Alessandro Zummo [Mon, 27 Mar 2006 09:16:37 +0000 (01:16 -0800)]
[PATCH] RTC subsystem: class
Add the basic RTC subsystem infrastructure to the kernel.
rtc/class.c - registration facilities for RTC drivers
rtc/interface.c - kernel/rtc interface functions
rtc/hctosys.c - snippet of code that copies hw clock to sw clock
at bootup, if configured to do so.
Alessandro Zummo [Mon, 27 Mar 2006 09:16:35 +0000 (01:16 -0800)]
[PATCH] RTC subsystem: ARM cleanup
This patch removes from the ARM subsytem some of the rtc-related functions
that have been included in the RTC subsystem. It also fixes some naming
collisions.
Alan Stern [Mon, 27 Mar 2006 09:16:30 +0000 (01:16 -0800)]
[PATCH] Notifier chain update: API changes
The kernel's implementation of notifier chains is unsafe. There is no
protection against entries being added to or removed from a chain while the
chain is in use. The issues were discussed in this thread:
We noticed that notifier chains in the kernel fall into two basic usage
classes:
"Blocking" chains are always called from a process context
and the callout routines are allowed to sleep;
"Atomic" chains can be called from an atomic context and
the callout routines are not allowed to sleep.
We decided to codify this distinction and make it part of the API. Therefore
this set of patches introduces three new, parallel APIs: one for blocking
notifiers, one for atomic notifiers, and one for "raw" notifiers (which is
really just the old API under a new name). New kinds of data structures are
used for the heads of the chains, and new routines are defined for
registration, unregistration, and calling a chain. The three APIs are
explained in include/linux/notifier.h and their implementation is in
kernel/sys.c.
With atomic and blocking chains, the implementation guarantees that the chain
links will not be corrupted and that chain callers will not get messed up by
entries being added or removed. For raw chains the implementation provides no
guarantees at all; users of this API must provide their own protections. (The
idea was that situations may come up where the assumptions of the atomic and
blocking APIs are not appropriate, so it should be possible for users to
handle these things in their own way.)
There are some limitations, which should not be too hard to live with. For
atomic/blocking chains, registration and unregistration must always be done in
a process context since the chain is protected by a mutex/rwsem. Also, a
callout routine for a non-raw chain must not try to register or unregister
entries on its own chain. (This did happen in a couple of places and the code
had to be changed to avoid it.)
Since atomic chains may be called from within an NMI handler, they cannot use
spinlocks for synchronization. Instead we use RCU. The overhead falls almost
entirely in the unregister routine, which is okay since unregistration is much
less frequent that calling a chain.
Here is the list of chains that we adjusted and their classifications. None
of them use the raw API, so for the moment it is only a placeholder.
It's possible that some of these classifications are wrong. If they are,
please let us know or submit a patch to fix them. Note that any chain that
gets called very frequently should be atomic, because the rwsem read-locking
used for blocking chains is very likely to incur cache misses on SMP systems.
(However, if the chain's callout routines may sleep then the chain cannot be
atomic.)
The patch set was written by Alan Stern and Chandra Seetharaman, incorporating
material written by Keith Owens and suggestions from Paul McKenney and Andrew
Morton.
[jes@sgi.com: restructure the notifier chain initialization macros] Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Signed-off-by: Jes Sorensen <jes@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Ingo Molnar [Mon, 27 Mar 2006 09:16:22 +0000 (01:16 -0800)]
[PATCH] lightweight robust futexes: core
Add the core infrastructure for robust futexes: structure definitions, the new
syscalls and the do_exit() based cleanup mechanism.
Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Arjan van de Ven <arjan@infradead.org> Acked-by: Ulrich Drepper <drepper@redhat.com> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Ingo Molnar [Mon, 27 Mar 2006 09:16:21 +0000 (01:16 -0800)]
[PATCH] lightweight robust futexes: arch defaults
This patchset provides a new (written from scratch) implementation of robust
futexes, called "lightweight robust futexes". We believe this new
implementation is faster and simpler than the vma-based robust futex solutions
presented before, and we'd like this patchset to be adopted in the upstream
kernel. This is version 1 of the patchset.
Background
----------
What are robust futexes? To answer that, we first need to understand what
futexes are: normal futexes are special types of locks that in the
noncontended case can be acquired/released from userspace without having to
enter the kernel.
