Oleg Nesterov [Wed, 29 Mar 2006 00:11:30 +0000 (16:11 -0800)]
[PATCH] send_sigqueue: simplify and fix the race
send_sigqueue() checks PF_EXITING, then locks p->sighand->siglock. This is
unsafe: 'p' can exit in between and set ->sighand = NULL. The race is
theoretical, the window is tiny and irqs are disabled by the caller, so I
don't think we need the fix for -stable tree.
Convert send_sigqueue() to use lock_task_sighand() helper.
Also, delete 'p->flags & PF_EXITING' re-check, it is unneeded and the
comment is wrong.
The previous patch has changed callsites of do_notify_parent_cldstop() so that
to_self == (->ptrace & PT_PTRACED) always (as it should be). We can remove
this parameter now.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: john stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Oleg Nesterov [Wed, 29 Mar 2006 00:11:28 +0000 (16:11 -0800)]
[PATCH] simplify do_signal_stop()
do_signal_stop() considers 'thread_group_empty()' as a special case.
This was needed to avoid taking tasklist_lock. Since this lock is
unneeded any longer, we can remove this special case and simplify
the code even more.
Also, before this patch, finish_stop() was called with stop_count == -1
for 'thread_group_empty()' case. This is not strictly wrong, but confusing
and unneeded.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: john stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Move 'tsk->sighand = NULL' from cleanup_sighand() to __exit_signal(). This
makes the exit path more understandable and allows us to do
cleanup_sighand() outside of ->siglock protected section.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Oleg Nesterov [Wed, 29 Mar 2006 00:11:26 +0000 (16:11 -0800)]
[PATCH] make fork() atomic wrt pgrp/session signals
Eric W. Biederman wrote:
>
> Ok. SUSV3/Posix is clear, fork is atomic with respect
> to signals. Either a signal comes before or after a
> fork but not during. (See the rationale section).
> http://www.opengroup.org/onlinepubs/000095399/functions/fork.html
>
> The tasklist_lock does not stop forks from adding to a process
> group. The forks stall while the tasklist_lock is held, but a fork
> that began before we grabbed the tasklist_lock simply completes
> afterwards, and the child does not receive the signal.
This also means that SIGSTOP or sig_kernel_coredump() signal can't
be delivered to pgrp/session reliably.
With this patch copy_process() returns -ERESTARTNOINTR when it
detects a pending signal, fork() will be restarted transparently
after handling the signals.
This patch also deletes now unneeded "group_stop_count > 0" check,
copy_process() can no longer succeed while group stop in progress.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-By: Eric Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Oleg Nesterov [Wed, 29 Mar 2006 00:11:25 +0000 (16:11 -0800)]
[PATCH] pids: kill PIDTYPE_TGID
This patch kills PIDTYPE_TGID pid_type thus saving one hash table in
kernel/pid.c and speeding up subthreads create/destroy a bit. It is also a
preparation for the further tref/pids rework.
This patch adds 'struct list_head thread_group' to 'struct task_struct'
instead.
We don't detach group leader from PIDTYPE_PID namespace until another
thread inherits it's ->pid == ->tgid, so we are safe wrt premature
free_pidmap(->tgid) call.
Currently there are no users of find_task_by_pid_type(PIDTYPE_TGID).
Should the need arise, we can use find_task_by_pid()->group_leader.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-By: Eric Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Oleg Nesterov [Wed, 29 Mar 2006 00:11:20 +0000 (16:11 -0800)]
[PATCH] do __unhash_process() under ->siglock
This patch moves __unhash_process() call from realease_task() to
__exit_signal(), so __detach_pid() is called with ->siglock held.
This means we don't need tasklist_lock to iterate over thread group anymore:
copy_process() was already changed to do attach_pid()
under ->siglock.
Eric's "pidhash-kill-switch_exec_pids.patch" from -mm
changed de_thread() so it doesn't touch PIDTYPE_TGID.
NOTE: de_thread() still needs some attention. It still changes task->pid
lockless. Taking ->sighand.siglock here allows to do more tasklist_lock
removals.
Oleg Nesterov [Wed, 29 Mar 2006 00:11:19 +0000 (16:11 -0800)]
[PATCH] revert "Optimize sys_times for a single thread process"
This patch reverts 'CONFIG_SMP && thread_group_empty()' optimization in
sys_times(). The reason is that the next patch breaks memory ordering which
is needed for that optimization.
tasklist_lock in sys_times() will be eliminated completely by further patch.
