From: Chunguang Xu <[email protected]>
While iommu_dma_forcedac disable, for PCI device kernel
try SAC first, if failed then try DAC. Since now rcache
does not distinguish SAC and DAC, if all PFNs contained
in cpu loaded cache is larger than SAC max PFN, but the
SAC address space is sufficient, as cpu loaded cached is
not empty, kernel will iova_alloc () to alloc IOVA. For
PCI device, kernel alloc SAC most, loaded cache may
invalid for SAC alloc for a long time, kernel will enter
alloc_iova() slow path frequencely, as result performance
is degrade. To circumvent this problem, SAC and DAC maybe
better to use separate caches.
Signed-off-by: Chunguang Xu <[email protected]>
---
drivers/iommu/iova.c | 28 +++++++++++++++++++++-------
1 file changed, 21 insertions(+), 7 deletions(-)
diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index 47d1983dfa2a..d5775719a143 100644
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -16,6 +16,7 @@
#define IOVA_ANCHOR ~0UL
#define IOVA_RANGE_CACHE_MAX_SIZE 6 /* log of max cached IOVA range size (in pages) */
+#define IOVA_RANGE_CACHE_ARRAY_SIZE (2 * IOVA_RANGE_CACHE_MAX_SIZE)
static bool iova_rcache_insert(struct iova_domain *iovad,
unsigned long pfn,
@@ -723,13 +724,13 @@ int iova_domain_init_rcaches(struct iova_domain *iovad)
unsigned int cpu;
int i, ret;
- iovad->rcaches = kcalloc(IOVA_RANGE_CACHE_MAX_SIZE,
+ iovad->rcaches = kcalloc(IOVA_RANGE_CACHE_ARRAY_SIZE,
sizeof(struct iova_rcache),
GFP_KERNEL);
if (!iovad->rcaches)
return -ENOMEM;
- for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
+ for (i = 0; i < IOVA_RANGE_CACHE_ARRAY_SIZE; ++i) {
struct iova_cpu_rcache *cpu_rcache;
struct iova_rcache *rcache;
@@ -825,11 +826,15 @@ static bool iova_rcache_insert(struct iova_domain *iovad, unsigned long pfn,
unsigned long size)
{
unsigned int log_size = order_base_2(size);
+ unsigned int index;
if (log_size >= IOVA_RANGE_CACHE_MAX_SIZE)
return false;
- return __iova_rcache_insert(iovad, &iovad->rcaches[log_size], pfn);
+ if (pfn > DMA_BIT_MASK(32))
+ index = log_size + IOVA_RANGE_CACHE_MAX_SIZE;
+
+ return __iova_rcache_insert(iovad, &iovad->rcaches[index], pfn);
}
/*
@@ -881,11 +886,20 @@ static unsigned long iova_rcache_get(struct iova_domain *iovad,
unsigned long limit_pfn)
{
unsigned int log_size = order_base_2(size);
+ unsigned long iova_pfn;
+ unsigned int index;
if (log_size >= IOVA_RANGE_CACHE_MAX_SIZE || !iovad->rcaches)
return 0;
- return __iova_rcache_get(&iovad->rcaches[log_size], limit_pfn - size);
+ iova_pfn = __iova_rcache_get(&iovad->rcaches[log_size], limit_pfn - size);
+
+ if (!iova_pfn && limit_pfn > DMA_BIT_MASK(32)) {
+ index = log_size + IOVA_RANGE_CACHE_MAX_SIZE;
+ iova_pfn = __iova_rcache_get(&iovad->rcaches[index], limit_pfn - size);
+ }
+
+ return iova_pfn
}
/*
@@ -898,7 +912,7 @@ static void free_iova_rcaches(struct iova_domain *iovad)
unsigned int cpu;
int i, j;
- for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
+ for (i = 0; i < IOVA_RANGE_CACHE_ARRAY_SIZE; ++i) {
rcache = &iovad->rcaches[i];
if (!rcache->cpu_rcaches)
break;
@@ -926,7 +940,7 @@ static void free_cpu_cached_iovas(unsigned int cpu, struct iova_domain *iovad)
unsigned long flags;
int i;
- for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
+ for (i = 0; i < IOVA_RANGE_CACHE_ARRAY_SIZE; ++i) {
rcache = &iovad->rcaches[i];
