Revision a927bd6ba952d13c52b8b385030943032f659a3e authored by Dan Williams on 22 November 2020, 06:17:05 UTC, committed by Linus Torvalds on 22 November 2020, 18:48:22 UTC
The core-mm has a default __weak implementation of phys_to_target_node() to mirror the weak definition of memory_add_physaddr_to_nid(). That symbol is exported for modules. However, while the export in mm/memory_hotplug.c exported the symbol in the configuration cases of: CONFIG_NUMA_KEEP_MEMINFO=y CONFIG_MEMORY_HOTPLUG=y ...and: CONFIG_NUMA_KEEP_MEMINFO=n CONFIG_MEMORY_HOTPLUG=y ...it failed to export the symbol in the case of: CONFIG_NUMA_KEEP_MEMINFO=y CONFIG_MEMORY_HOTPLUG=n Not only is that broken, but Christoph points out that the kernel should not be exporting any __weak symbol, which means that memory_add_physaddr_to_nid() example that phys_to_target_node() copied is broken too. Rework the definition of phys_to_target_node() and memory_add_physaddr_to_nid() to not require weak symbols. Move to the common arch override design-pattern of an asm header defining a symbol to replace the default implementation. The only common header that all memory_add_physaddr_to_nid() producing architectures implement is asm/sparsemem.h. In fact, powerpc already defines its memory_add_physaddr_to_nid() helper in sparsemem.h. Double-down on that observation and define phys_to_target_node() where necessary in asm/sparsemem.h. An alternate consideration that was discarded was to put this override in asm/numa.h, but that entangles with the definition of MAX_NUMNODES relative to the inclusion of linux/nodemask.h, and requires powerpc to grow a new header. The dependency on NUMA_KEEP_MEMINFO for DEV_DAX_HMEM_DEVICES is invalid now that the symbol is properly exported / stubbed in all combinations of CONFIG_NUMA_KEEP_MEMINFO and CONFIG_MEMORY_HOTPLUG. [dan.j.williams@intel.com: v4] Link: https://lkml.kernel.org/r/160461461867.1505359.5301571728749534585.stgit@dwillia2-desk3.amr.corp.intel.com [dan.j.williams@intel.com: powerpc: fix create_section_mapping compile warning] Link: https://lkml.kernel.org/r/160558386174.2948926.2740149041249041764.stgit@dwillia2-desk3.amr.corp.intel.com Fixes: a035b6bf863e ("mm/memory_hotplug: introduce default phys_to_target_node() implementation") Reported-by: Randy Dunlap <rdunlap@infradead.org> Reported-by: Thomas Gleixner <tglx@linutronix.de> Reported-by: kernel test robot <lkp@intel.com> Reported-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Randy Dunlap <rdunlap@infradead.org> Tested-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Joao Martins <joao.m.martins@oracle.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Link: https://lkml.kernel.org/r/160447639846.1133764.7044090803980177548.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent bc2dc44
percpu_test.c
// SPDX-License-Identifier: GPL-2.0-only
#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");
Computing file changes ...