* [PATCH] iommu/arm-smmu-v3: Poll for CMDQ drain completion more effectively @ 2017-04-27 11:13 sunil.kovvuri 2017-05-03 13:19 ` Sunil Kovvuri 2017-05-03 15:33 ` Robin Murphy 0 siblings, 2 replies; 9+ messages in thread From: sunil.kovvuri @ 2017-04-27 11:13 UTC (permalink / raw) To: will.deacon, robin.murphy, iommu Cc: linux-kernel, linux-arm-kernel, robert.richter, jcm, Sunil Goutham, Geetha From: Sunil Goutham <sgoutham@cavium.com> Modified polling on CMDQ consumer similar to how polling is done for TLB SYNC completion in SMMUv2 driver. Code changes are done with reference to 8513c8930069 iommu/arm-smmu: Poll for TLB sync completion more effectively Poll timeout has been increased which addresses issue of 100us timeout not sufficient, when command queue is full with TLB invalidation commands. Signed-off-by: Sunil Goutham <sgoutham@cavium.com> Signed-off-by: Geetha <gakula@cavium.com> --- drivers/iommu/arm-smmu-v3.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c index d412bdd..34599d4 100644 --- a/drivers/iommu/arm-smmu-v3.c +++ b/drivers/iommu/arm-smmu-v3.c @@ -379,6 +379,9 @@ #define CMDQ_SYNC_0_CS_NONE (0UL << CMDQ_SYNC_0_CS_SHIFT) #define CMDQ_SYNC_0_CS_SEV (2UL << CMDQ_SYNC_0_CS_SHIFT) +#define CMDQ_DRAIN_TIMEOUT_US 1000 +#define CMDQ_SPIN_COUNT 10 + /* Event queue */ #define EVTQ_ENT_DWORDS 4 #define EVTQ_MAX_SZ_SHIFT 7 @@ -737,7 +740,8 @@ static void queue_inc_prod(struct arm_smmu_queue *q) */ static int queue_poll_cons(struct arm_smmu_queue *q, bool drain, bool wfe) { - ktime_t timeout = ktime_add_us(ktime_get(), ARM_SMMU_POLL_TIMEOUT_US); + ktime_t timeout = ktime_add_us(ktime_get(), CMDQ_DRAIN_TIMEOUT_US); + unsigned int spin_cnt, delay = 1; while (queue_sync_cons(q), (drain ? !queue_empty(q) : queue_full(q))) { if (ktime_compare(ktime_get(), timeout) > 0) @@ -746,8 +750,13 @@ static int queue_poll_cons(struct arm_smmu_queue *q, bool drain, bool wfe) if (wfe) { wfe(); } else { - cpu_relax(); - udelay(1); + for (spin_cnt = 0; + spin_cnt < CMDQ_SPIN_COUNT; spin_cnt++) { + cpu_relax(); + continue; + } + udelay(delay); + delay *= 2; } } -- 2.7.4 ^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH] iommu/arm-smmu-v3: Poll for CMDQ drain completion more effectively 2017-04-27 11:13 [PATCH] iommu/arm-smmu-v3: Poll for CMDQ drain completion more effectively sunil.kovvuri @ 2017-05-03 13:19 ` Sunil Kovvuri 2017-05-03 15:37 ` Will Deacon 2017-05-03 15:33 ` Robin Murphy 1 sibling, 1 reply; 9+ messages in thread From: Sunil Kovvuri @ 2017-05-03 13:19 UTC (permalink / raw) To: Will Deacon, Robin Murphy, iommu Cc: LKML, LAKML, Robert Richter, jcm, Sunil Goutham, Geetha On Thu, Apr 27, 2017 at 4:43 PM, <sunil.kovvuri@gmail.com> wrote: > From: Sunil Goutham <sgoutham@cavium.com> > > Modified polling on CMDQ consumer similar to how polling is done for TLB SYNC > completion in SMMUv2 driver. Code changes are done with reference to > > 8513c8930069 iommu/arm-smmu: Poll for TLB sync completion more effectively > > Poll timeout has been increased which addresses issue of 100us timeout not > sufficient, when command queue is full with TLB invalidation commands. > > Signed-off-by: Sunil Goutham <sgoutham@cavium.com> > Signed-off-by: Geetha <gakula@cavium.com> > --- > drivers/iommu/arm-smmu-v3.c | 15 ++++++++++++--- > 1 file changed, 12 insertions(+), 3 deletions(-) > > diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c > index d412bdd..34599d4 100644 > --- a/drivers/iommu/arm-smmu-v3.c > +++ b/drivers/iommu/arm-smmu-v3.c > @@ -379,6 +379,9 @@ > #define CMDQ_SYNC_0_CS_NONE (0UL << CMDQ_SYNC_0_CS_SHIFT) > #define CMDQ_SYNC_0_CS_SEV (2UL << CMDQ_SYNC_0_CS_SHIFT) > > +#define CMDQ_DRAIN_TIMEOUT_US 