cpu_rcache = per_cpu_ptr(rcache->cpu_rcaches, cpu);
spin_lock_irqsave(&cpu_rcache->lock, flags);
@@ -945,7 +959,7 @@ static void free_global_cached_iovas(struct iova_domain *iovad)
unsigned long flags;
int i, j;
- for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
+ for (i = 0; i < IOVA_RANGE_CACHE_ARRAY_SIZE; ++i) {
rcache = &iovad->rcaches[i];
spin_lock_irqsave(&rcache->lock, flags);
for (j = 0; j < rcache->depot_size; ++j) {
--
2.31.1
On 2022-09-16 16:46, brookxu.cn wrote:
> From: Chunguang Xu <[email protected]>
>
> While iommu_dma_forcedac disable, for PCI device kernel
> try SAC first, if failed then try DAC. Since now rcache
> does not distinguish SAC and DAC, if all PFNs contained
> in cpu loaded cache is larger than SAC max PFN, but the
> SAC address space is sufficient, as cpu loaded cached is
> not empty, kernel will iova_alloc () to alloc IOVA. For
> PCI device, kernel alloc SAC most, loaded cache may
> invalid for SAC alloc for a long time, kernel will enter
> alloc_iova() slow path frequencely, as result performance
> is degrade. To circumvent this problem, SAC and DAC maybe
> better to use separate caches.
I really dislike the idea of doubling the already significantly large
footprint of rcaches purely to optimise for the stupid case. If you've
got to the point of hitting contention in the SAC path, you presumably
don't have broken hardware/drivers so you're infinitely better off using
forcedac and avoiding it entirely to begin with. And frankly even if you
*do* have broken hardware, if you care about performance you're still
better off fixing the relevant driver(s) to set correct DMA masks so you
can use forcedac.
Since this mechanism now officially serves as a bandage for broken
hardware/drivers and little else, I had an idea to make it a lot better,
guess it's time to have a go at writing that patch up...
Thanks,
Robin.
> Signed-off-by: Chunguang Xu <[email protected]>
> ---
> drivers/iommu/iova.c | 28 +++++++++++++++++++++-------
> 1 file changed, 21 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
> index 47d1983dfa2a..d5775719a143 100644
> --- a/drivers/iommu/iova.c
> +++ b/drivers/iommu/iova.c
> @@ -16,6 +16,7 @@
> #define IOVA_ANCHOR ~0UL
>
> #define IOVA_RANGE_CACHE_MAX_SIZE 6 /* log of max cached IOVA range size (in pages) */
> +#define IOVA_RANGE_CACHE_ARRAY_SIZE (2 * IOVA_RANGE_CACHE_MAX_SIZE)
>
> static bool iova_rcache_insert(struct iova_domain *iovad,
> unsigned long pfn,
> @@ -723,13 +724,13 @@ int iova_domain_init_rcaches(struct iova_domain *iovad)
> unsigned int cpu;
> int i, ret;
>
> - iovad->rcaches = kcalloc(IOVA_RANGE_CACHE_MAX_SIZE,
> + iovad->rcaches = kcalloc(IOVA_RANGE_CACHE_ARRAY_SIZE,
> sizeof(struct iova_rcache),
> GFP_KERNEL);
> if (!iovad->rcaches)
> return -ENOMEM;
>
> - for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
> + for (i = 0; i < IOVA_RANGE_CACHE_ARRAY_SIZE; ++i) {
> struct iova_cpu_rcache *cpu_rcache;
> struct iova_rcache *rcache;
>
> @@ -825,11 +826,15 @@ static bool iova_rcache_insert(struct iova_domain *iovad, unsigned long pfn,
> unsigned long size)
> {
> unsigned int log_size = order_base_2(size);
> + unsigned int index;
>
> if (log_size >= IOVA_RANGE_CACHE_MAX_SIZE)
> return false;
>
> - return __iova_rcache_insert(iovad, &iovad->rcaches[log_size], pfn);
> + if (pfn > DMA_BIT_MASK(32))
