Hugh Dickins [Wed, 3 Aug 2011 00:52:55 +0000 (10:52 +1000)]
We have already acknowledged that swapoff of a tmpfs file is slower than
it was before conversion to the generic radix_tree: a little slower there
will be acceptable, if the hotter paths are faster.
But it was a shock to find swapoff of a 500MB file 20 times slower on my
laptop, taking 10 minutes; and at that rate it significantly slows down my
testing.
Now, most of that turned out to be overhead from PROVE_LOCKING and
PROVE_RCU: without those it was only 4 times slower than before; and more
realistic tests on other machines don't fare as badly.
I've tried a number of things to improve it, including tagging the swap
entries, then doing lookup by tag: I'd expected that to halve the time,
but in practice it's erratic, and often counter-productive.
The only change I've so far found to make a consistent improvement, is to
short-circuit the way we go back and forth, gang lookup packing entries
into the array supplied, then shmem scanning that array for the target
entry. Scanning in place doubles the speed, so it's now only twice as
slow as before (or three times slower when the PROVEs are on).
So, add radix_tree_locate_item() as an expedient, once-off, single-caller
hack to do the lookup directly in place. #ifdef it on CONFIG_SHMEM and
CONFIG_SWAP, as much to document its limited applicability as save space
in other configurations. And, sadly, #include sched.h for cond_resched().
Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Hugh Dickins [Wed, 3 Aug 2011 00:52:54 +0000 (10:52 +1000)]
Remove PageSwapBacked (!page_is_file_cache) cases from
add_to_page_cache_locked() and add_to_page_cache_lru(): those pages now go
through shmem_add_to_page_cache().
Remove a comment on maximum tmpfs size from fsstack_copy_inode_size(), and
add a comment on swap entries to invalidate_mapping_pages().
And mincore_page() uses find_get_page() on what might be shmem or a tmpfs
file: allow for a radix_tree_exceptional_entry(), and proceed to
find_get_page() on swapper_space if so (oh, swapper_space needs #ifdef).
Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Hugh Dickins [Wed, 3 Aug 2011 00:52:54 +0000 (10:52 +1000)]
But we've not yet removed the old swp_entry_t i_direct[16] from
shmem_inode_info. That's because it was still being shared with the
inline symlink. Remove it now (saving 64 or 128 bytes from shmem inode
size), and use kmemdup() for short symlinks, say, those up to 128 bytes.
I wonder why mpol_free_shared_policy() is done in shmem_destroy_inode()
rather than shmem_evict_inode(), where we usually do such freeing? I
guess it doesn't matter, and I'm not into NUMA mpol testing right now.
Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Rik van Riel <riel@redhat.com> Reviewed-by: Pekka Enberg <penberg@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Hugh Dickins [Wed, 3 Aug 2011 00:52:54 +0000 (10:52 +1000)]
Convert shmem_writepage() to use shmem_delete_from_page_cache() to use
shmem_radix_tree_replace() to substitute swap entry for page pointer
atomically in the radix tree.
As with shmem_add_to_page_cache(), it's not entirely satisfactory to be
copying such code from delete_from_swap_cache, but again judged easier to
sell than making its other callers go through the extras.
Remove the toy implementation's shmem_put_swap() and shmem_get_swap(), now
unreferenced, and the hack to disable swap: it's now good to go.
The way things have worked out, info->lock no longer helps to guard the
shmem_swaplist: we increment swapped under shmem_swaplist_mutex only.
That global mutex exclusion between shmem_writepage() and shmem_unuse() is
not pretty, and we ought to find another way; but it's been forced on us
by recent race discoveries, not a consequence of this patchset.
And what has become of the WARN_ON_ONCE(1) free_swap_and_cache() if a swap
entry was found already present? That's no longer possible, the (unknown)
one inserting this page into filecache would hit the swap entry occupying
that slot.
Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Hugh Dickins [Wed, 3 Aug 2011 00:52:53 +0000 (10:52 +1000)]
Remove mem_cgroup_shmem_charge_fallback(): it was only required when we
had to move swappage to filecache with GFP_NOWAIT.
Remove the GFP_NOWAIT special case from mem_cgroup_cache_charge(), by
moving its call out from shmem_add_to_page_cache() to two of thats three
callers. But leave it doing mem_cgroup_uncharge_cache_page() on error:
although asymmetrical, it's easier for all 3 callers to handle.
These two changes would also be appropriate if anyone were to start using
shmem_read_mapping_page_gfp() with GFP_NOWAIT.
Remove mem_cgroup_get_shmem_target(): mc_handle_file_pte() can test
radix_tree_exceptional_entry() to get what it needs for itself.
Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Hugh Dickins [Wed, 3 Aug 2011 00:52:53 +0000 (10:52 +1000)]
Convert shmem_getpage_gfp(), the engine-room of shmem, to expect page or
swap entry returned from radix tree by find_lock_page().
Whereas the repetitive old method proceeded mainly under info->lock,
dropping and repeating whenever one of the conditions needed was not met,
now we can proceed without it, leaving shmem_add_to_page_cache() to check
for a race.
This way there is no need to preallocate a page, no need for an early
radix_tree_preload(), no need for mem_cgroup_shmem_charge_fallback().
Move the error unwinding down to the bottom instead of repeating it
throughout. ENOSPC handling is a little different from before: there is
no longer any race between find_lock_page() and finding swap, but we can
arrive at ENOSPC before calling shmem_recalc_inode(), which might
occasionally discover freed space.
Be stricter to check i_size before returning. info->lock is used for
little but alloced, swapped, i_blocks updates. Move i_blocks updates out
from under the max_blocks check, so even an unlimited size=0 mount can
show accurate du.
Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Hugh Dickins [Wed, 3 Aug 2011 00:52:53 +0000 (10:52 +1000)]
Convert shmem_unuse_inode() to use a lockless gang lookup of the radix
tree, searching for matching swap.
This is somewhat slower than the old method: because of repeated radix
tree descents, because of copying entries up, but probably most because
the old method noted and skipped once a vector page was cleared of swap.
Perhaps we can devise a use of radix tree tagging to achieve that later.
shmem_add_to_page_cache() uses shmem_radix_tree_replace() to compensate
for the lockless lookup by checking that the expected entry is in place,
under lock. It is not very satisfactory to be copying this much from
add_to_page_cache_locked(), but I think easier to sell than insisting that
every caller of add_to_page_cache*() go through the extras.
Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Hugh Dickins [Wed, 3 Aug 2011 00:52:52 +0000 (10:52 +1000)]
Disable the toy swapping implementation in shmem_writepage() - it's hard
to support two schemes at once - and convert shmem_truncate_range() to a
lockless gang lookup of swap entries along with pages, freeing both.
Since the second loop tightens its noose until all entries of either kind
have been squeezed out (and we shall make sure that there's not an instant
when neither is visible), there is no longer a need for yet another pass
below.
shmem_radix_tree_replace() compensates for the lockless lookup by checking
that the expected entry is in place, under lock, before replacing it.
Here it just deletes, but will be used in later patches to substitute swap
entry for page or page for swap entry.
Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Hugh Dickins [Wed, 3 Aug 2011 00:52:52 +0000 (10:52 +1000)]
Bring truncate.c's code for truncate_inode_pages_range() inline into
shmem_truncate_range(), replacing its first call (there's a followup call
below, but leave that one, it will disappear next).
Don't play with it yet, apart from leaving out the cleancache flush, and
(importantly) the nrpages == 0 skip, and moving shmem_setattr()'s partial
page preparation into its partial page handling.
Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Hugh Dickins [Wed, 3 Aug 2011 00:52:52 +0000 (10:52 +1000)]
While it's at its least, make a number of boring nitpicky cleanups to
shmem.c, mostly for consistency of variable naming. Things like "swap"
instead of "entry", "pgoff_t index" instead of "unsigned long idx".
And since everything else here is prefixed "shmem_",
better change init_tmpfs() to shmem_init().
Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Hugh Dickins [Wed, 3 Aug 2011 00:52:52 +0000 (10:52 +1000)]
The maximum size of a shmem/tmpfs file has been limited by the maximum
size of its triple-indirect swap vector. With 4kB page size, maximum
filesize was just over 2TB on a 32-bit kernel, but sadly one eighth of
that on a 64-bit kernel. (With 8kB page size, maximum filesize was just
over 4TB on a 64-bit kernel, but 16TB on a 32-bit kernel, MAX_LFS_FILESIZE
being then more restrictive than swap vector layout.)
It's a shame that tmpfs should be more restrictive than ramfs, and this
limitation has now been noticed. Add another level to the swap vector?
No, it became obscure and hard to maintain, once I complicated it to make
use of highmem pages nine years ago: better choose another way.
Surely, if 2.4 had had the radix tree pagecache introduced in 2.5, then
tmpfs would never have invented its own peculiar radix tree: we would have
fitted swap entries into the common radix tree instead, in much the same
way as we fit swap entries into page tables.
And why should each file have a separate radix tree for its pages and for
its swap entries? The swap entries are required precisely where and when
the pages are not. We want to put them together in a single radix tree:
which can then avoid much of the locking which was needed to prevent them
from being exchanged underneath us.
This also avoids the waste of memory devoted to swap vectors, first in the
shmem_inode itself, then at least two more pages once a file grew beyond
16 data pages (pages accounted by df and du, but not by memcg). Allocated
upfront, to avoid allocation when under swapping pressure, but pure waste
when CONFIG_SWAP is not set - I have never spattered around the ifdefs to
prevent that, preferring this move to sharing the common radix tree
instead.
There are three downsides to sharing the radix tree. One, that it binds
tmpfs more tightly to the rest of mm, either requiring knowledge of swap
entries in radix tree there, or duplication of its code here in shmem.c.
I believe that the simplications and memory savings (and probable higher
performance, not yet measured) justify that.
Two, that on HIGHMEM systems with SWAP enabled, it's the lowmem radix
nodes that cannot be freed under memory pressure - whereas before it was
the less precious highmem swap vector pages that could not be freed. I'm
hoping that 64-bit has now been accessible for long enough, that the
highmem argument has grown much less persuasive.
Three, that swapoff is slower than it used to be on tmpfs files, since
it's using a simple generic mechanism not tailored to it: I find this
noticeable, and shall want to improve, but maybe nobody else will notice.
So... now remove most of the old swap vector code from shmem.c. But, for
the moment, keep the simple i_direct vector of 16 pages, with simple
accessors shmem_put_swap() and shmem_get_swap(), as a toy implementation
to help mark where swap needs to be handled in subsequent patches.
Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Hugh Dickins [Wed, 3 Aug 2011 00:52:51 +0000 (10:52 +1000)]
If swap entries are to be stored along with struct page pointers in a
radix tree, they need to be distinguished as exceptional entries.
Most of the handling of swap entries in radix tree will be contained in
shmem.c, but a few functions in filemap.c's common code need to check for
their appearance: find_get_page(), find_lock_page(), find_get_pages() and
find_get_pages_contig().
