Vote for the MSM bus bandwidth required by SDHC driver
based on the clock speed and bus width of the card.
Otherwise, the system clocks may run at minimum clock
speed and thus affecting the performance.
Adapt to the new ICB framework for bus bandwidth voting.
This requires the source/destination port ids.
Also this requires a tuple of values.
The tuple is for two different paths - from SDHC master
to BIMC slave. The other is from CPU master to SDHC slave.
This tuple consists of the average and peak bandwidth.
This change is based on Georgi Djakov [RFC]
(https://lkml.org/lkml/2018/10/11/499)
---
changed since v1:
* Addressed all the Review comments.
* Minor code rebasing.
Pradeep P V K (2):
dt-bindings: mmc: sdhci-msm: Add Bus BW vote supported strings
mmc: sdhci-msm: Add support for bus bandwidth voting
.../devicetree/bindings/mmc/sdhci-msm.txt | 32 ++
drivers/mmc/host/sdhci-msm.c | 366 ++++++++++++++++++++-
2 files changed, 395 insertions(+), 3 deletions(-)
--
1.9.1
Vote for the MSM bus bandwidth required by SDHC driver
based on the clock frequency and bus width of the card.
Otherwise,the system clocks may run at minimum clock speed
and thus affecting the performance.
This change is based on Georgi Djakov [RFC]
(https://lkml.org/lkml/2018/10/11/499)
Signed-off-by: Sahitya Tummala <[email protected]>
Signed-off-by: Subhash Jadavani <[email protected]>
Signed-off-by: Veerabhadrarao Badiganti <[email protected]>
Co-Developed-by: Pradeep P V K <[email protected]>
Signed-off-by: Pradeep P V K <[email protected]>
---
drivers/mmc/host/sdhci-msm.c | 366 ++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 363 insertions(+), 3 deletions(-)
diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
index b75c82d..a12e0c6 100644
--- a/drivers/mmc/host/sdhci-msm.c
+++ b/drivers/mmc/host/sdhci-msm.c
@@ -11,6 +11,7 @@
#include <linux/mmc/mmc.h>
#include <linux/pm_runtime.h>
#include <linux/slab.h>
+#include <linux/interconnect.h>
#include <linux/iopoll.h>
#include <linux/regulator/consumer.h>
@@ -228,6 +229,31 @@ struct sdhci_msm_variant_info {
const struct sdhci_msm_offset *offset;
};
+struct msm_bus_vectors {
+ u64 ab;
+ u64 ib;
+};
+
+struct msm_bus_path {
+ unsigned int num_paths;
+ struct msm_bus_vectors *vec;
+};
+
+struct sdhci_msm_bus_vote_data {
+ const char *name;
+ unsigned int num_usecase;
+ struct msm_bus_path *usecase;
+
+ unsigned int *bw_vecs;
+ unsigned int bw_vecs_size;
+
+ struct icc_path *sdhc_ddr;
+ struct icc_path *cpu_sdhc;
+
+ u32 curr_vote;
+
+};
+
struct sdhci_msm_host {
struct platform_device *pdev;
void __iomem *core_mem; /* MSM SDCC mapped address */
@@ -253,8 +279,13 @@ struct sdhci_msm_host {
const struct sdhci_msm_offset *offset;
bool use_cdr;
u32 transfer_mode;
+ bool skip_bus_bw_voting;
+ struct sdhci_msm_bus_vote_data *bus_vote_data;
+ struct delayed_work bus_vote_work;
};
+static void sdhci_msm_bus_voting(struct sdhci_host *host, u32 enable);
+
static const struct sdhci_msm_offset *sdhci_priv_msm_offset(struct sdhci_host *host)
{
struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
@@ -1557,6 +1588,8 @@ static void sdhci_msm_set_clock(struct sdhci_host *host, unsigned int clock)
msm_set_clock_rate_for_bus_mode(host, clock);
out:
+ if (!msm_host->skip_bus_bw_voting)
+ sdhci_msm_bus_voting(host, !!clock);
__sdhci_msm_set_clock(host, clock);
}
@@ -1678,6 +1711,315 @@ static void sdhci_msm_set_regulator_caps(struct sdhci_msm_host *msm_host)
pr_debug("%s: supported caps: 0x%08x\n", mmc_hostname(mmc), caps);
}
+static int sdhci_msm_dt_get_array(struct device *dev, const char *prop_name,
+ u32 **bw_vecs, int *len, u32 size)
+{
+ int ret = 0;
+ struct device_node *np = dev->of_node;
+ size_t sz;
+ u32 *arr = NULL;
+
+ if (!of_get_property(np, prop_name, len)) {
+ ret = -EINVAL;
+ goto out;
+ }
+ sz = *len = *len / sizeof(*arr);
+ if (sz <= 0 || (size > 0 && (sz > size))) {
+ dev_err(dev, "%s invalid size\n", prop_name);
+ ret = -EINVAL;
+ goto out;
+ }
+
+ arr = devm_kzalloc(dev, sz * sizeof(*arr), GFP_KERNEL);
+ if (!arr) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ ret = of_property_read_u32_array(np, prop_name, arr, sz);
+ if (ret < 0) {
+ dev_err(dev, "%s failed reading array %d\n", prop_name, ret);
+ goto out;
+ }
+ *bw_vecs = arr;
+out:
+ if (ret)
+ *len = 0;
+ return ret;
+}
+
+/* Returns required bandwidth in Bytes per Sec */
+static unsigned long sdhci_get_bw_required(struct sdhci_host *host,
+ struct mmc_ios *ios)
+{
+ unsigned long bw;
+ struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+ struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
+
+ bw = msm_host->clk_rate;
+
+ if (ios->bus_width == MMC_BUS_WIDTH_4)
+ bw /= 2;
+ else if (ios->bus_width == MMC_BUS_WIDTH_1)
+ bw /= 8;
+
+ return bw;
+}
+
+static int sdhci_msm_bus_get_vote_for_bw(struct sdhci_msm_host *host,
+ unsigned int bw)
+{
+ struct sdhci_msm_bus_vote_data *bvd = host->bus_vote_data;
+
+ const unsigned int *table = bvd->bw_vecs;
+ unsigned int size = bvd->bw_vecs_size;
+ int i;
+
+ for (i = 0; i < size; i++) {
+ if (bw <= table[i])
+ return i;
+ }
+
+ return i - 1;
+}
+
+/*
+ * Caller of this function should ensure that msm bus client
+ * handle is not null.
+ */
+static inline int sdhci_msm_bus_set_vote(struct sdhci_msm_host *msm_host,
+ int vote)
+{
+ struct sdhci_host *host = platform_get_drvdata(msm_host->pdev);
+ struct sdhci_msm_bus_vote_data *bvd = msm_host->bus_vote_data;
+ struct msm_bus_path *usecase = bvd->usecase;
+ struct msm_bus_vectors *vec = usecase[vote].vec;
+ int ddr_rc = 0, cpu_rc = 0;
+
+ if (vote != bvd->curr_vote) {
+ pr_debug("%s: vote:%d sdhc_ddr ab:%llu ib:%llu cpu_sdhc ab:%llu ib:%llu\n",
+ mmc_hostname(host->mmc), vote, vec[0].ab,
+ vec[0].ib, vec[1].ab, vec[1].ib);
+ ddr_rc = icc_set_bw(bvd->sdhc_ddr, vec[0].ab, vec[0].ib);
+ cpu_rc = icc_set_bw(bvd->cpu_sdhc, vec[1].ab, vec[1].ib);
+ if (ddr_rc || cpu_rc) {
+ pr_err("%s: icc_set() failed\n",
+ mmc_hostname(host->mmc));
+ goto out;
+ }
+ bvd->curr_vote = vote;
+ }
+out:
+ return cpu_rc;
+}
+
+/*
+ * Internal work. Work to set 0 bandwidth for msm bus.
