Re: [PATCH 04/10] irqchip/gic-v3-its: Move pending table allocation to init time
Hi Julien, On 24/09/18 12:58, Julien Thierry wrote: Hi Marc, On 21/09/18 20:59, Marc Zyngier wrote: Pending tables for the redistributors are currently allocated one at a time as each CPU boots. This is causing some grief for Linux/RT (allocation from within a CPU hotplug notifier is frown upon). Let's more this allocation to take place at init time, when we only have a single CPU. It means we're allocating memory for CPUs that are not online yet, but most system will boot all of their CPUs anyway, so that's not completely wasted. Signed-off-by: Marc Zyngier --- drivers/irqchip/irq-gic-v3-its.c | 80 +++--- include/linux/irqchip/arm-gic-v3.h | 1 + 2 files changed, 53 insertions(+), 28 deletions(-) diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c index 7ef6baea2d78..462bba422189 100644 --- a/drivers/irqchip/irq-gic-v3-its.c +++ b/drivers/irqchip/irq-gic-v3-its.c @@ -173,6 +173,7 @@ static DEFINE_RAW_SPINLOCK(vmovp_lock); static DEFINE_IDA(its_vpeid_ida); #define gic_data_rdist() (raw_cpu_ptr(gic_rdists->rdist)) +#define gic_data_rdist_cpu(cpu)(per_cpu_ptr(gic_rdists->rdist, cpu)) #define gic_data_rdist_rd_base() (gic_data_rdist()->rd_base) #define gic_data_rdist_vlpi_base() (gic_data_rdist_rd_base() + SZ_128K) @@ -1625,7 +1626,7 @@ static void its_free_prop_table(struct page *prop_page) get_order(LPI_PROPBASE_SZ)); } -static int __init its_alloc_lpi_tables(void) +static int __init its_alloc_lpi_prop_table(void) A bit of a nit, but there is already a function called "its_allocate_prop_table" which I find very easy to confuse with this one. And patch 3 factored the initialization out of its_allocate_prop_table. So I was wondering whether it would not actually be better to open-code it here and get rid of that function. Otherwise I'd suggest having more distinct names. its_allocate_prop_table is also used by the VLPI code to allocate guest property tables, so I'd rather not open-code it. How about renaming this function to its_setup_lpi_prop_table? Thanks, M. -- Jazz is not dead. It just smells funny...
Re: [PATCH 04/10] irqchip/gic-v3-its: Move pending table allocation to init time
Hi Marc, On 21/09/18 20:59, Marc Zyngier wrote: Pending tables for the redistributors are currently allocated one at a time as each CPU boots. This is causing some grief for Linux/RT (allocation from within a CPU hotplug notifier is frown upon). Let's more this allocation to take place at init time, when we only have a single CPU. It means we're allocating memory for CPUs that are not online yet, but most system will boot all of their CPUs anyway, so that's not completely wasted. Signed-off-by: Marc Zyngier --- drivers/irqchip/irq-gic-v3-its.c | 80 +++--- include/linux/irqchip/arm-gic-v3.h | 1 + 2 files changed, 53 insertions(+), 28 deletions(-) diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c index 7ef6baea2d78..462bba422189 100644 --- a/drivers/irqchip/irq-gic-v3-its.c +++ b/drivers/irqchip/irq-gic-v3-its.c @@ -173,6 +173,7 @@ static DEFINE_RAW_SPINLOCK(vmovp_lock); static DEFINE_IDA(its_vpeid_ida); #define gic_data_rdist() (raw_cpu_ptr(gic_rdists->rdist)) +#define gic_data_rdist_cpu(cpu)(per_cpu_ptr(gic_rdists->rdist, cpu)) #define gic_data_rdist_rd_base() (gic_data_rdist()->rd_base) #define gic_data_rdist_vlpi_base()(gic_data_rdist_rd_base() + SZ_128K) @@ -1625,7 +1626,7 @@ static void its_free_prop_table(struct page *prop_page) get_order(LPI_PROPBASE_SZ)); } -static int __init