1000 > +#define CMDQ_SPIN_COUNT 10 > + > /* Event queue */ > #define EVTQ_ENT_DWORDS 4 > #define EVTQ_MAX_SZ_SHIFT 7 > @@ -737,7 +740,8 @@ static void queue_inc_prod(struct arm_smmu_queue *q) > */ > static int queue_poll_cons(struct arm_smmu_queue *q, bool drain, bool wfe) > { > - ktime_t timeout = ktime_add_us(ktime_get(), ARM_SMMU_POLL_TIMEOUT_US); > + ktime_t timeout = ktime_add_us(ktime_get(), CMDQ_DRAIN_TIMEOUT_US); > + unsigned int spin_cnt, delay = 1; > > while (queue_sync_cons(q), (drain ? !queue_empty(q) : queue_full(q))) { > if (ktime_compare(ktime_get(), timeout) > 0) > @@ -746,8 +750,13 @@ static int queue_poll_cons(struct arm_smmu_queue *q, bool drain, bool wfe) > if (wfe) { > wfe(); > } else { > - cpu_relax(); > - udelay(1); > + for (spin_cnt = 0; > + spin_cnt < CMDQ_SPIN_COUNT; spin_cnt++) { > + cpu_relax(); > + continue; > + } > + udelay(delay); > + delay *= 2; > } > } > > -- > 2.7.4 > Sorry for the ignorance. Is there a patchwork where I can check current status of ARM IOMMU related patches ? And is this patch accepted, if not any comments / feedback ? Thanks, Sunil. ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] iommu/arm-smmu-v3: Poll for CMDQ drain completion more effectively 2017-05-03 13:19 ` Sunil Kovvuri @ 2017-05-03 15:37 ` Will Deacon 2017-05-03 15:54 ` Sunil Kovvuri 0 siblings, 1 reply; 9+ messages in thread From: Will Deacon @ 2017-05-03 15:37 UTC (permalink / raw) To: Sunil Kovvuri Cc: Robin Murphy, iommu, LKML, LAKML, Robert Richter, jcm, Sunil Goutham, Geetha On Wed, May 03, 2017 at 06:49:09PM +0530, Sunil Kovvuri wrote: > On Thu, Apr 27, 2017 at 4:43 PM, <sunil.kovvuri@gmail.com> wrote: > > From: Sunil Goutham <sgoutham@cavium.com> > > > > Modified polling on CMDQ consumer similar to how polling is done for TLB SYNC > > completion in SMMUv2 driver. Code changes are done with reference to > > > > 8513c8930069 iommu/arm-smmu: Poll for TLB sync completion more effectively > > > > Poll timeout has been increased which addresses issue of 100us timeout not > > sufficient, when command queue is full with TLB invalidation commands. > > > > Signed-off-by: Sunil Goutham <sgoutham@cavium.com> > > Signed-off-by: Geetha <gakula@cavium.com> > > --- > > drivers/iommu/arm-smmu-v3.c | 15 ++++++++++++--- > > 1 file changed, 12 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c > > index d412bdd..34599d4 100644 > > --- a/drivers/iommu/arm-smmu-v3.c > > +++ b/drivers/iommu/arm-smmu-v3.c > > @@ -379,6 +379,9 @@ > > #define CMDQ_SYNC_0_CS_NONE (0UL << CMDQ_SYNC_0_CS_SHIFT) > > #define CMDQ_SYNC_0_CS_SEV (2UL << CMDQ_SYNC_0_CS_SHIFT) > > > > +#define CMDQ_DRAIN_TIMEOUT_US 1000 > > +#define CMDQ_SPIN_COUNT 10 > > + > > /* Event queue */ > > #define EVTQ_ENT_DWORDS 4 > > #define EVTQ_MAX_SZ_SHIFT 7 > > @@ -737,7 +740,8 @@ static void queue_inc_prod(struct arm_smmu_queue *q) > > */ > > static int queue_poll_cons(struct arm_smmu_queue *q, bool drain, bool wfe) > > { > > - ktime_t timeout = ktime_add_us(ktime_get(), ARM_SMMU_POLL_TIMEOUT_US); > > + ktime_t timeout = ktime_add_us(ktime_get(), CMDQ_DRAIN_TIMEOUT_US); > > + unsigned int spin_cnt, delay = 1; > > > > while (queue_sync_cons(q), (drain ? !queue_empty(q) : queue_full(q))) { > > if (ktime_compare(ktime_get(), timeout) > 0) > > @@ -746,8 +750,13 @@ static int queue_poll_cons(struct arm_smmu_queue *q, bool drain, bool wfe) > > if (wfe) { > > wfe(); > > } else { > > - cpu_relax(); > > - udelay(1); > > + for (spin_cnt = 0; > > + spin_cnt < CMDQ_SPIN_COUNT; spin_cnt++) { > > + cpu_relax(); > > + continue; > > + } > > + udelay(delay); > > + delay *= 2; > > } > > } > > > > -- > > 2.7.4 > > > > Sorry for the ignorance. > Is there