> + index = log_size + IOVA_RANGE_CACHE_MAX_SIZE;
> +
> + return __iova_rcache_insert(iovad, &iovad->rcaches[index], pfn);
> }
>
> /*
> @@ -881,11 +886,20 @@ static unsigned long iova_rcache_get(struct iova_domain *iovad,
> unsigned long limit_pfn)
> {
> unsigned int log_size = order_base_2(size);
> + unsigned long iova_pfn;
> + unsigned int index;
>
> if (log_size >= IOVA_RANGE_CACHE_MAX_SIZE || !iovad->rcaches)
> return 0;
>
> - return __iova_rcache_get(&iovad->rcaches[log_size], limit_pfn - size);
> + iova_pfn = __iova_rcache_get(&iovad->rcaches[log_size], limit_pfn - size);
> +
> + if (!iova_pfn && limit_pfn > DMA_BIT_MASK(32)) {
> + index = log_size + IOVA_RANGE_CACHE_MAX_SIZE;
> + iova_pfn = __iova_rcache_get(&iovad->rcaches[index], limit_pfn - size);
> + }
> +
> + return iova_pfn
> }
>
> /*
> @@ -898,7 +912,7 @@ static void free_iova_rcaches(struct iova_domain *iovad)
> unsigned int cpu;
> int i, j;
>
> - for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
> + for (i = 0; i < IOVA_RANGE_CACHE_ARRAY_SIZE; ++i) {
> rcache = &iovad->rcaches[i];
> if (!rcache->cpu_rcaches)
> break;
> @@ -926,7 +940,7 @@ static void free_cpu_cached_iovas(unsigned int cpu, struct iova_domain *iovad)
> unsigned long flags;
> int i;
>
> - for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
> + for (i = 0; i < IOVA_RANGE_CACHE_ARRAY_SIZE; ++i) {
> rcache = &iovad->rcaches[i];
> cpu_rcache = per_cpu_ptr(rcache->cpu_rcaches, cpu);
> spin_lock_irqsave(&cpu_rcache->lock, flags);
> @@ -945,7 +959,7 @@ static void free_global_cached_iovas(struct iova_domain *iovad)
> unsigned long flags;
> int i, j;
>
> - for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
> + for (i = 0; i < IOVA_RANGE_CACHE_ARRAY_SIZE; ++i) {
> rcache = &iovad->rcaches[i];
> spin_lock_irqsave(&rcache->lock, flags);
> for (j = 0; j < rcache->depot_size; ++j) {
Hi brookxu.cn",
Thank you for the patch! Yet something to improve:
[auto build test ERROR on v6.0-rc5]
[also build test ERROR on linus/master next-20220916]
[cannot apply to joro-iommu/next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/brookxu-cn/iommu-iova-using-separate-rcache-for-SAC-and-DAC/20220916-234845
base: 80e78fcce86de0288793a0ef0f6acf37656ee4cf
config: x86_64-rhel-8.3 (https://download.01.org/0day-ci/archive/20220917/[email protected]/config)
compiler: gcc-11 (Debian 11.3.0-5) 11.3.0
reproduce (this is a W=1 build):
# https://github.com/intel-lab-lkp/linux/commit/fa50a31c6b74157cac20cd44b3717c19b934ff76
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review brookxu-cn/iommu-iova-using-separate-rcache-for-SAC-and-DAC/20220916-234845
git checkout fa50a31c6b74157cac20cd44b3717c19b934ff76
# save the config file
mkdir build_dir && cp config build_dir/.config
make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash drivers/
If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <[email protected]>
All errors (new ones prefixed by >>):
drivers/iommu/iova.c: In function 'iova_rcache_get':
>> drivers/iommu/iova.c:902:24: error: expected ';' before '}' token
902 | return iova_pfn
| ^
| ;
903 | }
| ~
vim +902 drivers/iommu/iova.c
878
879 /*
880 * Try to satisfy IOVA allocation range from rcache. Fail if requested
881 * size is too big or the DMA limit we are given isn't satisfied by the
882 * top element in the magazine.