A futex is in essence a user-space address, e.g. a 32-bit lock variable
field. If userspace notices contention (the lock is already owned and someone
else wants to grab it too) then the lock is marked with a value that says
"there's a waiter pending", and the sys_futex(FUTEX_WAIT) syscall is used to
wait for the other guy to release it. The kernel creates a 'futex queue'
internally, so that it can later on match up the waiter with the waker -
without them having to know about each other. When the owner thread releases
the futex, it notices (via the variable value) that there were waiter(s)
pending, and does the sys_futex(FUTEX_WAKE) syscall to wake them up. Once all
waiters have taken and released the lock, the futex is again back to
'uncontended' state, and there's no in-kernel state associated with it. The
kernel completely forgets that there ever was a futex at that address. This
method makes futexes very lightweight and scalable.
"Robustness" is about dealing with crashes while holding a lock: if a process
exits prematurely while holding a pthread_mutex_t lock that is also shared
with some other process (e.g. yum segfaults while holding a pthread_mutex_t,
or yum is kill -9-ed), then waiters for that lock need to be notified that the
last owner of the lock exited in some irregular way.
To solve such types of problems, "robust mutex" userspace APIs were created:
pthread_mutex_lock() returns an error value if the owner exits prematurely -
and the new owner can decide whether the data protected by the lock can be
recovered safely.
There is a big conceptual problem with futex based mutexes though: it is the
kernel that destroys the owner task (e.g. due to a SEGFAULT), but the kernel
cannot help with the cleanup: if there is no 'futex queue' (and in most cases
there is none, futexes being fast lightweight locks) then the kernel has no
information to clean up after the held lock! Userspace has no chance to clean
up after the lock either - userspace is the one that crashes, so it has no
opportunity to clean up. Catch-22.
In practice, when e.g. yum is kill -9-ed (or segfaults), a system reboot is
needed to release that futex based lock. This is one of the leading
bugreports against yum.
To solve this problem, 'Robust Futex' patches were created and presented on
lkml: the one written by Todd Kneisel and David Singleton is the most advanced
at the moment. These patches all tried to extend the futex abstraction by
registering futex-based locks in the kernel - and thus give the kernel a
chance to clean up.
E.g. in David Singleton's robust-futex-6.patch, there are 3 new syscall
variants to sys_futex(): FUTEX_REGISTER, FUTEX_DEREGISTER and FUTEX_RECOVER.
The kernel attaches such robust futexes to vmas (via
vma->vm_file->f_mapping->robust_head), and at do_exit() time, all vmas are
searched to see whether they have a robust_head set.
Lots of work went into the vma-based robust-futex patch, and recently it has
improved significantly, but unfortunately it still has two fundamental
problems left:
- they have quite complex locking and race scenarios. The vma-based
patches had been pending for years, but they are still not completely
reliable.
- they have to scan _every_ vma at sys_exit() time, per thread!
The second disadvantage is a real killer: pthread_exit() takes around 1
microsecond on Linux, but with thousands (or tens of thousands) of vmas every
pthread_exit() takes a millisecond or more, also totally destroying the CPU's
L1 and L2 caches!
This is very much noticeable even for normal process sys_exit_group() calls:
the kernel has to do the vma scanning unconditionally! (this is because the
kernel has no knowledge about how many robust futexes there are to be cleaned
up, because a robust futex might have been registered in another task, and the
futex variable might have been simply mmap()-ed into this process's address
space).
This huge overhead forced the creation of CONFIG_FUTEX_ROBUST, but worse than
that: the overhead makes robust futexes impractical for any type of generic
Linux distribution.
So it became clear to us, something had to be done. Last week, when Thomas
Gleixner tried to fix up the vma-based robust futex patch in the -rt tree, he
found a handful of new races and we were talking about it and were analyzing
the situation. At that point a fundamentally different solution occured to
me. This patchset (written in the past couple of days) implements that new
solution. Be warned though - the patchset does things we normally dont do in
Linux, so some might find the approach disturbing. Parental advice
recommended ;-)
New approach to robust futexes
------------------------------
At the heart of this new approach there is a per-thread private list of robust
locks that userspace is holding (maintained by glibc) - which userspace list
is registered with the kernel via a new syscall [this registration happens at
most once per thread lifetime]. At do_exit() time, the kernel checks this
user-space list: are there any robust futex locks to be cleaned up?
In the common case, at do_exit() time, there is no list registered, so the
cost of robust futexes is just a simple current->robust_list != NULL
comparison. If the thread has registered a list, then normally the list is
empty. If the thread/process crashed or terminated in some incorrect way then
the list might be non-empty: in this case the kernel carefully walks the list
[not trusting it], and marks all locks that are owned by this thread with the
FUTEX_OWNER_DEAD bit, and wakes up one waiter (if any).
