* [PATCH 3/15] arch/ia64: Use DIV_ROUND_CLOSEST @ 2009-08-02 8:45 ` Julia Lawall 0 siblings, 0 replies; 8+ messages in thread From: Julia Lawall @ 2009-08-02 8:45 UTC (permalink / raw) To: fenghua.yu, tony.luck, linux-ia64, linux-kernel, kernel-janitors From: Julia Lawall <julia@diku.dk> The kernel.h macro DIV_ROUND_CLOSEST performs the computation (x + d/2)/d but is perhaps more readable. The semantic patch that makes this change is as follows: (http://www.emn.fr/x-info/coccinelle/) // <smpl> @haskernel@ @@ #include <linux/kernel.h> @depends on haskernel@ expression x,__divisor; @@ - (((x) + ((__divisor) / 2)) / (__divisor)) + DIV_ROUND_CLOSEST(x,__divisor) // </smpl> Signed-off-by: Julia Lawall <julia@diku.dk> --- arch/ia64/kernel/time.c | 10 ++++++---- 1 files changed, 6 insertions(+), 4 deletions(-) diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c index 4990495..aaa6651 100644 --- a/arch/ia64/kernel/time.c +++ b/arch/ia64/kernel/time.c @@ -314,7 +314,7 @@ ia64_init_itm (void) itc_freq = (platform_base_freq*itc_ratio.num)/itc_ratio.den; - local_cpu_data->itm_delta = (itc_freq + HZ/2) / HZ; + local_cpu_data->itm_delta = DIV_ROUND_CLOSEST(itc_freq, HZ); printk(KERN_DEBUG "CPU %d: base freq=%lu.%03luMHz, ITC ratio=%u/%u, " "ITC freq=%lu.%03luMHz", smp_processor_id(), platform_base_freq / 1000000, (platform_base_freq / 1000) % 1000, @@ -330,9 +330,11 @@ ia64_init_itm (void) local_cpu_data->proc_freq = (platform_base_freq*proc_ratio.num)/proc_ratio.den; local_cpu_data->itc_freq = itc_freq; - local_cpu_data->cyc_per_usec = (itc_freq + USEC_PER_SEC/2) / USEC_PER_SEC; - local_cpu_data->nsec_per_cyc = ((NSEC_PER_SEC<<IA64_NSEC_PER_CYC_SHIFT) - + itc_freq/2)/itc_freq; + local_cpu_data->cyc_per_usec + DIV_ROUND_CLOSEST(itc_freq, USEC_PER_SEC); + local_cpu_data->nsec_per_cyc + DIV_ROUND_CLOSEST(NSEC_PER_SEC << IA64_NSEC_PER_CYC_SHIFT, + itc_freq); if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT)) { #ifdef CONFIG_SMP ^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH 3/15] arch/ia64: Use DIV_ROUND_CLOSEST @ 2009-08-02 8:45 ` Julia Lawall 0 siblings, 0 replies; 8+ messages in thread From: Julia Lawall @ 2009-08-02 8:45 UTC (permalink / raw) To: fenghua.yu, tony.luck, linux-ia64, linux-kernel, kernel-janitors From: Julia Lawall <julia@diku.dk> The kernel.h macro DIV_ROUND_CLOSEST performs the computation (x + d/2)/d but is perhaps more readable. The semantic patch that makes this change is as follows: (http://www.emn.fr/x-info/coccinelle/) // <smpl> @haskernel@ @@ #include <linux/kernel.h> @depends on haskernel@ expression x,__divisor; @@ - (((x) + ((__divisor) / 2)) / (__divisor)) + DIV_ROUND_CLOSEST(x,__divisor) // </smpl> Signed-off-by: Julia Lawall <julia@diku.dk> --- arch/ia64/kernel/time.c | 10 ++++++---- 1 files changed, 6 insertions(+), 4 deletions(-) diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c index 4990495..aaa6651 100644 --- a/arch/ia64/kernel/time.c +++ b/arch/ia64/kernel/time.c @@ -314,7 +314,7 @@ ia64_init_itm (void) itc_freq = (platform_base_freq*itc_ratio.num)/itc_ratio.den; - local_cpu_data->itm_delta = (itc_freq + HZ/2) / HZ; + local_cpu_data->itm_delta = DIV_ROUND_CLOSEST(itc_freq, HZ); printk(KERN_DEBUG "CPU %d: base freq=%lu.