Oleg Nesterov [Wed, 29 Mar 2006 00:11:18 +0000 (16:11 -0800)]
[PATCH] move __exit_signal() to kernel/exit.c
__exit_signal() is private to release_task() now. I think it is better to
make it static in kernel/exit.c and export flush_sigqueue() instead - this
function is much more simple and straightforward.
__exit_signal() does important cleanups atomically under ->siglock. It is
also called from copy_process's error path. This is not good, for example we
can't move __unhash_process() under ->siglock for that reason.
We should not mix these 2 paths, just look at ugly 'if (p->sighand)' under
'bad_fork_cleanup_sighand:' label. For copy_process() case it is sufficient
to just backout copy_signal(), nothing more.
Again, nobody can see this task yet. For CLONE_THREAD case we just decrement
signal->count, otherwise nobody can see this ->signal and we can free it
lockless.
This patch assumes it is safe to do exit_thread_group_keys() without
tasklist_lock.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Oleg Nesterov [Wed, 29 Mar 2006 00:11:13 +0000 (16:11 -0800)]
[PATCH] introduce lock_task_sighand() helper
Add lock_task_sighand() helper and converts group_send_sig_info() to use
it. Hopefully we will have more users soon.
This patch also removes '!sighand->count' and '!p->usage' checks, I think
they both are bogus, racy and unneeded (but probably it makes sense to
restore them as BUG_ON()s).
->sighand is cleared and it's ->count is decremented in release_task() with
sighand->siglock held, so it is a bug to have '!p->usage || !->count' after
we already locked and verified it is the same. On the other hand, an
already dead task without ->sighand can have a non-zero ->usage due to
ptrace, for example.
If we read the stale value of ->sighand we must see the change after
spin_lock(), because that change was done while holding that same old
->sighand.siglock.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Oleg Nesterov [Wed, 29 Mar 2006 00:11:12 +0000 (16:11 -0800)]
[PATCH] convert sighand_cache to use SLAB_DESTROY_BY_RCU
This patch borrows a clever Hugh's 'struct anon_vma' trick.
Without tasklist_lock held we can't trust task->sighand until we locked it
and re-checked that it is still the same.
But this means we don't need to defer 'kmem_cache_free(sighand)'. We can
return the memory to slab immediately, all we need is to be sure that
sighand->siglock can't dissapear inside rcu protected section.
To do so we need to initialize ->siglock inside ctor function,
SLAB_DESTROY_BY_RCU does the rest.
Oleg Nesterov [Wed, 29 Mar 2006 00:11:09 +0000 (16:11 -0800)]
[PATCH] pidhash: don't use zero pids
daemonize() calls set_special_pids(1,1), while init and kernel threads spawned
from init/main.c:init() run with 0,0 special pids. This patch changes
INIT_SIGNALS() so that that they run with ->pgrp == ->session == 1 also. This
patch relies on fact that swapper's pid == 1.
Now we have no hashed zero pids in pid_hash[].
User-space visibible change is that now /sbin/init runs with (1,1) special
pids and becomes a session leader.
Quoting Eric W. Biederman:
>
> daemonize consuming pids (1,1) then consumes pgrp 1. So that when
> /sbin/init calls setsid() it thinks /sbin/init is a process group
> leader and setsid() fails. So /sbin/init wants pgrp 1 session 1
> but doesn't get it. I am pretty certain daemonize did not exist so
> /sbin/init got pgrp 1 session 1 in 2.4.
>
> That is the bug that is being fixed.
>
> This patch takes things one step farther and essentially calls
> setsid() for pid == 1 before init is execed. That is new behavior
> but it cleans up the kernel as we now do not need to support the
> case of a process without a process group or a session.
>
> The only process that could have possibly cared was /sbin/init
> and it already calls setsid() because it doesn't want that.
>
> If this was going to break anything noticeable the change in behavior
> from 2.4 to 2.6 would have already done that.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Oleg Nesterov [Wed, 29 Mar 2006 00:11:07 +0000 (16:11 -0800)]
[PATCH] pidhash: don't count idle threads
fork_idle() does unhash_process() just after copy_process(). Contrary,
boot_cpu's idle thread explicitely registers itself for each pid_type with nr
= 0.
copy_process() already checks p->pid != 0 before process_counts++, I think we
can just skip attach_pid() calls and job control inits for idle threads and
kill unhash_process(). We don't need to cleanup ->proc_dentry in fork_idle()
because with this patch idle threads are never hashed in
kernel/pid.c:pid_hash[].