The list is guaranteed to be private and per-thread, so it's lockless. There
is one race possible though: since adding to and removing from the list is
done after the futex is acquired by glibc, there is a few instructions window
for the thread (or process) to die there, leaving the futex hung. To protect
against this possibility, userspace (glibc) also maintains a simple per-thread
'list_op_pending' field, to allow the kernel to clean up if the thread dies
after acquiring the lock, but just before it could have added itself to the
list. Glibc sets this list_op_pending field before it tries to acquire the
futex, and clears it after the list-add (or list-remove) has finished.
That's all that is needed - all the rest of robust-futex cleanup is done in
userspace [just like with the previous patches].
Ulrich Drepper has implemented the necessary glibc support for this new
mechanism, which fully enables robust mutexes. (Ulrich plans to commit these
changes to glibc-HEAD later today.)
Key differences of this userspace-list based approach, compared to the vma
based method:
- it's much, much faster: at thread exit time, there's no need to loop
over every vma (!), which the VM-based method has to do. Only a very
simple 'is the list empty' op is done.
- no VM changes are needed - 'struct address_space' is left alone.
- no registration of individual locks is needed: robust mutexes dont need
any extra per-lock syscalls. Robust mutexes thus become a very lightweight
primitive - so they dont force the application designer to do a hard choice
between performance and robustness - robust mutexes are just as fast.
- no per-lock kernel allocation happens.
- no resource limits are needed.
- no kernel-space recovery call (FUTEX_RECOVER) is needed.
- the implementation and the locking is "obvious", and there are no
interactions with the VM.
Performance
-----------
I have benchmarked the time needed for the kernel to process a list of 1
million (!) held locks, using the new method [on a 2GHz CPU]:
- with FUTEX_WAIT set [contended mutex]: 130 msecs
- without FUTEX_WAIT set [uncontended mutex]: 30 msecs
I have also measured an approach where glibc does the lock notification [which
it currently does for !pshared robust mutexes], and that took 256 msecs -
clearly slower, due to the 1 million FUTEX_WAKE syscalls userspace had to do.
(1 million held locks are unheard of - we expect at most a handful of locks to
be held at a time. Nevertheless it's nice to know that this approach scales
nicely.)
Implementation details
----------------------
The patch adds two new syscalls: one to register the userspace list, and one
to query the registered list pointer:
asmlinkage long
sys_set_robust_list(struct robust_list_head __user *head,
size_t len);
List registration is very fast: the pointer is simply stored in
current->robust_list. [Note that in the future, if robust futexes become
widespread, we could extend sys_clone() to register a robust-list head for new
threads, without the need of another syscall.]
So there is virtually zero overhead for tasks not using robust futexes, and
even for robust futex users, there is only one extra syscall per thread
lifetime, and the cleanup operation, if it happens, is fast and
straightforward. The kernel doesnt have any internal distinction between
robust and normal futexes.
If a futex is found to be held at exit time, the kernel sets the highest bit
of the futex word:
#define FUTEX_OWNER_DIED 0x40000000
and wakes up the next futex waiter (if any). User-space does the rest of
the cleanup.
Otherwise, robust futexes are acquired by glibc by putting the TID into the
futex field atomically. Waiters set the FUTEX_WAITERS bit:
#define FUTEX_WAITERS 0x80000000
and the remaining bits are for the TID.
Testing, architecture support
-----------------------------
I've tested the new syscalls on x86 and x86_64, and have made sure the parsing
of the userspace list is robust [ ;-) ] even if the list is deliberately
corrupted.
i386 and x86_64 syscalls are wired up at the moment, and Ulrich has tested the
new glibc code (on x86_64 and i386), and it works for his robust-mutex
testcases.
All other architectures should build just fine too - but they wont have the
new syscalls yet.
Architectures need to implement the new futex_atomic_cmpxchg_inuser() inline
function before writing up the syscalls (that function returns -ENOSYS right
now).
This patch:
Add placeholder futex_atomic_cmpxchg_inuser() implementations to every
architecture that supports futexes. It returns -ENOSYS.
Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Arjan van de Ven <arjan@infradead.org> Acked-by: Ulrich Drepper <drepper@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Ingo Molnar [Mon, 27 Mar 2006 09:16:09 +0000 (01:16 -0800)]
[PATCH] s390: add ptr_to_compat()
Add ptr_to_compat() to s390 - needed by the new robust-futex code.
Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
untested. CHECKME: am i right about the 0x7fffffffUL masking?
Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Dave Hansen [Mon, 27 Mar 2006 09:16:04 +0000 (01:16 -0800)]
[PATCH] unify PFN_* macros
Just about every architecture defines some macros to do operations on pfns.
They're all virtually identical. This patch consolidates all of them.
One minor glitch is that at least i386 uses them in a very skeletal header
file. To keep away from #include dependency hell, I stuck the new
definitions in a new, isolated header.
Of all of the implementations, sh64 is the only one that varied by a bit.
It used some masks to ensure that any sign-extension got ripped away before
the arithmetic is done. This has been posted to that sh64 maintainers and
the development list.
Compiles on x86, x86_64, ia64 and ppc64.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Helper functions for for_each_online_pgdat/for_each_zone look too big to be
inlined. Speed of these helper macro itself is not very important. (inner
loops are tend to do more work than this)
This patch make helper function to be out-of-lined.
This patch defines for_each_online_pgdat() as a replacement of
for_each_pgdat()
Now, online nodes are managed by node_online_map. But for_each_pgdat()
uses pgdat_link to iterate over all nodes(pgdat). This means management
structure for online pgdat is duplicated.
I think using node_online_map for for_each_pgdat() is simple and sane
rather ather than pgdat_link. New macro is named as
for_each_online_pgdat(). Following patch will fix callers of
for_each_pgdat().
The bootmem allocater uses for_each_pgdat() before pgdat initialization. I
don't think it's sane. Following patch will fix it.
pfn_to_page uses pgdat, page_to_pfn uses zone. page_to_pfn can use pgdat
instead of zone, which is only one user of zone_mem_map. By modifing it,
we can remove zone_mem_map.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Christoph Lameter <christoph@lameter.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: William Lee Irwin III <wli@holomorphy.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
There are 3 memory models, FLATMEM, DISCONTIGMEM, SPARSEMEM.
Each arch has its own page_to_pfn(), pfn_to_page() for each models.
But most of them can use the same arithmetic.
This patch adds asm-generic/memory_model.h, which includes generic
page_to_pfn(), pfn_to_page() definitions for each memory model.
When CONFIG_OUT_OF_LINE_PFN_TO_PAGE=y, out-of-line functions are
used instead of macro. This is enabled by some archs and reduces
text size.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Andi Kleen <ak@muc.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Ian Molton <spyro@f2s.com> Cc: Mikael Starvik <starvik@axis.com> Cc: David Howells <dhowells@redhat.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Hirokazu Takata <takata.hirokazu@renesas.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp> Cc: Richard Curnow <rc@rc0.org.uk> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Miles Bader <uclinux-v850@lsi.nec.co.jp> Cc: Chris Zankel <chris@zankel.net> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Siddha, Suresh B [Mon, 27 Mar 2006 09:15:23 +0000 (01:15 -0800)]
[PATCH] sched: fix group power for allnodes_domains
Current sched groups power calculation for allnodes_domains is wrong. We
should really be using cumulative power of the physical packages in that
group (similar to the calculation in node_domains)
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Siddha, Suresh B [Mon, 27 Mar 2006 09:15:22 +0000 (01:15 -0800)]
[PATCH] sched: new sched domain for representing multi-core
Add a new sched domain for representing multi-core with shared caches
between cores. Consider a dual package system, each package containing two
cores and with last level cache shared between cores with in a package. If
there are two runnable processes, with this appended patch those two
processes will be scheduled on different packages.
On such systems, with this patch we have observed 8% perf improvement with
specJBB(2 warehouse) benchmark and 35% improvement with CFP2000 rate(with 2
users).
This new domain will come into play only on multi-core systems with shared
caches. On other systems, this sched domain will be removed by domain
degeneration code. This new domain can be also used for implementing power
savings policy (see OLS 2005 CMP kernel scheduler paper for more details..
I will post another patch for power savings policy soon)
Most of the arch/* file changes are for cpu_coregroup_map() implementation.
Martin Andersson [Mon, 27 Mar 2006 09:15:18 +0000 (01:15 -0800)]
[PATCH] sched: fix task interactivity calculation
Is a truncation error in kernel/sched.c triggered when the nice value is
negative. The affected code is used in the TASK_INTERACTIVE macro.
