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authorLinus Torvalds <torvalds@linux-foundation.org>2013-11-13 10:45:43 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2013-11-13 10:45:43 +0400
commit5cbb3d216e2041700231bcfc383ee5f8b7fc8b74 (patch)
treea738fa82dbcefa9bd283c08bc67f38827be63937 /lib/percpu_test.c
parent9bc9ccd7db1c9f043f75380b5a5b94912046a60e (diff)
parent4e9b45a19241354daec281d7a785739829b52359 (diff)
downloadlinux-5cbb3d216e2041700231bcfc383ee5f8b7fc8b74.tar.xz
Merge branch 'akpm' (patches from Andrew Morton)
Merge first patch-bomb from Andrew Morton: "Quite a lot of other stuff is banked up awaiting further next->mainline merging, but this batch contains: - Lots of random misc patches - OCFS2 - Most of MM - backlight updates - lib/ updates - printk updates - checkpatch updates - epoll tweaking - rtc updates - hfs - hfsplus - documentation - procfs - update gcov to gcc-4.7 format - IPC" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (269 commits) ipc, msg: fix message length check for negative values ipc/util.c: remove unnecessary work pending test devpts: plug the memory leak in kill_sb ./Makefile: export initial ramdisk compression config option init/Kconfig: add option to disable kernel compression drivers: w1: make w1_slave::flags long to avoid memory corruption drivers/w1/masters/ds1wm.cuse dev_get_platdata() drivers/memstick/core/ms_block.c: fix unreachable state in h_msb_read_page() drivers/memstick/core/mspro_block.c: fix attributes array allocation drivers/pps/clients/pps-gpio.c: remove redundant of_match_ptr kernel/panic.c: reduce 1 byte usage for print tainted buffer gcov: reuse kbasename helper kernel/gcov/fs.c: use pr_warn() kernel/module.c: use pr_foo() gcov: compile specific gcov implementation based on gcc version gcov: add support for gcc 4.7 gcov format gcov: move gcov structs definitions to a gcc version specific file kernel/taskstats.c: return -ENOMEM when alloc memory fails in add_del_listener() kernel/taskstats.c: add nla_nest_cancel() for failure processing between nla_nest_start() and nla_nest_end() kernel/sysctl_binary.c: use scnprintf() instead of snprintf() ...
Diffstat (limited to 'lib/percpu_test.c')
-rw-r--r--lib/percpu_test.c138
1 files changed, 138 insertions, 0 deletions
diff --git a/lib/percpu_test.c b/lib/percpu_test.c
new file mode 100644
index 000000000000..0b5d14dadd1a
--- /dev/null
+++ b/lib/percpu_test.c
@@ -0,0 +1,138 @@
+#include <linux/module.h>
+
+/* validate @native and @pcp counter values match @expected */
+#define CHECK(native, pcp, expected) \
+ do { \
+ WARN((native) != (expected), \
+ "raw %ld (0x%lx) != expected %lld (0x%llx)", \
+ (native), (native), \
+ (long long)(expected), (long long)(expected)); \
+ WARN(__this_cpu_read(pcp) != (expected), \
+ "pcp %ld (0x%lx) != expected %lld (0x%llx)", \
+ __this_cpu_read(pcp), __this_cpu_read(pcp), \
+ (long long)(expected), (long long)(expected)); \
+ } while (0)
+
+static DEFINE_PER_CPU(long, long_counter);
+static DEFINE_PER_CPU(unsigned long, ulong_counter);
+
+static int __init percpu_test_init(void)
+{
+ /*
+ * volatile prevents compiler from optimizing it uses, otherwise the
+ * +ul_one/-ul_one below would replace with inc/dec instructions.
+ */
+ volatile unsigned int ui_one = 1;
+ long l = 0;
+ unsigned long ul = 0;
+
+ pr_info("percpu test start\n");
+
+ preempt_disable();
+
+ l += -1;
+ __this_cpu_add(long_counter, -1);
+ CHECK(l, long_counter, -1);
+
+ l += 1;
+ __this_cpu_add(long_counter, 1);
+ CHECK(l, long_counter, 0);
+
+ ul = 0;
+ __this_cpu_write(ulong_counter, 0);
+
+ ul += 1UL;
+ __this_cpu_add(ulong_counter, 1UL);
+ CHECK(ul, ulong_counter, 1);
+
+ ul += -1UL;
+ __this_cpu_add(ulong_counter, -1UL);
+ CHECK(ul, ulong_counter, 0);
+
+ ul += -(unsigned long)1;
+ __this_cpu_add(ulong_counter, -(unsigned long)1);
+ CHECK(ul, ulong_counter, -1);
+
+ ul = 0;
+ __this_cpu_write(ulong_counter, 0);
+
+ ul -= 1;
+ __this_cpu_dec(ulong_counter);
+ CHECK(ul, ulong_counter, -1);
+ CHECK(ul, ulong_counter, ULONG_MAX);
+
+ l += -ui_one;
+ __this_cpu_add(long_counter, -ui_one);
+ CHECK(l, long_counter, 0xffffffff);
+
+ l += ui_one;
+ __this_cpu_add(long_counter, ui_one);
+ CHECK(l, long_counter, (long)0x100000000LL);
+
+
+ l = 0;
+ __this_cpu_write(long_counter, 0);
+
+ l -= ui_one;
+ __this_cpu_sub(long_counter, ui_one);
+ CHECK(l, long_counter, -1);
+
+ l = 0;
+ __this_cpu_write(long_counter, 0);
+
+ l += ui_one;
+ __this_cpu_add(long_counter, ui_one);
+ CHECK(l, long_counter, 1);
+
+ l += -ui_one;
+ __this_cpu_add(long_counter, -ui_one);
+ CHECK(l, long_counter, (long)0x100000000LL);
+
+ l = 0;
+ __this_cpu_write(long_counter, 0);
+
+ l -= ui_one;
+ this_cpu_sub(long_counter, ui_one);
+ CHECK(l, long_counter, -1);
+ CHECK(l, long_counter, ULONG_MAX);
+
+ ul = 0;
+ __this_cpu_write(ulong_counter, 0);
+
+ ul += ui_one;
+ __this_cpu_add(ulong_counter, ui_one);
+ CHECK(ul, ulong_counter, 1);
+
+ ul = 0;
+ __this_cpu_write(ulong_counter, 0);
+
+ ul -= ui_one;
+ __this_cpu_sub(ulong_counter, ui_one);
+ CHECK(ul, ulong_counter, -1);
+ CHECK(ul, ulong_counter, ULONG_MAX);
+
+ ul = 3;
+ __this_cpu_write(ulong_counter, 3);
+
+ ul = this_cpu_sub_return(ulong_counter, ui_one);
+ CHECK(ul, ulong_counter, 2);
+
+ ul = __this_cpu_sub_return(ulong_counter, ui_one);
+ CHECK(ul, ulong_counter, 1);
+
+ preempt_enable();
+
+ pr_info("percpu test done\n");
+ return -EAGAIN; /* Fail will directly unload the module */
+}
+
+static void __exit percpu_test_exit(void)
+{
+}
+
+module_init(percpu_test_init)
+module_exit(percpu_test_exit)
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Greg Thelen");
+MODULE_DESCRIPTION("percpu operations test");