Eric Dumazet 8a81252b77 fs/file.c: don't acquire files->file_lock in fd_install() ... Mateusz Guzik reported : Currently obtaining a new file descriptor results in locking fdtable twice - once in order to reserve a slot and second time to fill it. Holding the spinlock in __fd_install() is needed in case a resize is done, or to prevent a resize. Mateusz provided an RFC patch and a micro benchmark : http://people.redhat.com/~mguzik/pipebench.c A resize is an unlikely operation in a process lifetime, as table size is at least doubled at every resize. We can use RCU instead of the spinlock. __fd_install() must wait if a resize is in progress. The resize must block new __fd_install() callers from starting, and wait that ongoing install are finished (synchronize_sched()) resize should be attempted by a single thread to not waste resources. rcu_sched variant is used, as __fd_install() and expand_fdtable() run from process context. It gives us a ~30% speedup using pipebench on a dual Intel(R) Xeon(R) CPU E5-2696 v2 @ 2.50GHz Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Mateusz Guzik <mguzik@redhat.com> Acked-by: Mateusz Guzik <mguzik@redhat.com> Tested-by: Mateusz Guzik <mguzik@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>		2015-07-01 02:30:09 -04:00
..
caching	FS-Cache: Count the number of initialised operations	2015-04-02 14:28:53 +01:00
cifs	update CIFS TODO list	2014-08-02 01:26:07 -05:00
configfs	configfs: convert to umode_t	2012-01-03 22:54:57 -05:00
nfs	rdma: replace deprecated ifconfig in doc	2015-04-15 16:06:39 -04:00
pohmelfs	Documentation: Fix multiple typo in Documentation	2012-03-07 16:08:24 +01:00
.gitignore	Documentation: update .gitignore files	2014-09-26 11:02:59 +02:00
9p.txt	9p: update documentation	2014-01-24 10:55:21 -06:00
00-INDEX	dax: replace XIP documentation with DAX documentation	2015-02-16 17:56:03 -08:00
adfs.txt
affs.txt	affs: add mount option to avoid filename truncates	2014-04-07 16:36:08 -07:00
afs.txt
autofs4-mount-control.txt	doc: fix double words	2014-03-21 13:16:58 +01:00
autofs4.txt	autofs: the documentation I wanted to read	2014-10-14 02:18:17 +02:00
automount-support.txt	Documentation: remove outdated information from automount-support.txt	2015-05-15 01:10:38 -04:00
befs.txt	Documentation: befs.txt: no maintainer, orphaned	2011-08-13 18:34:03 -07:00
bfs.txt
btrfs.txt	btrfs: Add treelog mount option.	2014-01-28 13:20:20 -08:00
ceph.txt	ceph: enable/disable dentry complete flags via mount option	2012-01-12 11:00:40 -08:00
coda.txt
cramfs.txt
dax.txt	dax: does not work correctly with virtual aliasing caches	2015-02-16 17:56:04 -08:00
debugfs.txt	debugfs: Have debugfs_print_regs32() return void	2014-11-05 14:13:38 -05:00
devpts.txt
directory-locking	vfs: take i_mutex on renamed file	2013-11-09 00:16:40 -05:00
dlmfs.txt	ocfs2: update web page + git tree in documentation	2015-02-28 09:57:50 -08:00
dnotify_test.c
dnotify.txt
ecryptfs.txt
efivarfs.txt	efivarfs: Add documentation for the EFI variable filesystem	2012-10-30 10:39:18 +00:00
exofs.txt
ext2.txt	ext2: get rid of most mentions of XIP in ext2	2015-02-16 17:56:04 -08:00