its_alloc_lpi_tables(void) +static int __init its_alloc_lpi_prop_table(void) A bit of a nit, but there is already a function called "its_allocate_prop_table" which I find very easy to confuse with this one. And patch 3 factored the initialization out of its_allocate_prop_table. So I was wondering whether it would not actually be better to open-code it here and get rid of that function. Otherwise I'd suggest having more distinct names. Otherwise the patch looks good. Thanks, { phys_addr_t paddr; @@ -1944,30 +1945,47 @@ static void its_free_pending_table(struct page *pt) free_pages((unsigned long)page_address(pt), get_order(LPI_PENDBASE_SZ)); } -static void its_cpu_init_lpis(void) +static int __init allocate_lpi_tables(void) { - void __iomem *rbase = gic_data_rdist_rd_base(); - struct page *pend_page; - u64 val, tmp; + int err, cpu; - /* If we didn't allocate the pending table yet, do it now */ - pend_page = gic_data_rdist()->pend_page; - if (!pend_page) { - phys_addr_t paddr; + err = its_alloc_lpi_prop_table(); + if (err) + return err; + + /* +* We allocate all the pending tables anyway, as we may have a +* mix of RDs that have had LPIs enabled, and some that +* don't. We'll free the unused ones as each CPU comes online. +*/ + for_each_possible_cpu(cpu) { + struct page *pend_page; pend_page = its_allocate_pending_table(GFP_NOWAIT); if (!pend_page) { - pr_err("Failed to allocate PENDBASE for CPU%d\n", - smp_processor_id()); - return; + pr_err("Failed to allocate PENDBASE for CPU%d\n", cpu); + return -ENOMEM; } - paddr = page_to_phys(pend_page); - pr_info("CPU%d: using LPI pending table @%pa\n", - smp_processor_id(), &paddr); - gic_data_rdist()->pend_page = pend_page; + gic_data_rdist_cpu(cpu)->pend_page = pend_page; } + return 0; +} + +static void its_cpu_init_lpis(void) +{ + void __iomem *rbase = gic_data_rdist_rd_base(); + struct page *pend_page; + phys_addr_t paddr; + u64 val, tmp; + + if (gic_data_rdist()->lpi_enabled) + return; + + pend_page = gic_data_rdist()->pend_page; + paddr = page_to_phys(pend_page); + /* set PROPBASE */ val = (page_to_phys(gic_rdists->prop_page) | GICR_PROPBASER_InnerShareable | @@ -2019,6 +2037,10 @@ static void its_cpu_init_lpis(void) /* Make sure the GIC has seen the above */ dsb(sy); + gic_data_rdist()->lpi_enabled = true; + pr_info("GICv3: CPU%d: using LPI pending table @%pa\n", + smp_processor_id(), + &paddr); } static void its_cpu_init_collection(struct its_node *its) @@ -3497,16 +3519,6 @@ static int redist_disable_lpis(void) u64 timeout = USEC_PER_SEC; u64 val; - /* -* If coming via a CPU hotplug event, we don't need to disable -* LPIs before trying to re-enable them. They are already -* configured and all is well in the world. Detect this case -* by checking the allocation of the pending table for the -* current CPU. -*/ - if (gic_data_rdist()->pend_page) - return 0; - if (!gic_rdists_supports_plpis())
[PATCH 04/10] irqchip/gic-v3-its: Move pending table allocation to init time
Pending tables for the redistributors are currently allocated one at a time as each CPU boots. This is causing some grief for Linux/RT (allocation from within a CPU hotplug notifier is frown upon). Let's more this allocation to take place at init time, when we only have a single CPU. It means we're allocating memory for CPUs that are not online yet, but most system will boot all of their CPUs anyway, so that's not completely wasted. Signed-off-by: Marc Zyngier --- drivers/irqchip/irq-gic-v3-its.c | 80 +++--- include/linux/irqchip/arm-gic-v3.h | 1 + 2 files changed, 53 