+ */
+static void sdhci_msm_bus_work(struct work_struct *work)
+{
+ struct sdhci_msm_host *msm_host;
+ struct sdhci_host *host;
+
+ msm_host = container_of(work, struct sdhci_msm_host,
+ bus_vote_work.work);
+ host = platform_get_drvdata(msm_host->pdev);
+
+ if (!msm_host->bus_vote_data->sdhc_ddr ||
+ !msm_host->bus_vote_data->cpu_sdhc)
+ return;
+ /* don't vote for 0 bandwidth if any request is in progress */
+ if (!host->mmc->ongoing_mrq)
+ sdhci_msm_bus_set_vote(msm_host, 0);
+ else
+ pr_debug("Transfer in progress. Skipping bus voting to 0\n");
+}
+
+/*
+ * This function cancels any scheduled delayed work and sets the bus
+ * vote based on bw (bandwidth) argument.
+ */
+static void sdhci_msm_bus_cancel_work_and_set_vote(struct sdhci_host *host,
+ unsigned int bw)
+{
+ int vote;
+ struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+ struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
+
+ if (!msm_host->bus_vote_data->sdhc_ddr ||
+ !msm_host->bus_vote_data->cpu_sdhc)
+ return;
+ cancel_delayed_work_sync(&msm_host->bus_vote_work);
+ vote = sdhci_msm_bus_get_vote_for_bw(msm_host, bw);
+ sdhci_msm_bus_set_vote(msm_host, vote);
+}
+
+#define MSM_MMC_BUS_VOTING_DELAY 200 /* msecs */
+#define VOTE_ZERO 0
+
+/*
+ * This function queues a work which will set the bandwidth
+ * requirement to 0.
+ */
+static void sdhci_msm_bus_queue_work(struct sdhci_host *host)
+{
+ struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+ struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
+
+ if (msm_host->bus_vote_data->curr_vote != VOTE_ZERO)
+ queue_delayed_work(system_wq,
+ &msm_host->bus_vote_work,
+ msecs_to_jiffies(MSM_MMC_BUS_VOTING_DELAY));
+}
+
+static struct sdhci_msm_bus_vote_data *sdhci_msm_get_bus_vote_data(struct device
+ *dev, struct sdhci_msm_host *host)
+
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct device_node *of_node = dev->of_node;
+ struct sdhci_msm_bus_vote_data *bvd = NULL;
+ struct msm_bus_path *usecase = NULL;
+ int ret = 0, i = 0, j, num_paths, len;
+ const u32 *vec_arr = NULL;
+
+ if (!pdev) {
+ dev_err(dev, "Null platform device!\n");
+ return NULL;
+ }
+
+ bvd = devm_kzalloc(dev, sizeof(*bvd), GFP_KERNEL);
+ if (!bvd) {
+ ret = -ENOMEM;
+ return bvd;
+ }
+ ret = sdhci_msm_dt_get_array(dev, "bus-bw-vectors-bps",
+ &bvd->bw_vecs, &bvd->bw_vecs_size, 0);
+ if (ret) {
+ if (ret == -EINVAL) {
+ dev_dbg(dev, "No dt property of bus bw. voting defined!\n");
+ dev_dbg(dev, "Skipping Bus BW voting now!!\n");
+ host->skip_bus_bw_voting = true;
+ goto err;
+ }
+ goto out;
+ }
+
+ ret = of_property_read_string(of_node, "msm-bus,name", &bvd->name);
+ if (ret) {
+ dev_err(dev, "Bus name missing err:(%d)\n", ret);
+ goto out;
+ }
+
+ ret = of_property_read_u32(of_node, "msm-bus,num-cases",
+ &bvd->num_usecase);
+ if (ret) {