a patchwork where I can check current status of ARM IOMMU > related patches ? > > And is this patch accepted, if not any comments / feedback ? Please be patient: the merge window is open and it's not been long since you posted the patch, which looks pretty bonkers at first glance. Will ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] iommu/arm-smmu-v3: Poll for CMDQ drain completion more effectively 2017-05-03 15:37 ` Will Deacon @ 2017-05-03 15:54 ` Sunil Kovvuri 2017-05-03 15:59 ` Will Deacon 0 siblings, 1 reply; 9+ messages in thread From: Sunil Kovvuri @ 2017-05-03 15:54 UTC (permalink / raw) To: Will Deacon Cc: Robin Murphy, iommu, LKML, LAKML, Robert Richter, jcm, Sunil Goutham, Geetha On Wed, May 3, 2017 at 9:07 PM, Will Deacon <will.deacon@arm.com> wrote: > On Wed, May 03, 2017 at 06:49:09PM +0530, Sunil Kovvuri wrote: >> On Thu, Apr 27, 2017 at 4:43 PM, <sunil.kovvuri@gmail.com> wrote: >> > From: Sunil Goutham <sgoutham@cavium.com> >> > >> > Modified polling on CMDQ consumer similar to how polling is done for TLB SYNC >> > completion in SMMUv2 driver. Code changes are done with reference to >> > >> > 8513c8930069 iommu/arm-smmu: Poll for TLB sync completion more effectively >> > >> > Poll timeout has been increased which addresses issue of 100us timeout not >> > sufficient, when command queue is full with TLB invalidation commands. >> > >> > Signed-off-by: Sunil Goutham <sgoutham@cavium.com> >> > Signed-off-by: Geetha <gakula@cavium.com> >> > --- >> > drivers/iommu/arm-smmu-v3.c | 15 ++++++++++++--- >> > 1 file changed, 12 insertions(+), 3 deletions(-) >> > >> > diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c >> > index d412bdd..34599d4 100644 >> > --- a/drivers/iommu/arm-smmu-v3.c >> > +++ b/drivers/iommu/arm-smmu-v3.c >> > @@ -379,6 +379,9 @@ >> > #define CMDQ_SYNC_0_CS_NONE (0UL << CMDQ_SYNC_0_CS_SHIFT) >> > #define CMDQ_SYNC_0_CS_SEV (2UL << CMDQ_SYNC_0_CS_SHIFT) >> > >> > +#define CMDQ_DRAIN_TIMEOUT_US 1000 >> > +#define CMDQ_SPIN_COUNT 10 >> > + >> > /* Event queue */ >> > #define EVTQ_ENT_DWORDS 4 >> > #define EVTQ_MAX_SZ_SHIFT 7 >> > @@ -737,7 +740,8 @@ static void queue_inc_prod(struct arm_smmu_queue *q) >> > */ >> > static int queue_poll_cons(struct arm_smmu_queue *q, bool drain, bool wfe) >> > { >> > - ktime_t timeout = ktime_add_us(ktime_get(), ARM_SMMU_POLL_TIMEOUT_US); >> > + ktime_t timeout = ktime_add_us(ktime_get(), CMDQ_DRAIN_TIMEOUT_US); >> > + unsigned int spin_cnt, delay = 1; >> > >> > while (queue_sync_cons(q), (drain ? !queue_empty(q) : queue_full(q))) { >> > if (ktime_compare(ktime_get(), timeout) > 0) >> > @@ -746,8 +750,13 @@ static int queue_poll_cons(struct arm_smmu_queue *q, bool drain, bool wfe) >> > if (wfe) { >> > wfe(); >> > } else { >> > - cpu_relax(); >> > - udelay(1); >> > + for (spin_cnt = 0; >> > + spin_cnt < CMDQ_SPIN_COUNT; spin_cnt++) { >> > + cpu_relax(); >> > + continue; >> > + } >> > + udelay(delay); >> > + delay *= 2; >> > } >> > } >> > >> > -- >> > 2.7.4 >> > >> >> Sorry for the ignorance. >> Is there a patchwork where I can check current status of ARM IOMMU >> related patches ? >> >> And is this patch accepted, if not any comments / feedback ? > > Please be patient: the merge window is open and it's not been long since you > posted the patch, which looks pretty bonkers at first glance. > > Will Look at this https://lkml.org/lkml/2017/4/3/605 The same thing, i pinged after a week and you said you already picked it up. All I am asking is how do i know the current status, how many days would normally be considered being patient ? Instead of troubling you, is there a patchwork where i can check the status ? Thanks, Sunil. ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] iommu/arm-smmu-v3: Poll for CMDQ drain completion more effectively 2017-05-03 15:54 ` Sunil Kovvuri @ 2017-05-03 15:59 ` Will Deacon 2017-05-03 16:24 ` Sunil Kovvuri 0 siblings, 1 reply; 9+ messages in thread From: Will Deacon @ 2017-05-03 15:59 UTC (permalink / raw) To: Sunil Kovvuri Cc: Robin Murphy, iommu, LKML, LAKML, Robert Richter, jcm, Sunil Goutham, Geetha On Wed, May 03, 2017 at 09:24:13PM +0530, Sunil Kovvuri wrote: > On Wed, May 3, 2017 at 9:07 PM, Will Deacon <will.deacon@arm.com> wrote: > > On Wed, May 03, 2017 at 06:49:09PM +0530, Sunil Kovvuri wrote: > >> On Thu, Apr 27, 2017 at 4:43 PM, <sunil.kovvuri@gmail.com> wrote: > >> > From: Sunil Goutham <sgoutham@cavium.com> > >> > > >> > Modified polling on CMDQ consumer similar to how polling is done for TLB SYNC > >> > completion in SMMUv2 driver. Code changes are done with reference to > >> > > >> > 8513c8930069 iommu/arm-smmu: Poll for TLB sync completion more effectively > >> > > >> > Poll timeout has been increased which addresses issue of 100us timeout not > >> > sufficient, when command queue is full with TLB invalidation commands. > >> > > >> > Signed-off-by: Sunil Goutham <sgoutham@cavium.com> > >> > Signed-off-by: Geetha <gakula@cavium.com> > >> > --- > >> > drivers/iommu/arm-smmu-v3.c | 15 ++++++++++++--- > >> > 1 file changed, 12 insertions(+), 3 deletions(-) > >> > > >> > diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c > >> > index d412bdd..34599d4 100644 > >> > --- a/drivers/iommu/arm-smmu-v3.c > >> > +++ b/drivers/iommu/arm-smmu-v3.c > >> > @@ -379,6 +379,9 @@ > >> > #define CMDQ_SYNC_0_CS_NONE (0UL << CMDQ_SYNC_0_CS_SHIFT) > >> > #define CMDQ_SYNC_0_CS_SEV (2UL << CMDQ_SYNC_0_CS_SHIFT) > >> > > >> > +#define CMDQ_DRAIN_TIMEOUT_US 1000 > >> > +#define CMDQ_SPIN_COUNT 10 > >> > + > >> > /* Event queue */ > >> > #define EVTQ_ENT_DWORDS 4 > >> > #define EVTQ_MAX_SZ_SHIFT 7 > >> > @@ -737,7 +740,8 @@ static void queue_inc_prod(struct arm_smmu_queue *q) > >> > */ > >> > static int queue_poll_cons(struct arm_smmu_queue *q, bool drain, bool wfe) > >> > { > >> > - ktime_t timeout = ktime_add_us(ktime_get(), ARM_SMMU_POLL_TIMEOUT_US); > >> > + ktime_t timeout = ktime_add_us(ktime_get(), CMDQ_DRAIN_TIMEOUT_US); > >> > + unsigned int spin_cnt, delay = 1; > >> > > >> > while (queue_sync_cons(q), (drain ? !queue_empty(q) : queue_full(q))) { > >> > if (ktime_compare(ktime_get(), timeout) > 0) > >> > @@ -746,8 +750,13 @@ static int queue_poll_cons(struct arm_smmu_queue *q, bool drain, bool wfe) > >> > if (wfe) { > >> > wfe(); > >> > } else { > >> > - cpu_relax(); > >> > - udelay(1); > >> > + for (spin_cnt = 0; > >> > + spin_cnt < CMDQ_SPIN_COUNT; spin_cnt++) { > >> > + cpu_relax(); > >> > + continue; > >> > + } > >> > + udelay(delay); > >> > + delay *= 2; > >> > } > >> > } > >> > > >> > -- > >> > 2.7.4 > >> > > >> > >> Sorry for the ignorance. > >> Is there a patchwork where I can check current status of ARM IOMMU > >> related patches ? > >> > >> And is this patch accepted, if not any comments / feedback ? > > > > Please be patient: the merge window is open and it's not been long since you > > posted the patch, which looks pretty bonkers at first glance. > > > > Will > > Look at this > https://lkml.org/lkml/2017/4/3/605 > The same thing, i pinged after a week and you said you already picked it up. > All I am asking is how do i know the current status, how many days > would normally > be considered being patient ? At least wait until the merge window is over if it's not a fix, or keep an eye on the relevant branches (see below). > Instead of troubling you, is there a patchwork where i