Optimize select and poll by a using stack space for small fd sets
This brings back an old optimization from Linux 2.0. Using the stack is
faster than kmalloc. On a Intel P4 system it speeds up a select of a
single pty fd by about 13% (~4000 cycles -> ~3500)
It also saves memory because a daemon hanging in select or poll will
usually save one or two less pages. This can add up - e.g. if you have 10
daemons blocking in poll/select you save 40KB of memory.
I did a patch for this long ago, but it was never applied. This version is
a reimplementation of the old patch that tries to be less intrusive. I
only did the minimal changes needed for the stack allocation.
The cut off point before external memory is allocated is currently at
832bytes. The system calls always allocate this much memory on the stack.
These 832 bytes are divided into 256 bytes frontend data (for the select
bitmaps of the pollfds) and the rest of the space for the wait queues used
by the low level drivers. There are some extreme cases where this won't
work out for select and it falls back to allocating memory too early -
especially with very sparse large select bitmaps - but the majority of
processes who only have a small number of file descriptors should be ok.
[TBD: 832/256 might not be the best split for select or poll]
I suspect more optimizations might be possible, but they would be more
complicated. One way would be to cache the select/poll context over
multiple system calls because typically the input values should be similar.
Problem is when to flush the file descriptors out though.
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add a proper prototype for autofs4_dentry_release() to autofs_i.h.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add proper prototypes for fat_cache_init() and fat_cache_destroy() in
msdos_fs.h.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Adding bd_claim_by_kobject() function which takes kobject as additional
signature of holder device and creates sysfs symlinks between holder device
and claimed device. bd_release_from_kobject() is a counterpart of
bd_claim_by_kobject.
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Remove all the CONFIG_SYSFS stuff. That's supposed to all be implemented up
in header files.
Yes, the CONFIG_SYSFS=n data structures will be a little larger than
necessary, but that's a tradeoff we can decide to make.
Cc: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Creating "slaves" and "holders" directories in /sys/block/<disk> and
creating "holders" directory under /sys/block/<disk>/<partition>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
We can now make some code static.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Cc: Neil Brown <neilb@suse.de>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
.. it makes some of the code nicer.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
These were an unnecessary wart. Also only have one 'DefineSimpleCache..'
instead of two.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Current svc_expkey holds a pointer to the svc_export structure, so updates to
that structure have to be in-place, which is a wart on the whole cache
infrastruct. So we break that linkage and just do a second lookup.
If this became a performance issue, it would be possible to put a direct link
back in which was only used conditionally. i.e. when an object is replaced
in the cache, we set a flag in the old object. When dereferencing the link
from svc_expkey, if the flag is set, we drop the reference and do a fresh
lookup.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The 'auth_domain's are simply handles on internal data structures. They do
not cache information from user-space, and forcing them into the mold of a
'cache' misrepresents their true nature and causes confusion.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix accidental underflow of the atomic counter.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This functionality is also need for operation of autofs v5 direct mounts.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
We have to have a valid sbi here, or we'd have oopsed already. (There's a
dereference of sbi->catatonic a few lines above)
Coverity #740
Signed-off-by: Dave Jones <davej@redhat.com>
Cc: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch define a new autofs packet for autofs v5 and updates the waitq.c
functions to handle the additional packet type.
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Al Viro <viro@ftp.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch adds expire logic for autofs direct mounts.
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Al Viro <viro@ftp.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch adds a follow_link inode method for the root of an autofs direct
mount trigger. It also adds the corresponding mount options and updates the
show_mount method.
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Al Viro <viro@ftp.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
In order to be able to trigger a mount using the follow_link inode method the
nameidata struct that is passed in needs to have the vfsmount of the autofs
trigger not its parent.
During a path walk if an autofs trigger is mounted on a dentry, when the
follow_link method is called, the nameidata struct contains the vfsmount and
mountpoint dentry of the parent mount while the dentry that is passed in is
the root of the autofs trigger mount. I believe it is impossible to get the
vfsmount of the trigger mount, within the follow_link method, when only the
parent vfsmount and the root dentry of the trigger mount are known.
This patch updates the nameidata struct on entry to __do_follow_link if it
detects that it is out of date. It moves the path_to_nameidata to above
__do_follow_link to facilitate calling it from there. The dput_path is moved
as well as that seemed sensible. No changes are made to these two functions.
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Al Viro <viro@ftp.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Change the functions may_umount and may_umount_tree to boolean functions to
aid code readability.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Rename the function simple_empty_nolock to __simple_empty in line with kernel
naming conventions.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Whitespace and formating changes to waitq code.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add show_options method to display autofs4 mount options in the proc
filesystem.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Remove the update of i_atime from autofs4 in favour of having VFS update it.
i_atime is never used for expire in autofs4.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Alter the expire semantics that define how "busyness" is determined.
Currently a last_used counter is updated on every revalidate from processes
other than the mount owner process group.
This patch changes that so that an expire candidate is busy only if it has a
reference count greater than the expected minimum, such as when there is an
open file or working directory in use.
This method is the only way that busyness can be established for direct mounts
within the new implementation. For consistency the expire semantic is made
the same for all mounts.
A side effect of the patch is that mounts which remain mounted unessessarily
in the presence of some GUI programs that scan the filesystem should now
expire.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix the case where an expire returns busy on a tree mount when it is in fact
not busy. This case was overlooked when the patch to prevent the expiring
away of "scaffolding" directories for tree mounts was applied.
The problem arises when a tree of mounts is a member of a map with other keys.