+ dev_err(dev, "num-usecases not found err:(%d)\n", ret);
+ goto out;
+ }
+
+ usecase = devm_kzalloc(dev, (sizeof(struct msm_bus_path) *
+ bvd->num_usecase), GFP_KERNEL);
+ if (!usecase)
+ goto out;
+
+ ret = of_property_read_u32(of_node, "msm-bus,num-paths",
+ &num_paths);
+ if (ret) {
+ dev_err(dev, "num_paths not found err:(%d)\n", ret);
+ goto out;
+ }
+
+ vec_arr = of_get_property(of_node, "msm-bus,vectors-KBps", &len);
+ if (!vec_arr) {
+ dev_err(dev, "Vector array not found\n");
+ goto out;
+ }
+
+ for (i = 0; i < bvd->num_usecase; i++) {
+ usecase[i].num_paths = num_paths;
+ usecase[i].vec = devm_kcalloc(dev, num_paths,
+ sizeof(struct msm_bus_vectors),
+ GFP_KERNEL);
+ if (!usecase[i].vec)
+ goto out;
+ for (j = 0; j < num_paths; j++) {
+ int idx = ((i * num_paths) + j) * 2;
+
+ usecase[i].vec[j].ab = (u64)
+ be32_to_cpu(vec_arr[idx]);
+ usecase[i].vec[j].ib = (u64)
+ be32_to_cpu(vec_arr[idx + 1]);
+ }
+ }
+
+ bvd->usecase = usecase;
+ return bvd;
+err:
+ devm_kfree(dev, bvd);
+out:
+ bvd = NULL;
+ return bvd;
+}
+
+static int sdhci_msm_bus_register(struct sdhci_msm_host *host,
+ struct platform_device *pdev)
+{
+ struct sdhci_msm_bus_vote_data *bsd;
+ struct device *dev = &pdev->dev;
+ int ret = 0;
+
+ bsd = sdhci_msm_get_bus_vote_data(dev, host);
+ if (!bsd) {
+ dev_err(&pdev->dev, "Failed to get bus_scale data\n");
+ return -EINVAL;
+ }
+ host->bus_vote_data = bsd;
+
+ bsd->sdhc_ddr = of_icc_get(&pdev->dev, "sdhc-ddr");
+ if (IS_ERR(bsd->sdhc_ddr)) {
+ dev_err(&pdev->dev, "(%ld): failed getting %s path\n",
+ PTR_ERR(bsd->sdhc_ddr), "sdhc-ddr");
+ ret = PTR_ERR(bsd->sdhc_ddr);
+ bsd->sdhc_ddr = NULL;
+ return ret;
+ }
+
+ bsd->cpu_sdhc = of_icc_get(&pdev->dev, "cpu-sdhc");
+ if (IS_ERR(bsd->cpu_sdhc)) {
+ dev_err(&pdev->dev, "(%ld): failed getting %s path\n",
+ PTR_ERR(bsd->cpu_sdhc), "cpu-sdhc");
+ ret = PTR_ERR(bsd->cpu_sdhc);
+ bsd->cpu_sdhc = NULL;
+ return ret;
+ }
+
+ INIT_DELAYED_WORK(&host->bus_vote_work, sdhci_msm_bus_work);
+
+ return ret;
+}
+
+static void sdhci_msm_bus_unregister(struct device *dev,
+ struct sdhci_msm_host *host)
+{
+ struct sdhci_msm_bus_vote_data *bsd = host->bus_vote_data;
+
+ icc_put(bsd->sdhc_ddr);
+ icc_put(bsd->cpu_sdhc);
+}
+
+static void sdhci_msm_bus_voting(struct sdhci_host *host, u32 enable)
+{
+ struct mmc_ios *ios = &host->mmc->ios;
+ unsigned int bw;
+
+ bw = sdhci_get_bw_required(host, ios);
+ if (enable)
+ sdhci_msm_bus_cancel_work_and_set_vote(host, bw);
+ else
+ sdhci_msm_bus_queue_work(host);
+}
+
static const struct sdhci_msm_variant_ops mci_var_ops = {
.msm_readl_relaxed = sdhci_msm_mci_variant_readl_relaxed,
.msm_writel_relaxed = sdhci_msm_mci_variant_writel_relaxed,
@@ -1839,6 +2181,15 @@ static int sdhci_msm_probe(struct platform_device *pdev)
dev_warn(&pdev->dev, "TCXO clk not present (%d)\n", ret);
}