can check the status ? No, but I pick patches up on my iommu/devel branch here: https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git/ and at some point they appear on for-joerg/arm-smmu/updates, which I send to Joerg (who is the iommu maintainer). He then puts them into linux-next before they get sent for inclusion in mainline during the next merge window. Will ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] iommu/arm-smmu-v3: Poll for CMDQ drain completion more effectively 2017-05-03 15:59 ` Will Deacon @ 2017-05-03 16:24 ` Sunil Kovvuri 0 siblings, 0 replies; 9+ messages in thread From: Sunil Kovvuri @ 2017-05-03 16:24 UTC (permalink / raw) To: Will Deacon Cc: Robin Murphy, iommu, LKML, LAKML, Robert Richter, jcm, Sunil Goutham, Geetha On Wed, May 3, 2017 at 9:29 PM, Will Deacon <will.deacon@arm.com> wrote: > On Wed, May 03, 2017 at 09:24:13PM +0530, Sunil Kovvuri wrote: >> On Wed, May 3, 2017 at 9:07 PM, Will Deacon <will.deacon@arm.com> wrote: >> > On Wed, May 03, 2017 at 06:49:09PM +0530, Sunil Kovvuri wrote: >> >> On Thu, Apr 27, 2017 at 4:43 PM, <sunil.kovvuri@gmail.com> wrote: >> >> > From: Sunil Goutham <sgoutham@cavium.com> >> >> > >> >> > Modified polling on CMDQ consumer similar to how polling is done for TLB SYNC >> >> > completion in SMMUv2 driver. Code changes are done with reference to >> >> > >> >> > 8513c8930069 iommu/arm-smmu: Poll for TLB sync completion more effectively >> >> > >> >> > Poll timeout has been increased which addresses issue of 100us timeout not >> >> > sufficient, when command queue is full with TLB invalidation commands. >> >> > >> >> > Signed-off-by: Sunil Goutham <sgoutham@cavium.com> >> >> > Signed-off-by: Geetha <gakula@cavium.com> >> >> > --- >> >> > drivers/iommu/arm-smmu-v3.c | 15 ++++++++++++--- >> >> > 1 file changed, 12 insertions(+), 3 deletions(-) >> >> > >> >> > diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c >> >> > index d412bdd..34599d4 100644 >> >> > --- a/drivers/iommu/arm-smmu-v3.c >> >> > +++ b/drivers/iommu/arm-smmu-v3.c >> >> > @@ -379,6 +379,9 @@ >> >> > #define CMDQ_SYNC_0_CS_NONE (0UL << CMDQ_SYNC_0_CS_SHIFT) >> >> > #define CMDQ_SYNC_0_CS_SEV (2UL << CMDQ_SYNC_0_CS_SHIFT) >> >> > >> >> > +#define CMDQ_DRAIN_TIMEOUT_US 1000 >> >> > +#define CMDQ_SPIN_COUNT 10 >> >> > + >> >> > /* Event queue */ >> >> > #define EVTQ_ENT_DWORDS 4 >> >> > #define EVTQ_MAX_SZ_SHIFT 7 >> >> > @@ -737,7 +740,8 @@ static void queue_inc_prod(struct arm_smmu_queue *q) >> >> > */ >> >> > static int queue_poll_cons(struct arm_smmu_queue *q, bool drain, bool wfe) >> >> > { >> >> > - ktime_t timeout = ktime_add_us(ktime_get(), ARM_SMMU_POLL_TIMEOUT_US); >> >> > + ktime_t timeout = ktime_add_us(ktime_get(), CMDQ_DRAIN_TIMEOUT_US); >> >> > + unsigned int spin_cnt, delay = 1; >> >> > >> >> > while (queue_sync_cons(q), (drain ? !queue_empty(q) : queue_full(q))) { >> >> > if (ktime_compare(ktime_get(), timeout) > 0) >> >> > @@ -746,8 +750,13 @@ static int queue_poll_cons(struct arm_smmu_queue *q, bool drain, bool wfe) >> >> > if (wfe) { >> >> > wfe(); >> >> > } else { >> >> > - cpu_relax(); >> >> > - udelay(1); >> >> > + for (spin_cnt = 0; >> >> > + spin_cnt < CMDQ_SPIN_COUNT; spin_cnt++) { >> >> > + cpu_relax(); >> >> > + continue; >> >> > + } >> >> > + udelay(delay); >> >> > + delay *= 2; >> >> > } >> >> > } >> >> > >> >> > -- >> >> > 2.7.4 >> >> > >> >> >> >> Sorry for the ignorance. >> >> Is there a patchwork where I can check current status of ARM IOMMU >> >> related patches ? >> >> >> >> And is this patch accepted, if not any comments / feedback ? >> > >> > Please be patient: the merge window is open and it's not been long since you >> > posted