81243eacfa
Current supplementary groups code can massively overallocate memory and is implemented in a way so that access to individual gid is done via 2D array. If number of gids is <= 32, memory allocation is more or less tolerable (140/148 bytes). But if it is not, code allocates full page (!) regardless and, what's even more fun, doesn't reuse small 32-entry array. 2D array means dependent shifts, loads and LEAs without possibility to optimize them (gid is never known at compile time). All of the above is unnecessary. Switch to the usual trailing-zero-len-array scheme. Memory is allocated with kmalloc/vmalloc() and only as much as needed. Accesses become simpler (LEA 8(gi,idx,4) or even without displacement). Maximum number of gids is 65536 which translates to 256KB+8 bytes. I think kernel can handle such allocation. On my usual desktop system with whole 9 (nine) aux groups, struct group_info shrinks from 148 bytes to 44 bytes, yay! Nice side effects: - "gi->gid[i]" is shorter than "GROUP_AT(gi, i)", less typing, - fix little mess in net/ipv4/ping.c should have been using GROUP_AT macro but this point becomes moot, - aux group allocation is persistent and should be accounted as such. Link: http://lkml.kernel.org/r/20160817201927.GA2096@p183.telecom.by Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Vasily Kulikov <segoon@openwall.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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include/linux | ||
lnet | ||
lustre | ||
Kconfig | ||
Makefile | ||
README.txt | ||
sysfs-fs-lustre | ||
TODO |
Lustre Parallel Filesystem Client ================================= The Lustre file system is an open-source, parallel file system that supports many requirements of leadership class HPC simulation environments. Born from from a research project at Carnegie Mellon University, the Lustre file system is a widely-used option in HPC. The Lustre file system provides a POSIX compliant file system interface, can scale to thousands of clients, petabytes of storage and hundreds of gigabytes per second of I/O bandwidth. Unlike shared disk storage cluster filesystems (e.g. OCFS2, GFS, GPFS), Lustre has independent Metadata and Data servers that clients can access in parallel to maximize performance. In order to use Lustre client you will need to download the "lustre-client" package that contains the userspace tools from http://lustre.org/download/ You will need to install and configure your Lustre servers separately. Mount Syntax ============ After you installed the lustre-client tools including mount.lustre binary you can mount your Lustre filesystem with: mount -t lustre mgs:/fsname mnt where mgs is the host name or ip address of your Lustre MGS(management service) fsname is the name of the filesystem you would like to mount. Mount Options ============= noflock Disable posix file locking (Applications trying to use the functionality will get ENOSYS) localflock Enable local flock support, using only client-local flock (faster, for applications that require flock but do not run on multiple nodes). flock Enable cluster-global posix file locking coherent across all client nodes. user_xattr, nouser_xattr Support "user." extended attributes (or not) user_fid2path, nouser_fid2path Enable FID to path translation by regular users (or not) checksum, nochecksum Verify data consistency on the wire and in memory as it passes between the layers (or not). lruresize, nolruresize Allow lock LRU to be controlled by memory pressure on the server (or only 100 (default, controlled by lru_size proc parameter) locks per CPU per server on this client). lazystatfs, nolazystatfs Do not block in statfs() if some of the servers are down. 32bitapi Shrink inode numbers to fit into 32 bits. This is necessary if you plan to reexport Lustre filesystem from this client via NFSv4. verbose, noverbose Enable mount/umount console messages (or not) More Information ================ You can get more information at the Lustre website: http://wiki.lustre.org/ Source for the userspace tools and out-of-tree client and server code is available at: http://git.hpdd.intel.com/fs/lustre-release.git Latest binary packages: http://lustre.org/download/