883 */
884 static unsigned long iova_rcache_get(struct iova_domain *iovad,
885 unsigned long size,
886 unsigned long limit_pfn)
887 {
888 unsigned int log_size = order_base_2(size);
889 unsigned long iova_pfn;
890 unsigned int index;
891
892 if (log_size >= IOVA_RANGE_CACHE_MAX_SIZE || !iovad->rcaches)
893 return 0;
894
895 iova_pfn = __iova_rcache_get(&iovad->rcaches[log_size], limit_pfn - size);
896
897 if (!iova_pfn && limit_pfn > DMA_BIT_MASK(32)) {
898 index = log_size + IOVA_RANGE_CACHE_MAX_SIZE;
899 iova_pfn = __iova_rcache_get(&iovad->rcaches[index], limit_pfn - size);
900 }
901
> 902 return iova_pfn
903 }
904
--
0-DAY CI Kernel Test Service
https://01.org/lkp
在 2022/9/17 1:03, Robin Murphy 写道:
> On 2022-09-16 16:46, brookxu.cn wrote:
>> From: Chunguang Xu <[email protected]>
>>
>> While iommu_dma_forcedac disable, for PCI device kernel
>> try SAC first, if failed then try DAC. Since now rcache
>> does not distinguish SAC and DAC, if all PFNs contained
>> in cpu loaded cache is larger than SAC max PFN, but the
>> SAC address space is sufficient, as cpu loaded cached is
>> not empty, kernel will iova_alloc () to alloc IOVA. For
>> PCI device, kernel alloc SAC most, loaded cache may
>> invalid for SAC alloc for a long time, kernel will enter
>> alloc_iova() slow path frequencely, as result performance
>> is degrade. To circumvent this problem, SAC and DAC maybe
>> better to use separate caches.
>
> I really dislike the idea of doubling the already significantly large
> footprint of rcaches purely to optimise for the stupid case. If you've
> got to the point of hitting contention in the SAC path, you presumably
> don't have broken hardware/drivers so you're infinitely better off using
> forcedac and avoiding it entirely to begin with. And frankly even if you
> *do* have broken hardware, if you care about performance you're still
> better off fixing the relevant driver(s) to set correct DMA masks so you
> can use forcedac.
Some of our NICs have poor performance after heavy traffic impact. We
found that it maybe caused by a large number of 1-2 order IOVA SAC
address applications to make SAC address space fragmentation during
taffic impact, which in turn causes some 3 order IOVA SAC address
applications to fail. Kernel will try DAC address and release it into
rcache. After the traffic recovery, and SAC address space recovery from
fragmentation, but due to the existence of several DAC PFN on the cache
of a certain CPU, which will broken the usage of rcache for SAC address
application. As a result, kernel will enter alloc_iova() slow path
frequencely and performance is poor. So I think this issue should be not
too much of a broken hardware or driver, but they maybe can also be
optimized.
>
> Since this mechanism now officially serves as a bandage for broken
> hardware/drivers and little else, I had an idea to make it a lot better,
> guess it's time to have a go at writing that patch up...
>
> Thanks,
> Robin.