the patch, which looks pretty bonkers at first glance. >> > >> > Will >> >> Look at this >> https://lkml.org/lkml/2017/4/3/605 >> The same thing, i pinged after a week and you said you already picked it up. >> All I am asking is how do i know the current status, how many days >> would normally >> be considered being patient ? > > At least wait until the merge window is over if it's not a fix, or keep an > eye on the relevant branches (see below). > >> Instead of troubling you, is there a patchwork where i can check the status ? > > No, but I pick patches up on my iommu/devel branch here: > > https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git/ > > and at some point they appear on for-joerg/arm-smmu/updates, which I send > to Joerg (who is the iommu maintainer). He then puts them into linux-next > before they get sent for inclusion in mainline during the next merge window. > > Will Thanks for the info. Sunil. ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] iommu/arm-smmu-v3: Poll for CMDQ drain completion more effectively 2017-04-27 11:13 [PATCH] iommu/arm-smmu-v3: Poll for CMDQ drain completion more effectively sunil.kovvuri 2017-05-03 13:19 ` Sunil Kovvuri @ 2017-05-03 15:33 ` Robin Murphy 2017-05-03 15:40 ` Will Deacon 1 sibling, 1 reply; 9+ messages in thread From: Robin Murphy @ 2017-05-03 15:33 UTC (permalink / raw) To: sunil.kovvuri, will.deacon, iommu Cc: linux-kernel, linux-arm-kernel, robert.richter, jcm, Sunil Goutham, Geetha On 27/04/17 12:13, sunil.kovvuri@gmail.com wrote: > From: Sunil Goutham <sgoutham@cavium.com> > > Modified polling on CMDQ consumer similar to how polling is done for TLB SYNC > completion in SMMUv2 driver. Code changes are done with reference to > > 8513c8930069 iommu/arm-smmu: Poll for TLB sync completion more effectively > > Poll timeout has been increased which addresses issue of 100us timeout not > sufficient, when command queue is full with TLB invalidation commands. > > Signed-off-by: Sunil Goutham <sgoutham@cavium.com> > Signed-off-by: Geetha <gakula@cavium.com> > --- > drivers/iommu/arm-smmu-v3.c | 15 ++++++++++++--- > 1 file changed, 12 insertions(+), 3 deletions(-) > > diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c > index d412bdd..34599d4 100644 > --- a/drivers/iommu/arm-smmu-v3.c > +++ b/drivers/iommu/arm-smmu-v3.c > @@ -379,6 +379,9 @@ > #define CMDQ_SYNC_0_CS_NONE (0UL << CMDQ_SYNC_0_CS_SHIFT) > #define CMDQ_SYNC_0_CS_SEV (2UL << CMDQ_SYNC_0_CS_SHIFT) > > +#define CMDQ_DRAIN_TIMEOUT_US 1000 > +#define CMDQ_SPIN_COUNT 10 > + > /* Event queue */ > #define EVTQ_ENT_DWORDS 4 > #define EVTQ_MAX_SZ_SHIFT 7 > @@ -737,7 +740,8 @@ static void queue_inc_prod(struct arm_smmu_queue *q) > */ > static int queue_poll_cons(struct arm_smmu_queue *q, bool drain, bool wfe) > { > - ktime_t timeout = ktime_add_us(ktime_get(), ARM_SMMU_POLL_TIMEOUT_US); > + ktime_t timeout = ktime_add_us(ktime_get(), CMDQ_DRAIN_TIMEOUT_US); > + unsigned int spin_cnt, delay = 1; > > while (queue_sync_cons(q), (drain ? !queue_empty(q) : queue_full(q))) { > if (ktime_compare(ktime_get(), timeout) > 0) > @@ -746,8 +750,13 @@ static int queue_poll_cons(struct arm_smmu_queue *q, bool drain, bool wfe) > if (wfe) { > wfe(); > } else { > - cpu_relax(); > - udelay(1); > + for (spin_cnt = 0; > + spin_cnt < CMDQ_SPIN_COUNT; spin_cnt++) { > + cpu_relax(); > + continue; > + } > + udelay(delay); > + delay *= 2; Sorry, I can't make sense of this. The referenced commit uses the spin loop to poll opportunistically a few times before delaying. This loop just adds a short open-coded udelay to an exponential udelay, and it's not really clear that that's any better than a fixed