From: Vibhav Pant vibhavp@gmail.com
On Linux, get the minimum supported hugepage size from directory entries /sys/kernel/mm/hugepages, and set the LargePageMinimum field in user_shared_data to it, if supported. --- server/mapping.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 75 insertions(+)
diff --git a/server/mapping.c b/server/mapping.c index 0b6a4116f09..8a108e0dd3e 100644 --- a/server/mapping.c +++ b/server/mapping.c @@ -29,6 +29,14 @@ #include <sys/stat.h> #include <sys/mman.h> #include <unistd.h> +#ifdef HAVE_MEMFD_CREATE +#include <linux/memfd.h> +#endif +#ifdef __linux__ /* For detecting hugepage support. */ +#include <dirent.h> +#include <errno.h> +#include <limits.h> +#endif
#include "ntstatus.h" #define WIN32_NO_STATUS @@ -1426,6 +1434,66 @@ obj_locator_t get_shared_object_locator( const volatile void *object_shm ) return locator; }
+#ifdef __linux__ +static size_t linux_get_min_hugepage_size( void ) +{ + DIR *sysfs_hugepages; + struct dirent *supported_size; + size_t min_size = 0; + size_t total_supported_sizes = 0; + + errno = 0; + sysfs_hugepages = opendir("/sys/kernel/mm/hugepages"); + if (sysfs_hugepages == NULL) + { + return -1; + } + + while(1) + { + long hugepage_size; + + supported_size = readdir( sysfs_hugepages ); + if ( supported_size == NULL ) + { + break; + } + if (strncmp( supported_size->d_name, "hugepages-", 10) != 0) + { + continue; + } + errno = 0; + hugepage_size = strtol( &supported_size->d_name[10], NULL, 10 ); + if (hugepage_size == 0 || hugepage_size == LONG_MAX || hugepage_size == LONG_MIN) + { + if (errno != 0) + { + fprintf( stderr, + "could not parse page size from directory entry '%s': %s\n", + supported_size->d_name, strerror( errno ) ); + } + continue; + } + hugepage_size *= 1024; + min_size = ( total_supported_sizes == 0 ) + ? hugepage_size + : ( hugepage_size < min_size ? hugepage_size : min_size ); + total_supported_sizes++; + } + + closedir(sysfs_hugepages); + return min_size; +} +#endif /* __linux__ */ + +static size_t get_min_large_page_size( void ) +{ +#ifdef __linux__ + return linux_get_min_hugepage_size(); +#endif + return 0; +} + struct object *create_user_data_mapping( struct object *root, const struct unicode_str *name, unsigned int attr, const struct security_descriptor *sd ) { @@ -1437,8 +1505,15 @@ struct object *create_user_data_mapping( struct object *root, const struct unico ptr = mmap( NULL, mapping->size, PROT_WRITE, MAP_SHARED, get_unix_fd( mapping->fd ), 0 ); if (ptr != MAP_FAILED) { + ULONG min_large_page_size; + user_shared_data = ptr; user_shared_data->SystemCall = 1; + min_large_page_size = get_min_large_page_size(); + if (min_large_page_size != 0) + { + user_shared_data->LargePageMinimum = min_large_page_size; + } } return &mapping->obj; }