%03luMHz, ITC ratio=%u/%u, " "ITC freq=%lu.%03luMHz", smp_processor_id(), platform_base_freq / 1000000, (platform_base_freq / 1000) % 1000, @@ -330,9 +330,11 @@ ia64_init_itm (void) local_cpu_data->proc_freq = (platform_base_freq*proc_ratio.num)/proc_ratio.den; local_cpu_data->itc_freq = itc_freq; - local_cpu_data->cyc_per_usec = (itc_freq + USEC_PER_SEC/2) / USEC_PER_SEC; - local_cpu_data->nsec_per_cyc = ((NSEC_PER_SEC<<IA64_NSEC_PER_CYC_SHIFT) - + itc_freq/2)/itc_freq; + local_cpu_data->cyc_per_usec = + DIV_ROUND_CLOSEST(itc_freq, USEC_PER_SEC); + local_cpu_data->nsec_per_cyc = + DIV_ROUND_CLOSEST(NSEC_PER_SEC << IA64_NSEC_PER_CYC_SHIFT, + itc_freq); if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT)) { #ifdef CONFIG_SMP ^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH 1/4] Bug Fix drivers/pci/intel-iommu.c: correct sglist size calculation 2009-08-02 8:45 ` Julia Lawall @ 2009-08-04 22:09 ` Fenghua Yu -1 siblings, 0 replies; 8+ messages in thread From: Fenghua Yu @ 2009-08-04 22:09 UTC (permalink / raw) To: David Woodhouse, Tony Luck; +Cc: iommu, linux-ia64, linux-kernel, Fenghua Yu When calculating a scatter gather list size in intel_map_sg(), the size of an sg entry should be based on sg->addr, sg->offset, and sg->length instead of just sg->offset and sg->length. And the size of a scatter gather list should be passed to domain_sg_mapping() directly because it has been aligned to VTD_PAGE_SIZE already. Because of the issue, system can not boot when PAGE_SIZE>VTD_PAGE_SIZE e.g. on ia64 platforms. Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> --- drivers/pci/intel-iommu.c | 28 ++++++++++++++++------------ 1 files changed, 16 insertions(+), 12 deletions(-) diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c index bec29ed..54ee63d 100644 --- a/drivers/pci/intel-iommu.c +++ b/drivers/pci/intel-iommu.c @@ -1645,6 +1645,15 @@ static int domain_context_mapped(struct pci_dev *pdev) tmp->devfn); } +/* Returns a number of VTD pages, but aligned to MM page size */ +static inline unsigned long aligned_nrpages(unsigned long host_addr, + size_t size) +{ + host_addr &= ~PAGE_MASK; + return PAGE_ALIGN(host_addr + size) >> VTD_PAGE_SHIFT; +} + + static int __domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn, struct scatterlist *sg, unsigned long phys_pfn, unsigned long nr_pages, int prot) @@ -1672,7 +1681,8 @@ static int __domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn, uint64_t tmp; if (!sg_res) { - sg_res = (sg->offset + sg->length + VTD_PAGE_SIZE - 1) >> VTD_PAGE_SHIFT; + dma_addr_t addr = sg_phys(sg); + sg_res = aligned_nrpages(addr, sg->length); sg->dma_address = ((dma_addr_t)iov_pfn << VTD_PAGE_SHIFT) + sg->offset; sg->dma_length = sg->length; pteval = page_to_phys(sg_page(sg)) | prot; @@ -2411,14 +2425,6 @@ error: return ret; } -/* Returns a number of VTD pages, but aligned to MM page size */ -static inline unsigned long aligned_nrpages(unsigned long host_addr, - size_t size) -{ - host_addr &= ~PAGE_MASK; - return PAGE_ALIGN(host_addr + size) >> VTD_PAGE_SHIFT; -} - /* This takes a number of _MM_ pages, not VTD pages */ static struct iova *intel_alloc_iova(struct device *dev, struct dmar_domain *domain, @@ -2861,8 +2868,10 @@ static int intel_map_sg(struct device *hwdev, struct scatterlist *sglist, int ne iommu = domain_get_iommu(domain); - for_each_sg(sglist, sg, nelems, i) - size += aligned_nrpages(sg->offset, sg->length); + for_each_sg(sglist, sg, nelems, i) { + dma_addr_t addr = sg_phys(sg); + size += aligned_nrpages(addr, sg->length); + } iova = intel_alloc_iova(hwdev, domain, dma_to_mm_pfn(size), pdev->dma_mask); @@ -2883,7 +2892,7 @@ static int intel_map_sg(struct device *hwdev, struct scatterlist *sglist, int ne start_vpfn = mm_to_dma_pfn(iova->pfn_lo); - ret = domain_sg_mapping(domain, start_vpfn, sglist, mm_to_dma_pfn(size), prot); + ret = domain_sg_mapping(domain, start_vpfn, sglist, size, prot); if (unlikely(ret)) { /* clear the page */ dma_pte_clear_range(domain, start_vpfn, ^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH 1/4] Bug Fix drivers/pci/intel-iommu.c: correct sglist size calculation @ 2009-08-04 22:09 ` Fenghua Yu 0 siblings, 0 replies; 8+ messages in thread From: Fenghua Yu @ 2009-08-04 22:09 UTC (permalink / raw) To: David Woodhouse, Tony Luck; +Cc: iommu, linux-ia64, linux-kernel, Fenghua Yu When calculating a scatter gather list size in intel_map_sg(), the size of an sg entry should be based on sg->addr, sg->offset, and sg->length instead of just sg->offset and sg->length. And the size of a scatter gather list should be passed to domain_sg_mapping() directly because it has been aligned to VTD_PAGE_SIZE already. Because of the issue, system can not boot when PAGE_SIZE>VTD_PAGE_SIZE e.g. on ia64 platforms. Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> --- drivers/pci/intel-iommu.c | 28 ++++++++++++++++------------ 1 files changed, 16 insertions(+), 12 deletions(-) diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c index bec29ed..54ee63d 100644 --- a/drivers/pci/intel-iommu.c +++ b/drivers/pci/intel-iommu.c @@ -1645,6 +1645,15 @@ static int domain_context_mapped(struct pci_dev *pdev) tmp->devfn); } +/* Returns a number of VTD pages, but aligned to MM page size */ +static inline unsigned long aligned_nrpages(unsigned long host_addr, + size_t size) +{ + host_addr &= ~PAGE_MASK; + return PAGE_ALIGN(host_addr + size) >> VTD_PAGE_SHIFT; +} + + static int __domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn, struct scatterlist *sg, unsigned long phys_pfn, unsigned long nr_pages, int prot) @@ -1672,7 +1681,8 @@ static int __domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn, uint64_t tmp; if (!sg_res) { - sg_res = (sg->offset + sg->length + VTD_PAGE_SIZE - 1) >> VTD_PAGE_SHIFT; + dma_addr_t addr = sg_phys(sg); + sg_res = aligned_nrpages(addr, sg->length); sg->dma_address = ((dma_addr_t)iov_pfn << VTD_PAGE_SHIFT) + sg->offset; sg->dma_length = sg->length; pteval = page_to_phys(sg_page(sg)) | prot; @@ -2411,14 +2425,6 @@ error: return ret; } -/* Returns a number of VTD pages, but aligned to MM page size */ -static inline unsigned long aligned_nrpages(unsigned