udelay (especially as the two cases in which we poll are somewhat different). What's wrong with simply increasing the timeout value alone? Robin. > } > } > > ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] iommu/arm-smmu-v3: Poll for CMDQ drain completion more effectively 2017-05-03 15:33 ` Robin Murphy @ 2017-05-03 15:40 ` Will Deacon 2017-05-03 16:23 ` Sunil Kovvuri 0 siblings, 1 reply; 9+ messages in thread From: Will Deacon @ 2017-05-03 15:40 UTC (permalink / raw) To: Robin Murphy Cc: sunil.kovvuri, iommu, linux-kernel, linux-arm-kernel, robert.richter, jcm, Sunil Goutham, Geetha On Wed, May 03, 2017 at 04:33:57PM +0100, Robin Murphy wrote: > On 27/04/17 12:13, sunil.kovvuri@gmail.com wrote: > > From: Sunil Goutham <sgoutham@cavium.com> > > > > Modified polling on CMDQ consumer similar to how polling is done for TLB SYNC > > completion in SMMUv2 driver. Code changes are done with reference to > > > > 8513c8930069 iommu/arm-smmu: Poll for TLB sync completion more effectively > > > > Poll timeout has been increased which addresses issue of 100us timeout not > > sufficient, when command queue is full with TLB invalidation commands. > > > > Signed-off-by: Sunil Goutham <sgoutham@cavium.com> > > Signed-off-by: Geetha <gakula@cavium.com> > > --- > > drivers/iommu/arm-smmu-v3.c | 15 ++++++++++++--- > > 1 file changed, 12 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c > > index d412bdd..34599d4 100644 > > --- a/drivers/iommu/arm-smmu-v3.c > > +++ b/drivers/iommu/arm-smmu-v3.c > > @@ -379,6 +379,9 @@ > > #define CMDQ_SYNC_0_CS_NONE (0UL << CMDQ_SYNC_0_CS_SHIFT) > > #define CMDQ_SYNC_0_CS_SEV (2UL << CMDQ_SYNC_0_CS_SHIFT) > > > > +#define CMDQ_DRAIN_TIMEOUT_US 1000 > > +#define CMDQ_SPIN_COUNT 10 > > + > > /* Event queue */ > > #define EVTQ_ENT_DWORDS 4 > > #define EVTQ_MAX_SZ_SHIFT 7 > > @@ -737,7 +740,8 @@ static void queue_inc_prod(struct arm_smmu_queue *q) > > */ > > static int queue_poll_cons(struct arm_smmu_queue *q, bool drain, bool wfe) > > { > > - ktime_t timeout = ktime_add_us(ktime_get(), ARM_SMMU_POLL_TIMEOUT_US); > > + ktime_t timeout = ktime_add_us(ktime_get(), CMDQ_DRAIN_TIMEOUT_US); > > + unsigned int spin_cnt, delay = 1; > > > > while (queue_sync_cons(q), (drain ? !queue_empty(q) : queue_full(q))) { > > if (ktime_compare(ktime_get(), timeout) > 0) > > @@ -746,8 +750,13 @@ static int queue_poll_cons(struct arm_smmu_queue *q, bool drain, bool wfe) > > if (wfe) { > > wfe(); > > } else { > > - cpu_relax(); > > - udelay(1); > > + for (spin_cnt = 0; > > + spin_cnt < CMDQ_SPIN_COUNT; spin_cnt++) { > > + cpu_relax(); > > + continue; > > + } > > + udelay(delay); > > + delay *= 2; > > Sorry, I can't make sense of this. The referenced commit uses the spin > loop to poll opportunistically a few times before delaying. This loop > just adds a short open-coded udelay to an exponential udelay, and it's > not really clear that that's any better than a fixed udelay (especially > as the two cases in which we poll are somewhat different). > > What's wrong with simply increasing the timeout value alone? I asked that the timeout is only increased for the drain case, and that we fix the issue here where we udelat if cons didn't move immediately: http://lists.infradead.org/pipermail/linux-arm-kernel/2017-April/503389.html but I don't think the patch above actually achieves any of that. Will ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] iommu/arm-smmu-v3: Poll for CMDQ drain completion more effectively 2017-05-03 15:40 ` Will Deacon @ 2017-05-03 16:23 ` Sunil Kovvuri 0 siblings, 0 replies; 9+ messages in thread From: Sunil Kovvuri @ 2017-05-03 16:23 UTC (permalink / raw) To: Will Deacon Cc: Robin Murphy, iommu, LKML, LAKML, Robert Richter, jcm, Sunil Goutham, Geetha On Wed, May 3, 2017 at 9:10 PM, Will Deacon <will.deacon@arm.com> wrote: > On Wed, May 03, 2017 at 04:33:57PM +0100, Robin Murphy wrote: >> On 27/04/17 12:13, sunil.kovvuri@gmail.com wrote: >> > From: Sunil Goutham <sgoutham@cavium.com> >> > >> > Modified polling on CMDQ consumer similar to how polling is done for TLB SYNC >> > completion in SMMUv2 driver. Code changes are done with reference to >> > >> > 8513c8930069 iommu/arm-smmu: Poll for TLB sync completion more effectively >> > >> > Poll timeout has been increased which addresses issue of 100us timeout not >> > sufficient, when command queue is full with TLB invalidation commands. >> > >> > Signed-off-by: Sunil Goutham <sgoutham@cavium.com> >> > Signed-off-by: Geetha <gakula@cavium.com> >> > --- >> > drivers/iommu/arm-smmu-v3.c | 15 ++++++++++++--- >> > 1 file changed, 12 insertions(+), 3 deletions(-) >> > >> > diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c >> > index d412bdd..34599d4 100644 >> > --- a/drivers/iommu/arm-smmu-v3.c >> > +++ b/drivers/iommu/arm-smmu-v3.c >> > @@ -379,6 +379,9 @@ >> > #define CMDQ_SYNC_0_CS_NONE (0UL << CMDQ_SYNC_0_CS_SHIFT) >> > #define CMDQ_SYNC_0_CS_SEV (2UL << CMDQ_SYNC_0_CS_SHIFT) >> > >> > +#define CMDQ_DRAIN_TIMEOUT_US 1000 >> > +#define CMDQ_SPIN_COUNT 10 >> > + >> > /* Event queue */ >> > #define EVTQ_ENT_DWORDS 4 >> > #define EVTQ_MAX_SZ_SHIFT 7 >> > @@ -737,7 +740,8 @@ static void queue_inc_prod(struct arm_smmu_queue *q) >> > */ >> > static int queue_poll_cons(struct arm_smmu_queue *q, bool drain, bool wfe) >> > { >> > - ktime_t timeout = ktime_add_us(ktime_get(), ARM_SMMU_POLL_TIMEOUT_US); >> > + ktime_t timeout = ktime_add_us(ktime_get(), CMDQ_DRAIN_TIMEOUT_US); >> > + unsigned int spin_cnt, delay = 1; >> > >> > while (queue_sync_cons(q), (drain ? !queue_empty(q) : queue_full(q))) { >> > if (ktime_compare(ktime_get(), timeout) > 0) >> > @@ -746,8 +750,13 @@ static int queue_poll_cons(struct arm_smmu_queue *q, bool drain, bool wfe) >> > if (wfe) { >> > wfe(); >> > } else { >> > - cpu_relax(); >> > - udelay(1); >> > + for (spin_cnt = 0; >> > + spin_cnt < CMDQ_SPIN_COUNT; spin_cnt++) { >> > + cpu_relax(); >> > + continue; >> > + } >> > + udelay(delay); >> > + delay *= 2; >> >> Sorry, I can't make sense of this. The referenced commit uses the spin >> loop to poll opportunistically a few times before delaying. This loop >> just adds a short open-coded udelay to an exponential udelay, and it's >> not really clear that that's any better than a fixed udelay (especially >> as the two cases in which we poll are somewhat different). >> >> What's wrong with simply increasing the timeout value alone? > > I asked that the timeout is only increased for the drain case, and that > we fix the issue here where we udelat if cons didn't move immediately: > > http://lists.infradead.org/pipermail/linux-arm-kernel/2017-April/503389.html > > but I don't think the patch above actually achieves any of that. > > Will Sorry, I completely screwed up the spin poll above. Will resubmit. Thanks, Sunil. ^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2017-05-03 16:24 UTC | newest] Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2017-04-27 11:13 [PATCH] iommu/arm-smmu-v3: Poll for CMDQ drain completion more effectively sunil.kovvuri 2017-05-03 13:19 ` Sunil Kovvuri 2017-05-03 15:37 ` Will Deacon 2017-05-03 15:54 ` Sunil Kovvuri 2017-05-03 15:59 ` Will Deacon 2017-05-03 16:24 ` Sunil Kovvuri 2017-05-03 15:33 ` Robin Murphy 2017-05-03 15:40 ` Will Deacon 2017-05-03 16:23 ` Sunil Kovvuri
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