26 ++++++++++++++++++++++++++
> >  3 files changed, 33 insertions(+), 16 deletions(-)
> > 
> > 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/qapi/string-output-visitor.c b/qapi/string-output-visitor.c
> > index 94ac821..53c2175 100644
> > --- a/qapi/string-output-visitor.c
> > +++ b/qapi/string-output-visitor.c
> > @@ -211,10 +211,8 @@ static void print_type_size(Visitor *v, const char *name, uint64_t *obj,
> >                              Error **errp)
> >  {
> >      StringOutputVisitor *sov = to_sov(v);
> > -    static const char suffixes[] = { 'B', 'K', 'M', 'G', 'T', 'P', 'E' };
> > -    uint64_t div, val;
> > -    char *out;
> > -    int i;
> > +    uint64_t val;
> > +    char *out, *psize;
> >  
> >      if (!sov->human) {
> >          out = g_strdup_printf("%"PRIu64, *obj);
> > @@ -223,19 +221,11 @@ static void print_type_size(Visitor *v, const char *name, uint64_t *obj,
> >      }
> >  
> >      val = *obj;
> > -
> > -    /* The exponent (returned in i) minus one gives us
> > -     * floor(log2(val * 1024 / 1000).  The correction makes us
> > -     * switch to the higher power when the integer part is >= 1000.
> > -     */
> > -    frexp(val / (1000.0 / 1024.0), &i);
> > -    i = (i - 1) / 10;
> > -    assert(i < ARRAY_SIZE(suffixes));
> > -    div = 1ULL << (i * 10);
> > -
> > -    out = g_strdup_printf("%"PRIu64" (%0.3g %c%s)", val,
> > -                          (double)val/div, suffixes[i], i ? "iB" : "");
> > +    psize = size_to_str(val);
> > +    out = g_strdup_printf("%"PRIu64" (%s)", val, psize);
> >      string_output_set(sov, out);
> > +
> > +    g_free(psize);
> >  }
> >  
> >  static void print_type_bool(Visitor *v, const char *name, bool *obj,
> > diff --git a/util/cutils.c b/util/cutils.c
> > index 50ad179..fa5ddec 100644
> > --- a/util/cutils.c
> > +++ b/util/cutils.c
> > @@ -619,3 +619,29 @@ const char *qemu_ether_ntoa(const MACAddr *mac)
> >  
> >      return ret;
> >  }
> > +
> > +/*
> > + * Return human readable string for size @val.
> > + * @val must be between (-1000Eib, 1000EiB), exclusively.
> > + * Use IEC binary units like KiB, MiB, and so forth.
> > + * Caller is responsible for passing it to g_free().
> > + */
> > +char *size_to_str(double val)
> > +{
> > +    static const char *suffixes[] = { "", "Ki", "Mi", "Gi", "Ti", "Pi", "Ei" };
> > +    unsigned long div;
> > +    int i;
> > +
> > +    /*
> > +     * The exponent (returned in i) minus one gives us
> > +     * floor(log2(val * 1024 / 1000).  The correction makes us
> > +     * switch to the higher power when the integer part is >= 1000.
> > +     * (see e41b509d68afb1f for more info)
> > +     */
> > +    frexp(val / (1000.0 / 1024.0), &i);
> > +    i = (i - 1) / 10;
> > +    assert(i < ARRAY_SIZE(suffixes));
> 
> Because your code takes a double, where as Paolo's only takes uint's,
> I think you have to be careful to check that i >= 0  as well,  for
> example, what would happen if someone did size_to_str(1.0/100.0) ?

Yes, you are right.

Let me stick to uint64_t then, after all double helps little in dump
sizes... /me chose an unwise parameter type.

And then it's safe to directly remove the assert() in this patch,
because even UINT64_MAX is only 16 EiB. Then I can further drop the
last patch...

I'll resend. Thanks,

-- 
Peter Xu