long host_addr, - size_t size) -{ - host_addr &= ~PAGE_MASK; - return PAGE_ALIGN(host_addr + size) >> VTD_PAGE_SHIFT; -} - /* This takes a number of _MM_ pages, not VTD pages */ static struct iova *intel_alloc_iova(struct device *dev, struct dmar_domain *domain, @@ -2861,8 +2868,10 @@ static int intel_map_sg(struct device *hwdev, struct scatterlist *sglist, int ne iommu = domain_get_iommu(domain); - for_each_sg(sglist, sg, nelems, i) - size += aligned_nrpages(sg->offset, sg->length); + for_each_sg(sglist, sg, nelems, i) { + dma_addr_t addr = sg_phys(sg); + size += aligned_nrpages(addr, sg->length); + } iova = intel_alloc_iova(hwdev, domain, dma_to_mm_pfn(size), pdev->dma_mask); @@ -2883,7 +2892,7 @@ static int intel_map_sg(struct device *hwdev, struct scatterlist *sglist, int ne start_vpfn = mm_to_dma_pfn(iova->pfn_lo); - ret = domain_sg_mapping(domain, start_vpfn, sglist, mm_to_dma_pfn(size), prot); + ret = domain_sg_mapping(domain, start_vpfn, sglist, size, prot); if (unlikely(ret)) { /* clear the page */ dma_pte_clear_range(domain, start_vpfn, ^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH 1/4] Bug Fix drivers/pci/intel-iommu.c: correct sglist 2009-08-04 22:09 ` Fenghua Yu @ 2009-08-05 7:59 ` David Woodhouse -1 siblings, 0 replies; 8+ messages in thread From: David Woodhouse @ 2009-08-05 7:59 UTC (permalink / raw) To: Fenghua Yu; +Cc: Tony Luck, iommu, linux-ia64, linux-kernel On Tue, 2009-08-04 at 15:09 -0700, Fenghua Yu wrote: > > - for_each_sg(sglist, sg, nelems, i) > - size += aligned_nrpages(sg->offset, sg->length); > + for_each_sg(sglist, sg, nelems, i) { > + dma_addr_t addr = sg_phys(sg); > + size += aligned_nrpages(addr, sg->length); > + } What's the point in this part? We mask off the high bits of the first argument to aligned_nrpages() -- we're only interested in the offset within the (mm) page. So sg->offset is fine; we don't need to use sg_phys(), surely? And this is in code where we're desperately trying to shave off as many cycles as we can... This version of the patch should suffice, yes? diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c index ebc9b8d..ed6109d 100644 --- a/drivers/pci/intel-iommu.c +++ b/drivers/pci/intel-iommu.c @@ -1648,6 +1648,15 @@ static int domain_context_mapped(struct pci_dev *pdev) tmp->devfn); } +/* Returns a number of VTD pages, but aligned to MM page size */ +static inline unsigned long aligned_nrpages(unsigned long host_addr, + size_t size) +{ + host_addr &= ~PAGE_MASK; + return PAGE_ALIGN(host_addr + size) >> VTD_PAGE_SHIFT; +} + + static int __domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn, struct scatterlist *sg, unsigned long phys_pfn, unsigned long nr_pages, int prot) @@ -1675,7 +1684,7 @@ static int __domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn, uint64_t tmp; if (!sg_res) { - sg_res = (sg->offset + sg->length + VTD_PAGE_SIZE - 1) >> VTD_PAGE_SHIFT; + sg_res = aligned_nrpages(sg->offset, sg->length); sg->dma_address = ((dma_addr_t)iov_pfn << VTD_PAGE_SHIFT) + sg->offset; sg->dma_length = sg->length; pteval = page_to_phys(sg_page(sg)) | prot; @@ -2415,14 +2424,6 @@ error: return