Pierre Peiffer [Fri, 8 Feb 2008 12:18:57 +0000 (04:18 -0800)]
IPC: make struct ipc_ids static in ipc_namespace
Each ipc_namespace contains a table of 3 pointers to struct ipc_ids (3 for
msg, sem and shm, structure used to store all ipcs) These 'struct ipc_ids'
are dynamically allocated for each icp_namespace as the ipc_namespace
itself (for the init namespace, they are initialized with pointers to
static variables instead)
It is so for historical reason: in fact, before the use of idr to store the
ipcs, the ipcs were stored in tables of variable length, depending of the
maximum number of ipc allowed. Now, these 'struct ipc_ids' have a fixed
size. As they are allocated in any cases for each new ipc_namespace, there
is no gain of memory in having them allocated separately of the struct
ipc_namespace.
This patch proposes to make this table static in the struct ipc_namespace.
Thus, we can allocate all in once and get rid of all the code needed to
allocate and free these ipc_ids separately.
Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net> Acked-by: Cedric Le Goater <clg@fr.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Nadia Derbey <Nadia.Derbey@bull.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pierre Peiffer [Fri, 8 Feb 2008 12:18:56 +0000 (04:18 -0800)]
IPC/semaphores: consolidate SEM_STAT and IPC_STAT commands
These commands (SEM_STAT and IPC_STAT) are rather doing the same things
(only the meaning of the id given as input and the return value differ).
However, for the semaphores, they are handled in two different places (two
different functions).
This patch consolidates this for clarification by handling these both
commands in the same place in semctl_nolock(). It also removes one unused
parameter for this function.
Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net> Cc: Nadia Derbey <Nadia.Derbey@bull.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pavel Emelyanov [Fri, 8 Feb 2008 12:18:54 +0000 (04:18 -0800)]
ipc: uninline some code from util.h
ipc_lock_check_down(), ipc_lock_check() and ipcget() seem too large to be
inline. Besides, they give no optimization being inline as they perform
calls inside in any case.
Moving them into ipc/util.c saves 500 bytes of vmlinux and shortens IPC
internal API.
The module subsystem cannot handle symbols that are zero. If symbols are
present that have a zero value then the module resolver prints out a
message that these symbols are unresolved.
[akinobu.mita@gmail.com: fix __find_symbl() error checks] Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Kay Sievers <kay.sievers@vrfy.org Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Heiko Carstens [Fri, 8 Feb 2008 12:18:39 +0000 (04:18 -0800)]
tty: let architectures override the user/kernel macros.
Give architectures that support the new termios2 the possibilty to overide the
user_termios_to_kernel_termios and kernel_termios_to_user_termios macros. As
soon as all architectures that use the generic variant have been converted the
ifdefs can go away again. Architectures in question are avr32, frv, powerpc
and s390.
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Paul Mackerras <paulus@samba.org> Cc: David Howells <dhowells@redhat.com> Cc: Haavard Skinnemoen <hskinnemoen@atmel.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mark gross [Fri, 8 Feb 2008 12:18:38 +0000 (04:18 -0800)]
intel-iommu: PMEN support
Add support for protected memory enable bits by clearing them if they are
set at startup time. Some future boot loaders or firmware could have this
bit set after it loads the kernel, and it needs to be cleared if DMA's are
going to happen effectively.
Signed-off-by: mark gross <mgross@intel.com> Acked-by: Muli Ben-Yehuda <muli@il.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alexey Dobriyan [Fri, 8 Feb 2008 12:18:37 +0000 (04:18 -0800)]
proc: fix ->open'less usage due to ->proc_fops flip
Typical PDE creation code looks like:
pde = create_proc_entry("foo", 0, NULL);
if (pde)
pde->proc_fops = &foo_proc_fops;
Notice that PDE is first created, only then ->proc_fops is set up to
final value. This is a problem because right after creation
a) PDE is fully visible in /proc , and
b) ->proc_fops are proc_file_operations which do not have ->open callback. So, it's
possible to ->read without ->open (see one class of oopses below).
The fix is new API called proc_create() which makes sure ->proc_fops are
set up before gluing PDE to main tree. Typical new code looks like:
pde = proc_create("foo", 0, NULL, &foo_proc_fops);
if (!pde)
return -ENOMEM;
Fix most networking users for a start.
In the long run, create_proc_entry() for regular files will go.
Long ago when the CLONE_THREAD support first went it someone thought it
would be wise to point /proc/self at /proc/<tgid> instead of /proc/<pid>.
