[02/14] nvdimm acpi: drop the lock of fit buffer
diff mbox

Message ID 1478517229-140028-3-git-send-email-guangrong.xiao@linux.intel.com
State New
Headers show

Commit Message

Xiao Guangrong Nov. 7, 2016, 11:13 a.m. UTC
as there is a global lock to protect vm-exit handlers and
QMP/monitor, this lock can be dropped

Suggested-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
---
 hw/acpi/nvdimm.c        | 11 +----------
 include/hw/mem/nvdimm.h | 17 +++++------------
 2 files changed, 6 insertions(+), 22 deletions(-)

Comments

Stefan Hajnoczi Nov. 7, 2016, 3:30 p.m. UTC | #1
On Mon, Nov 07, 2016 at 07:13:37PM +0800, Xiao Guangrong wrote:
> as there is a global lock to protect vm-exit handlers and
> QMP/monitor, this lock can be dropped
> 
> Suggested-by: Igor Mammedov <imammedo@redhat.com>
> Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
> ---
>  hw/acpi/nvdimm.c        | 11 +----------
>  include/hw/mem/nvdimm.h | 17 +++++------------
>  2 files changed, 6 insertions(+), 22 deletions(-)

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Igor Mammedov Nov. 9, 2016, 4:38 p.m. UTC | #2
On Mon,  7 Nov 2016 19:13:37 +0800
Xiao Guangrong <guangrong.xiao@linux.intel.com> wrote:

> as there is a global lock to protect vm-exit handlers and
> QMP/monitor, this lock can be dropped
> 
> Suggested-by: Igor Mammedov <imammedo@redhat.com>
> Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>

> ---
>  hw/acpi/nvdimm.c        | 11 +----------
>  include/hw/mem/nvdimm.h | 17 +++++------------
>  2 files changed, 6 insertions(+), 22 deletions(-)
> 
> diff --git a/hw/acpi/nvdimm.c b/hw/acpi/nvdimm.c
> index 623bb36..0fe3547 100644
> --- a/hw/acpi/nvdimm.c
> +++ b/hw/acpi/nvdimm.c
> @@ -371,17 +371,14 @@ static GArray *nvdimm_build_device_structure(void)
>  
>  static void nvdimm_init_fit_buffer(NvdimmFitBuffer *fit_buf)
>  {
> -    qemu_mutex_init(&fit_buf->lock);
>      fit_buf->fit = g_array_new(false, true /* clear */, 1);
>  }
>  
>  static void nvdimm_build_fit_buffer(NvdimmFitBuffer *fit_buf)
>  {
> -    qemu_mutex_lock(&fit_buf->lock);
>      g_array_free(fit_buf->fit, true);
>      fit_buf->fit = nvdimm_build_device_structure();
>      fit_buf->dirty = true;
> -    qemu_mutex_unlock(&fit_buf->lock);
>  }
>  
>  void nvdimm_acpi_hotplug(AcpiNVDIMMState *state)
> @@ -395,11 +392,10 @@ static void nvdimm_build_nfit(AcpiNVDIMMState *state, GArray *table_offsets,
>      NvdimmFitBuffer *fit_buf = &state->fit_buf;
>      unsigned int header;
>  
> -    qemu_mutex_lock(&fit_buf->lock);
>  
>      /* NVDIMM device is not plugged? */
>      if (!fit_buf->fit->len) {
> -        goto exit;
> +        return;
>      }
>  
>      acpi_add_table(table_offsets, table_data);
> @@ -413,9 +409,6 @@ static void nvdimm_build_nfit(AcpiNVDIMMState *state, GArray *table_offsets,
>      build_header(linker, table_data,
>                   (void *)(table_data->data + header), "NFIT",
>                   sizeof(NvdimmNfitHeader) + fit_buf->fit->len, 1, NULL, NULL);
> -
> -exit:
> -    qemu_mutex_unlock(&fit_buf->lock);
>  }
>  
>  struct NvdimmDsmIn {
> @@ -544,7 +537,6 @@ static void nvdimm_dsm_func_read_fit(AcpiNVDIMMState *state, NvdimmDsmIn *in,
>      read_fit = (NvdimmFuncReadFITIn *)in->arg3;
>      le32_to_cpus(&read_fit->offset);
>  
> -    qemu_mutex_lock(&fit_buf->lock);
>      fit = fit_buf->fit;
>  
>      nvdimm_debug("Read FIT: offset %#x FIT size %#x Dirty %s.\n",
> @@ -578,7 +570,6 @@ exit:
>      cpu_physical_memory_write(dsm_mem_addr, read_fit_out, size);
>  
>      g_free(read_fit_out);
> -    qemu_mutex_unlock(&fit_buf->lock);
>  }
>  
>  static void nvdimm_dsm_reserved_root(AcpiNVDIMMState *state, NvdimmDsmIn *in,
> diff --git a/include/hw/mem/nvdimm.h b/include/hw/mem/nvdimm.h
> index 33cd421..d3ffb25 100644
> --- a/include/hw/mem/nvdimm.h
> +++ b/include/hw/mem/nvdimm.h
> @@ -99,20 +99,13 @@ typedef struct NVDIMMClass NVDIMMClass;
>  #define NVDIMM_ACPI_IO_LEN      4
>  
>  /*
> - * The buffer, @fit, saves the FIT info for all the presented NVDIMM
> - * devices which is updated after the NVDIMM device is plugged or
> - * unplugged.
> - *
> - * Rules to use the buffer:
> - *    1) the user should hold the @lock to access the buffer.
> - *    2) mark @dirty whenever the buffer is updated.
> - *
> - * These rules preserve NVDIMM ACPI _FIT method to read incomplete
> - * or obsolete fit info if fit update happens during multiple RFIT
> - * calls.
> + * NvdimmFitBuffer:
> + * @fit: FIT structures for present NVDIMMs. It is updated when
> + *   the NVDIMM device is plugged or unplugged.
> + * @dirty: It allows OSPM to detect change and restart read in
> + *   progress if there is any.
>   */
>  struct NvdimmFitBuffer {
> -    QemuMutex lock;
>      GArray *fit;
>      bool dirty;
>  };