ret; } -/* Returns a number of VTD pages, but aligned to MM page size */ -static inline unsigned long aligned_nrpages(unsigned long host_addr, - size_t size) -{ - host_addr &= ~PAGE_MASK; - return PAGE_ALIGN(host_addr + size) >> VTD_PAGE_SHIFT; -} - /* This takes a number of _MM_ pages, not VTD pages */ static struct iova *intel_alloc_iova(struct device *dev, struct dmar_domain *domain, @@ -2875,7 +2876,7 @@ static int intel_map_sg(struct device *hwdev, struct scatterlist *sglist, int ne start_vpfn = mm_to_dma_pfn(iova->pfn_lo); - ret = domain_sg_mapping(domain, start_vpfn, sglist, mm_to_dma_pfn(size), prot); + ret = domain_sg_mapping(domain, start_vpfn, sglist, size, prot); if (unlikely(ret)) { /* clear the page */ dma_pte_clear_range(domain, start_vpfn, -- dwmw2 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH 1/4] Bug Fix drivers/pci/intel-iommu.c: correct sglist size calculation @ 2009-08-05 7:59 ` David Woodhouse 0 siblings, 0 replies; 8+ messages in thread From: David Woodhouse @ 2009-08-05 7:59 UTC (permalink / raw) To: Fenghua Yu; +Cc: Tony Luck, iommu, linux-ia64, linux-kernel On Tue, 2009-08-04 at 15:09 -0700, Fenghua Yu wrote: > > - for_each_sg(sglist, sg, nelems, i) > - size += aligned_nrpages(sg->offset, sg->length); > + for_each_sg(sglist, sg, nelems, i) { > + dma_addr_t addr = sg_phys(sg); > + size += aligned_nrpages(addr, sg->length); > + } What's the point in this part? We mask off the high bits of the first argument to aligned_nrpages() -- we're only interested in the offset within the (mm) page. So sg->offset is fine; we don't need to use sg_phys(), surely? And this is in code where we're desperately trying to shave off as many cycles as we can... This version of the patch should suffice, yes? diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c index ebc9b8d..ed6109d 100644 --- a/drivers/pci/intel-iommu.c +++ b/drivers/pci/intel-iommu.c @@ -1648,6 +1648,15 @@ static int domain_context_mapped(struct pci_dev *pdev) tmp->devfn); } +/* Returns a number of VTD pages, but aligned to MM page size */ +static inline unsigned long aligned_nrpages(unsigned long host_addr, + size_t size) +{ + host_addr &= ~PAGE_MASK; + return PAGE_ALIGN(host_addr + size) >> VTD_PAGE_SHIFT; +} + + static int __domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn, struct scatterlist *sg, unsigned long phys_pfn, unsigned long nr_pages, int prot) @@ -1675,7 +1684,7 @@ static int __domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn, uint64_t tmp; if (!sg_res) { - sg_res = (sg->offset + sg->length + VTD_PAGE_SIZE - 1) >> VTD_PAGE_SHIFT; + sg_res = aligned_nrpages(sg->offset, sg->length); sg->dma_address = ((dma_addr_t)iov_pfn << VTD_PAGE_SHIFT) + sg->offset; sg->dma_length = sg->length; pteval = page_to_phys(sg_page(sg)) | prot; @@ -2415,14 +2424,6 @@ error: return ret; } -/* Returns a number of VTD pages, but aligned to MM page size */ -static inline unsigned long aligned_nrpages(unsigned long host_addr, - size_t size) -{ - host_addr &= ~PAGE_MASK; - return PAGE_ALIGN(host_addr + size) >> VTD_PAGE_SHIFT; -} - /* This takes a number of _MM_ pages, not VTD pages */ static struct iova *intel_alloc_iova(struct device *dev, struct dmar_domain *domain, @@ -2875,7 +2876,7 @@ static int intel_map_sg(struct device *hwdev, struct scatterlist *sglist, int ne start_vpfn = mm_to_dma_pfn(iova->pfn_lo); - ret = domain_sg_mapping(domain, start_vpfn, sglist, mm_to_dma_pfn(size), prot); + ret = domain_sg_mapping(domain, start_vpfn, sglist, size, prot); if (unlikely(ret)) { /* clear the page */ dma_pte_clear_range(domain, start_vpfn, -- dwmw2 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* RE: [PATCH 3/15] arch/ia64: Use DIV_ROUND_CLOSEST 2009-08-02 8:45 ` Julia Lawall @ 2009-08-05 23:22 ` Yu, Fenghua -1 siblings, 0 replies; 8+ messages in thread From: Yu, Fenghua @ 2009-08-05 23:22 UTC (permalink / raw) To: 'Julia Lawall', Luck, Tony, 'linux-ia64@vger.kernel.org', 'linux-kernel@vger.kernel.org', 'kernel-janitors@vger.kernel.org' >-----Original Message----- >From: Julia Lawall [mailto:julia@diku.dk] >Sent: Sunday, August 02, 2009 1:45 AM >To: Yu, Fenghua; Luck, Tony; linux-ia64@vger.kernel.org; linux- >kernel@vger.kernel.org; kernel-janitors@vger.kernel.org >Subject: [PATCH 3/15] arch/ia64: Use DIV_ROUND_CLOSEST > >From: Julia Lawall <julia@diku.dk> > >The kernel.h macro DIV_ROUND_CLOSEST performs the computation (x + d/2)/d >but is perhaps more readable. > >The semantic patch that makes this change is as follows: >(http://www.emn.fr/x-info/coccinelle/) > >// <smpl> >@haskernel@ >@@ > >#include <linux/kernel.h> > >@depends on haskernel@ >expression x,__divisor; >@@ > >- (((x) + ((__divisor) / 2)) / (__divisor)) >+ DIV_ROUND_CLOSEST(x,__divisor) >// </smpl> > >Signed-off-by: Julia Lawall <julia@diku.dk> > >--- > arch/ia64/kernel/time.c | 10 ++++++---- > 1 files changed, 6 insertions(+), 4 deletions(-) > >diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c >index 4990495..aaa6651 100644 >--- a/arch/ia64/kernel/time.c >+++ b/arch/ia64/kernel/time.c >@@ -314,7 +314,7 @@ ia64_init_itm (void) > > itc_freq = (platform_base_freq*itc_ratio.num)/itc_ratio.den; > >- local_cpu_data->itm_delta = (itc_freq + HZ/2) / HZ; >+ local_cpu_data->itm_delta = DIV_ROUND_CLOSEST(itc_freq, HZ); > printk(KERN_DEBUG "CPU %d: base freq=%lu.%03luMHz, ITC ratio=%u/%u, " > "ITC freq=%lu.%03luMHz", smp_processor_id(), > platform_base_freq / 1000000, (platform_base_freq / 1000) % >1000, >@@ -330,9 +330,11 @@ ia64_init_itm (void) > > local_cpu_data->proc_freq >(platform_base_freq*proc_ratio.num)/proc_ratio.den; > local_cpu_data->itc_freq = itc_freq; >- local_cpu_data->cyc_per_usec = (itc_freq + USEC_PER_SEC/2) / >USEC_PER_SEC; >- local_cpu_data->nsec_per_cyc >((NSEC_PER_SEC<<IA64_NSEC_PER_CYC_SHIFT) >- + itc_freq/2)/itc_freq; >+ local_cpu_data->cyc_per_usec >+ DIV_ROUND_CLOSEST(itc_freq, USEC_PER_SEC); >+ local_cpu_data->nsec_per_cyc >+ DIV_ROUND_CLOSEST(NSEC_PER_SEC << IA64_NSEC_PER_CYC_SHIFT, >+ itc_freq); > > if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT)) { > #ifdef CONFIG_SMP Acked-by: Fenghua Yu <Fenghua.yu@intel.com> ^ permalink raw reply [flat|nested] 8+ messages in thread