ext3.txt	ext3: allow specifying external journal by pathname mount option	2013-07-31 22:11:15 +02:00
ext4.txt	ext4: add DAX functionality	2015-02-16 17:56:04 -08:00
f2fs.txt	f2fs: enable inline data by default	2015-04-10 15:08:52 -07:00
fiemap.txt	fsioctl.c: make generic_block_fiemap() signal-tolerant	2015-02-10 14:30:30 -08:00
files.txt	Wrap accesses to the fd_sets in struct fdtable	2012-02-19 10:30:52 -08:00
fuse.txt
gfs2-glocks.txt	GFS2: Update glock doc to add new stats info	2012-05-10 12:41:40 +01:00
gfs2-uevents.txt	Documentation: Fix multiple typo in Documentation	2012-03-07 16:08:24 +01:00
gfs2.txt	GFS2: Update main gfs2 doc	2012-05-10 11:45:31 +01:00
hfs.txt	Documentation: HFS is orphaned	2011-11-04 12:01:48 -07:00
hfsplus.txt	Documentation: update URL to hfsplus Technote 1150	2014-02-20 14:48:51 +01:00
hpfs.txt
inotify.txt	inotify: update documentation to reflect code changes	2015-02-10 14:30:28 -08:00
isofs.txt
jfs.txt	doc: fix misspellings with 'codespell' tool	2013-05-28 12:02:12 +02:00
Locking	switch ->put_link() from dentry to inode	2015-05-11 08:13:12 -04:00
locks.txt	doc: fix broken references	2011-09-27 18:08:04 +02:00
logfs.txt
Makefile	Documentation: add makefiles for more targets	2014-09-26 11:02:56 +02:00
mandatory-locking.txt
ncpfs.txt
nilfs2.txt	nilfs2: update project's web site in nilfs2.txt	2014-04-03 16:21:26 -07:00
ntfs.txt	NTFS: Remove changelog from Documentation/filesystems/ntfs.txt.	2014-10-16 12:43:57 +01:00
ocfs2.txt	ocfs2: update web page + git tree in documentation	2015-02-28 09:57:50 -08:00
omfs.txt
overlayfs.txt	ovl: document lower layer ordering	2015-01-08 15:09:15 +01:00
path-lookup.txt
porting	fs/file.c: don't acquire files->file_lock in fd_install()	2015-07-01 02:30:09 -04:00
proc.txt	The documentation tree update for 4.1. Numerous fixes, the overdue removal	2015-04-18 11:10:49 -04:00
qnx6.txt	doc: filesystems : Fix typo in Documentations/filesystems	2013-08-20 13:45:56 +02:00
quota.txt
ramfs-rootfs-initramfs.txt	initmpfs: use initramfs if rootfstype= or root= specified	2013-09-11 15:59:38 -07:00
relay.txt	doc: Fix typo in doucmentations	2013-07-25 12:34:15 +02:00
romfs.txt
seq_file.txt	Documentation: update seq_file	2014-12-29 15:40:18 -07:00
sharedsubtree.txt	doc: spelling error changes	2014-05-05 15:32:05 +02:00
spufs.txt
squashfs.txt	Squashfs: Add LZ4 compression configuration option	2014-11-27 18:48:44 +00:00
sysfs-pci.txt
sysfs-tagging.txt	doc: Fix typo in doucmentations	2013-07-25 12:34:15 +02:00
sysfs.txt	Documentation/filesystems/sysfs.txt: fix device_attribute declaration	2014-01-23 16:37:00 -08:00
sysv-fs.txt
tmpfs.txt
ubifs.txt	UBIFS: switch self-check knobs to debugfs	2011-07-04 10:54:28 +03:00
udf.txt
ufs.txt
vfat.txt	fs/fat/: add support for DOS 1.x formatted volumes	2014-06-06 16:08:10 -07:00
vfs.txt	update Documentation/filesystems/ regarding the follow_link/put_link changes	2015-05-15 01:10:36 -04:00
xfs-delayed-logging-design.txt
xfs-self-describing-metadata.txt	xfs: add metadata CRC documentation	2013-04-27 13:27:43 -05:00
xfs.txt	xfs: remove deprecated mount options	2015-02-24 10:17:04 +11:00