We don't need to hash pid == 0 in pidmap_init(). free_pidmap() is never
called with pid == 0 arg, so it will never be reused. So it is still possible
to use pid == 0 in any PIDTYPE_xxx namespace from kernel/pid.c's POV.
However with this patch we don't hash pid == 0 for PIDTYPE_PID case. We still
have have PIDTYPE_PGID/PIDTYPE_SID entries with pid == 0: /sbin/init and
kernel threads which don't call daemonize().
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Oleg Nesterov [Wed, 29 Mar 2006 00:11:06 +0000 (16:11 -0800)]
[PATCH] kill SET_LINKS/REMOVE_LINKS
Both SET_LINKS() and SET_LINKS/REMOVE_LINKS() have exactly one caller, and
these callers already check thread_group_leader().
This patch kills theese macros, they mix two different things: setting
process's parent and registering it in init_task.tasks list. Callers are
updated to do these actions by hand.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Oleg Nesterov [Wed, 29 Mar 2006 00:11:05 +0000 (16:11 -0800)]
[PATCH] don't use REMOVE_LINKS/SET_LINKS for reparenting
There are places where kernel uses REMOVE_LINKS/SET_LINKS while changing
process's ->parent. Use add_parent/remove_parent instead, they don't abuse
of global process list.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
switch_exec_pids is only called from de_thread by way of exec, and it is
only called when we are exec'ing from a non thread group leader.
Currently switch_exec_pids gives the leader the pid of the thread and
unhashes and rehashes all of the process groups. The leader is already in
the EXIT_DEAD state so no one cares about it's pids. The only concern for
the leader is that __unhash_process called from release_task will function
correctly. If we don't touch the leader at all we know that
__unhash_process will work fine so there is no need to touch the leader.
For the task becomming the thread group leader, we just need to give it the
pid of the old thread group leader, add it to the task list, and attach it
to the session and the process group of the thread group.
Currently de_thread is also adding the task to the task list which is just
silly.
Currently the only leader of __detach_pid besides detach_pid is
switch_exec_pids because of the ugly extra work that was being
performed.
So this patch removes switch_exec_pids because it is doing too much, it is
creating an unnecessary special case in pid.c, duing work duplicated in
de_thread, and generally obscuring what it is going on.
The necessary work is added to de_thread, and it seems to be a little
clearer there what is going on.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Kirill Korotaev <dev@sw.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I'm not really certain what the thinking was but the code obviously wanted to
walk processes other than just those in it's session, for purposes of do_SAK.
Just walking those tasks that don't have a session assigned sounds at the very
least incomplete.
So modify the code to kill everything in the session and anything else that
might have the tty open. Hopefully this helps if the do_SAK functionality is
ever finished.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
[PATCH] do_tty_hangup: use group_send_sig_info not send_group_sig_info
We already have the tasklist_lock so there is no need for us to reacquire it
with send_group_sig_info. reader/writer locks allow multiple readers and thus
recursion so the old code was ok just wastful.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
[PATCH] Remove dead kill_sl prototype from sched.h
The kill_sl function doesn't exist in the kernel so a prototype is completely
unnecessary.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
After looking at the problem of init calling exec some more I figured out
an easy way to make the code work.
The actual symptom without out this patch is that all threads will die
except pid == 1, and the thread calling exec. The thread calling exec will
wait forever for pid == 1 to die.
Since pid == 1 does not install a handler for SIGKILL it will never die.
This modifies the tests for init from current->pid == 1 to the equivalent
current == child_reaper. And then it causes exec in the ugly case to
modify child_reaper.
The only weird symptom is that you wind up with an init process that
doesn't have the oldest start time on the box.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Jody McIntyre [Wed, 29 Mar 2006 01:04:04 +0000 (20:04 -0500)]
ohci1394: cleanup the "Unexpected PCI resource length" warning.
This warning happens in practice because the resource length reported by
the chipset is too large. This is not actually a problem, so don't warn
about it. If it happens to be too small, warn about that, but with
a different message so people who are used to ignoring the old message
don't.
Stefan Richter [Wed, 29 Mar 2006 01:03:55 +0000 (20:03 -0500)]
sbp2: misc debug logging cleanups
- move call of scsi_print_command from sbp2_send_command to the beginning of
sbp2_queue_command to show also commands which are not sent
- put sbp2's name into scsi_print_sense
- use __FUNCTION__ in log messages
- remove a few less useful log messages and comments
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> Signed-off-by: Jody McIntyre <scjody@modernduck.com>
Stefan Richter [Wed, 29 Mar 2006 01:03:45 +0000 (20:03 -0500)]
sbp2: proper treatment of DID_OK
Sbp2 relied on DID_OK to be defined as 0. Always shift DID_OK into the right
position anyway, and explicitly return DID_OK together with CHECK_CONDITION.
