xfs: Print name and pid when memory allocation loops

This patch adds comm name and pid to warning messages printed by
kmem_alloc(), kmem_zone_alloc() and xfs_buf_allocate_memory().
This will help telling which memory allocations (e.g. kernel worker
threads, OOM victim tasks, neither) are stalling because these functions
are passing __GFP_NOWARN which suppresses not only backtrace but comm name
and pid.
Signed-off-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NDave Chinner <david@fromorbit.com>

fs/xfs/kmem.c

@@ -55,7 +55,8 @@ kmem_alloc(size_t size, xfs_km_flags_t flags)
 			return ptr;
 		if (!(++retries % 100))
 			xfs_err(NULL,
-		"possible memory allocation deadlock in %s (mode:0x%x)",
+		"%s(%u) possible memory allocation deadlock in %s (mode:0x%x)",
+				current->comm, current->pid,
 				__func__, lflags);
 		congestion_wait(BLK_RW_ASYNC, HZ/50);
 	} while (1);
@@ -120,7 +121,8 @@ kmem_zone_alloc(kmem_zone_t *zone, xfs_km_flags_t flags)
 			return ptr;
 		if (!(++retries % 100))
 			xfs_err(NULL,
-		"possible memory allocation deadlock in %s (mode:0x%x)",
+		"%s(%u) possible memory allocation deadlock in %s (mode:0x%x)",
+				current->comm, current->pid,
 				__func__, lflags);
 		congestion_wait(BLK_RW_ASYNC, HZ/50);
 	} while (1);

fs/xfs/xfs_buf.c

@@ -354,7 +354,8 @@ xfs_buf_allocate_memory(
 			 */
 			if (!(++retries % 100))
 				xfs_err(NULL,
-		"possible memory allocation deadlock in %s (mode:0x%x)",
+		"%s(%u) possible memory allocation deadlock in %s (mode:0x%x)",
+					current->comm, current->pid,
 					__func__, gfp_mask);
 
 			XFS_STATS_INC(xb_page_retries);