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Patch
diff mbox

diff --git a/hw/acpi/nvdimm.c b/hw/acpi/nvdimm.c
index 623bb36..0fe3547 100644
--- a/hw/acpi/nvdimm.c
+++ b/hw/acpi/nvdimm.c
@@ -371,17 +371,14 @@  static GArray *nvdimm_build_device_structure(void)
 
 static void nvdimm_init_fit_buffer(NvdimmFitBuffer *fit_buf)
 {
-    qemu_mutex_init(&fit_buf->lock);
     fit_buf->fit = g_array_new(false, true /* clear */, 1);
 }
 
 static void nvdimm_build_fit_buffer(NvdimmFitBuffer *fit_buf)
 {
-    qemu_mutex_lock(&fit_buf->lock);
     g_array_free(fit_buf->fit, true);
     fit_buf->fit = nvdimm_build_device_structure();
     fit_buf->dirty = true;
-    qemu_mutex_unlock(&fit_buf->lock);
 }
 
 void nvdimm_acpi_hotplug(AcpiNVDIMMState *state)
@@ -395,11 +392,10 @@  static void nvdimm_build_nfit(AcpiNVDIMMState *state, GArray *table_offsets,
     NvdimmFitBuffer *fit_buf = &state->fit_buf;
     unsigned int header;
 
-    qemu_mutex_lock(&fit_buf->lock);
 
     /* NVDIMM device is not plugged? */
     if (!fit_buf->fit->len) {
-        goto exit;
+        return;
     }
 
     acpi_add_table(table_offsets, table_data);
@@ -413,9 +409,6 @@  static void nvdimm_build_nfit(AcpiNVDIMMState *state, GArray *table_offsets,
     build_header(linker, table_data,
                  (void *)(table_data->data + header), "NFIT",
                  sizeof(NvdimmNfitHeader) + fit_buf->fit->len, 1, NULL, NULL);
-
-exit:
-    qemu_mutex_unlock(&fit_buf->lock);
 }
 
 struct NvdimmDsmIn {
@@ -544,7 +537,6 @@  static void nvdimm_dsm_func_read_fit(AcpiNVDIMMState *state, NvdimmDsmIn *in,
     read_fit = (NvdimmFuncReadFITIn *)in->arg3;
     le32_to_cpus(&read_fit->offset);
 
-    qemu_mutex_lock(&fit_buf->lock);
     fit = fit_buf->fit;
 
     nvdimm_debug("Read FIT: offset %#x FIT size %#x Dirty %s.\n",
@@ -578,7 +570,6 @@  exit:
     cpu_physical_memory_write(dsm_mem_addr, read_fit_out, size);
 
     g_free(read_fit_out);
-    qemu_mutex_unlock(&fit_buf->lock);
 }
 
 static void nvdimm_dsm_reserved_root(AcpiNVDIMMState *state, NvdimmDsmIn *in,
diff --git a/include/hw/mem/nvdimm.h b/include/hw/mem/nvdimm.h
index 33cd421..d3ffb25 100644
--- a/include/hw/mem/nvdimm.h
+++ b/include/hw/mem/nvdimm.h
@@ -99,20 +99,13 @@  typedef struct NVDIMMClass NVDIMMClass;
 #define NVDIMM_ACPI_IO_LEN      4
 
 /*
- * The buffer, @fit, saves the FIT info for all the presented NVDIMM
- * devices which is updated after the NVDIMM device is plugged or
- * unplugged.
- *
- * Rules to use the buffer:
- *    1) the user should hold the @lock to access the buffer.
- *    2) mark @dirty whenever the buffer is updated.
- *
- * These rules preserve NVDIMM ACPI _FIT method to read incomplete
- * or obsolete fit info if fit update happens during multiple RFIT
- * calls.
+ * NvdimmFitBuffer:
+ * @fit: FIT structures for present NVDIMMs. It is updated when
+ *   the NVDIMM device is plugged or unplugged.
+ * @dirty: It allows OSPM to detect change and restart read in
+ *   progress if there is any.
  */
 struct NvdimmFitBuffer {
-    QemuMutex lock;
     GArray *fit;
     bool dirty;
 };