#include #include #include #include #include #include #include #include #include "irq.h" #include "str.h" #include "die.h" int device_irq_number(const char *ifname) { int irq = 0; char buff[128], sysname[128]; FILE *fp; if (!strncmp("lo", ifname, strlen("lo"))) return 0; slprintf(sysname, sizeof(sysname), "/sys/class/net/%s/device/irq", ifname); fp = fopen(sysname, "r"); if (!fp) return -ENOENT; memset(buff, 0, sizeof(buff)); if (fgets(buff, sizeof(buff), fp) != NULL) { buff[sizeof(buff) - 1] = 0; irq = atoi(buff); } fclose(fp); return irq; } static char nic_irq_affinity_list[128]; static bool nic_irq_stored = false; static int nic_irq = -1; static void device_save_irq_affinity_list(void) { int ret, fd; char file[128]; bug_on(nic_irq_stored); slprintf(file, sizeof(file), "/proc/irq/%d/smp_affinity_list", nic_irq); fd = open(file, O_RDONLY); if (fd < 0) return; memset(nic_irq_affinity_list, 0, sizeof(nic_irq_affinity_list)); ret = read(fd, nic_irq_affinity_list, sizeof(nic_irq_affinity_list)); if (ret < 0) panic("Cannot store NIC IRQ affinity!\n"); close(fd); nic_irq_stored = true; } void device_restore_irq_affinity_list(void) { int ret, fd; char file[128]; if (!nic_irq_stored) return; bug_on(nic_irq == -1); slprintf(file, sizeof(file), "/proc/irq/%d/smp_affinity_list", nic_irq); fd = open(file, O_WRONLY); if (fd < 0) return; ret = write(fd, nic_irq_affinity_list, sizeof(nic_irq_affinity_list)); if (ret < 0) panic("Cannot restore NIC IRQ affinity!\n"); close(fd); } int device_set_irq_affinity_list(int irq, unsigned long from, unsigned long to) { int ret, fd; char file[128], list[64]; if (unlikely(irq == 0)) return 0; if (!nic_irq_stored) { nic_irq = irq; device_save_irq_affinity_list(); } slprintf(file, sizeof(file), "/proc/irq/%d/smp_affinity_list", irq); slprintf(list, sizeof(list), "%lu-%lu\n", from, to); fd = open(file, O_WRONLY); if (fd < 0) return -ENOENT; ret = write(fd, list, strlen(list)); close(fd); return ret; } int device_set_irq_affinity(int irq, unsigned long cpu) { return device_set_irq_affinity_list(irq, cpu, cpu); } cgit.cgi/linux/net-next.git/log/tools/testing/selftests/powerpc/pmu'>
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authorSteven Rostedt (VMware) <rostedt@goodmis.org>2017-01-30 19:27:10 -0500
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2017-01-31 09:13:49 -0500
commit79c6f448c8b79c321e4a1f31f98194e4f6b6cae7 (patch)
tree370efda701f03cccf21e02bb1fdd3b852547d75c /tools/testing/selftests/powerpc/pmu
parent0c744ea4f77d72b3dcebb7a8f2684633ec79be88 (diff)
tracing: Fix hwlat kthread migration
The hwlat tracer creates a kernel thread at start of the tracer. It is pinned to a single CPU and will move to the next CPU after each period of running. If the user modifies the migration thread's affinity, it will not change after that happens. The original code created the thread at the first instance it was called, but later was changed to destroy the thread after the tracer was finished, and would not be created until the next instance of the tracer was established. The code that initialized the affinity was only called on the initial instantiation of the tracer. After that, it was not initialized, and the previous affinity did not match the current newly created one, making it appear that the user modified the thread's affinity when it did not, and the thread failed to migrate again. Cc: stable@vger.kernel.org Fixes: 0330f7aa8ee6 ("tracing: Have hwlat trace migrate across tracing_cpumask CPUs") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'tools/testing/selftests/powerpc/pmu')