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  1. Jun 22, 2005
    • Paolo 'Blaisorblade' Giarrusso's avatar
      [PATCH] uml: make hw_controller_type->release exist only for archs needing it · b77d6adc
      Paolo 'Blaisorblade' Giarrusso authored 
      

With Chris Wedgwood <cw@f00f.org>

As suggested by Chris, we can make the "just added" method ->release
conditional to UML only (better: to archs requesting it, i.e.  only UML
currently), so that other archs don't get this unneeded crud, and if UML
won't need it any more we can kill this.

Signed-off-by: default avatarPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
CC: Ingo Molnar <mingo@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      b77d6adc
    • Paolo 'Blaisorblade' Giarrusso's avatar
      [PATCH] uml: add and use generic hw_controller_type->release · dbce706e
      Paolo 'Blaisorblade' Giarrusso authored 
      

With Chris Wedgwood <cw@f00f.org>

Currently UML must explicitly call the UML-specific
free_irq_by_irq_and_dev() for each free_irq call it's done.

This is needed because ->shutdown and/or ->disable are only called when the
last "action" for that irq is removed.

Instead, for UML shared IRQs (UML IRQs are very often, if not always,
shared), for each dev_id some setup is done, which must be cleared on the
release of that fd.  For instance, for each open console a new instance
(i.e.  new dev_id) of the same IRQ is requested().

Exactly, a fd is stored in an array (pollfds), which is after read by a
host thread and passed to poll().  Each event registered by poll() triggers
an interrupt.  So, for each free_irq() we must remove the corresponding
host fd from the table, which we do via this -release() method.

In this patch we add an appropriate hook for this, and remove all uses of
it by pointing the hook to the said procedure; this is safe to do since the
said procedure.

Also some cosmetic improvements are included.

This is heavily based on some work by Chris Wedgwood, which however didn't
get the patch merged for something I'd call a "misunderstanding" (the need
for this patch wasn't cleanly explained, thus adding the generic hook was
felt as undesirable).

Signed-off-by: default avatarPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
CC: Ingo Molnar <mingo@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      dbce706e
    • Hugh Dickins's avatar
      [PATCH] dup_mmap: update comment on new vma · 45918e1a
      Hugh Dickins authored 
      

Remove part of comment on linking new vma in dup_mmap: since anon_vma rmap
came in, try_to_unmap_one knows the vma without needing find_vma.  But add
a comment to note that here vma is inserted without mmap_sem.

Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      45918e1a
    • Wolfgang Wander's avatar
      [PATCH] Avoiding mmap fragmentation · 1363c3cd
      Wolfgang Wander authored 
      

Ingo recently introduced a great speedup for allocating new mmaps using the
free_area_cache pointer which boosts the specweb SSL benchmark by 4-5% and
causes huge performance increases in thread creation.

The downside of this patch is that it does lead to fragmentation in the
mmap-ed areas (visible via /proc/self/maps), such that some applications
that work fine under 2.4 kernels quickly run out of memory on any 2.6
kernel.

The problem is twofold:

  1) the free_area_cache is used to continue a search for memory where
     the last search ended.  Before the change new areas were always
     searched from the base address on.

     So now new small areas are cluttering holes of all sizes
     throughout the whole mmap-able region whereas before small holes
     tended to close holes near the base leaving holes far from the base
     large and available for larger requests.

  2) the free_area_cache also is set to the location of the last
     munmap-ed area so in scenarios where we allocate e.g.  five regions of
     1K each, then free regions 4 2 3 in this order the next request for 1K
     will be placed in the position of the old region 3, whereas before we
     appended it to the still active region 1, placing it at the location
     of the old region 2.  Before we had 1 free region of 2K, now we only
     get two free regions of 1K -> fragmentation.

The patch addresses thes issues by introducing yet another cache descriptor
cached_hole_size that contains the largest known hole size below the
current free_area_cache.  If a new request comes in the size is compared
against the cached_hole_size and if the request can be filled with a hole
below free_area_cache the search is started from the base instead.