Given that /proc/<tgid> can return information about a very different task
(if enough things have been unshared) then our current process /proc/<tgid>
seems blatantly wrong. So far I have yet to think up an example where the
current behavior would be advantageous, and I can see several places where
it is seriously non-intuitive.
We may be stuck with the current broken behavior for backwards
compatibility reasons but lets try fixing our ancient bug for the 2.6.25
time frame and see if anyone screams.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: "Guillaume Chazarain" <guichaz@yahoo.fr> Cc: "Pavel Emelyanov" <xemul@openvz.org> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently if you access a /proc that is not mounted with your processes
current pid namespace /proc/self will point at a completely random task.
This patch fixes /proc/self to point to the current process if it is
available in the particular mount of /proc or to return -ENOENT if the
current process is not visible.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
proc: seqfile convert proc_pid_status to properly handle pid namespaces
Currently we possibly lookup the pid in the wrong pid namespace. So
seq_file convert proc_pid_status which ensures the proper pid namespaces is
passed in.
[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: another build fix]
[akpm@linux-foundation.org: s390 build fix]
[akpm@linux-foundation.org: fix task_name() output]
[akpm@linux-foundation.org: fix nommu build] Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Andrew Morgan <morgan@kernel.org> Cc: Serge Hallyn <serue@us.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
proc: rewrite do_task_stat to correctly handle pid namespaces.
Currently (as pointed out by Oleg) do_task_stat has a race when calling
task_pid_nr_ns with the task exiting. In addition do_task_stat is not
currently displaying information in the context of the pid namespace that
mounted the /proc filesystem. So "cut -d' ' -f 1 /proc/<pid>/stat" may not
equal <pid>.
This patch fixes the problem by converting to a single_open seq_file show
method. Getting the pid namespace from the filesystem superblock instead of
current, and simply using the the struct pid from the inode instead of
attempting to get that same pid from the task.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently many /proc/pid files use a crufty precursor to the current seq_file
api, and they don't have direct access to the pid_namespace or the pid of for
which they are displaying data.
So implement proc_single_file_operations to make the seq_file routines easy to
use, and to give access to the full state of the pid of we are displaying data
for.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pavel Emelyanov [Fri, 8 Feb 2008 12:18:24 +0000 (04:18 -0800)]
namespaces: cleanup the code managed with PID_NS option
Just like with the user namespaces, move the namespace management code into
the separate .c file and mark the (already existing) PID_NS option as "depend
on NAMESPACES"
[akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Kirill Korotaev <dev@sw.ru> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pavel Emelyanov [Fri, 8 Feb 2008 12:18:23 +0000 (04:18 -0800)]
namespaces: cleanup the code managed with the USER_NS option
Make the user_namespace.o compilation depend on this option and move the
init_user_ns into user.c file to make the kernel compile and work without the
namespaces support. This make the user namespace code be organized similar to
other namespaces'.
Also mask the USER_NS option as "depend on NAMESPACES".
[akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Kirill Korotaev <dev@sw.ru> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pavel Emelyanov [Fri, 8 Feb 2008 12:18:22 +0000 (04:18 -0800)]
namespaces: move the IPC namespace under IPC_NS option
Currently the IPC namespace management code is spread over the ipc/*.c files.
I moved this code into ipc/namespace.c file which is compiled out when needed.
The linux/ipc_namespace.h file is used to store the prototypes of the
functions in namespace.c and the stubs for NAMESPACES=n case. This is done
so, because the stub for copy_ipc_namespace requires the knowledge of the
CLONE_NEWIPC flag, which is in sched.h. But the linux/ipc.h file itself in
included into many many .c files via the sys.h->sem.h sequence so adding the
sched.h into it will make all these .c depend on sched.h which is not that
good. On the other hand the knowledge about the namespaces stuff is required
in 4 .c files only.
Besides, this patch compiles out some auxiliary functions from ipc/sem.c,
msg.c and shm.c files. It turned out that moving these functions into
namespaces.c is not that easy because they use many other calls and macros
from the original file. Moving them would make this patch complicated. On
the other hand all these functions can be consolidated, so I will send a
separate patch doing this a bit later.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Kirill Korotaev <dev@sw.ru> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When I replaced hugetlb_dynamic_pool with nr_overcommit_hugepages I used
proc_doulongvec_minmax() directly. However, hugetlb.c's locking rules
require that all counter modifications occur under the hugetlb_lock. Add a
callback into the hugetlb code similar to the one for nr_hugepages. Grab
the lock around the manipulation of nr_overcommit_hugepages in
proc_doulongvec_minmax().
Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com> Acked-by: Adam Litke <agl@us.ibm.com> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Linus Torvalds [Fri, 8 Feb 2008 03:12:12 +0000 (19:12 -0800)]
Merge branch 'for-linus' of git://oss.sgi.com:8090/xfs/xfs-2.6
* 'for-linus' of git://oss.sgi.com:8090/xfs/xfs-2.6: (62 commits)
[XFS] add __init/__exit mark to specific init/cleanup functions
[XFS] Fix oops in xfs_file_readdir()
[XFS] kill xfs_root
[XFS] keep i_nlink updated and use proper accessors
[XFS] stop updating inode->i_blocks
[XFS] Make xfs_ail_check check less by default
[XFS] Move AIL pushing into it's own thread
[XFS] use generic_permission
[XFS] stop re-checking permissions in xfs_swapext
[XFS] clean up xfs_swapext
[XFS] remove permission check from xfs_change_file_space
[XFS] prevent panic during log recovery due to bogus op_hdr length
[XFS] Cleanup various fid related bits:
[XFS] Fix xfs_lowbit64
[XFS] Remove CFORK macros and use code directly in IFORK and DFORK macros.
[XFS] kill superflous buffer locking (2nd attempt)
[XFS] Use kernel-supplied "roundup_pow_of_two" for simplicity
[XFS] Remove the BPCSHIFT and NB* based macros from XFS.
[XFS] Remove bogus assert
[XFS] optimize XFS_IS_REALTIME_INODE w/o realtime config
...
Nick Piggin [Fri, 8 Feb 2008 02:46:06 +0000 (18:46 -0800)]
Convert SG from nopage to fault.
Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Douglas Gilbert <dougg@torque.net> Cc: James Bottomley <James.Bottomley@steeleye.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Linus Torvalds [Fri, 8 Feb 2008 02:22:29 +0000 (18:22 -0800)]
Merge branch 'slub-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/christoph/vm
* 'slub-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/christoph/vm:
SLUB: fix checkpatch warnings
Use non atomic unlock
SLUB: Support for performance statistics
SLUB: Alternate fast paths using cmpxchg_local
SLUB: Use unique end pointer for each slab page.
SLUB: Deal with annoying gcc warning on kfree()
This patch adds extra information to the mirror status output, so that
it can be determined which device(s) have failed. For each mirror device,
a character is printed indicating the most severe error encountered. The
characters are:
* A => Alive - No failures
* D => Dead - A write failure occurred leaving mirror out-of-sync
* S => Sync - A sychronization failure occurred, mirror out-of-sync
* R => Read - A read failure occurred, mirror data unaffected
This allows userspace to properly reconfigure the mirror set.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This patch gives the ability to respond-to/record device failures
that happen during read operations. It also adds the ability to
read from mirror devices that are not the primary if they are
in-sync.
There are essentially two read paths in mirroring; the direct path
and the queued path. When a read request is mapped, if the region
is 'in-sync' the direct path is taken; otherwise the queued path
is taken.
If the direct path is taken, we must record bio information so that
if the read fails we can retry it. We then discover the status of
a direct read through mirror_end_io. If the read has failed, we will
mark the device from which the read was attempted as failed (so we
don't try to read from it again), restore the bio and try again.
If the queued path is taken, we discover the results of the read
from 'read_callback'. If the device failed, we will mark the device
as failed and attempt the read again if there is another device
where this region is known to be 'in-sync'.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This patch adds the ability to requeue write I/O to
core device-mapper when there is a log device failure.
If a write to the log produces and error, the pending writes are
put on the "failures" list. Since the log is marked as failed,
they will stay on the failures list until a suspend happens.
Suspends come in two phases, presuspend and postsuspend. We must
make sure that all the writes on the failures list are requeued
in the presuspend phase (a requirement of dm core). This means
that recovery must be complete (because writes may be delayed
behind it) and the failures list must be requeued before we
return from presuspend.
The mechanisms to ensure recovery is complete (or stopped) was
already in place, but needed to be moved from postsuspend to
presuspend. We rely on 'flush_workqueue' to ensure that the
mirror thread is complete and therefore, has requeued all writes
in the failures list.