The code is:
#define SCALE(v1,v1_max,v2_max) \
(v1) * (v2_max) / (v1_max)
which is used in this way:
SCALE(TASK_NICE(p), 40, MAX_BONUS)
Comments in the code says:
* This part scales the interactivity limit depending on niceness.
*
* We scale it linearly, offset by the INTERACTIVE_DELTA delta.
* Here are a few examples of different nice levels:
*
* TASK_INTERACTIVE(-20): [1,1,1,1,1,1,1,1,1,0,0]
* TASK_INTERACTIVE(-10): [1,1,1,1,1,1,1,0,0,0,0]
* TASK_INTERACTIVE( 0): [1,1,1,1,0,0,0,0,0,0,0]
* TASK_INTERACTIVE( 10): [1,1,0,0,0,0,0,0,0,0,0]
* TASK_INTERACTIVE( 19): [0,0,0,0,0,0,0,0,0,0,0]
*
* (the X axis represents the possible -5 ... 0 ... +5 dynamic
* priority range a task can explore, a value of '1' means the
* task is rated interactive.)
However, the current code does not scale it linearly and the result differs
from the given examples. If the mathematical function "floor" is used when
the nice value is negative instead of the truncation one gets when using
integer division, the result conforms to the documentation.
Signed-off-by: Martin Andersson <martin.andersson@control.lth.se> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Williams <pwil3058@bigpond.net.au> Cc: Con Kolivas <kernel@kolivas.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Adrian Bunk [Mon, 27 Mar 2006 09:15:10 +0000 (01:15 -0800)]
[PATCH] fs/nfsd/export.c,net/sunrpc/cache.c: make needlessly global code static
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>
NeilBrown [Mon, 27 Mar 2006 09:15:08 +0000 (01:15 -0800)]
[PATCH] knfsd: Unexport cache_fresh and fix a small race
Cache_fresh is now only used in cache.c, so unexport it.
Part of cache_fresh (setting CACHE_VALID) should really be done under the
lock, while part (calling cache_revisit_request etc) must be done outside the
lock. So we split it up appropriately.
Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
NeilBrown [Mon, 27 Mar 2006 09:15:07 +0000 (01:15 -0800)]
[PATCH] knfsd: An assortment of little fixes to the sunrpc cache code
- in cache_check, h must be non-NULL as it has been de-referenced,
so don't bother checking for NULL.
- When a cache-item is updated, we need to call cache_revisit_request to see
if there is a pending request waiting for that item. We were using
a transition to CACHE_VALID to see if that was needed, however that is
wrong as an expired entry will still be marked 'valid' (as the data is valid
and will need to be released). So instead use an off transition for
CACHE_PENDING which is exactly the right thing to test.
- Add a little bit more debugging info.
Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
NeilBrown [Mon, 27 Mar 2006 09:15:00 +0000 (01:15 -0800)]
[PATCH] knfsd: Break the hard linkage from svc_expkey to svc_export
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>
NeilBrown [Mon, 27 Mar 2006 09:14:59 +0000 (01:14 -0800)]
[PATCH] knfsd: Change the store of auth_domains to not be a 'cache'
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>
Dave Jones [Mon, 27 Mar 2006 09:14:57 +0000 (01:14 -0800)]
[PATCH] Remove redundant check from autofs4_put_super
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>
Ian Kent [Mon, 27 Mar 2006 09:14:55 +0000 (01:14 -0800)]
[PATCH] autofs4: add new packet type for v5 communications
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>
Ian Kent [Mon, 27 Mar 2006 09:14:55 +0000 (01:14 -0800)]
[PATCH] autofs4: add v5 expire logic
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>
Ian Kent [Mon, 27 Mar 2006 09:14:54 +0000 (01:14 -0800)]
[PATCH] autofs4: add v5 follow_link mount trigger method
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>
Ian Kent [Mon, 27 Mar 2006 09:14:53 +0000 (01:14 -0800)]
[PATCH] autofs4: nameidata needs to be up to date for follow_link
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>
Ian Kent [Mon, 27 Mar 2006 09:14:47 +0000 (01:14 -0800)]
[PATCH] autofs4: expire mounts that hold no (extra) references only
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>
Ian Kent [Mon, 27 Mar 2006 09:14:46 +0000 (01:14 -0800)]
[PATCH] autofs4: fix false negative return from expire
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>
Ian Kent [Mon, 27 Mar 2006 09:14:45 +0000 (01:14 -0800)]
[PATCH] autofs4: simplify expire tree traversal
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>
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