The results look promising: Whereas 2.6.12-rc4 fragments quickly and my
(earlier posted) leakme.c test program terminates after 50000+ iterations
with 96 distinct and fragmented maps in /proc/self/maps it performs nicely
(as expected) with thread creation, Ingo's test_str02 with 20000 threads
requires 0.7s system time.

Taking out Ingo's patch (un-patch available per request) by basically
deleting all mentions of free_area_cache from the kernel and starting the
search for new memory always at the respective bases we observe: leakme
terminates successfully with 11 distinctive hardly fragmented areas in
/proc/self/maps but thread creating is gringdingly slow: 30+s(!) system
time for Ingo's test_str02 with 20000 threads.

Now - drumroll ;-) the appended patch works fine with leakme: it ends with
only 7 distinct areas in /proc/self/maps and also thread creation seems
sufficiently fast with 0.71s for 20000 threads.

Signed-off-by: default avatarWolfgang Wander <wwc@rentec.com>
Credit-to: "Richard Purdie" <rpurdie@rpsys.net>
Signed-off-by: default avatarKen Chen <kenneth.w.chen@intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu> (partly)
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      1363c3cd
    • Martin Hicks's avatar
      [PATCH] VM: early zone reclaim · 753ee728
      Martin Hicks authored 
      This is the core of the (much simplified) early reclaim.  The goal of this
patch is to reclaim some easily-freed pages from a zone before falling back
onto another zone.

One of the major uses of this is NUMA machines.  With the default allocator
behavior the allocator would look for memory in another zone, which might be
off-node, before trying to reclaim from the current zone.

This adds a zone tuneable to enable early zone reclaim.  It is selected on a
per-zone basis and is turned on/off via syscall.

Adding some extra throttling on the reclaim was also required (patch
4/4).  Without the machine would grind to a crawl when doing a "make -j"
kernel build.  Even with this patch the System Time is higher on
average, but it seems tolerable.  Here are some numbers for kernbench
runs on a 2-node, 4cpu, 8Gig RAM Altix in the "make -j" run:

			wall  user   sys   %cpu  ctx sw.  sleeps
			----  ----   ---   ----   ------  ------
No patch		1009  1384   847   258   298170   504402
w/patch, no reclaim     880   1376   667   288   254064   396745
w/patch & reclaim       1079  1385   926   252   291625   548873

These numbers are the average of 2 runs of 3 "make -j" runs done right
after system boot.  Run-to-run variability for "make -j" is huge, so
these numbers aren't terribly useful except to seee that with reclaim
the benchmark still finishes in a reasonable amount of time.

I also looked at the NUMA hit/miss stats for the "make -j" runs and the
reclaim doesn't make any difference when the machine is thrashing away.

Doing a "make -j8" on a single node that is filled with page cache pages
takes 700 seconds with reclaim turned on and 735 seconds without reclaim
(due to remote memory accesses).

The simple zone_reclaim syscall program is at
http://www.bork.org/~mort/sgi/zone_reclaim.c



Signed-off-by: default avatarMartin Hicks <mort@sgi.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      753ee728
    • Ingo Molnar's avatar
      [PATCH] smp_processor_id() cleanup · 39c715b7
      Ingo Molnar authored 
      

This patch implements a number of smp_processor_id() cleanup ideas that
Arjan van de Ven and I came up with.

The previous __smp_processor_id/_smp_processor_id/smp_processor_id API
spaghetti was hard to follow both on the implementational and on the
usage side.

Some of the complexity arose from picking wrong names, some of the
complexity comes from the fact that not all architectures defined
__smp_processor_id.

In the new code, there are two externally visible symbols:

 - smp_processor_id(): debug variant.

 - raw_smp_processor_id(): nondebug variant. Replaces all existing
   uses of _smp_processor_id() and __smp_processor_id(). Defined
   by every SMP architecture in include/asm-*/smp.h.

There is one new internal symbol, dependent on DEBUG_PREEMPT:

 - debug_smp_processor_id(): internal debug variant, mapped to
                             smp_processor_id().

Also, i moved debug_smp_processor_id() from lib/kernel_lock.c into a new
lib/smp_processor_id.c file.  All related comments got updated and/or
clarified.

