gcc 4.6+ has support for a externally_visible attribute that prevents the
optimizer from optimizing unused symbols away. Add a __visible macro to
use it with that compiler version or later.
This is used (at least) by the "Link Time Optimization" patchset.
Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Andrew Vagin [Fri, 7 Sep 2012 00:17:45 +0000 (10:17 +1000)]
pid-namespace: limit value of ns_last_pid to (0, max_pid)
The kernel doesn't check the pid for negative values, so if you try to
write -2 to /proc/sys/kernel/ns_last_pid, you will get a kernel panic.
The crash happens because the next pid is -1, and alloc_pidmap() will try
to access to a nonexistent pidmap.
map = &pid_ns->pidmap[pid/BITS_PER_PAGE];
Signed-off-by: Andrew Vagin <avagin@openvz.org> Acked-by: Cyrill Gorcunov <gorcunov@openvz.org> Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Chuck Lever [Fri, 7 Sep 2012 00:17:45 +0000 (10:17 +1000)]
include/net/sock.h: squelch compiler warning in sk_rmem_schedule()
In file included from linux/include/linux/tcp.h:227:0,
from linux/include/linux/ipv6.h:221,
from linux/include/net/ipv6.h:16,
from linux/include/linux/sunrpc/clnt.h:26,
from linux/net/sunrpc/stats.c:22:
linux/include/net/sock.h: In function `sk_rmem_schedule':
linux/nfs-2.6/include/net/sock.h:1339:13: warning: comparison between
signed and unsigned integer expressions [-Wsign-compare]
Seen with gcc (GCC) 4.6.3 20120306 (Red Hat 4.6.3-2) using the
-Wextra option.
c76562b6 ("netvm: prevent a stream-specific deadlock") accidentally
replaced the "size" parameter of sk_rmem_schedule() with an unsigned int.
This changes the semantics of the comparison in the return statement.
In sk_wmem_schedule we have syntactically the same comparison, but "size"
is a signed integer. In addition, __sk_mem_schedule() takes a signed
integer for its "size" parameter, so there is an implicit type conversion
in sk_rmem_schedule() anyway.
Revert the "size" parameter back to a signed integer so that the semantics
of the expressions in both sk_[rw]mem_schedule() are exactly the same.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: David Miller <davem@davemloft.net> Cc: Joonsoo Kim <js1304@gmail.com> Cc: David Rientjes <rientjes@google.com> Cc: Pekka Enberg <penberg@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Joonsoo Kim [Fri, 7 Sep 2012 00:17:45 +0000 (10:17 +1000)]
slub: consider pfmemalloc_match() in get_partial_node()
get_partial() is currently not checking pfmemalloc_match() meaning that it
is possible for pfmemalloc pages to leak to non-pfmemalloc users. This is
a problem in the following situation. Assume that there is a request from
normal allocation and there are no objects in the per-cpu cache and no
node-partial slab.
In this case, slab_alloc enters the slow path and new_slab_objects() is
called which may return a PFMEMALLOC page. As the current user is not
allowed to access PFMEMALLOC page, deactivate_slab() is called ([5091b74a:
mm: slub: optimise the SLUB fast path to avoid pfmemalloc checks]) and
returns an object from PFMEMALLOC page.
Next time, when we get another request from normal allocation,
slab_alloc() enters the slow-path and calls new_slab_objects(). In
new_slab_objects(), we call get_partial() and get a partial slab which was
just deactivated but is a pfmemalloc page. We extract one object from it
and re-deactivate.
"deactivate -> re-get in get_partial -> re-deactivate" occures repeatedly.
As a result, access to PFMEMALLOC page is not properly restricted and it
can cause a performance degradation due to frequent deactivation.
deactivation frequently.
This patch changes get_partial_node() to take pfmemalloc_match() into
account and prevents the "deactivate -> re-get in get_partial() scenario.
Instead, new_slab() is called.
Signed-off-by: Joonsoo Kim <js1304@gmail.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: David Miller <davem@davemloft.net> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Pekka Enberg <penberg@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Joonsoo Kim [Fri, 7 Sep 2012 00:17:44 +0000 (10:17 +1000)]
slab: fix starting index for finding another object
In array cache, there is a object at index 0, check it.
Signed-off-by: Joonsoo Kim <js1304@gmail.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: David Miller <davem@davemloft.net> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: David Rientjes <rientjes@google.com> Cc: Pekka Enberg <penberg@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
slab: do ClearSlabPfmemalloc() for all pages of slab
Right now, we call ClearSlabPfmemalloc() for first page of slab when we
clear SlabPfmemalloc flag. This is fine for most swap-over-network use
cases as it is expected that order-0 pages are in use. Unfortunately it
is possible that that __ac_put_obj() checks SlabPfmemalloc on a tail page
and while this is harmless, it is sloppy. This patch ensures that the
head page is always used.
This problem was originally identified by Joonsoo Kim.
[js1304@gmail.com: Original implementation and problem identification] Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: David Miller <davem@davemloft.net> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Joonsoo Kim <js1304@gmail.com> Cc: David Rientjes <rientjes@google.com> Cc: Pekka Enberg <penberg@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Paul Clements [Fri, 7 Sep 2012 00:17:44 +0000 (10:17 +1000)]
nbd: clear waiting_queue on shutdown
Fix a serious but uncommon bug in nbd which occurs when there is heavy I/O
going to the nbd device while, at the same time, a failure (server,
network) or manual disconnect of the nbd connection occurs.
There is a small window between the time that the nbd_thread is stopped
and the socket is shutdown where requests can continue to be queued to
nbd's internal waiting_queue. When this happens, those requests are never
completed or freed.
The fix is to clear the waiting_queue on shutdown of the nbd device, in
the same way that the nbd request queue (queue_head) is already being cleared.
Signed-off-by: Paul Clements <paul.clements@steeleye.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Gang Wei [Fri, 7 Sep 2012 00:17:43 +0000 (10:17 +1000)]
MAINTAINERS: fix TXT maintainer list and source repo path
Signed-off-by: Gang Wei <gang.wei@intel.com> Cc: Richard L Maliszewski <richard.l.maliszewski@intel.com> Cc: Gang Wei <gang.wei@intel.com> Cc: Shane Wang <shane.wang@intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
linux-drf:/sys/devices/system/memory/memory0 # cat * 8000000000000000
cat: node0: Is a directory
cat: node1: Is a directory
cat: node2: Is a directory
cat: node3: Is a directory
0 8000000000000000
cat: power: Is a directory
1
online
cat: subsystem: Is a directory
And "echo offline > memory0/state" will cause following call trace:
kernel BUG at mm/memory_hotplug.c:885!
sh[6455]: bugcheck! 0 [1]
memory hotplug: reset pgdat->kswapd to NULL if creating kernel thread fails
If kthread_run() fails, pgdat->kswapd contains errno. When we stop this
thread, we only check whether pgdat->kswapd is NULL and access it. If it
contains errno, it will cause page fault. Reset pgdat->kswapd to NULL
when creating kernel thread fails can avoid this problem.
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com> Reviewed-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
projects / karo-tx-linux.git / log