+ ret = sdhci_msm_bus_register(msm_host, pdev);
+ if (ret && !msm_host->skip_bus_bw_voting) {
+ dev_err(&pdev->dev, "Bus registration failed (%d)\n", ret);
+ goto clk_disable;
+ }
+
+ if (!msm_host->skip_bus_bw_voting)
+ sdhci_msm_bus_voting(host, 1);
+
if (!msm_host->mci_removed) {
core_memres = platform_get_resource(pdev, IORESOURCE_MEM, 1);
msm_host->core_mem = devm_ioremap_resource(&pdev->dev,
@@ -1846,7 +2197,7 @@ static int sdhci_msm_probe(struct platform_device *pdev)
if (IS_ERR(msm_host->core_mem)) {
ret = PTR_ERR(msm_host->core_mem);
- goto clk_disable;
+ goto bus_unregister;
}
}
@@ -1918,7 +2269,7 @@ static int sdhci_msm_probe(struct platform_device *pdev)
msm_host->pwr_irq = platform_get_irq_byname(pdev, "pwr_irq");
if (msm_host->pwr_irq < 0) {
ret = msm_host->pwr_irq;
- goto clk_disable;
+ goto bus_unregister;
}
sdhci_msm_init_pwr_irq_wait(msm_host);
@@ -1931,7 +2282,7 @@ static int sdhci_msm_probe(struct platform_device *pdev)
dev_name(&pdev->dev), host);
if (ret) {
dev_err(&pdev->dev, "Request IRQ failed (%d)\n", ret);
- goto clk_disable;
+ goto bus_unregister;
}
pm_runtime_get_noresume(&pdev->dev);
@@ -1956,6 +2307,11 @@ static int sdhci_msm_probe(struct platform_device *pdev)
pm_runtime_disable(&pdev->dev);
pm_runtime_set_suspended(&pdev->dev);
pm_runtime_put_noidle(&pdev->dev);
+bus_unregister:
+ if (!msm_host->skip_bus_bw_voting) {
+ sdhci_msm_bus_cancel_work_and_set_vote(host, 0);
+ sdhci_msm_bus_unregister(&pdev->dev, msm_host);
+ }
clk_disable:
clk_bulk_disable_unprepare(ARRAY_SIZE(msm_host->bulk_clks),
msm_host->bulk_clks);
@@ -1985,6 +2341,10 @@ static int sdhci_msm_remove(struct platform_device *pdev)
msm_host->bulk_clks);
if (!IS_ERR(msm_host->bus_clk))
clk_disable_unprepare(msm_host->bus_clk);
+ if (!msm_host->skip_bus_bw_voting) {
+ sdhci_msm_bus_cancel_work_and_set_vote(host, 0);
+ sdhci_msm_bus_unregister(&pdev->dev, msm_host);
+ }
sdhci_pltfm_free(pdev);
return 0;
}
--
1.9.1
Hi Pradeep,
what is the status of this series, do you plan to send v3 soon or
is it abandonded?
Thanks
Matthias
On Fri, Nov 08, 2019 at 07:08:37PM +0530, Pradeep P V K wrote:
> Vote for the MSM bus bandwidth required by SDHC driver
> based on the clock speed and bus width of the card.
> Otherwise, the system clocks may run at minimum clock
> speed and thus affecting the performance.
>
> Adapt to the new ICB framework for bus bandwidth voting.
>
> This requires the source/destination port ids.
> Also this requires a tuple of values.
>
> The tuple is for two different paths - from SDHC master
> to BIMC slave. The other is from CPU master to SDHC slave.
> This tuple consists of the average and peak bandwidth.
>
> This change is based on Georgi Djakov [RFC]
> (https://lkml.org/lkml/2018/10/11/499)
>
> ---
> changed since v1:
> * Addressed all the Review comments.
> * Minor code rebasing.