I have build/boot tested the following 8 .config combinations on x86:

 {SMP,UP} x {PREEMPT,!PREEMPT} x {DEBUG_PREEMPT,!DEBUG_PREEMPT}

I have also build/boot tested x64 on UP/PREEMPT/DEBUG_PREEMPT.  (Other
architectures are untested, but should work just fine.)

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarArjan van de Ven <arjan@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      39c715b7
  3. Jun 20, 2005
  5. Jun 17, 2005
  7. Jun 14, 2005
  9. May 31, 2005
    • Roman Zippel's avatar
      [PATCH] flush icache in correct context · ae92ef8a
      Roman Zippel authored 
      

flush_icache_range() is used in two different situation - in binfmt_elf.c &
co for user space mappings and module.c for kernel modules.  On m68k
flush_icache_range() doesn't know which data to flush, as it has separate
address spaces and the pointer argument can be valid in either address
space.

First I considered splitting flush_icache_range(), but this patch is
simpler.  Setting the correct context gives flush_icache_range() enough
information to flush the correct data.

Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      ae92ef8a
  11. May 28, 2005
    • John Hawkes's avatar
      [PATCH] drop note_interrupt() for per-CPU for proper scaling · b60c1f6f
      John Hawkes authored 
      

The "unhandled interrupts" catcher, note_interrupt(), increments a global
desc->irq_count and grossly damages scaling of very large systems, e.g.,
>192p ia64 Altix, because of this highly contented cacheline, especially
for timer interrupts.  384p is severely crippled, and 512p is unuseable.

All calls to note_interrupt() can be disabled by booting with "noirqdebug",
but this disables the useful interrupt checking for all interrupts.

I propose eliminating note_interrupt() for all per-CPU interrupts.  This
was the behavior of linux-2.6.10 and earlier, but in 2.6.11 a code
restructuring added a call to note_interrupt() for per-CPU interrupts.
Besides, note_interrupt() is a bit racy for concurrent CPU calls anyway, as
the desc->irq_count++ increment isn't atomic (which, if done, would make
scaling even worse).

Signed-off-by: default avatarJohn Hawkes <hawkes@sgi.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      b60c1f6f
  13. May 27, 2005
    • Paul Jackson's avatar
      [PATCH] cpuset exit NULL dereference fix · 2efe86b8
      Paul Jackson authored 
      

There is a race in the kernel cpuset code, between the code
to handle notify_on_release, and the code to remove a cpuset.
The notify_on_release code can end up trying to access a
cpuset that has been removed.  In the most common case, this
causes a NULL pointer dereference from the routine cpuset_path.
However all manner of bad things are possible, in theory at least.

The existing code decrements the cpuset use count, and if the
count goes to zero, processes the notify_on_release request,
if appropriate.  However, once the count goes to zero, unless we
are holding the global cpuset_sem semaphore, there is nothing to
stop another task from immediately removing the cpuset entirely,
and recycling its memory.

The obvious fix would be to always hold the cpuset_sem
semaphore while decrementing the use count and dealing with
notify_on_release.  However we don't want to force a global
semaphore into the mainline task exit path, as that might create
a scaling problem.

The actual fix is almost as easy - since this is only an issue
for cpusets using notify_on_release, which the top level big
cpusets don't normally need to use, only take the cpuset_sem
for cpusets using notify_on_release.

This code has been run for hours without a hiccup, while running
a cpuset create/destroy stress test that could crash the existing
kernel in seconds.  This patch applies to the current -linus
git kernel.

Signed-off-by: default avatarPaul Jackson <pj@sgi.com>
Acked-by: default avatarSimon Derr <simon.derr@bull.net>
Acked-by: default avatarDinakar Guniguntala <dino@in.ibm.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      2efe86b8
    • David Woodhouse's avatar
      AUDIT: Record working directory when syscall arguments are pathnames · 8f37d47c
      David Woodhouse authored 
      

Signed-off-by: default avatarDavid Woodhouse <dwmw2@infradead.org>
      8f37d47c
  15. May 26, 2005
    • David Woodhouse's avatar
      AUDIT: Defer freeing aux items until audit_free_context() · 7551ced3
      David Woodhouse authored 
      

While they were all just simple blobs it made sense to just free them
as we walked through and logged them. Now that there are pointers to
other objects which need refcounting, we might as well revert to
_only_ logging them in audit_log_exit(), and put the code to free them
properly in only one place -- in audit_free_aux().

