3.18-stable patches

added patches:
	mm-get-rid-of-vmacache_flush_all-entirely.patch

diff --git a/queue-3.18/mm-get-rid-of-vmacache_flush_all-entirely.patch b/queue-3.18/mm-get-rid-of-vmacache_flush_all-entirely.patch
new file mode 100644 (file)
index 0000000..39a0e0f
--- /dev/null
+++ b/queue-3.18/mm-get-rid-of-vmacache_flush_all-entirely.patch
@@ -0,0 +1,147 @@
+From 7a9cdebdcc17e426fb5287e4a82db1dfe86339b2 Mon Sep 17 00:00:00 2001
+From: Linus Torvalds <torvalds@linux-foundation.org>
+Date: Wed, 12 Sep 2018 23:57:48 -1000
+Subject: mm: get rid of vmacache_flush_all() entirely
+
+From: Linus Torvalds <torvalds@linux-foundation.org>
+
+commit 7a9cdebdcc17e426fb5287e4a82db1dfe86339b2 upstream.
+
+Jann Horn points out that the vmacache_flush_all() function is not only
+potentially expensive, it's buggy too.  It also happens to be entirely
+unnecessary, because the sequence number overflow case can be avoided by
+simply making the sequence number be 64-bit.  That doesn't even grow the
+data structures in question, because the other adjacent fields are
+already 64-bit.
+
+So simplify the whole thing by just making the sequence number overflow
+case go away entirely, which gets rid of all the complications and makes
+the code faster too.  Win-win.
+
+[ Oleg Nesterov points out that the VMACACHE_FULL_FLUSHES statistics
+  also just goes away entirely with this ]
+
+Reported-by: Jann Horn <jannh@google.com>
+Suggested-by: Will Deacon <will.deacon@arm.com>
+Acked-by: Davidlohr Bueso <dave@stgolabs.net>
+Cc: Oleg Nesterov <oleg@redhat.com>
+Cc: stable@kernel.org
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ include/linux/mm_types.h |    2 +-
+ include/linux/sched.h    |    2 +-
+ include/linux/vmacache.h |    5 -----
+ mm/debug.c               |    4 ++--
+ mm/vmacache.c            |   36 ------------------------------------
+ 5 files changed, 4 insertions(+), 45 deletions(-)
+
+--- a/include/linux/mm_types.h
++++ b/include/linux/mm_types.h
+@@ -345,7 +345,7 @@ struct kioctx_table;
+ struct mm_struct {
+       struct vm_area_struct *mmap;            /* list of VMAs */
+       struct rb_root mm_rb;
+-      u32 vmacache_seqnum;                   /* per-thread vmacache */
++      u64 vmacache_seqnum;                   /* per-thread vmacache */
+ #ifdef CONFIG_MMU
+       unsigned long (*get_unmapped_area) (struct file *filp,
+                               unsigned long addr, unsigned long len,
+--- a/include/linux/sched.h
++++ b/include/linux/sched.h
+@@ -1315,7 +1315,7 @@ struct task_struct {
+       unsigned brk_randomized:1;
+ #endif
+       /* per-thread vma caching */
+-      u32 vmacache_seqnum;
++      u64 vmacache_seqnum;
+       struct vm_area_struct *vmacache[VMACACHE_SIZE];
+ #if defined(SPLIT_RSS_COUNTING)
+       struct task_rss_stat    rss_stat;
+--- a/include/linux/vmacache.h
++++ b/include/linux/vmacache.h
+@@ -15,7 +15,6 @@ static inline void vmacache_flush(struct
+       memset(tsk->vmacache, 0, sizeof(tsk->vmacache));
+ }
+ 
+-extern void vmacache_flush_all(struct mm_struct *mm);
+ extern void vmacache_update(unsigned long addr, struct vm_area_struct *newvma);
+ extern struct vm_area_struct *vmacache_find(struct mm_struct *mm,
+                                                   unsigned long addr);
+@@ -29,10 +28,6 @@ extern struct vm_area_struct *vmacache_f
+ static inline void vmacache_invalidate(struct mm_struct *mm)
+ {
+       mm->vmacache_seqnum++;
+-
+-      /* deal with overflows */
+-      if (unlikely(mm->vmacache_seqnum == 0))
+-              vmacache_flush_all(mm);
+ }
+ 
+ #endif /* __LINUX_VMACACHE_H */
+--- a/mm/debug.c
++++ b/mm/debug.c
+@@ -166,7 +166,7 @@ EXPORT_SYMBOL(dump_vma);
+ 
+ void dump_mm(const struct mm_struct *mm)
+ {
+-      pr_emerg("mm %p mmap %p seqnum %d task_size %lu\n"
++      pr_emerg("mm %p mmap %p seqnum %llu task_size %lu\n"
+ #ifdef CONFIG_MMU
+               "get_unmapped_area %p\n"
+ #endif
+@@ -196,7 +196,7 @@ void dump_mm(const struct mm_struct *mm)
+ #endif
+               "%s",   /* This is here to hold the comma */
+ 
+-              mm, mm->mmap, mm->vmacache_seqnum, mm->task_size,
++              mm, mm->mmap, (long long) mm->vmacache_seqnum, mm->task_size,
+ #ifdef CONFIG_MMU
+               mm->get_unmapped_area,
+ #endif
+--- a/mm/vmacache.c
++++ b/mm/vmacache.c
+@@ -6,42 +6,6 @@
+ #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;
+-
+-      /*
+-       * 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

diff --git a/queue-3.18/series b/queue-3.18/series
index 5c854496912256246541326aa6156f85ac2d9582..6a8691d2ea20eb769447f10a71b25cde3858a3a6 100644 (file)
--- a/queue-3.18/series
+++ b/queue-3.18/series
@@ -58,3 +58,4 @@ f2fs-fix-to-do-sanity-check-with-sit-nat-_ver_bitmap_bytesize.patch
 mips-warn_on-invalid-dma-cache-maintenance-not-bug_on.patch
 xhci-fix-use-after-free-in-xhci_free_virt_device.patch
 netfilter-x_tables-avoid-stack-out-of-bounds-read-in-xt_copy_counters_from_user.patch
+mm-get-rid-of-vmacache_flush_all-entirely.patch