Because we are using flush_workqueue, we must ensure that no
additional 'queue_work' calls will produce additional I/O
that we need to requeue (because once we return from
presuspend, we are unable to do anything about it). 'queue_work'
is called in response to the following functions:
- complete_resync_work = NA, recovery is stopped
- rh_dec (mirror_end_io) = NA, only calls 'queue_work' if it
is ready to recover the region
(recovery is stopped) or it needs
to clear the region in the log*
**this doesn't get called while
suspending**
- rh_recovery_end = NA, recovery is stopped
- rh_recovery_start = NA, recovery is stopped
- write_callback = 1) Writes w/o failures simply call
bio_endio -> mirror_end_io -> rh_dec
(see rh_dec above)
2) Writes with failures are put on
the failures list and queue_work is
called**
** write_callbacks don't happen
during suspend **
- do_failures = NA, 'queue_work' not called if suspending
- add_mirror (initialization) = NA, only done on mirror creation
- queue_bio = NA, 1) delayed I/O scheduled before flush_workqueue
is called. 2) No more I/Os are being issued.
3) Re-attempted READs can still be handled.
(Write completions are handled through rh_dec/
write_callback - mention above - and do not
use queue_bio.)
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This patch adds the calls to 'fail_mirror' if an error occurs during
mirror recovery (aka resynchronization). 'fail_mirror' is responsible
for recording the type of error by mirror device and ensuring an event
gets raised for the purpose of notifying userspace.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This patch gives mirror the ability to handle device failures
during normal write operations.
The 'write_callback' function is called when a write completes.
If all the writes failed or succeeded, we report failure or
success respectively. If some of the writes failed, we call
fail_mirror; which increments the error count for the device, notes
the type of error encountered (DM_RAID1_WRITE_ERROR), and
selects a new primary (if necessary). Note that the primary
device can never change while the mirror is not in-sync (IOW,
while recovery is happening.) This means that the scenario
where a failed write changes the primary and gives
recovery_complete a chance to misread the primary never happens.
The fact that the primary can change has necessitated the change
to the default_mirror field. We need to protect against reading
garbage while the primary changes. We then add the bio to a new
list in the mirror set, 'failures'. For every bio in the 'failures'
list, we call a new function, '__bio_mark_nosync', where we mark
the region 'not-in-sync' in the log and properly set the region
state as, RH_NOSYNC. Userspace must also be notified of the
failure. This is done by 'raising an event' (dm_table_event()).
If fail_mirror is called in process context the event can be raised
right away. If in interrupt context, the event is deferred to the
kmirrord thread - which raises the event if 'event_waiting' is set.
Backwards compatibility is maintained by ignoring errors if
the DM_FEATURES_HANDLE_ERRORS flag is not present.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Milan Broz [Fri, 8 Feb 2008 02:11:27 +0000 (02:11 +0000)]
dm snapshot: combine consecutive exceptions in memory
Provided sector_t is 64 bits, reduce the in-memory footprint of the
snapshot exception table by the simple method of using unused bits of
the chunk number to combine consecutive entries.
Signed-off-by: Milan Broz <mbroz@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Brian Wood [Fri, 8 Feb 2008 02:11:24 +0000 (02:11 +0000)]
dm: stripe enhanced status return
This patch adds additional information to the status line. It is added at the
end of the returned text so it will not interfere with existing
implementations using this data. The addition of this information will allow
for a common return interface to match that returned with the dm-raid1.c
status line (with Jonathan Brassow's patches).
Here is a sample of what is returned with a mirror "status" call:
isw_eeaaabgfg_mirror: 0 488390920 mirror 2 8:16 8:32 3727/3727 1 AA 1 core
Here's what's returned with this patch for a stripe "status" call:
isw_dheeijjdej_stripe: 0 976783872 striped 2 8:16 8:32 1 AA
Signed-off-by: Brian Wood <brian.j.wood@intel.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Brian Wood [Fri, 8 Feb 2008 02:11:22 +0000 (02:11 +0000)]
dm: stripe trigger event on failure
This patch adds the stripe_end_io function to process errors that might
occur after an IO operation. As part of this there are a number of
enhancements made to record and trigger events:
- New atomic variable in struct stripe to record the number of
errors each stripe volume device has experienced (could be used
later with uevents to report back directly to userspace)
- New workqueue/work struct setup to process the trigger_event function
- New end_io function. It is here that testing for BIO error conditions
take place. It determines the exact stripe that cause the error,
records this in the new atomic variable, and calls the queue_work() function
- New trigger_event function to process failure events. This
calls dm_table_event()
Signed-off-by: Brian Wood <brian.j.wood@intel.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Milan Broz [Fri, 8 Feb 2008 02:10:22 +0000 (02:10 +0000)]
dm: refactor deferred bio_list processing
Refactor deferred bio_list processing.
- use separate _merge_pushback_list function
- move deferred bio list pick up to flush function
- use bio_list_pop instead of bio_list_get
- simplify noflush flag use
No real functional change in this patch.
