Re: [RFC PATCH v2 5/7] KVM: selftests: List all hugetlb src types specified with page sizes

"wangyanan (Y)" <wangyanan55@xxxxxxxxxx> · Fri, 26 Feb 2021 13:45:32 +0800

On 2021/2/26 7:42, Ben Gardon wrote:
On Wed, Feb 24, 2021 at 10:03 PM Yanan Wang <wangyanan55@xxxxxxxxxx> wrote:
With VM_MEM_SRC_ANONYMOUS_HUGETLB, we currently can only use system
default hugetlb pages to back the testing guest memory. In order to
add flexibility, now list all the known hugetlb backing src types with
different page sizes, so that we can specify use of hugetlb pages of the
exact granularity that we want. And as all the known hugetlb page sizes
are listed, it's appropriate for all architectures.

Besides, the helper get_backing_src_pagesz() is added to get the
granularity of different backing src types(anonumous, thp, hugetlb).

Signed-off-by: Yanan Wang <wangyanan55@xxxxxxxxxx>
---
  .../testing/selftests/kvm/include/test_util.h | 19 ++++++-
  tools/testing/selftests/kvm/lib/kvm_util.c    |  2 +-
  tools/testing/selftests/kvm/lib/test_util.c   | 56 +++++++++++++++----
  3 files changed, 63 insertions(+), 14 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/test_util.h b/tools/testing/selftests/kvm/include/test_util.h
index ef24c76ba89a..be5d08bcdca7 100644
--- a/tools/testing/selftests/kvm/include/test_util.h
+++ b/tools/testing/selftests/kvm/include/test_util.h
@@ -70,16 +70,31 @@ struct timespec timespec_div(struct timespec ts, int divisor);
  enum vm_mem_backing_src_type {
         VM_MEM_SRC_ANONYMOUS,
         VM_MEM_SRC_ANONYMOUS_THP,
-       VM_MEM_SRC_ANONYMOUS_HUGETLB,
+       VM_MEM_SRC_ANONYMOUS_HUGETLB_16KB,
+       VM_MEM_SRC_ANONYMOUS_HUGETLB_64KB,
+       VM_MEM_SRC_ANONYMOUS_HUGETLB_512KB,
+       VM_MEM_SRC_ANONYMOUS_HUGETLB_1MB,
+       VM_MEM_SRC_ANONYMOUS_HUGETLB_2MB,
+       VM_MEM_SRC_ANONYMOUS_HUGETLB_8MB,
+       VM_MEM_SRC_ANONYMOUS_HUGETLB_16MB,
+       VM_MEM_SRC_ANONYMOUS_HUGETLB_32MB,
+       VM_MEM_SRC_ANONYMOUS_HUGETLB_256MB,
+       VM_MEM_SRC_ANONYMOUS_HUGETLB_512MB,
+       VM_MEM_SRC_ANONYMOUS_HUGETLB_1GB,
+       VM_MEM_SRC_ANONYMOUS_HUGETLB_2GB,
+       VM_MEM_SRC_ANONYMOUS_HUGETLB_16GB,
+       NUM_SRC_TYPES,
  };

  struct vm_mem_backing_src_alias {
         const char *name;
-       enum vm_mem_backing_src_type type;
+       uint32_t flag;
  };

  bool thp_configured(void);
  size_t get_trans_hugepagesz(void);
+const struct vm_mem_backing_src_alias *vm_mem_backing_src_alias(uint32_t i);
+size_t get_backing_src_pagesz(uint32_t i);
  void backing_src_help(void);
  enum vm_mem_backing_src_type parse_backing_src_type(const char *type_name);

diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index cc22c4ab7d67..b91c8e3a7ee1 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -757,7 +757,7 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm,
         region->mmap_start = mmap(NULL, region->mmap_size,
                                   PROT_READ | PROT_WRITE,
                                   MAP_PRIVATE | MAP_ANONYMOUS
-                                 | (src_type == VM_MEM_SRC_ANONYMOUS_HUGETLB ? MAP_HUGETLB : 0),
+                                 | vm_mem_backing_src_alias(src_type)->flag,
                                   -1, 0);
         TEST_ASSERT(region->mmap_start != MAP_FAILED,
                     "test_malloc failed, mmap_start: %p errno: %i",
diff --git a/tools/testing/selftests/kvm/lib/test_util.c b/tools/testing/selftests/kvm/lib/test_util.c
index f2d133f76c67..6780aa058f35 100644
--- a/tools/testing/selftests/kvm/lib/test_util.c
+++ b/tools/testing/selftests/kvm/lib/test_util.c
@@ -11,6 +11,7 @@
  #include <stdlib.h>
  #include <time.h>
  #include <sys/stat.h>
+#include <linux/mman.h>
  #include "linux/kernel.h"

  #include "test_util.h"
@@ -112,12 +113,6 @@ void print_skip(const char *fmt, ...)
         puts(", skipping test");
  }