insertions(+), 28 deletions(-) diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c index 7ef6baea2d78..462bba422189 100644 --- a/drivers/irqchip/irq-gic-v3-its.c +++ b/drivers/irqchip/irq-gic-v3-its.c @@ -173,6 +173,7 @@ static DEFINE_RAW_SPINLOCK(vmovp_lock); static DEFINE_IDA(its_vpeid_ida); #define gic_data_rdist() (raw_cpu_ptr(gic_rdists->rdist)) +#define gic_data_rdist_cpu(cpu)(per_cpu_ptr(gic_rdists->rdist, cpu)) #define gic_data_rdist_rd_base() (gic_data_rdist()->rd_base) #define gic_data_rdist_vlpi_base() (gic_data_rdist_rd_base() + SZ_128K) @@ -1625,7 +1626,7 @@ static void its_free_prop_table(struct page *prop_page) get_order(LPI_PROPBASE_SZ)); } -static int __init its_alloc_lpi_tables(void) +static int __init its_alloc_lpi_prop_table(void) { phys_addr_t paddr; @@ -1944,30 +1945,47 @@ static void its_free_pending_table(struct page *pt) free_pages((unsigned long)page_address(pt), get_order(LPI_PENDBASE_SZ)); } -static void its_cpu_init_lpis(void) +static int __init allocate_lpi_tables(void) { - void __iomem *rbase = gic_data_rdist_rd_base(); - struct page *pend_page; - u64 val, tmp; + int err, cpu; - /* If we didn't allocate the pending table yet, do it now */ - pend_page = gic_data_rdist()->pend_page; - if (!pend_page) { - phys_addr_t paddr; + err = its_alloc_lpi_prop_table(); + if (err) + return err; + + /* +* We allocate all the pending tables anyway, as we may have a +* mix of RDs that have had LPIs enabled, and some that +* don't. We'll free the unused ones as each CPU comes online. +*/ + for_each_possible_cpu(cpu) { + struct page *pend_page; pend_page = its_allocate_pending_table(GFP_NOWAIT); if (!pend_page) { - pr_err("Failed to allocate PENDBASE for CPU%d\n", - smp_processor_id()); - return; + pr_err("Failed to allocate PENDBASE for CPU%d\n", cpu); + return -ENOMEM; } - paddr = page_to_phys(pend_page); - pr_info("CPU%d: using LPI pending table @%pa\n", - smp_processor_id(), &paddr); - gic_data_rdist()->pend_page = pend_page; + gic_data_rdist_cpu(cpu)->pend_page = pend_page; } + return 0; +} + +static void its_cpu_init_lpis(void) +{ + void __iomem *rbase = gic_data_rdist_rd_base(); + struct page *pend_page; + phys_addr_t paddr; + u64 val, tmp; + + if (gic_data_rdist()->lpi_enabled) + return; + + pend_page = gic_data_rdist()->pend_page; + paddr = page_to_phys(pend_page); + /* set PROPBASE */ val = (page_to_phys(gic_rdists->prop_page) | GICR_PROPBASER_InnerShareable | @@ -2019,6 +2037,10 @@ static void its_cpu_init_lpis(void) /* Make sure the GIC has seen the above */ dsb(sy); + gic_data_rdist()->lpi_enabled = true; + pr_info("GICv3: CPU%d: using LPI pending table @%pa\n", + smp_processor_id(), + &paddr); } static void its_cpu_init_collection(struct its_node *its) @@ -3497,16 +3519,6 @@ static int redist_disable_lpis(void) u64 timeout = USEC_PER_SEC; u64 val; - /* -* If coming via a CPU hotplug event, we don't need to disable -* LPIs before trying to re-enable them. They are already -* configured and all is well in the world. Detect this case -* by checking the allocation of the pending table for the -* current CPU. -*/ - if (gic_data_rdist()->pend_page) - return 0; - if (!gic_rdists_supports_plpis()) { pr_info("CPU%d: LPIs not supported\n", smp_processor_id()); return -ENXIO; @@ -3516,7 +3528,18 @@ static int redist_disable_lpis(void) if (!(val & GICR_CTLR_ENABLE_LPIS)) return 0; - pr_warn("CPU%d: Booted with LPIs enabled, memory probably corrupted\n", + /* +* If coming via a CPU hotplug event, we don't need to disable +* LPIs before trying to re-e