>
>> Signed-off-by: Chunguang Xu <[email protected]>
>> ---
>> drivers/iommu/iova.c | 28 +++++++++++++++++++++-------
>> 1 file changed, 21 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
>> index 47d1983dfa2a..d5775719a143 100644
>> --- a/drivers/iommu/iova.c
>> +++ b/drivers/iommu/iova.c
>> @@ -16,6 +16,7 @@
>> #define IOVA_ANCHOR ~0UL
>> #define IOVA_RANGE_CACHE_MAX_SIZE 6 /* log of max cached IOVA
>> range size (in pages) */
>> +#define IOVA_RANGE_CACHE_ARRAY_SIZE (2 * IOVA_RANGE_CACHE_MAX_SIZE)
>> static bool iova_rcache_insert(struct iova_domain *iovad,
>> unsigned long pfn,
>> @@ -723,13 +724,13 @@ int iova_domain_init_rcaches(struct iova_domain
>> *iovad)
>> unsigned int cpu;
>> int i, ret;
>> - iovad->rcaches = kcalloc(IOVA_RANGE_CACHE_MAX_SIZE,
>> + iovad->rcaches = kcalloc(IOVA_RANGE_CACHE_ARRAY_SIZE,
>> sizeof(struct iova_rcache),
>> GFP_KERNEL);
>> if (!iovad->rcaches)
>> return -ENOMEM;
>> - for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
>> + for (i = 0; i < IOVA_RANGE_CACHE_ARRAY_SIZE; ++i) {
>> struct iova_cpu_rcache *cpu_rcache;
>> struct iova_rcache *rcache;
>> @@ -825,11 +826,15 @@ static bool iova_rcache_insert(struct
>> iova_domain *iovad, unsigned long pfn,
>> unsigned long size)
>> {
>> unsigned int log_size = order_base_2(size);
>> + unsigned int index;
>> if (log_size >= IOVA_RANGE_CACHE_MAX_SIZE)
>> return false;
>> - return __iova_rcache_insert(iovad, &iovad->rcaches[log_size], pfn);
>> + if (pfn > DMA_BIT_MASK(32))
>> + index = log_size + IOVA_RANGE_CACHE_MAX_SIZE;
>> +
>> + return __iova_rcache_insert(iovad, &iovad->rcaches[index], pfn);
>> }
>> /*
>> @@ -881,11 +886,20 @@ static unsigned long iova_rcache_get(struct
>> iova_domain *iovad,
>> unsigned long limit_pfn)
>> {
>> unsigned int log_size = order_base_2(size);
>> + unsigned long iova_pfn;
>> + unsigned int index;
>> if (log_size >= IOVA_RANGE_CACHE_MAX_SIZE || !iovad->rcaches)
>> return 0;
>> - return __iova_rcache_get(&iovad->rcaches[log_size], limit_pfn -
>> size);
>> + iova_pfn = __iova_rcache_get(&iovad->rcaches[log_size], limit_pfn
>> - size);
>> +
>> + if (!iova_pfn && limit_pfn > DMA_BIT_MASK(32)) {
>> + index = log_size + IOVA_RANGE_CACHE_MAX_SIZE;
>> + iova_pfn = __iova_rcache_get(&iovad->rcaches[index],
>> limit_pfn - size);
>> + }
>> +
>> + return iova_pfn
>> }
>> /*
>> @@ -898,7 +912,7 @@ static void free_iova_rcaches(struct iova_domain
>> *iovad)
>> unsigned int cpu;
>> int i, j;
>> - for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
>> + for (i = 0; i < IOVA_RANGE_CACHE_ARRAY_SIZE; ++i) {
>> rcache = &iovad->rcaches[i];
>> if (!rcache->cpu_rcaches)
>> break;
>> @@ -926,7 +940,7 @@ static void free_cpu_cached_iovas(unsigned int
>> cpu, struct iova_domain *iovad)
>> unsigned long flags;
>> int i;
>> - for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
>> + for (i = 0; i < IOVA_RANGE_CACHE_ARRAY_SIZE; ++i) {
>> rcache = &iovad->rcaches[i];
>> cpu_rcache = per_cpu_ptr(rcache->cpu_rcaches, cpu);
>> spin_lock_irqsave(&cpu_rcache->lock, flags);
>> @@ -945,7 +959,7 @@ static void free_global_cached_iovas(struct
>> iova_domain *iovad)
>> unsigned long flags;
>> int i, j;
>> - for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
>> + for (i = 0; i < IOVA_RANGE_CACHE_ARRAY_SIZE; ++i) {
>> rcache = &iovad->rcaches[i];
>> spin_lock_irqsave(&rcache->lock, flags);
>> for (j = 0; j < rcache->depot_size; ++j) {
On 2022-09-19 04:02, [email protected] wrote:
>
>
> 在 2022/9/17 1:03, Robin Murphy 写道:
>> On 2022-09-16 16:46, brookxu.cn wrote:
>>> From: Chunguang Xu <[email protected]>
>>>
>>> While iommu_dma_forcedac disable, for PCI device kernel
>>> try SAC first, if failed then try DAC. Since now rcache
>>> does not distinguish SAC and DAC, if all PFNs contained
>>> in cpu loaded cache is larger than SAC max PFN, but the
>>> SAC address space is sufficient, as cpu loaded cached is
>>> not empty, kernel will iova_alloc () to alloc IOVA. For
>>> PCI device, kernel alloc SAC most, loaded cache may
>>> invalid for SAC alloc for a long time, kernel will enter
>>> alloc_iova() slow path frequencely, as result performance
>>> is degrade. To circumvent this problem, SAC and DAC maybe
>>> better to use separate caches.