So as not to slow their fast paths, tuck those checks inside the existing
checks for unlikely radix_tree_deref_slot(); except for find_lock_page(),
where it is an added test. And make it a BUG in find_get_pages_tag(),
which is not applied to tmpfs files.
A part of the reason for eliminating shmem_readpage() earlier, was to
minimize the places where common code would need to allow for swap
entries.
The swp_entry_t known to swapfile.c must be massaged into a slightly
different form when stored in the radix tree, just as it gets massaged
into a pte_t when stored in page tables.
In an i386 kernel this limits its information (type and page offset) to 30
bits: given 32 "types" of swapfile and 4kB pagesize, that's a maximum
swapfile size of 128GB. Which is less than the 512GB we previously
allowed with X86_PAE (where the swap entry can occupy the entire upper 32
bits of a pte_t), but not a new limitation on 32-bit without PAE; and
there's not a new limitation on 64-bit (where swap filesize is already
limited to 16TB by a 32-bit page offset). Thirty areas of 128GB is
probably still enough swap for a 64GB 32-bit machine.
Provide swp_to_radix_entry() and radix_to_swp_entry() conversions, and
enforce filesize limit in read_swap_header(), just as for ptes.
Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Hugh Dickins [Wed, 3 Aug 2011 00:52:51 +0000 (10:52 +1000)]
A patchset to extend tmpfs to MAX_LFS_FILESIZE by abandoning its peculiar
swap vector, instead keeping a file's swap entries in the same radix tree
as its struct page pointers: thus saving memory, and simplifying its code
and locking.
This patch:
The radix_tree is used by several subsystems for different purposes. A
major use is to store the struct page pointers of a file's pagecache for
memory management. But what if mm wanted to store something other than
page pointers there too?
The low bit of a radix_tree entry is already used to denote an indirect
pointer, for internal use, and the unlikely radix_tree_deref_retry() case.
Define the next bit as denoting an exceptional entry, and supply inline
functions radix_tree_exception() to return non-0 in either unlikely case,
and radix_tree_exceptional_entry() to return non-0 in the second case.
If a subsystem already uses radix_tree with that bit set, no problem: it
does not affect internal workings at all, but is defined for the
convenience of those storing well-aligned pointers in the radix_tree.
The radix_tree_gang_lookups have an implicit assumption that the caller
can deduce the offset of each entry returned e.g. by the page->index of a
struct page. But that may not be feasible for some kinds of item to be
stored there.
radix_tree_gang_lookup_slot() allow for an optional indices argument,
output array in which to return those offsets. The same could be added to
other radix_tree_gang_lookups, but for now keep it to the only one for
which we need it.
Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Rientjes [Wed, 3 Aug 2011 00:52:51 +0000 (10:52 +1000)]
After selecting a task to kill, the oom killer iterates all processes and
kills all other threads that share the same mm_struct in different thread
groups. It would not otherwise be helpful to kill a thread if its memory
would not be subsequently freed.
A kernel thread, however, may assume a user thread's mm by using
use_mm(). This is only temporary and should not result in sending a
SIGKILL to that kthread.
This patch ensures that only user threads and not kthreads are sent a
SIGKILL if they share the same mm_struct as the oom killed task.
Signed-off-by: David Rientjes <rientjes@google.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Shaohua Li [Wed, 3 Aug 2011 00:52:50 +0000 (10:52 +1000)]
per-task block plug can reduce block queue lock contention and increase
request merge. Currently page reclaim doesn't support it. I originally
thought page reclaim doesn't need it, because kswapd thread count is
limited and file cache write is done at flusher mostly.
When I test a workload with heavy swap in a 4-node machine, each CPU is
doing direct page reclaim and swap. This causes block queue lock
contention. In my test, without below patch, the CPU utilization is about
2% ~ 7%. With the patch, the CPU utilization is about 1% ~ 3%. Disk
throughput isn't changed. This should improve normal kswapd write and
file cache write too (increase request merge for example), but might not
be so obvious as I explain above.
Signed-off-by: Shaohua Li <shaohua.li@intel.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Minchan Kim [Wed, 3 Aug 2011 00:52:49 +0000 (10:52 +1000)]
In __zone_reclaim case, we don't want to shrink mapped page. Nonetheless,
we have isolated mapped page and re-add it into LRU's head. It's
unnecessary CPU overhead and makes LRU churning.
Of course, when we isolate the page, the page might be mapped but when we
try to migrate the page, the page would be not mapped. So it could be
migrated. But race is rare and although it happens, it's no big deal.
Signed-off-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Minchan Kim [Wed, 3 Aug 2011 00:52:49 +0000 (10:52 +1000)]
In async mode, compaction doesn't migrate dirty or writeback pages. So,
it's meaningless to pick the page and re-add it to lru list.
Of course, when we isolate the page in compaction, the page might be dirty
or writeback but when we try to migrate the page, the page would be not
dirty, writeback. So it could be migrated. But it's very unlikely as
isolate and migration cycle is much faster than writeout.
So, this patch helps cpu overhead and prevent unnecessary LRU churning.
Signed-off-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Mel Gorman <mgorman@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Minchan Kim [Wed, 3 Aug 2011 00:52:49 +0000 (10:52 +1000)]
Change ISOLATE_XXX macro with bitwise isolate_mode_t type. Normally,
macro isn't recommended as it's type-unsafe and making debugging harder as
symbol cannot be passed throught to the debugger.
Quote from Johannes
" Hmm, it would probably be cleaner to fully convert the isolation mode
into independent flags. INACTIVE, ACTIVE, BOTH is currently a
tri-state among flags, which is a bit ugly."