Signed-off-by: default avatarDavid Woodhouse <dwmw2@infradead.org>
----------------------------------------------------------
      7551ced3
  17. May 25, 2005
  19. May 23, 2005
  21. May 21, 2005
    • David Woodhouse's avatar
      AUDIT: Assign serial number to non-syscall messages · bfb4496e
      David Woodhouse authored 
      

Move audit_serial() into audit.c and use it to generate serial numbers 
on messages even when there is no audit context from syscall auditing.  
This allows us to disambiguate audit records when more than one is 
generated in the same millisecond.

Based on a patch by Steve Grubb after he observed the problem.

Signed-off-by: default avatarDavid Woodhouse <dwmw2@infradead.org>
      bfb4496e
    • Samuel Thibault's avatar
      [PATCH] spin_unlock_bh() and preempt_check_resched() · 10f02d1c
      Samuel Thibault authored 
      

In _spin_unlock_bh(lock):
	do { \
		_raw_spin_unlock(lock); \
		preempt_enable(); \
		local_bh_enable(); \
		__release(lock); \
	} while (0)

there is no reason for using preempt_enable() instead of a simple
preempt_enable_no_resched()

Since we know bottom halves are disabled, preempt_schedule() will always
return at once (preempt_count!=0), and hence preempt_check_resched() is
useless here...

This fixes it by using "preempt_enable_no_resched()" instead of the
"preempt_enable()", and thus avoids the useless preempt_check_resched()
just before re-enabling bottom halves.

Signed-off-by: default avatarSamuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      10f02d1c
  23. May 20, 2005
  25. May 19, 2005
    • David Woodhouse's avatar
      AUDIT: Honour audit_backlog_limit again. · fb19b4c6
      David Woodhouse authored 
      

The limit on the number of outstanding audit messages was inadvertently
removed with the switch to queuing skbs directly for sending by a kernel
thread. Put it back again.

Signed-off-by: default avatarDavid Woodhouse <dwmw2@infradead.org>
      fb19b4c6
    • David Woodhouse's avatar
      AUDIT: Quis Custodiet Ipsos Custodes? · 7ca00264
      David Woodhouse authored 
      

Nobody does. Really, it gets very silly if auditd is recording its
own actions.

Signed-off-by: default avatarDavid Woodhouse <dwmw2@infradead.org>
      7ca00264
    • David Woodhouse's avatar
      AUDIT: Send netlink messages from a separate kernel thread · b7d11258
      David Woodhouse authored 
      

netlink_unicast() will attempt to reallocate and will free messages if
the socket's rcvbuf limit is reached unless we give it an infinite 
timeout. So do that, from a kernel thread which is dedicated to spewing
stuff up the netlink socket.

Signed-off-by: default avatarDavid Woodhouse <dwmw2@infradead.org>
      b7d11258
    • Steve Grubb's avatar
      AUDIT: Clean up logging of untrusted strings · 168b7173
      Steve Grubb authored 
      

* If vsnprintf returns -1, it will mess up the sk buffer space accounting. 
This is fixed by not calling skb_put with bogus len values.

* audit_log_hex was a loop that called audit_log_vformat with %02X for each 
character. This is very inefficient since conversion from unsigned character 
to Ascii representation is essentially masking, shifting, and byte lookups. 
Also, the length of the converted string is well known - it's twice the 
original. Fixed by rewriting the function.

* audit_log_untrustedstring had no comments. This makes it hard for 
someone to understand what the string format will be.

* audit_log_d_path was never fixed to use untrustedstring. This could mess
up user space parsers. This was fixed to make a temp buffer, call d_path, 
and log temp buffer using untrustedstring. 

From: Steve Grubb <sgrubb@redhat.com>
Signed-off-by: default avatarDavid Woodhouse <dwmw2@infradead.org>
      168b7173
  27. May 18, 2005
  29. May 17, 2005
  31. May 13, 2005
  33. May 11, 2005