* RE: [PATCH 3/15] arch/ia64: Use DIV_ROUND_CLOSEST @ 2009-08-05 23:22 ` Yu, Fenghua 0 siblings, 0 replies; 8+ messages in thread From: Yu, Fenghua @ 2009-08-05 23:22 UTC (permalink / raw) To: 'Julia Lawall', Luck, Tony, 'linux-ia64@vger.kernel.org', 'linux-kernel@vger.kernel.org', 'kernel-janitors@vger.kernel.org' >-----Original Message----- >From: Julia Lawall [mailto:julia@diku.dk] >Sent: Sunday, August 02, 2009 1:45 AM >To: Yu, Fenghua; Luck, Tony; linux-ia64@vger.kernel.org; linux- >kernel@vger.kernel.org; kernel-janitors@vger.kernel.org >Subject: [PATCH 3/15] arch/ia64: Use DIV_ROUND_CLOSEST > >From: Julia Lawall <julia@diku.dk> > >The kernel.h macro DIV_ROUND_CLOSEST performs the computation (x + d/2)/d >but is perhaps more readable. > >The semantic patch that makes this change is as follows: >(http://www.emn.fr/x-info/coccinelle/) > >// <smpl> >@haskernel@ >@@ > >#include <linux/kernel.h> > >@depends on haskernel@ >expression x,__divisor; >@@ > >- (((x) + ((__divisor) / 2)) / (__divisor)) >+ DIV_ROUND_CLOSEST(x,__divisor) >// </smpl> > >Signed-off-by: Julia Lawall <julia@diku.dk> > >--- > arch/ia64/kernel/time.c | 10 ++++++---- > 1 files changed, 6 insertions(+), 4 deletions(-) > >diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c >index 4990495..aaa6651 100644 >--- a/arch/ia64/kernel/time.c >+++ b/arch/ia64/kernel/time.c >@@ -314,7 +314,7 @@ ia64_init_itm (void) > > itc_freq = (platform_base_freq*itc_ratio.num)/itc_ratio.den; > >- local_cpu_data->itm_delta = (itc_freq + HZ/2) / HZ; >+ local_cpu_data->itm_delta = DIV_ROUND_CLOSEST(itc_freq, HZ); > printk(KERN_DEBUG "CPU %d: base freq=%lu.%03luMHz, ITC ratio=%u/%u, " > "ITC freq=%lu.%03luMHz", smp_processor_id(), > platform_base_freq / 1000000, (platform_base_freq / 1000) % >1000, >@@ -330,9 +330,11 @@ ia64_init_itm (void) > > local_cpu_data->proc_freq = >(platform_base_freq*proc_ratio.num)/proc_ratio.den; > local_cpu_data->itc_freq = itc_freq; >- local_cpu_data->cyc_per_usec = (itc_freq + USEC_PER_SEC/2) / >USEC_PER_SEC; >- local_cpu_data->nsec_per_cyc = >((NSEC_PER_SEC<<IA64_NSEC_PER_CYC_SHIFT) >- + itc_freq/2)/itc_freq; >+ local_cpu_data->cyc_per_usec = >+ DIV_ROUND_CLOSEST(itc_freq, USEC_PER_SEC); >+ local_cpu_data->nsec_per_cyc = >+ DIV_ROUND_CLOSEST(NSEC_PER_SEC << IA64_NSEC_PER_CYC_SHIFT, >+ itc_freq); > > if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT)) { > #ifdef CONFIG_SMP Acked-by: Fenghua Yu <Fenghua.yu@intel.com> ^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2009-08-05 23:22 UTC | newest] Thread overview: 8+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2009-08-02 8:45 [PATCH 3/15] arch/ia64: Use DIV_ROUND_CLOSEST Julia Lawall 2009-08-02 8:45 ` Julia Lawall 2009-08-04 22:09 ` [PATCH 1/4] Bug Fix drivers/pci/intel-iommu.c: correct sglist size calculation Fenghua Yu 2009-08-04 22:09 ` Fenghua Yu 2009-08-05 7:59 ` [PATCH 1/4] Bug Fix drivers/pci/intel-iommu.c: correct sglist David Woodhouse 2009-08-05 7:59 ` [PATCH 1/4] Bug Fix drivers/pci/intel-iommu.c: correct sglist size calculation David Woodhouse 2009-08-05 23:22 ` [PATCH 3/15] arch/ia64: Use DIV_ROUND_CLOSEST Yu, Fenghua 2009-08-05 23:22 ` Yu, Fenghua
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