The current logic will not expire the tree if any other mount in the map is
busy. The solution is to maintain a "minimum" use count for each autofs
dentry and compare this to the actual dentry usage count during expire.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Simplify the expire tree traversal code by using a function from namespace.c
to calculate the next entry in the top down tree traversals carried out during
the expire operation.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Change the names of the boolean functions autofs4_check_mount and
autofs4_check_tree to autofs4_mount_busy and autofs4_tree_busy respectively
and alters their return codes to suit in order to aid code readabilty.
A couple of white space cleanups are included as well.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Addresse a problem where stale dentrys stop mounts from happening.
When a mount point directory is pre-created and a non-existent entry within it
is requested a dentry ends up being created within the mount point directory
which stops future mounts. The problem is solved by ignoring negative,
unhashed dentrys in the mount point d_subdirs list.
Additionally the apparent cacheing of -ENOENT returns from requests is
removed. The test on d_time is a tautology and d_time is not initialised and
has an unexpected value. In short it doesn't do what it's meant to.
The cacheing of failed requests to the daemon is important and will be
followed up later.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Change readdir routines to use the cursor based routines in libfs.c. This
removes reliance on old readdir code from 2.4 and should improve efficiency of
readdir in autofs4.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Whitespace and formating changes to lookup code.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Noted by Oleg Drokin:
We initialized an extra slot of struct kstatfs.spare, sometimes
causing stack corruption.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Oleg Drokin <green@clusterfs.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/bunk/trivial:
drivers/char/ftape/lowlevel/fdc-io.c: Correct a comment
Kconfig help: MTD_JEDECPROBE already supports Intel
Remove ugly debugging stuff
do_mounts.c: Minor ROOT_DEV comment cleanup
BUG_ON() Conversion in drivers/s390/block/dasd_devmap.c
BUG_ON() Conversion in mm/mempool.c
BUG_ON() Conversion in mm/memory.c
BUG_ON() Conversion in kernel/fork.c
BUG_ON() Conversion in ipc/sem.c
BUG_ON() Conversion in fs/ext2/
BUG_ON() Conversion in fs/hfs/
BUG_ON() Conversion in fs/dcache.c
BUG_ON() Conversion in fs/buffer.c
BUG_ON() Conversion in input/serio/hp_sdc_mlc.c
BUG_ON() Conversion in md/dm-table.c
BUG_ON() Conversion in md/dm-path-selector.c
BUG_ON() Conversion in drivers/isdn
BUG_ON() Conversion in drivers/char
BUG_ON() Conversion in drivers/mtd/
Now the only user who are using generic_ffs() is ntfs filesystem. This patch
isolates generic_ffs() as ntfs_ffs() for ntfs.
Signed-off-by: Akinobu Mita <mita@miraclelinux.com>
Cc: Anton Altaparmakov <aia21@cantab.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The nanosleep cleanup allows to remove the data field of hrtimer. The
callback function can use container_of() to get it's own data. Since the
hrtimer structure is anyway embedded in other structures, this adds no
overhead.
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Remove the it_real_value from /proc/*/stat, during 1.2.x was the last time it
returned useful data (as it was directly maintained by the scheduler), now
it's only a waste of time to calculate it. Return 0 instead.
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
There is no valid reason why we can't support "nobh" option for filesystems
with blocksize != PAGESIZE.
This patch lets them use "nobh" option for writeback mode for blocksize <
pagesize.
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Mingming Cao recently added multi-block allocation support for ext3,
currently used only by DIO. I added support to map multiple blocks for
mpage_readpages(). This patch add support for ext3_get_block() to deal
with multi-block mapping. Basically it renames ext3_direct_io_get_blocks()
as ext3_get_block().
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
- Clean up a few little layout things and comments.
- Add a WARN_ON to a case which I was wondering about.
- Tune up some inlines.
Cc: Mingming Cao <cmm@us.ibm.com>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Now that get_block() can handle mapping multiple disk blocks, no need to have
->get_blocks(). This patch removes fs specific ->get_blocks() added for DIO
and makes it users use get_block() instead.
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch changes mpage_readpages() and get_block() to get the disk mapping
information for multiple blocks at the same time.
b_size represents the amount of disk mapping that needs to mapped. On the
successful get_block() b_size indicates the amount of disk mapping thats
actually mapped. Only the filesystems who care to use this information and
provide multiple disk blocks at a time can choose to do so.
No changes are needed for the filesystems who wants to ignore this.
[akpm@osdl.org: cleanups]
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Pass amount of disk needs to be mapped to get_block(). This way one can
modify the fs ->get_block() functions to map multiple blocks at the same time.
[akpm@osdl.org: performance tweak]
[akpm@osdl.org: remove unneeded assignments]
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Increase the size of the buffer_head b_size field (only) for 64 bit platforms.
Update some old and moldy comments in and around the structure as well.
The b_size increase allows us to perform larger mappings and allocations for
large I/O requests from userspace, which tie in with other changes allowing
the get_block_t() interface to map multiple blocks at once.
Signed-off-by: Nathan Scott <nathans@sgi.com>
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Optimize the block reservation and the multiple block allocation: with the
knowledge of the total number of blocks ahead, set or adjust the reservation
window size properly (based on the number of blocks needed) before block
allocation happens: if there isn't any reservation yet, make sure the
reservation window equals to or greater than the number of blocks needed,
before create an reservation window; if a reservation window is already
exists, try to extends the window size to match the number of blocks to
allocate. This could increase the possibility of completing multiple blocks
allocation in a single request, as blocks are only allocated in the range of
the inode's reservation window.
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