>
> Pradeep P V K (2):
> dt-bindings: mmc: sdhci-msm: Add Bus BW vote supported strings
> mmc: sdhci-msm: Add support for bus bandwidth voting
>
> .../devicetree/bindings/mmc/sdhci-msm.txt | 32 ++
> drivers/mmc/host/sdhci-msm.c | 366 ++++++++++++++++++++-
> 2 files changed, 395 insertions(+), 3 deletions(-)
>
> --
> 1.9.1
>
Hi Matthias,
Will send my next series by end of this week.
Thanks and Regards,
Pradeep
On 2020-01-31 03:08, Matthias Kaehlcke wrote:
> Hi Pradeep,
>
> what is the status of this series, do you plan to send v3 soon or
> is it abandonded?
>
> Thanks
>
> Matthias
>
> On Fri, Nov 08, 2019 at 07:08:37PM +0530, Pradeep P V K wrote:
>> Vote for the MSM bus bandwidth required by SDHC driver
>> based on the clock speed and bus width of the card.
>> Otherwise, the system clocks may run at minimum clock
>> speed and thus affecting the performance.
>>
>> Adapt to the new ICB framework for bus bandwidth voting.
>>
>> This requires the source/destination port ids.
>> Also this requires a tuple of values.
>>
>> The tuple is for two different paths - from SDHC master
>> to BIMC slave. The other is from CPU master to SDHC slave.
>> This tuple consists of the average and peak bandwidth.
>>
>> This change is based on Georgi Djakov [RFC]
>> (https://lkml.org/lkml/2018/10/11/499)
>>
>> ---
>> changed since v1:
>> * Addressed all the Review comments.
>> * Minor code rebasing.
>>
>> Pradeep P V K (2):
>> dt-bindings: mmc: sdhci-msm: Add Bus BW vote supported strings
>> mmc: sdhci-msm: Add support for bus bandwidth voting
>>
>> .../devicetree/bindings/mmc/sdhci-msm.txt | 32 ++
>> drivers/mmc/host/sdhci-msm.c | 366
>> ++++++++++++++++++++-
>> 2 files changed, 395 insertions(+), 3 deletions(-)
>>
>> --
>> 1.9.1
>>
Hi,
On Fri, Nov 8, 2019 at 5:45 AM Pradeep P V K <[email protected]> wrote:
>
> + if (msm_host->bus_vote_data->curr_vote != VOTE_ZERO)
> + queue_delayed_work(system_wq,
> + &msm_host->bus_vote_work,
> + msecs_to_jiffies(MSM_MMC_BUS_VOTING_DELAY));
> +}
Drive-by feedback here without any full review of your patch...
Someone had your patch applied and sent me a stack trace with a
warning on it. That warning showed:
workqueue: WQ_MEM_RECLAIM kblockd:blk_mq_run_work_fn is flushing
!WQ_MEM_RECLAIM events:sdhci_msm_bus_work
The trace shown was:
check_flush_dependency+0x108/0x110
__flush_work+0xa8/0x1e8
__cancel_work_timer+0x130/0x1c4
cancel_delayed_work_sync+0x20/0x30
sdhci_msm_bus_cancel_work_and_set_vote+0x3c/0x8c
sdhci_msm_bus_voting+0x40/0x7c
sdhci_msm_runtime_resume+0xdc/0xf4
pm_generic_runtime_resume+0x34/0x48
__rpm_callback+0x70/0xfc
rpm_callback+0x5c/0x8c
rpm_resume+0x3fc/0x534
__pm_runtime_resume+0x7c/0xa0
__mmc_claim_host+0x1f4/0x230
mmc_get_card+0x34/0x40
mmc_mq_queue_rq+0x18c/0x244
blk_mq_dispatch_rq_list+0x27c/0x560
blk_mq_do_dispatch_sched+0xe0/0x140
blk_mq_sched_dispatch_requests+0x138/0x1b8
__blk_mq_run_hw_queue+0xc0/0x118
blk_mq_run_work_fn+0x24/0x30
I believe the way to interpret this is that you need to be running
your work on a workqueue marked for memory reclaim. That means you
can't use the system_wq to queue your work. Without being an expert,
a quick guess would be that you should be queueing your work on the
"kblockd_workqueue" using one of the functions for this.