>>
>> I really dislike the idea of doubling the already significantly large
>> footprint of rcaches purely to optimise for the stupid case. If you've
>> got to the point of hitting contention in the SAC path, you presumably
>> don't have broken hardware/drivers so you're infinitely better off
>> using forcedac and avoiding it entirely to begin with. And frankly
>> even if you *do* have broken hardware, if you care about performance
>> you're still better off fixing the relevant driver(s) to set correct
>> DMA masks so you can use forcedac.
>
> Some of our NICs have poor performance after heavy traffic impact. We
> found that it maybe caused by a large number of 1-2 order IOVA SAC
> address applications to make SAC address space fragmentation during
> taffic impact, which in turn causes some 3 order IOVA SAC address
> applications to fail. Kernel will try DAC address and release it into
> rcache. After the traffic recovery, and SAC address space recovery from
> fragmentation, but due to the existence of several DAC PFN on the cache
> of a certain CPU, which will broken the usage of rcache for SAC address
> application. As a result, kernel will enter alloc_iova() slow path
> frequencely and performance is poor. So I think this issue should be not
> too much of a broken hardware or driver, but they maybe can also be
> optimized.
My point is that your system *isn't* broken, because the DAC addresses
work fine, so there's really no need for it to spend any time messing
about with SAC constraints at all. Please try my patch[1].
Thanks,
Robin.
[1]
https://lore.kernel.org/linux-iommu/2b0ca6254dd0102bf559b2a73e9b51da089afbe3.1663764627.git.robin.murphy@arm.com/
>
>>
>> Since this mechanism now officially serves as a bandage for broken
>> hardware/drivers and little else, I had an idea to make it a lot
>> better, guess it's time to have a go at writing that patch up...
>>
>> Thanks,
>> Robin.