This patch moves isolate mode from swap.h to mmzone.h by memcontrol.h
Signed-off-by: Minchan Kim <minchan.kim@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Minchan Kim [Wed, 3 Aug 2011 00:52:49 +0000 (10:52 +1000)]
acct_isolated of compaction uses page_lru_base_type which returns only
base type of LRU list so it never returns LRU_ACTIVE_ANON or
LRU_ACTIVE_FILE. In addtion, cc->nr_[anon|file] is used in only
acct_isolated so it doesn't have fields in conpact_control.
This patch removes fields from compact_control and makes clear function of
acct_issolated which counts the number of anon|file pages isolated.
Signed-off-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Mel Gorman <mgorman@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
- Change behaviour so process_vm_readv and process_vm_writev return
the number of bytes successfully read or written even if an error
occurs
- Add more kernel doc interface comments
- rename some internal functions (process_vm_rw_check_iovecs,
process_vm_rw) so they make more sense.
- Add licence message
- Fix kernel-doc comment format
Still need to do benchmarking to see if the optimisation for small copies
using a local on-stack array in process_vm_rw_core is worth it.
Signed-off-by: Chris Yeoh <cyeoh@au1.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The basic idea behind cross memory attach is to allow MPI programs doing
intra-node communication to do a single copy of the message rather than a
double copy of the message via shared memory.
The following patch attempts to achieve this by allowing a destination
process, given an address and size from a source process, to copy memory
directly from the source process into its own address space via a system
call. There is also a symmetrical ability to copy from the current
process's address space into a destination process's address space.
- Use of /proc/pid/mem has been considered, but there are issues with
using it:
- Does not allow for specifying iovecs for both src and dest, assuming
preadv or pwritev was implemented either the area read from or
written to would need to be contiguous.
- Currently mem_read allows only processes who are currently
ptrace'ing the target and are still able to ptrace the target to read
from the target. This check could possibly be moved to the open call,
but its not clear exactly what race this restriction is stopping
(reason appears to have been lost)
- Having to send the fd of /proc/self/mem via SCM_RIGHTS on unix
domain socket is a bit ugly from a userspace point of view,
especially when you may have hundreds if not (eventually) thousands
of processes that all need to do this with each other
- Doesn't allow for some future use of the interface we would like to
consider adding in the future (see below)
- Interestingly reading from /proc/pid/mem currently actually
involves two copies! (But this could be fixed pretty easily)
As mentioned previously use of vmsplice instead was considered, but has
problems. Since you need the reader and writer working co-operatively if
the pipe is not drained then you block. Which requires some wrapping to
do non blocking on the send side or polling on the receive. In all to all
communication it requires ordering otherwise you can deadlock. And in the
example of many MPI tasks writing to one MPI task vmsplice serialises the
copying.
There are some cases of MPI collectives where even a single copy interface
does not get us the performance gain we could. For example in an
MPI_Reduce rather than copy the data from the source we would like to
instead use it directly in a mathops (say the reduce is doing a sum) as
this would save us doing a copy. We don't need to keep a copy of the data
from the source. I haven't implemented this, but I think this interface
could in the future do all this through the use of the flags - eg could
specify the math operation and type and the kernel rather than just
copying the data would apply the specified operation between the source
and destination and store it in the destination.
Although we don't have a "second user" of the interface (though I've had
some nibbles from people who may be interested in using it for intra
process messaging which is not MPI). This interface is something which
hardware vendors are already doing for their custom drivers to implement
fast local communication. And so in addition to this being useful for
OpenMPI it would mean the driver maintainers don't have to fix things up
when the mm changes.
There was some discussion about how much faster a true zero copy would
go. Here's a link back to the email with some testing I did on that:
There is a basic man page for the proposed interface here:
http://ozlabs.org/~cyeoh/cma/process_vm_readv.txt
This has been implemented for x86 and powerpc, other architecture should
mainly (I think) just need to add syscall numbers for the process_vm_readv
and process_vm_writev. There are 32 bit compatibility versions for
64-bit kernels.
For arch maintainers there are some simple tests to be able to quickly
verify that the syscalls are working correctly here:
Stephen Boyd [Wed, 3 Aug 2011 00:52:46 +0000 (10:52 +1000)]
Instead of open coding this function use kstrtoul_from_user() directly.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Cc: Doug Gilbert <dgilbert@interlog.com> Cc: Douglas Gilbert <dougg@torque.net> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jesper Juhl [Wed, 3 Aug 2011 00:52:45 +0000 (10:52 +1000)]
We leak in drivers/scsi/aacraid/commctrl.c::aac_send_raw_srb() :
We allocate memory:
...
struct user_sgmap* usg;
usg = kmalloc(actual_fibsize - sizeof(struct aac_srb)
+ sizeof(struct sgmap), GFP_KERNEL);
and then neglect to free it:
...
for (i = 0; i < usg->count; i++) {
u64 addr;
void* p;
if (usg->sg[i].count >
((dev->adapter_info.options &
AAC_OPT_NEW_COMM) ?
(dev->scsi_host_ptr->max_sectors << 9) :
65536)) {
rcode = -EINVAL;
goto cleanup;
... this 'goto' makes 'usg' go out of scope and leak the memory we
allocated.
Other exits properly kfree(usg), it's just here it is neglected.