-Doug
Hi Doug,
You no longer seeing this warning stack with the latest patch set.
https://lkml.org/lkml/2020/3/23/407
The latest patch set is based on OPP framework and no workqueue's used to queue the work.
Can you give a try with the latest patch and check if this helps ?
Thanks and Regards,
Pradeep
-----Original Message-----
From: Doug Anderson <[email protected]>
Sent: Friday, April 3, 2020 10:34 PM
To: Pradeep P V K <[email protected]>
Cc: Adrian Hunter <[email protected]>; Georgi Djakov <[email protected]>; Rob Herring <[email protected]>; Ulf Hansson <[email protected]>; Asutosh Das <[email protected]>; Veerabhadrarao Badiganti <[email protected]>; Sahitya Tummala <[email protected]>; Sayali Lokhande <[email protected]>; Ram Prakash Gupta <[email protected]>; Stephen Boyd <[email protected]>; Linux MMC List <[email protected]>; LKML <[email protected]>; linux-arm-msm <[email protected]>; open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS <[email protected]>; Andy Gross <[email protected]>; [email protected]; Subhash Jadavani <[email protected]>
Subject: Re: [RFC-v2 2/2] mmc: sdhci-msm: Add support for bus bandwidth voting
Hi,
On Fri, Nov 8, 2019 at 5:45 AM Pradeep P V K <[email protected]> wrote:
>
> + if (msm_host->bus_vote_data->curr_vote != VOTE_ZERO)
> + queue_delayed_work(system_wq,
> + &msm_host->bus_vote_work,
> +
> +msecs_to_jiffies(MSM_MMC_BUS_VOTING_DELAY));
> +}
Drive-by feedback here without any full review of your patch...
Someone had your patch applied and sent me a stack trace with a warning on it. That warning showed:
workqueue: WQ_MEM_RECLAIM kblockd:blk_mq_run_work_fn is flushing !WQ_MEM_RECLAIM events:sdhci_msm_bus_work
The trace shown was:
check_flush_dependency+0x108/0x110
__flush_work+0xa8/0x1e8
__cancel_work_timer+0x130/0x1c4
cancel_delayed_work_sync+0x20/0x30
sdhci_msm_bus_cancel_work_and_set_vote+0x3c/0x8c
sdhci_msm_bus_voting+0x40/0x7c
sdhci_msm_runtime_resume+0xdc/0xf4
pm_generic_runtime_resume+0x34/0x48
__rpm_callback+0x70/0xfc
rpm_callback+0x5c/0x8c
rpm_resume+0x3fc/0x534
__pm_runtime_resume+0x7c/0xa0
__mmc_claim_host+0x1f4/0x230
mmc_get_card+0x34/0x40
mmc_mq_queue_rq+0x18c/0x244
blk_mq_dispatch_rq_list+0x27c/0x560
blk_mq_do_dispatch_sched+0xe0/0x140
blk_mq_sched_dispatch_requests+0x138/0x1b8
__blk_mq_run_hw_queue+0xc0/0x118
blk_mq_run_work_fn+0x24/0x30
I believe the way to interpret this is that you need to be running your work on a workqueue marked for memory reclaim. That means you can't use the system_wq to queue your work. Without being an expert, a quick guess would be that you should be queueing your work on the "kblockd_workqueue" using one of the functions for this.
-Doug
Hi,
On Wed, Apr 8, 2020 at 5:58 AM <[email protected]> wrote:
>
> Hi Doug,
>
> You no longer seeing this warning stack with the latest patch set.
> https://lkml.org/lkml/2020/3/23/407
>
> The latest patch set is based on OPP framework and no workqueue's used to queue the work.
> Can you give a try with the latest patch and check if this helps ?
I was only analyzing an error log provided by someone else. I will
let them know that they should make sure they're on the latest patch
series.
-Doug