diff options
Diffstat (limited to 'fs/Kconfig')
| -rw-r--r-- | fs/Kconfig | 24 |
1 files changed, 19 insertions, 5 deletions
diff --git a/fs/Kconfig b/fs/Kconfig index d8207a1b8c44..47af46a573ba 100644 --- a/fs/Kconfig +++ b/fs/Kconfig @@ -43,7 +43,7 @@ source "fs/f2fs/Kconfig" source "fs/zonefs/Kconfig" config FS_DAX - bool "Direct Access (DAX) support" + bool "File system based Direct Access (DAX) support" depends on MMU depends on !(ARM || MIPS || SPARC) select DEV_PAGEMAP_OPS if (ZONE_DEVICE && !FS_DAX_LIMITED) @@ -53,8 +53,23 @@ config FS_DAX Direct Access (DAX) can be used on memory-backed block devices. If the block device supports DAX and the filesystem supports DAX, then you can avoid using the pagecache to buffer I/Os. Turning - on this option will compile in support for DAX; you will need to - mount the filesystem using the -o dax option. + on this option will compile in support for DAX. + + For a DAX device to support file system access it needs to have + struct pages. For the nfit based NVDIMMs this can be enabled + using the ndctl utility: + + # ndctl create-namespace --force --reconfig=namespace0.0 \ + --mode=fsdax --map=mem + + See the 'create-namespace' man page for details on the overhead of + --map=mem: + https://docs.pmem.io/ndctl-user-guide/ndctl-man-pages/ndctl-create-namespace + + For ndctl to work CONFIG_DEV_DAX needs to be enabled as well. For most + file systems DAX support needs to be manually enabled globally or + per-inode using a mount option as well. See the file documentation in + Documentation/filesystems/dax.rst for details. If you do not have a block device that is capable of using this, or if unsure, say N. Saying Y will increase the size of the kernel @@ -219,8 +234,7 @@ config ARCH_SUPPORTS_HUGETLBFS config HUGETLBFS bool "HugeTLB file system support" - depends on X86 || IA64 || SPARC64 || (S390 && 64BIT) || \ - ARCH_SUPPORTS_HUGETLBFS || BROKEN + depends on X86 || IA64 || SPARC64 || ARCH_SUPPORTS_HUGETLBFS || BROKEN help hugetlbfs is a filesystem backing for HugeTLB pages, based on ramfs. For architectures that support it, say Y here and read |