Also comment on some #if 0 code. The patch does not change current behaviour.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> Signed-off-by: Jody McIntyre <scjody@modernduck.com>
Stefan Richter [Wed, 29 Mar 2006 00:59:42 +0000 (19:59 -0500)]
sbp2: check for ARM failure
Sbp2 did not check for successful registration of the lower address range
when CONFIG_IEEE1394_SBP2_PHYS_DMA was set. If hpsb_register_addrspace
failed, a "login timed-out" would occur which is misleading. Now sbp2 logs
a sensible error message.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> Signed-off-by: Jody McIntyre <scjody@modernduck.com>
Stefan Richter [Wed, 29 Mar 2006 00:57:34 +0000 (19:57 -0500)]
ohci1394: clean up asynchronous and physical request filters programming
Various cleanups of how ohci1394 programs AsynchronousRequestFilter,
PhysicalRequestFilter, and physUpperBoundOffset. In particular, do not
rewrite registers within the bus reset interrupt handler if bus resets
do not affect the registers in the first place.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> Signed-off-by: Jody McIntyre <scjody@modernduck.com>
Stefan Richter [Wed, 29 Mar 2006 00:54:52 +0000 (19:54 -0500)]
sbp2: prevent unloading of 1394 low-level driver
When a new SBP-2 unit is added, sbp2 now takes a reference on the 1394
low-level driver (ohci1394 or pcilynx). This prevents the 1394 host driver
module from being unloaded, e.g. by an administrative routine cleanup of
unused kernel modules or when another 1394 driver which depends on ohci1394
is unloaded.
The reference is dropped when the SBP-2 unit was disconnected, when sbp2 is
unloaded or detached from the unit, or when addition of the SBP-2 unit failed.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> Signed-off-by: Jody McIntyre <scjody@modernduck.com>
* master.kernel.org:/home/rmk/linux-2.6-serial:
[SERIAL] Provide Cirrus EP93xx AMBA PL010 serial support.
[SERIAL] amba-pl010: allow platforms to specify modem control method
[SERIAL] Remove obsoleted au1x00_uart driver
[SERIAL] Small time UART configuration fix for AU1100 processor
This patch adds support for the Intel ixp23xx series of CPUs. The
ixp23xx is an XSC3 based CPU with 512K of L2 cache, a 64bit 66MHz PCI
interface, two DDR RAM interfaces, QDR RAM interfaces, two gigabit
MACs, two 10/100 MACs, expansion bus, four microengines, a Media and
Switch Fabric unit almost identical to the one on the ixp2400, two
xscale (8250ish) UARTs and a bunch of other stuff.
This patch adds the core ixp23xx support code, and support for the
ADI Engineering Roadrunner, Intel IXDP2351, and IP Fabrics Double
Espresso platforms.
Signed-off-by: Deepak Saxena <dsaxena@plexity.net> Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
[ARM] 3417/1: add support for logicpd pxa270 card engine
Patch from Lennert Buytenhek
Add support for the LogicPD PXA270 Card Engine.
Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org> Signed-off-by: Nicolas Pitre <nico@cam.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch adds support for the new XScale v3 core. This is an
ARMv5 ISA core with the following additions:
- L2 cache
- I/O coherency support (on select chipsets)
- Low-Locality Reference cache attributes (replaces mini-cache)
- Supersections (v6 compatible)
- 36-bit addressing (v6 compatible)
- Single instruction cache line clean/invalidate
- LRU cache replacement (vs round-robin)
I attempted to merge the XSC3 support into proc-xscale.S, but XSC3
cores have separate errata and have to handle things like L2, so it
is simpler to keep it separate.
L2 cache support is currently a build option because the L2 enable
bit must be set before we enable the MMU and there is no easy way to
capture command line parameters at this point.
There are still optimizations that can be done such as using LLR for
copypage (in theory using the exisiting mini-cache code) but those
can be addressed down the road.
