+/**
+ * mm_account_fault - Do page fault accountings
+ *
+ * @regs: the pt_regs struct pointer. When set to NULL, will skip accounting
+ * of perf event counters, but we'll still do the per-task accounting to
+ * the task who triggered this page fault.
+ * @address: the faulted address.
+ * @flags: the fault flags.
+ * @ret: the fault retcode.
+ *
+ * This will take care of most of the page fault accountings. Meanwhile, it
+ * will also include the PERF_COUNT_SW_PAGE_FAULTS_[MAJ|MIN] perf counter
+ * updates. However note that the handling of PERF_COUNT_SW_PAGE_FAULTS should
+ * still be in per-arch page fault handlers at the entry of page fault.
+ */
+static inline void mm_account_fault(struct pt_regs *regs,
+ unsigned long address, unsigned int flags,
+ vm_fault_t ret)
+{
+ bool major;
+
+ /*
+ * We don't do accounting for some specific faults:
+ *
+ * - Unsuccessful faults (e.g. when the address wasn't valid). That
+ * includes arch_vma_access_permitted() failing before reaching here.
+ * So this is not a "this many hardware page faults" counter. We
+ * should use the hw profiling for that.
+ *
+ * - Incomplete faults (VM_FAULT_RETRY). They will only be counted
+ * once they're completed.
+ */
+ if (ret & (VM_FAULT_ERROR | VM_FAULT_RETRY))
+ return;
+
+ /*
+ * We define the fault as a major fault when the final successful fault
+ * is VM_FAULT_MAJOR, or if it retried (which implies that we couldn't
+ * handle it immediately previously).
+ */
+ major = (ret & VM_FAULT_MAJOR) || (flags & FAULT_FLAG_TRIED);
+
+ if (major)
+ current->maj_flt++;
+ else
+ current->min_flt++;
+
+ /*
+ * If the fault is done for GUP, regs will be NULL. We only do the
+ * accounting for the per thread fault counters who triggered the
+ * fault, and we skip the perf event updates.
+ */
+ if (!regs)
+ return;
+
+ if (major)
+ perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, address);
+ else
+ perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, address);
+}
+