Signed-off-by: Jesper Juhl <jj@chaosbits.net> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Randy Dunlap [Wed, 3 Aug 2011 00:52:45 +0000 (10:52 +1000)]
Fix sparse warnings of right shift bigger than source value size:
drivers/scsi/megaraid.c:311:65: warning: right shift by bigger than source value
drivers/scsi/megaraid.c:313:65: warning: right shift by bigger than source value
drivers/scsi/megaraid.c:317:67: warning: right shift by bigger than source value
drivers/scsi/megaraid.c:319:67: warning: right shift by bigger than source value
Patch suggestion from email by Al Viro:
"Since both are claimed to be strings, I really suspect that this >> 8 is
misspelled >> 4 and they have a character followed by pair of two-digit
packed decimals in there..."
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Neela Syam Kolli <megaraidlinux@lsi.com> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
For headers that get exported to userland and make use of u32 style
type names, it is advised to include linux/types.h.
This fixes a headers_check warning.
Signed-off-by: Alexander Shishkin <virtuoso@slind.org> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jean Delvare [Wed, 3 Aug 2011 00:52:44 +0000 (10:52 +1000)]
The current implementation of dmi_name_in_vendors() is an invitation to
lazy coding and false positives [1]. Searching for a string in 8 know
what you're looking for, so you should know where to look. strstr isn't
fast, especially when it fails, so we should avoid calling it when it just
can't succeed.
Looking at the current users of the function, it seems clear to me that
they are looking for a system or board vendor name, so let's limit
dmi_name_in_vendors to these two DMI fields. This much better matches the
function name, BTW.
[1] We currently have code looking for short names in DMI data, such
as "IBM", "ASUS" or "Acer". I let you guess what will happen the day
other vendors ship products named, for example, "SCHREIBMEISTER",
"PEGASUS" or "Acerola".
Signed-off-by: Jean Delvare <khali@linux-fr.org> Cc: Andi Kleen <andi@firstfloor.org> Cc: Jesse Barnes <jbarnes@virtuousgeek.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Yinghai Lu [Wed, 3 Aug 2011 00:52:44 +0000 (10:52 +1000)]
When do pci remove/rescan on system that have more iommus, got
[ 894.089745] Set context mapping for c4:00.0
[ 894.110890] mpt2sas3: Allocated physical memory: size(4293 kB)
[ 894.112556] mpt2sas3: Current Controller Queue Depth(1883), Max Controller Queue Depth(2144)
[ 894.127278] mpt2sas3: Scatter Gather Elements per IO(128)
[ 894.361295] DRHD: handling fault status reg 2
[ 894.364053] DMAR:[DMA Read] Request device [c4:00.0] fault addr fffbe000
[ 894.364056] DMAR:[fault reason 02] Present bit in context entry is cl
it turns out when remove/rescan, pci dev will be freed and will get
another new dev. but drhd units still keep old one... so
dmar_find_matched_drhd_unit will return wrong drhd and iommu for the
device that is not on first iommu.
So need to update devices in drhd_units during pci remove/rescan.
Could save domain/bus/device/function aside in the list and according that
info restore new dev to drhd_units later. Then
dmar_find_matched_drdh_unit and device_to_iommu could return right drhd
and iommu.
Add remove_dev_from_drhd/restore_dev_to_drhd functions to do the real
work. call them in device ADD_DEVICE and UNBOUND_DRIVER
Need to do the samething to atsr. (expose dmar_atsr_units and add
atsru->segment)
After patch, will right iommu for the new dev and will not get DMAR error
any more.
Signed-off-by: Yinghai Lu <yinghai@kernel.org> Cc: Jesse Barnes <jbarnes@virtuousgeek.org> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Vinod Koul <vinod.koul@intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Akinobu Mita [Wed, 3 Aug 2011 00:52:43 +0000 (10:52 +1000)]
The dqc_bitmap field of struct ocfs2_local_disk_chunk is 32-bit aligned,
but not 64-bit aligned. The dqc_bitmap is accessed by ocfs2_set_bit(),
ocfs2_clear_bit(), ocfs2_test_bit(), or ocfs2_find_next_zero_bit(). These
are wrapper macros for ext2_*_bit() which need to take an unsigned long
aligned address (though some architectures are able to handle unaligned
address correctly)
So some 64bit architectures may not be able to access the dqc_bitmap
correctly.
This avoids such unaligned access by using another wrapper functions for
ext2_*_bit(). The code is taken from fs/ext4/mballoc.c which also need to
handle unaligned bitmap access.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Acked-by: Joel Becker <jlbec@evilplan.org> Cc: Mark Fasheh <mfasheh@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Akinobu Mita [Wed, 3 Aug 2011 00:52:43 +0000 (10:52 +1000)]
ext4_{set,clear}_bit() is defined as __test_and_{set,clear}_bit_le() for
ext4. Only two ext4_{set,clear}_bit() calls check the return value. The
rest of calls ignore the return value and they can be replaced with
__{set,clear}_bit_le().
This changes ext4_{set,clear}_bit() from __test_and_{set,clear}_bit_le()
to __{set,clear}_bit_le() and introduces ext4_test_and_{set,clear}_bit()
for the two places where old bit needs to be returned.
This ext4_{set,clear}_bit() change is considered safe, because if someone
uses these macros without noticing the change, new ext4_{set,clear}_bit
don't have return value and causes compiler errors where the return value
is used.
This also removes unused ext4_find_first_zero_bit().
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Christine Chan [Wed, 3 Aug 2011 00:52:42 +0000 (10:52 +1000)]
del_timer_sync() calls debug_object_assert_init() to assert that a timer
has been initialized before calling lock_timer_base(). lock_timer_base()
would spin forever on a NULL(uninit-ed) base. The check is added to
del_timer() to prevent silent failure, even though it would not get stuck
in an infinite loop.
