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authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/mm/vmacache.c
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/mm/vmacache.c')
-rw-r--r--kernel/mm/vmacache.c134
1 files changed, 134 insertions, 0 deletions
diff --git a/kernel/mm/vmacache.c b/kernel/mm/vmacache.c
new file mode 100644
index 000000000..b6e3662fe
--- /dev/null
+++ b/kernel/mm/vmacache.c
@@ -0,0 +1,134 @@
+/*
+ * Copyright (C) 2014 Davidlohr Bueso.
+ */
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/vmacache.h>
+
+/*
+ * Flush vma caches for threads that share a given mm.
+ *
+ * The operation is safe because the caller holds the mmap_sem
+ * exclusively and other threads accessing the vma cache will
+ * have mmap_sem held at least for read, so no extra locking
+ * is required to maintain the vma cache.
+ */
+void vmacache_flush_all(struct mm_struct *mm)
+{
+ struct task_struct *g, *p;
+
+ count_vm_vmacache_event(VMACACHE_FULL_FLUSHES);
+
+ /*
+ * Single threaded tasks need not iterate the entire
+ * list of process. We can avoid the flushing as well
+ * since the mm's seqnum was increased and don't have
+ * to worry about other threads' seqnum. Current's
+ * flush will occur upon the next lookup.
+ */
+ if (atomic_read(&mm->mm_users) == 1)
+ return;
+
+ rcu_read_lock();
+ for_each_process_thread(g, p) {
+ /*
+ * Only flush the vmacache pointers as the
+ * mm seqnum is already set and curr's will
+ * be set upon invalidation when the next
+ * lookup is done.
+ */
+ if (mm == p->mm)
+ vmacache_flush(p);
+ }
+ rcu_read_unlock();
+}
+
+/*
+ * This task may be accessing a foreign mm via (for example)
+ * get_user_pages()->find_vma(). The vmacache is task-local and this
+ * task's vmacache pertains to a different mm (ie, its own). There is
+ * nothing we can do here.
+ *
+ * Also handle the case where a kernel thread has adopted this mm via use_mm().
+ * That kernel thread's vmacache is not applicable to this mm.
+ */
+static bool vmacache_valid_mm(struct mm_struct *mm)
+{
+ return current->mm == mm && !(current->flags & PF_KTHREAD);
+}
+
+void vmacache_update(unsigned long addr, struct vm_area_struct *newvma)
+{
+ if (vmacache_valid_mm(newvma->vm_mm))
+ current->vmacache[VMACACHE_HASH(addr)] = newvma;
+}
+
+static bool vmacache_valid(struct mm_struct *mm)
+{
+ struct task_struct *curr;
+
+ if (!vmacache_valid_mm(mm))
+ return false;
+
+ curr = current;
+ if (mm->vmacache_seqnum != curr->vmacache_seqnum) {
+ /*
+ * First attempt will always be invalid, initialize
+ * the new cache for this task here.
+ */
+ curr->vmacache_seqnum = mm->vmacache_seqnum;
+ vmacache_flush(curr);
+ return false;
+ }
+ return true;
+}
+
+struct vm_area_struct *vmacache_find(struct mm_struct *mm, unsigned long addr)
+{
+ int i;
+
+ if (!vmacache_valid(mm))
+ return NULL;
+
+ count_vm_vmacache_event(VMACACHE_FIND_CALLS);
+
+ for (i = 0; i < VMACACHE_SIZE; i++) {
+ struct vm_area_struct *vma = current->vmacache[i];
+
+ if (!vma)
+ continue;
+ if (WARN_ON_ONCE(vma->vm_mm != mm))
+ break;
+ if (vma->vm_start <= addr && vma->vm_end > addr) {
+ count_vm_vmacache_event(VMACACHE_FIND_HITS);
+ return vma;
+ }
+ }
+
+ return NULL;
+}
+
+#ifndef CONFIG_MMU
+struct vm_area_struct *vmacache_find_exact(struct mm_struct *mm,
+ unsigned long start,
+ unsigned long end)
+{
+ int i;
+
+ if (!vmacache_valid(mm))
+ return NULL;
+
+ count_vm_vmacache_event(VMACACHE_FIND_CALLS);
+
+ for (i = 0; i < VMACACHE_SIZE; i++) {
+ struct vm_area_struct *vma = current->vmacache[i];
+
+ if (vma && vma->vm_start == start && vma->vm_end == end) {
+ count_vm_vmacache_event(VMACACHE_FIND_HITS);
+ return vma;
+ }
+ }
+
+ return NULL;
+}
+#endif