Signed-off-by: Deepak Saxena <dsaxena@plexity.net> Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* master.kernel.org:/pub/scm/linux/kernel/git/davej/cpufreq:
[CPUFREQ] cpufreq_conservative: keep ignore_nice_load and freq_step values when reselected
[CPUFREQ] powernow: remove private for_each_cpu_mask()
[CPUFREQ] hotplug cpu fix for powernow-k8
[PATCH] cpufreq_ondemand: add range check
[PATCH] cpufreq_ondemand: keep ignore_nice_load value when it is reselected
[PATCH] cpufreq_ondemand: Warn if it cannot run due to too long transition latency
[PATCH] cpufreq_conservative: alternative initialise approach
[PATCH] cpufreq_conservative: make for_each_cpu() safe
[PATCH] cpufreq_conservative: alter default responsiveness
[PATCH] cpufreq_conservative: aligning of codebase with ondemand
Linus Torvalds [Tue, 28 Mar 2006 17:25:44 +0000 (09:25 -0800)]
Merge branch 'cfq-merge' of git://brick.kernel.dk/data/git/linux-2.6-block
* 'cfq-merge' of git://brick.kernel.dk/data/git/linux-2.6-block:
[BLOCK] cfq-iosched: seek and async performance fixes
[PATCH] ll_rw_blk: fix 80-col offender in put_io_context()
[PATCH] cfq-iosched: small cfq_choose_req() optimization
[PATCH] [BLOCK] cfq-iosched: change cfq io context linking from list to tree
Andrew Morton [Tue, 28 Mar 2006 09:56:55 +0000 (01:56 -0800)]
[PATCH] compat_sys_futex() warning fix
kernel/futex_compat.c: In function `compat_sys_futex':
kernel/futex_compat.c:140: warning: passing arg 1 of `do_futex' makes integer from pointer without a cast
kernel/futex_compat.c:140: warning: passing arg 5 of `do_futex' makes integer from pointer without a cast
Not sure what Ingo was thinking of here. Put the casts back in.
Matthias Gehre [Tue, 28 Mar 2006 09:56:48 +0000 (01:56 -0800)]
[PATCH] Replace 0xff.. with correct DMA_xBIT_MASK
Replace all occurences of 0xff.. in calls to function pci_set_dma_mask()
and pci_set_consistant_dma_mask() with the corresponding DMA_xBIT_MASK from
linux/dma-mapping.h.
Arjan van de Ven [Tue, 28 Mar 2006 09:56:42 +0000 (01:56 -0800)]
[PATCH] Make most file operations structs in fs/ const
This is a conversion to make the various file_operations structs in fs/
const. Basically a regexp job, with a few manual fixups
The goal is both to increase correctness (harder to accidentally write to
shared datastructures) and reducing the false sharing of cachelines with
things that get dirty in .data (while .rodata is nicely read only and thus
cache clean)
Signed-off-by: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Arjan van de Ven [Tue, 28 Mar 2006 09:56:41 +0000 (01:56 -0800)]
[PATCH] mark f_ops const in the inode
Mark the f_ops members of inodes as const, as well as fix the
ripple-through this causes by places that copy this f_ops and then "do
stuff" with it.
Signed-off-by: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
for_each_cpu() is a for-loop over cpu_possible_map. for_each_online_cpu is
for-loop cpu over cpu_online_map. .....for_each_cpu() is not sufficiently
explicit and can lead to mistakes.
This patch adds for_each_possible_cpu() in preparation for the removal of
for_each_cpu().
Vadim Lobanov [Tue, 28 Mar 2006 09:56:35 +0000 (01:56 -0800)]
[PATCH] Fold select_bits_alloc/free into caller code.
Remove an unnecessary level of indirection in allocating and freeing select
bits, as per the select_bits_alloc() and select_bits_free() functions.
Both select.c and compat.c are updated.
Andi Kleen [Tue, 28 Mar 2006 09:56:33 +0000 (01:56 -0800)]
[PATCH] Optimize select/poll by putting small data sets on the stack
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>
Alan Cox [Tue, 28 Mar 2006 09:56:31 +0000 (01:56 -0800)]
[PATCH] Small fixes backported to old IDE SiS driver
Some quick backport bits from the libata PATA work to fix things found in
the sis driver. The piix driver needs some fixes too but those are way to
large and need someone working on old IDE with time to do them.
This patch fixes the case where random bits get loaded into SIS timing
registers according to the description of the correct behaviour from
Vojtech Pavlik. It also adds the SiS5517 ATA16 chipset which is not
currently supported by the driver. Thanks to Conrad Harriss for loaning me
the machine with the 5517 chipset.
Signed-off-by: Alan Cox <alan@redhat.com> Acked-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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