Signed-off-by: Christine Chan <cschan@codeaurora.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <john.stultz@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Andrew Morton [Wed, 3 Aug 2011 00:52:42 +0000 (10:52 +1000)]
i386 allmodconfig:
drivers/built-in.o: In function `aat2870_bl_remove':
aat2870_bl.c:(.text+0x414f9): undefined reference to `backlight_device_unregister'
drivers/built-in.o: In function `aat2870_bl_probe':
aat2870_bl.c:(.text+0x418fc): undefined reference to `backlight_device_register'
aat2870_bl.c:(.text+0x41a31): undefined reference to `backlight_device_unregiste
Cc: Jin Park <jinyoungp@nvidia.com> Cc: Samuel Ortiz <sameo@linux.intel.com> Cc: Axel Lin <axel.lin@gmail.com> Cc: Richard Purdie <rpurdie@rpsys.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Axel Lin [Wed, 3 Aug 2011 00:52:42 +0000 (10:52 +1000)]
1. current implementation tests wrong value for setting aat2870_bl->max_current.
2. In current implementation, we cannot differentiate below 2 cases:
a) if pdata->max_current is not set , or
b) pdata->max_current is set to AAT2870_CURRENT_0_45 ( which is also 0 ).
fix it by setting AAT2870_CURRENT_0_45 to be 1 and adjust the equation
in aat2870_brightness() accordingly.
Signed-off-by: Axel Lin <axel.lin@gmail.com> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Samuel Ortiz <sameo@linux.intel.com> Tested-by: Jin Park <jinyoungp@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Axel Lin [Wed, 3 Aug 2011 00:52:41 +0000 (10:52 +1000)]
backlight_device_register() returns ERR_PTR() on error.
Signed-off-by: Axel Lin <axel.lin@gmail.com> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Jin Park <jinyoungp@nvidia.com> Cc: Samuel Ortiz <sameo@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mark Brown [Wed, 3 Aug 2011 00:52:40 +0000 (10:52 +1000)]
Unless I'm very much missing something these tests are intended to check
if bit zero is set, rather than checking if msk is entirely zero (in which
case the logic would be very confusing. I haven't actually observed any
runtime issues so this may be a misreading of the code on my part.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
A straightforward looking use of idr for a device id.
Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Tejun Heo <tj@kernel.org> Cc: Guenter Roeck <guenter.roeck@ericsson.com> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Acked-by: Darrick J. Wong <djwong@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Andrea Righi [Wed, 3 Aug 2011 00:52:39 +0000 (10:52 +1000)]
fb_set_suspend() must be called with the console semaphore held, which
means the code path coming in here will first take the console_lock() and
then call lock_fb_info().
However several framebuffer ioctl commands acquire these locks in reverse
order (lock_fb_info() and then console_lock()). This gives rise to
potential AB-BA deadlock.
Fix this by changing the order of acquisition in the ioctl commands that
make use of console_lock().
Signed-off-by: Andrea Righi <arighi@develer.com> Reported-by: Peter Nordström (Palm GBU) <peter.nordstrom@palm.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mark Brown [Wed, 3 Aug 2011 00:52:39 +0000 (10:52 +1000)]
When doing a single register write we use work_buf for both the register
and the value with the buffer formatted for sending directly to the device
so we can just do a write() directly. This saves allocating a temporary
buffer if we can't do gather writes and is likely to be faster than doing
a gather write.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jesper Juhl [Wed, 3 Aug 2011 00:52:38 +0000 (10:52 +1000)]
A call to va_copy() should always be followed by a call to va_end() in the
same function. In kernel/autit.c::audit_log_vformat() this is not always
done. This patch makes sure va_end() is always called.
Signed-off-by: Jesper Juhl <jj@chaosbits.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Eric Paris <eparis@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mathias Krause [Wed, 3 Aug 2011 00:52:38 +0000 (10:52 +1000)]
The address limit is already set in flush_old_exec() so this
set_fs(USER_DS) is redundant.
Signed-off-by: Mathias Krause <minipli@googlemail.com> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The current interrupt traces from irq_handler_entry and irq_handler_exit
provide when an interrupt is handled. They provide good data about when
the system has switched to kernel space and how it affects the currently
running processes.
There are some IRQ vectors which trigger the system into kernel space,
which are not handled in generic IRQ handlers. Tracing such events gives
us the information about IRQ interaction with other system events.
The trace also tells where the system is spending its time. We want to
know which cores are handling interrupts and how they are affecting other
processes in the system. Also, the trace provides information about when
the cores are idle and which interrupts are changing that state.
The following patch adds the event definition and trace instrumentation
for interrupt vectors. For x86, a lookup table is provided to print out
readable IRQ vector names. The template can be used to provide interrupt
vector lookup tables on other architectures.
Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Michael Rubin <mrubin@google.com> Cc: David Sharp <dhsharp@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Ed Wildgoose [Wed, 3 Aug 2011 00:52:36 +0000 (10:52 +1000)]
This new driver replaces the old PCEngines Alix 2/3 LED driver with a new
driver that controls the LEDs through the leds-gpio driver. The old
driver accessed GPIOs directly, which created a conflict and prevented
also loading the cs5535-gpio driver to read other GPIOs on the Alix board.
With this new driver, we hook into leds-gpio which in turn uses GPIO to
control the LEDs and therefore it's possible to control both the LEDs and
access onboard GPIOs
Driver is moved to platform/geode and any other geode initialisation
modules should move here also.
This driver is inspired by leds-net5501.c by Alessandro Zummo.
Ideally, leds-net5501.c should also be moved to platform/geode.
Additionally the driver relies on parts of the patch: 7f131cf3ed ("leds:
leds-alix2c - take port address from MSR) by Daniel Mack to perform
detection of the Alix board.
