linux/fs/nfsd
Alexey Dobriyan 81243eacfa cred: simpler, 1D supplementary groups
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>
2016-10-07 18:46:30 -07:00
..
acl.h nfsd4: remove nfs4_acl_new 2014-07-08 17:14:27 -04:00
auth.c cred: simpler, 1D supplementary groups 2016-10-07 18:46:30 -07:00
auth.h nfsd: Remove nfsd_luid, nfsd_lgid, nfsd_ruid and nfsd_rgid 2013-02-13 06:15:51 -08:00
blocklayout.c Highlights: 2016-08-04 19:59:06 -04:00
blocklayoutxdr.c Highlights: 2016-08-04 19:59:06 -04:00
blocklayoutxdr.h nfsd: add SCSI layout support 2016-03-18 11:42:53 -04:00
cache.h nfsd: Remove the cache_hash list 2014-08-17 12:00:12 -04:00
current_stateid.h
export.c nfsd: allow nfsd to advertise multiple layout types 2016-07-15 15:31:32 -04:00
export.h nfsd: allow nfsd to advertise multiple layout types 2016-07-15 15:31:32 -04:00
fault_inject.c nfsd: remove old fault injection infrastructure 2014-08-05 10:55:10 -04:00
flexfilelayout.c nfsd: Add a super simple flex file server 2016-07-13 15:40:48 -04:00
flexfilelayoutxdr.c nfsd: Add a super simple flex file server 2016-07-13 15:40:48 -04:00
flexfilelayoutxdr.h nfsd: Add a super simple flex file server 2016-07-13 15:40:48 -04:00
idmap.h nfsd: Remove duplicate define of IDMAP_NAMESZ/IDMAP_TYPE_xx 2015-07-20 14:58:46 -04:00
Kconfig xfs: abstract block export operations from nfsd layouts 2016-07-15 15:31:29 -04:00
lockd.c lockd: constify nlmsvc_binding structure 2016-01-07 10:10:50 -05:00
Makefile nfsd: Add a super simple flex file server 2016-07-13 15:40:48 -04:00
netns.h nfsd: recover: constify nfsd4_client_tracking_ops structures 2015-11-23 12:15:30 -07:00
nfs2acl.c nfsd: check permissions when setting ACLs 2016-06-24 12:11:52 -04:00
nfs3acl.c nfsd: check permissions when setting ACLs 2016-06-24 12:11:52 -04:00
nfs3proc.c don't bother with ->d_inode->i_sb - it's always equal to ->d_sb 2016-04-10 17:11:51 -04:00
nfs3xdr.c A very quiet cycle for nfsd, mainly just an RDMA update from Chuck Lever. 2016-05-24 14:39:20 -07:00
nfs4acl.c nfsd: check permissions when setting ACLs 2016-06-24 12:11:52 -04:00
nfs4callback.c nfsd4/rpc: move backchannel create logic into rpc code 2016-06-15 10:32:25 -04:00
nfs4idmap.c nfsd: Remove duplicate define of IDMAP_NAMESZ/IDMAP_TYPE_xx 2015-07-20 14:58:46 -04:00
nfs4layouts.c nfsd: allow nfsd to advertise multiple layout types 2016-07-15 15:31:32 -04:00
nfs4proc.c nfsd: drop unnecessary MAY_EXEC check from create 2016-08-04 17:11:52 -04:00
nfs4recover.c Various bugfixes, a RDMA update from Chuck Lever, and support for a new 2016-03-24 10:41:00 -07:00
nfs4state.c cred: simpler, 1D supplementary groups 2016-10-07 18:46:30 -07:00
nfs4xdr.c nfsd: allow nfsd to advertise multiple layout types 2016-07-15 15:31:32 -04:00
nfscache.c nfsd: remove recurring workqueue job to clean DRC 2015-11-10 09:25:51 -05:00
nfsctl.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2016-07-29 15:54:19 -07:00
nfsd.h nfsd: implement machine credential support for some operations 2016-07-13 15:32:47 -04:00
nfsfh.c nfsd: check d_can_lookup in fh_verify of directories 2016-08-04 17:11:48 -04:00
nfsfh.h wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
nfsproc.c nfsd: reorganize nfsd_create 2016-08-04 17:11:49 -04:00
nfssvc.c nfsd: Fix nfsd leaks sunrpc module references 2016-01-07 10:10:51 -05:00
nfsxdr.c nfsd: Fix some indent inconsistancy 2016-07-13 15:53:41 -04:00
pnfs.h nfsd: Add a super simple flex file server 2016-07-13 15:40:48 -04:00
state.h nfsd: implement machine credential support for some operations 2016-07-13 15:32:47 -04:00
stats.c drop redundant ->owner initializations 2016-05-29 19:08:00 -04:00
stats.h nfsd: move <linux/nfsd/stats.h> to fs/nfsd 2014-05-06 17:54:55 -04:00
trace.c nfsd: move include of state.h from trace.c to trace.h 2015-10-23 15:57:29 -04:00
trace.h nfsd: add new io class tracepoint 2016-01-14 17:32:51 -05:00
vfs.c nfsd: fix dentry refcounting on create 2016-08-11 11:42:08 -04:00
vfs.h nfsd: reorganize nfsd_create 2016-08-04 17:11:49 -04:00
xdr3.h nfsd: fix encode_entryplus_baggage stack usage 2014-01-23 13:50:27 -05:00
xdr4.h nfsd: implement machine credential support for some operations 2016-07-13 15:32:47 -04:00
xdr4cb.h nfsd: implement pNFS layout recalls 2015-02-02 18:09:43 +01:00
xdr.h nfsd: handle vfs_getattr errors in acl protocol 2013-02-26 02:46:09 -05:00