From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43175) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c4VtC-0006sr-Py for qemu-devel@nongnu.org; Wed, 09 Nov 2016 11:38:19 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1c4Vt8-0003J0-RQ for qemu-devel@nongnu.org; Wed, 09 Nov 2016 11:38:18 -0500 Received: from mx1.redhat.com ([209.132.183.28]:42330) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1c4Vt8-0003Ia-Jp for qemu-devel@nongnu.org; Wed, 09 Nov 2016 11:38:14 -0500 Date: Wed, 9 Nov 2016 17:38:10 +0100 From: Igor Mammedov Message-ID: <20161109173810.688e4132@nial.brq.redhat.com> In-Reply-To: <1478517229-140028-3-git-send-email-guangrong.xiao@linux.intel.com> References: <1478517229-140028-1-git-send-email-guangrong.xiao@linux.intel.com> <1478517229-140028-3-git-send-email-guangrong.xiao@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 02/14] nvdimm acpi: drop the lock of fit buffer List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Xiao Guangrong Cc: pbonzini@redhat.com, gleb@kernel.org, mtosatti@redhat.com, stefanha@redhat.com, mst@redhat.com, rth@twiddle.net, ehabkost@redhat.com, dan.j.williams@intel.com, kvm@vger.kernel.org, qemu-devel@nongnu.org On Mon, 7 Nov 2016 19:13:37 +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 > Signed-off-by: Xiao Guangrong Reviewed-by: Igor Mammedov > --- > 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; > };