Signed-off-by: Ed Wildgoose <kernel@wildgooses.com> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Daniel Mack <daniel@caiaq.de> Reviewed-by: Grant Likely <grant.likely@secretlab.ca> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Richard Purdie <rpurdie@rpsys.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Ludwig Nussel [Wed, 3 Aug 2011 00:52:36 +0000 (10:52 +1000)]
On x86_32 casting the unsigned int result of get_random_int() to long may
result in a negative value. On x86_32 the range of mmap_rnd() therefore
was -255 to 255. The 32bit mode on x86_64 used 0 to 255 as intended.
The bug was introduced by 675a081 ("x86: unify mmap_{32|64}.c") in January
2008.
Signed-off-by: Ludwig Nussel <ludwig.nussel@suse.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Shérab [Wed, 3 Aug 2011 00:52:36 +0000 (10:52 +1000)]
This makes the iris driver use the platform API, so it is properly exposed
in /sys.
[akpm@linux-foundation.org: remove commented-out code, add missing space to printk, clean up code layout] Signed-off-by: Shérab <Sebastien.Hinderer@ens-lyon.org> Cc: Len Brown <lenb@kernel.org> Cc: Matthew Garrett <mjg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
hank [Wed, 3 Aug 2011 00:52:34 +0000 (10:52 +1000)]
The parameter's origin type is long. On an i386 architecture, it can
easily be larger than 0x80000000, causing this function to convert it to a
sign-extended u64 type. Change the type to unsigned long so we get the
correct result.
[akpm@linux-foundation.org: build fix] Signed-off-by: hank <pyu@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <john.stultz@linaro.org> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tejun Heo [Wed, 3 Aug 2011 00:52:34 +0000 (10:52 +1000)]
lockdep_init_map() only initializes parts of lockdep_map and triggers
kmemcheck warning when it is copied as a whole. There isn't anything to
be gained by clearing selectively. memset() the whole structure and
remove loop for ->class_cache[] clearing.
WANG Cong [Wed, 3 Aug 2011 00:52:33 +0000 (10:52 +1000)]
arch/cris/arch-v10/kernel/irq.c:239: error: implicit declaration of function 'kgdb_init'
arch/cris/arch-v10/kernel/irq.c:240: error: implicit declaration of function 'breakpoint'
Declare these two functions.
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com> Cc: Mikael Starvik <starvik@axis.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Because of x86-implement-strict-user-copy-checks-for-x86_64.patch
When compiling mm/mempolicy.c the following warning is shown.
In file included from arch/x86/include/asm/uaccess.h:572,
from include/linux/uaccess.h:5,
from include/linux/highmem.h:7,
from include/linux/pagemap.h:10,
from include/linux/mempolicy.h:70,
from mm/mempolicy.c:68:
In function `copy_from_user',
inlined from `compat_sys_get_mempolicy' at mm/mempolicy.c:1415:
arch/x86/include/asm/uaccess_64.h:64: warning: call to `copy_from_user_overflow' declared with attribute warning: copy_from_user() buffer size is not provably correct
LD mm/built-in.o
Fix this by passing correct buffer size value.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Vasiliy Kulikov [Wed, 3 Aug 2011 00:52:32 +0000 (10:52 +1000)]
On thread exit shm_exit_ns() is called, it uses shm_ids(ns).rw_mutex. It
is initialized in shm_init(), but it is not called yet at the moment of
kernel threads exit. Some kernel threads are created in
do_pre_smp_initcalls(), and shm_init() is called in do_initcalls().
Static initialization of shm_ids(init_ipc_ns).rw_mutex fixes the race.
It fixes a kernel oops:
Unable to handle kernel NULL pointer dereference at virtual address 00000000
...
[<c0320090>] (__down_write_nested+0x88/0xe0) from [<c015da08>] (exit_shm+0x28/0x48)
[<c015da08>] (exit_shm+0x28/0x48) from [<c002e550>] (do_exit+0x59c/0x750)
[<c002e550>] (do_exit+0x59c/0x750) from [<c003eaac>] (____call_usermodehelper+0x13c/0x154)
[<c003eaac>] (____call_usermodehelper+0x13c/0x154) from [<c000f630>] (kernel_thread_exit+0x0/0x8)
Code: 1afffffae597c00ce58d0000e587d00c (e58cd000)
Reported-by: Manuel Lauss <manuel.lauss@googlemail.com> Reported-by: Richard Weinberger <richard@nod.at> Reported-by: Marc Zyngier <maz@misterjones.org> Tested-by: Manuel Lauss <manuel.lauss@googlemail.com> Tested-by: Richard Weinberger <richard@nod.at> Tested-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Vasiliy Kulikov <segoon@openwall.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Johannes Weiner [Wed, 3 Aug 2011 00:52:31 +0000 (10:52 +1000)]
__GFP_OTHER_NODE is used for NUMA allocations on behalf of other nodes.
It's supposed to be passed through from the page allocator to
zone_statistics(), but it never gets there as gfp_allowed_mask is not wide
enough and masks out the flag early in the allocation path.
The result is an accounting glitch where successful NUMA allocations
by-agent are not properly attributed as local.
Increase __GFP_BITS_SHIFT so that it includes __GFP_OTHER_NODE.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Andi Kleen <ak@linux.intel.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sergiu Iordache [Wed, 3 Aug 2011 00:52:31 +0000 (10:52 +1000)]
Update the module parameters when platform data is used. This means that
they can be read from /sys/module/ramoops/parameters in order to parse the
memory area.