Signed-off-by: Milan Broz <mbroz@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Andrew Morton [Fri, 8 Feb 2008 02:10:11 +0000 (02:10 +0000)]
dm snapshot: use uninitialized_var
drivers/md/dm-exception-store.c: In function 'persistent_read_metadata':
drivers/md/dm-exception-store.c:452: warning: 'new_snapshot' may be used uninitialized in this function
Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
[clameter: rediffed against Pekka's cleanup patch, omitted
moves of the name of a function to the start of line] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Christoph Lameter <clameter@sgi.com>
The statistics provided here allow the monitoring of allocator behavior but
at the cost of some (minimal) loss of performance. Counters are placed in
SLUB's per cpu data structure. The per cpu structure may be extended by the
statistics to grow larger than one cacheline which will increase the cache
footprint of SLUB.
There is a compile option to enable/disable the inclusion of the runtime
statistics and its off by default.
The slabinfo tool is enhanced to support these statistics via two options:
-D Switches the line of information displayed for a slab from size
mode to activity mode.
-A Sorts the slabs displayed by activity. This allows the display of
the slabs most important to the performance of a certain load.
-r Report option will report detailed statistics on
Total: The total number of allocation and frees that occurred for a
slab
Fastpath: The number of allocations/frees that used the fastpath.
Slowpath: Other allocations
Page Alloc: Number of calls to the page allocator as a result of slowpath
processing
Add Partial: Number of slabs added to the partial list through free or
alloc (occurs during cpuslab flushes)
Remove Partial: Number of slabs removed from the partial list as a result of
allocations retrieving a partial slab or by a free freeing
the last object of a slab.
RemoteObj/Froz: How many times were remotely freed object encountered when a
slab was about to be deactivated. Frozen: How many times was
free able to skip list processing because the slab was in use
as the cpuslab of another processor.
Flushes: Number of times the cpuslab was flushed on request
(kmem_cache_shrink, may result from races in __slab_alloc)
Refill: Number of times we were able to refill the cpuslab from
remotely freed objects for the same slab.
Deactivate: Statistics how slabs were deactivated. Shows how they were
put onto the partial list.
In general fastpath is very good. Slowpath without partial list processing is
also desirable. Any touching of partial list uses node specific locks which
may potentially cause list lock contention.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Provide an alternate implementation of the SLUB fast paths for alloc
and free using cmpxchg_local. The cmpxchg_local fast path is selected
for arches that have CONFIG_FAST_CMPXCHG_LOCAL set. An arch should only
set CONFIG_FAST_CMPXCHG_LOCAL if the cmpxchg_local is faster than an
interrupt enable/disable sequence. This is known to be true for both
x86 platforms so set FAST_CMPXCHG_LOCAL for both arches.
Currently another requirement for the fastpath is that the kernel is
compiled without preemption. The restriction will go away with the
introduction of a new per cpu allocator and new per cpu operations.
The advantages of a cmpxchg_local based fast path are:
1. Potentially lower cycle count (30%-60% faster)
2. There is no need to disable and enable interrupts on the fast path.
Currently interrupts have to be disabled and enabled on every
slab operation. This is likely avoiding a significant percentage
of interrupt off / on sequences in the kernel.
3. The disposal of freed slabs can occur with interrupts enabled.
The alternate path is realized using #ifdef's. Several attempts to do the
same with macros and inline functions resulted in a mess (in particular due
to the strange way that local_interrupt_save() handles its argument and due
to the need to define macros/functions that sometimes disable interrupts
and sometimes do something else).
[clameter: Stripped preempt bits and disabled fastpath if preempt is enabled] Signed-off-by: Christoph Lameter <clameter@sgi.com> Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
We use a NULL pointer on freelists to signal that there are no more objects.
However the NULL pointers of all slabs match in contrast to the pointers to
the real objects which are in different ranges for different slab pages.
Change the end pointer to be a pointer to the first object and set bit 0.
Every slab will then have a different end pointer. This is necessary to ensure
that end markers can be matched to the source slab during cmpxchg_local.
Bring back the use of the mapping field by SLUB since we would otherwise have
to call a relatively expensive function page_address() in __slab_alloc(). Use
of the mapping field allows avoiding a call to page_address() in various other
functions as well.
There is no need to change the page_mapping() function since bit 0 is set on
the mapping as also for anonymous pages. page_mapping(slab_page) will
therefore still return NULL although the mapping field is overloaded.
Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
gcc 4.2 spits out an annoying warning if one casts a const void *
pointer to a void * pointer. No warning is generated if the
conversion is done through an assignment.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
projects / linux-2.6 / log