percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Kernel bugzilla #15239 On some workloads, it is quite possible to get a huge dst list to process in dst_gc_task(), and trigger soft lockup detection. Fix is to call cond_resched(), as we run in process context. Reported-by: Pawel Staszewski <pstaszewski@itcare.pl> Tested-by: Pawel Staszewski <pstaszewski@itcare.pl> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
During tbench/oprofile sessions, I found that dst_release() was in third position. CPU: Core 2, speed 2999.68 MHz (estimated) Counted CPU_CLK_UNHALTED events (Clock cycles when not halted) with a unit mask of 0x00 (Unhalted core cycles) count 100000 samples % symbol name 483726 9.0185 __copy_user_zeroing_intel 191466 3.5697 __copy_user_intel 185475 3.4580 dst_release 175114 3.2648 ip_queue_xmit 153447 2.8608 tcp_sendmsg 108775 2.0280 tcp_recvmsg 102659 1.9140 sysenter_past_esp 101450 1.8914 tcp_current_mss 95067 1.7724 __copy_from_user_ll 86531 1.6133 tcp_transmit_skb Of course, all CPUS fight on the dst_entry associated with 127.0.0.1 Instead of first checking the refcount value, then decrement it, we use atomic_dec_return() to help CPU to make the right memory transaction (ie getting the cache line in exclusive mode) dst_release() is now at the fifth position, and tbench a litle bit faster ;) CPU: Core 2, speed 3000.1 MHz (estimated) Counted CPU_CLK_UNHALTED events (Clock cycles when not halted) with a unit mask of 0x00 (Unhalted core cycles) count 100000 samples % symbol name 647107 8.8072 __copy_user_zeroing_intel 258840 3.5229 ip_queue_xmit 258302 3.5155 __copy_user_intel 209629 2.8531 tcp_sendmsg 165632 2.2543 dst_release 149232 2.0311 tcp_current_mss 147821 2.0119 tcp_recvmsg 137893 1.8767 sysenter_past_esp 127473 1.7349 __copy_from_user_ll 121308 1.6510 ip_finish_output 118510 1.6129 tcp_transmit_skb 109295 1.4875 tcp_v4_rcv Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
The dst garbage collector dst_gc_task() may not be scheduled as we expect it to be in __dst_free(). Indeed, when the dst_gc_timer was replaced by the delayed_work dst_gc_work, the mod_timer() call used to schedule the garbage collector at an earlier date was replaced by a schedule_delayed_work() (see commit 86bba269d08f0c545ae76c90b56727f65d62d57f). But, the behaviour of mod_timer() and schedule_delayed_work() is different in the way they handle the delay. mod_timer() stops the timer and re-arm it with the new given delay, whereas schedule_delayed_work() only check if the work is already queued in the workqueue (and queue it (with delay) if it is not) BUT it does NOT take into account the new delay (even if the new delay is earlier in time). schedule_delayed_work() returns 0 if it didn't queue the work, but we don't check the return code in __dst_free(). If I understand the code in __dst_free() correctly, we want dst_gc_task to be queued after DST_GC_INC jiffies if we pass the test (and not in some undetermined time in the future), so I think we should add a call to cancel_delayed_work() before schedule_delayed_work(). Patch below. Or we should at least test the return code of schedule_delayed_work(), and reset the values of dst_garbage.timer_inc and dst_garbage.timer_expires back to their former values if schedule_delayed_work() failed. Otherwise the subsequent calls to __dst_free will test the wrong values and assume wrong thing about when the garbage collector is supposed to be scheduled. dst_gc_task() also calls schedule_delayed_work() without checking its return code (or calling cancel_scheduled_work() first), but it should fine there: dst_gc_task is the routine of the delayed_work, so no dst_gc_work should be pending in the queue when it's running. Signed-off-by: Benjamin Thery <benjamin.thery@bull.net> Acked-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Codiff stats (allyesconfig, v2.6.24-mm1): -16420 187 funcs, 103 +, 16523 -, diff: -16420 --- dst_release Without number of debug related CONFIGs (v2.6.25-rc2-mm1): -7257 186 funcs, 70 +, 7327 -, diff: -7257 --- dst_release dst_release | +40 Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
Introduce per-net_device inlines: dev_net(), dev_net_set(). Without CONFIG_NET_NS, no namespace other than &init_net exists. Let's explicitly define them to help compiler optimizations. Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Device inside the namespace can be started and downed. So, active routing cache should be cleaned up on device stop. Signed-off-by: Denis V. Lunev <den@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
The garbage collection function receive the dst_ops structure as parameter. This is useful for the next incoming patchset because it will need the dst_ops (there will be several instances) and the network namespace pointer (contained in the dst_ops). The protocols which do not take care of the namespaces will not be impacted by this change (expect for the function signature), they do just ignore the parameter. Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This cleanup shrinks size of net/core/dst.o on i386 from 1299 to 1289 bytes. (This is because dev_hold()/dev_put() are doing atomic_inc()/atomic_dec() and force compiler to re-evaluate memory contents.) Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Move dst entries to a namespace loopback to catch refcounting leaks. Signed-off-by: Denis V. Lunev <den@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>