>>
>>> Signed-off-by: Chunguang Xu <[email protected]>
>>> ---
>>> drivers/iommu/iova.c | 28 +++++++++++++++++++++-------
>>> 1 file changed, 21 insertions(+), 7 deletions(-)
>>>
>>> diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
>>> index 47d1983dfa2a..d5775719a143 100644
>>> --- a/drivers/iommu/iova.c
>>> +++ b/drivers/iommu/iova.c
>>> @@ -16,6 +16,7 @@
>>> #define IOVA_ANCHOR ~0UL
>>> #define IOVA_RANGE_CACHE_MAX_SIZE 6 /* log of max cached IOVA
>>> range size (in pages) */
>>> +#define IOVA_RANGE_CACHE_ARRAY_SIZE (2 * IOVA_RANGE_CACHE_MAX_SIZE)
>>> static bool iova_rcache_insert(struct iova_domain *iovad,
>>> unsigned long pfn,
>>> @@ -723,13 +724,13 @@ int iova_domain_init_rcaches(struct iova_domain
>>> *iovad)
>>> unsigned int cpu;
>>> int i, ret;
>>> - iovad->rcaches = kcalloc(IOVA_RANGE_CACHE_MAX_SIZE,
>>> + iovad->rcaches = kcalloc(IOVA_RANGE_CACHE_ARRAY_SIZE,
>>> sizeof(struct iova_rcache),
>>> GFP_KERNEL);
>>> if (!iovad->rcaches)
>>> return -ENOMEM;
>>> - for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
>>> + for (i = 0; i < IOVA_RANGE_CACHE_ARRAY_SIZE; ++i) {
>>> struct iova_cpu_rcache *cpu_rcache;
>>> struct iova_rcache *rcache;
>>> @@ -825,11 +826,15 @@ static bool iova_rcache_insert(struct
>>> iova_domain *iovad, unsigned long pfn,
>>> unsigned long size)
>>> {
>>> unsigned int log_size = order_base_2(size);
>>> + unsigned int index;
>>> if (log_size >= IOVA_RANGE_CACHE_MAX_SIZE)
>>> return false;
>>> - return __iova_rcache_insert(iovad, &iovad->rcaches[log_size], pfn);
>>> + if (pfn > DMA_BIT_MASK(32))
>>> + index = log_size + IOVA_RANGE_CACHE_MAX_SIZE;
>>> +
>>> + return __iova_rcache_insert(iovad, &iovad->rcaches[index], pfn);
>>> }
>>> /*
>>> @@ -881,11 +886,20 @@ static unsigned long iova_rcache_get(struct
>>> iova_domain *iovad,
>>> unsigned long limit_pfn)
>>> {
>>> unsigned int log_size = order_base_2(size);
>>> + unsigned long iova_pfn;
>>> + unsigned int index;
>>> if (log_size >= IOVA_RANGE_CACHE_MAX_SIZE || !iovad->rcaches)
>>> return 0;
>>> - return __iova_rcache_get(&iovad->rcaches[log_size], limit_pfn -
>>> size);
>>> + iova_pfn = __iova_rcache_get(&iovad->rcaches[log_size],
>>> limit_pfn - size);
>>> +
>>> + if (!iova_pfn && limit_pfn > DMA_BIT_MASK(32)) {
>>> + index = log_size + IOVA_RANGE_CACHE_MAX_SIZE;
>>> + iova_pfn = __iova_rcache_get(&iovad->rcaches[index],
>>> limit_pfn - size);
>>> + }
>>> +
>>> + return iova_pfn
>>> }
>>> /*
>>> @@ -898,7 +912,7 @@ static void free_iova_rcaches(struct iova_domain
>>> *iovad)
>>> unsigned int cpu;
>>> int i, j;
>>> - for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
>>> + for (i = 0; i < IOVA_RANGE_CACHE_ARRAY_SIZE; ++i) {
>>> rcache = &iovad->rcaches[i];
>>> if (!rcache->cpu_rcaches)
>>> break;
>>> @@ -926,7 +940,7 @@ static void free_cpu_cached_iovas(unsigned int
>>> cpu, struct iova_domain *iovad)
>>> unsigned long flags;
>>> int i;
>>> - for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
>>> + for (i = 0; i < IOVA_RANGE_CACHE_ARRAY_SIZE; ++i) {
>>> rcache = &iovad->rcaches[i];
>>> cpu_rcache = per_cpu_ptr(rcache->cpu_rcaches, cpu);
>>> spin_lock_irqsave(&cpu_rcache->lock, flags);
>>> @@ -945,7 +959,7 @@ static void free_global_cached_iovas(struct
>>> iova_domain *iovad)
>>> unsigned long flags;
>>> int i, j;
>>> - for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
>>> + for (i = 0; i < IOVA_RANGE_CACHE_ARRAY_SIZE; ++i) {
>>> rcache = &iovad->rcaches[i];
>>> spin_lock_irqsave(&rcache->lock, flags);
>>> for (j = 0; j < rcache->depot_size; ++j) {