Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

Trivial conflicts in net/can/isotp.c and
tools/testing/selftests/net/mptcp/mptcp_connect.sh

scaled_ppm_to_ppb() was moved from drivers/ptp/ptp_clock.c
to include/linux/ptp_clock_kernel.h in -next so re-apply
the fix there.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 20 insertions, 7 deletions

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index ed6862eacb52..862f88a8c28a 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -452,13 +452,6 @@ struct mm_struct {
 		 */
 		atomic_t has_pinned;
 
-		/**
-		 * @write_protect_seq: Locked when any thread is write
-		 * protecting pages mapped by this mm to enforce a later COW,
-		 * for instance during page table copying for fork().
-		 */
-		seqcount_t write_protect_seq;
-
 #ifdef CONFIG_MMU
 		atomic_long_t pgtables_bytes;	/* PTE page table pages */
 #endif
@@ -467,6 +460,18 @@ struct mm_struct {
 		spinlock_t page_table_lock; /* Protects page tables and some
 					     * counters
 					     */
+		/*
+		 * With some kernel config, the current mmap_lock's offset
+		 * inside 'mm_struct' is at 0x120, which is very optimal, as
+		 * its two hot fields 'count' and 'owner' sit in 2 different
+		 * cachelines,  and when mmap_lock is highly contended, both
+		 * of the 2 fields will be accessed frequently, current layout
+		 * will help to reduce cache bouncing.
+		 *
+		 * So please be careful with adding new fields before
+		 * mmap_lock, which can easily push the 2 fields into one
+		 * cacheline.
+		 */
 		struct rw_semaphore mmap_lock;
 
 		struct list_head mmlist; /* List of maybe swapped mm's.	These
@@ -487,7 +492,15 @@ struct mm_struct {
 		unsigned long stack_vm;	   /* VM_STACK */
 		unsigned long def_flags;
 
+		/**
+		 * @write_protect_seq: Locked when any thread is write
+		 * protecting pages mapped by this mm to enforce a later COW,
+		 * for instance during page table copying for fork().
+		 */
+		seqcount_t write_protect_seq;
+
 		spinlock_t arg_lock; /* protect the below fields */
+
 		unsigned long start_code, end_code, start_data, end_data;
 		unsigned long start_brk, brk, start_stack;
 		unsigned long arg_start, arg_end, env_start, env_end;