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[209.85.210.49]) by smtp.gmail.com with ESMTPSA id s22sm884242otr.57.2020.03.05.23.50.38 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 05 Mar 2020 23:50:39 -0800 (PST) Received: by mail-ot1-f49.google.com with SMTP id v19so1550233ote.8 for ; Thu, 05 Mar 2020 23:50:38 -0800 (PST) X-Received: by 2002:a05:6830:2105:: with SMTP id i5mr1419255otc.141.1583481037437; Thu, 05 Mar 2020 23:50:37 -0800 (PST) MIME-Version: 1.0 References: <1583472756-7611-1-git-send-email-mansur@codeaurora.org> In-Reply-To: <1583472756-7611-1-git-send-email-mansur@codeaurora.org> From: Alexandre Courbot Date: Fri, 6 Mar 2020 16:50:25 +0900 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] venus: avoid extra locking in driver To: Mansur Alisha Shaik Cc: Linux Media Mailing List , Stanimir Varbanov , LKML , linux-arm-msm@vger.kernel.org, Vikash Garodia Content-Type: text/plain; charset="UTF-8" Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Fri, Mar 6, 2020 at 2:34 PM Mansur Alisha Shaik wrote: > > This change will avoid extra locking in driver. Could you elaborate a bit more on the problem that this patch solves? > > Signed-off-by: Mansur Alisha Shaik > --- > drivers/media/platform/qcom/venus/core.c | 2 +- > drivers/media/platform/qcom/venus/core.h | 2 +- > drivers/media/platform/qcom/venus/helpers.c | 11 +++++++++-- > drivers/media/platform/qcom/venus/pm_helpers.c | 8 ++++---- > 4 files changed, 15 insertions(+), 8 deletions(-) > > diff --git a/drivers/media/platform/qcom/venus/core.c b/drivers/media/platform/qcom/venus/core.c > index 194b10b9..75d38b8 100644 > --- a/drivers/media/platform/qcom/venus/core.c > +++ b/drivers/media/platform/qcom/venus/core.c > @@ -447,7 +447,7 @@ static const struct freq_tbl sdm845_freq_table[] = { > { 244800, 100000000 }, /* 1920x1080@30 */ > }; > > -static struct codec_freq_data sdm845_codec_freq_data[] = { > +static const struct codec_freq_data sdm845_codec_freq_data[] = { > { V4L2_PIX_FMT_H264, VIDC_SESSION_TYPE_ENC, 675, 10 }, > { V4L2_PIX_FMT_HEVC, VIDC_SESSION_TYPE_ENC, 675, 10 }, > { V4L2_PIX_FMT_VP8, VIDC_SESSION_TYPE_ENC, 675, 10 }, > diff --git a/drivers/media/platform/qcom/venus/core.h b/drivers/media/platform/qcom/venus/core.h > index ab7c360..8c8d0e9 100644 > --- a/drivers/media/platform/qcom/venus/core.h > +++ b/drivers/media/platform/qcom/venus/core.h > @@ -245,7 +245,7 @@ struct venus_buffer { > struct clock_data { > u32 core_id; > unsigned long freq; > - const struct codec_freq_data *codec_freq_data; > + struct codec_freq_data codec_freq_data; > }; > > #define to_venus_buffer(ptr) container_of(ptr, struct venus_buffer, vb) > diff --git a/drivers/media/platform/qcom/venus/helpers.c b/drivers/media/platform/qcom/venus/helpers.c > index bcc6038..550c4ff 100644 > --- a/drivers/media/platform/qcom/venus/helpers.c > +++ b/drivers/media/platform/qcom/venus/helpers.c > @@ -807,6 +807,7 @@ int venus_helper_init_codec_freq_data(struct venus_inst *inst) > unsigned int i, data_size; > u32 pixfmt; > int ret = 0; > + bool found = false; > > if (!IS_V4(inst->core)) > return 0; > @@ -816,16 +817,22 @@ int venus_helper_init_codec_freq_data(struct venus_inst *inst) > pixfmt = inst->session_type == VIDC_SESSION_TYPE_DEC ? > inst->fmt_out->pixfmt : inst->fmt_cap->pixfmt; > > + memset(&inst->clk_data.codec_freq_data, 0, > + sizeof(inst->clk_data.codec_freq_data)); > + > for (i = 0; i < data_size; i++) { > if (data[i].pixfmt == pixfmt && > data[i].session_type == inst->session_type) { > - inst->clk_data.codec_freq_data = &data[i]; > + inst->clk_data.codec_freq_data = data[i]; >From the patch I'd infer that inst->clk_data.codec_freq_data needs to change at runtime. Is this what happens? Why? I'd expect that frequency tables remain constant, and thus that the global sdm845_codec_freq_data can remain constant while clock_data::codec_freq_data is a const reference to it. What prevents this from happening? > + found = true; > break; > } > } > > - if (!inst->clk_data.codec_freq_data) > + if (!found) { > + dev_err(inst->core->dev, "cannot find codec freq data\n"); > ret = -EINVAL; > + } > > return ret; > } > diff --git a/drivers/media/platform/qcom/venus/pm_helpers.c b/drivers/media/platform/qcom/venus/pm_helpers.c > index abf9315..240845e 100644 > --- a/drivers/media/platform/qcom/venus/pm_helpers.c > +++ b/drivers/media/platform/qcom/venus/pm_helpers.c > @@ -496,7 +496,7 @@ min_loaded_core(struct venus_inst *inst, u32 *min_coreid, u32 *min_load) > list_for_each_entry(inst_pos, &core->instances, list) { > if (inst_pos == inst) > continue; > - vpp_freq = inst_pos->clk_data.codec_freq_data->vpp_freq; > + vpp_freq = inst_pos->clk_data.codec_freq_data.vpp_freq; > coreid = inst_pos->clk_data.core_id; > > mbs_per_sec = load_per_instance(inst_pos); > @@ -545,7 +545,7 @@ static int decide_core(struct venus_inst *inst) > return 0; > > inst_load = load_per_instance(inst); > - inst_load *= inst->clk_data.codec_freq_data->vpp_freq; > + inst_load *= inst->clk_data.codec_freq_data.vpp_freq; > max_freq = core->res->freq_tbl[0].freq; > > min_loaded_core(inst, &min_coreid, &min_load); > @@ -848,10 +848,10 @@ static unsigned long calculate_inst_freq(struct venus_inst *inst, > > mbs_per_sec = load_per_instance(inst) / fps; > > - vpp_freq = mbs_per_sec * inst->clk_data.codec_freq_data->vpp_freq; > + vpp_freq = mbs_per_sec * inst->clk_data.codec_freq_data.vpp_freq; > /* 21 / 20 is overhead factor */ > vpp_freq += vpp_freq / 20; > - vsp_freq = mbs_per_sec * inst->clk_data.codec_freq_data->vsp_freq; > + vsp_freq = mbs_per_sec * inst->clk_data.codec_freq_data.vsp_freq; > > /* 10 / 7 is overhead factor */ > if (inst->session_type == VIDC_SESSION_TYPE_ENC) > -- > 2.7.4 >