Signed-off-by: Sergiu Iordache <sergiu@chromium.org> Cc: Marco Stornelli <marco.stornelli@gmail.com> Cc: Seiji Aguchi <seiji.aguchi@hds.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Will Drewry [Wed, 3 Aug 2011 00:52:31 +0000 (10:52 +1000)]
Update kernel-parameters.txt to point users to the authoritative comment
for name_to_dev_t. In addition, updates other places where some
name_to_dev_t behavior was discussed. All other references to root=
appear to be for explicit sample usage or just side comments when
discussing other kernel parameters.
Signed-off-by: Will Drewry <wad@chromium.org> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Randy Dunlap <rdunlap@xenotime.net> Cc: Namhyung Kim <namhyung@gmail.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Will Drewry [Wed, 3 Aug 2011 00:52:30 +0000 (10:52 +1000)]
This patch makes two changes:
- check for trailing characters after parsing PARTNROFF=%d
- disable root_wait if a syntax error is seen
The former assures that bad input like
root=PARTUUID=<validuuid>/PARTNROFF=5abc
properly fails by attempting to parse an extra character after the
integer. If the integer is missing, sscanf will fail, but if it is
present, and there is a trailing non-nul character, then the extra
field will be parsed and the error case will be hit.
The latter assures that if rootwait has been specified, the error
message isn't flooded to the screen during rootwait's loop. Instead of
adding printk ratelimiting, root_wait was disabled. This stays true to
the rootwait goal of support asynchronous device arrival while still
providing users with helpful messages. With ratelimiting or disabling
logging on rootwait, a range of edge cases turn up where the user would
not be informed of an error properly.
Signed-off-by: Will Drewry <wad@chromium.org> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Randy Dunlap <rdunlap@xenotime.net> Cc: Namhyung Kim <namhyung@gmail.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Will Drewry [Wed, 3 Aug 2011 00:52:30 +0000 (10:52 +1000)]
Expand root=PARTUUID=UUID syntax to support selecting a root partition by
integer offset from a known, unique partition. This approach provides
similar properties to specifying a device and partition number, but using
the UUID as the unique path prior to evaluating the offset.
For example,
root=PARTUUID=99DE9194-FC15-4223-9192-FC243948F88B/PARTNROFF=1
selects the partition with UUID 99DE.. then select the next
partition.
This change is motivated by a particular usecase in Chromium OS where the
bootloader can easily determine what partition it is on (by UUID) but
doesn't perform general partition table walking.
That said, support for this model provides a direct mechanism for the user
to modify the root partition to boot without specifically needing to
extract each UUID or update the bootloader explicitly when the root
partition UUID is changed (if it is recreated to be larger, for instance).
Pinning to a /boot-style partition UUID allows the arbitrary root
partition reconfiguration/modifications with slightly less ambiguity than
just [dev][partition] and less stringency than the specific root partition
UUID.
Signed-off-by: Will Drewry <wad@chromium.org> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Randy Dunlap <rdunlap@xenotime.net> Cc: Namhyung Kim <namhyung@gmail.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Oleg Nesterov [Wed, 3 Aug 2011 00:52:29 +0000 (10:52 +1000)]
When send_cpu_listeners() finds the orphaned listener it marks it as
!valid and drops listeners->sem. Before it takes this sem for writing,
s->pid can be reused and add_del_listener() can wrongly try to re-use this
entry.
Oleg Nesterov [Wed, 3 Aug 2011 00:52:28 +0000 (10:52 +1000)]
1. 26c4caea "don't allow duplicate entries in listener mode"
changed add_del_listener(REGISTER) so that "next_cpu:" can
reuse the listener allocated for the previous cpu, this
doesn't look exactly right even if minor.
Change the code to kfree() in the already-registered case,
this case is unlikely anyway so the extra kmalloc_node()
shouldn't hurt but looke more correct and clean.
2. use the plain list_for_each_entry() instead of _safe() to
scan listeners->list.
3. Remove the unneeded INIT_LIST_HEAD(&s->list), we are going
to list_add(&s->list).
Daniel Glöckner [Wed, 3 Aug 2011 00:52:28 +0000 (10:52 +1000)]
As the comment explains, the intention of the code is to clear the
OMAP_RTC_CTRL_MODE_12_24 bit, but instead it only clears the
OMAP_RTC_CTRL_SPLIT and OMAP_RTC_CTRL_AUTO_COMP bits, which should be
kept. OMAP_RTC_CTRL_DISABLE, OMAP_RTC_CTRL_SET_32_COUNTER,
OMAP_RTC_CTRL_TEST, and OMAP_RTC_CTRL_ROUND_30S are also better off
being cleared.
Signed-off-by: Daniel Glöckner <dg@emlix.com> Cc: Alessandro Zummo <a.zummo@towertech.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Akinobu Mita [Wed, 3 Aug 2011 00:52:27 +0000 (10:52 +1000)]
init_fault_attr_dentries() is used to export fault_attr via debugfs. But
it can only export it in debugfs root directory.
Per Forlin is working on mmc_fail_request which adds support to inject
data errors after a completed host transfer in MMC subsystem.
The fault_attr for mmc_fail_request should be defined per mmc host and
export it in debugfs directory per mmc host like
/sys/kernel/debug/mmc0/mmc_fail_request.
init_fault_attr_dentries() doesn't help for mmc_fail_request. So this
introduces fault_create_debugfs_attr() which is able to create a directory
in the arbitrary directory and replace init_fault_attr_dentries().
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Tested-by: Per Forlin <per.forlin@linaro.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Matt Mackall <mpm@selenic.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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