-const struct vm_mem_backing_src_alias backing_src_aliases[] = {
-       {"anonymous", VM_MEM_SRC_ANONYMOUS,},
-       {"anonymous_thp", VM_MEM_SRC_ANONYMOUS_THP,},
-       {"anonymous_hugetlb", VM_MEM_SRC_ANONYMOUS_HUGETLB,},
-};
-
  bool thp_configured(void)
  {
         int ret;
@@ -153,22 +148,61 @@ size_t get_trans_hugepagesz(void)
         return size;
  }

+const struct vm_mem_backing_src_alias *vm_mem_backing_src_alias(uint32_t i)
+{
+       static const struct vm_mem_backing_src_alias aliases[] = {
+               { "anonymous",               0                            },
+               { "anonymous_thp",           0                            },
+               { "anonymous_hugetlb_16kb",  MAP_HUGETLB | MAP_HUGE_16KB  },
+               { "anonymous_hugetlb_64kb",  MAP_HUGETLB | MAP_HUGE_64KB  },
+               { "anonymous_hugetlb_512kb", MAP_HUGETLB | MAP_HUGE_512KB },
+               { "anonymous_hugetlb_1mb",   MAP_HUGETLB | MAP_HUGE_1MB   },
+               { "anonymous_hugetlb_2mb",   MAP_HUGETLB | MAP_HUGE_2MB   },
+               { "anonymous_hugetlb_8mb",   MAP_HUGETLB | MAP_HUGE_8MB   },
+               { "anonymous_hugetlb_16mb",  MAP_HUGETLB | MAP_HUGE_16MB  },
+               { "anonymous_hugetlb_32mb",  MAP_HUGETLB | MAP_HUGE_32MB  },
+               { "anonymous_hugetlb_256mb", MAP_HUGETLB | MAP_HUGE_256MB },
+               { "anonymous_hugetlb_512mb", MAP_HUGETLB | MAP_HUGE_512MB },
+               { "anonymous_hugetlb_1gb",   MAP_HUGETLB | MAP_HUGE_1GB   },
+               { "anonymous_hugetlb_2gb",   MAP_HUGETLB | MAP_HUGE_2GB   },
+               { "anonymous_hugetlb_16gb",  MAP_HUGETLB | MAP_HUGE_16GB  },
+       };
+       _Static_assert(ARRAY_SIZE(aliases) == NUM_SRC_TYPES,
+                      "Missing new backing src types?");
+
+       TEST_ASSERT(i < NUM_SRC_TYPES, "Backing src type ID %d too big", i);
+
+       return aliases + i;
NIT: This would be easier for me to read as return &aliases[i];
Ok, will change it.

+}
+
+size_t get_backing_src_pagesz(uint32_t i)
+{
+       uint32_t flag = vm_mem_backing_src_alias(i)->flag;
+
+       if (i == VM_MEM_SRC_ANONYMOUS)
+               return getpagesize();
+       if (i == VM_MEM_SRC_ANONYMOUS_THP)
+               return get_trans_hugepagesz();
+
+       return 1ULL << (flag >> HUGETLB_FLAG_ENCODE_SHIFT);
It might also be nice to add a macro where MAP_HUGE_1GB and company
are defined to get the size for a given hugeTLB type. I think you're
mixing macros here too (which works because they're defined off one
another) but it's a little confusing.
MAP_HUGE_1GB and company are defined in
tools/include/uapi/linux/mman.h as equal to the values
HUGETLB_FLAG_ENCODE_1GB and friends in
tools/include/asm-generic/hugetlb_encode.h, but it seems like it would
be good to use MAP_HUGE_SHIFT to match in that case. I think this all
also relies on MAP_HUGETLB being in the bits less than MAP_HUGE_SHIFT
which isn't stated here. All up, I would add a macro to
tools/include/uapi/linux/mman.h:

#define MAP_HUGE_PAGE_SIZE(x) (1ULL << ((x >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK))
Good idea. This will be more stable and easier to read. Thanks.

Or something similar, and use that here.

+}
+
  void backing_src_help(void)
  {
         int i;

         printf("Available backing src types:\n");
-       for (i = 0; i < ARRAY_SIZE(backing_src_aliases); i++)
-               printf("\t%s\n", backing_src_aliases[i].name);
+       for (i = 0; i < NUM_SRC_TYPES; i++)
+               printf("\t%s\n", vm_mem_backing_src_alias(i)->name);
  }

  enum vm_mem_backing_src_type parse_backing_src_type(const char *type_name)
  {
         int i;

-       for (i = 0; i < ARRAY_SIZE(backing_src_aliases); i++)
-               if (!strcmp(type_name, backing_src_aliases[i].name))
-                       return backing_src_aliases[i].type;
+       for (i = 0; i < NUM_SRC_TYPES; i++)
+               if (!strcmp(type_name, vm_mem_backing_src_alias(i)->name))
+                       return i;

         backing_src_help();
         TEST_FAIL("Unknown backing src type: %s", type_name);
--
2.19.1

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