drm/vmwgfx: Add a mksstat counter for cotable resizes

There's been a lot of cotable resizes on startup which we can track
by adding a mks stat to measure both the invocation count and
time spent doing cotable resizes.

This is only used if kernel is configured with CONFIG_DRM_VMWGFX_MKSSTATS
The stats are collected on the host size inside the vmware-stats.log
file.

Signed-off-by: Zack Rusin <[e-mail]>
Reviewed-by: Michael Banack <[e-mail]>
Reviewed-by: Martin Krastev <[e-mail]>
Reviewed-by: Maaz Mombasawala <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/vmwgfx/vmwgfx_cotable.c

···
 #include <drm/ttm/ttm_placement.h>
 
 #include "vmwgfx_drv.h"
+#include "vmwgfx_mksstat.h"
 #include "vmwgfx_resource_priv.h"
 #include "vmwgfx_so.h"
 
···
 	int ret;
 	size_t i;
 
+	MKS_STAT_TIME_DECL(MKSSTAT_KERN_COTABLE_RESIZE);
+	MKS_STAT_TIME_PUSH(MKSSTAT_KERN_COTABLE_RESIZE);
+
 	ret = vmw_cotable_readback(res);
 	if (ret)
-		return ret;
+		goto out_done;
 
 	cur_size_read_back = vcotbl->size_read_back;
 	vcotbl->size_read_back = old_size_read_back;
···
 			    true, true, vmw_bo_bo_free, &buf);
 	if (ret) {
 		DRM_ERROR("Failed initializing new cotable MOB.\n");
-		return ret;
+		goto out_done;
 	}
 
 	bo = &buf->base;
···
 	/* Release the pin acquired in vmw_bo_init */
 	ttm_bo_unpin(bo);
 
+	MKS_STAT_TIME_POP(MKSSTAT_KERN_COTABLE_RESIZE);
+
 	return 0;
 
 out_map_new:
···
 	ttm_bo_unpin(bo);
 	ttm_bo_unreserve(bo);
 	vmw_bo_unreference(&buf);
+
+out_done:
+	MKS_STAT_TIME_POP(MKSSTAT_KERN_COTABLE_RESIZE);
 
 	return ret;
 }

drivers/gpu/drm/vmwgfx/vmwgfx_mksstat.h

···
 #define _VMWGFX_MKSSTAT_H_
 
 #include <asm/page.h>
+#include <linux/kconfig.h>
 
 /* Reservation marker for mksstat pid's */
 #define MKSSTAT_PID_RESERVED -1
···
 
 typedef enum {
 	MKSSTAT_KERN_EXECBUF, /* vmw_execbuf_ioctl */
+	MKSSTAT_KERN_COTABLE_RESIZE,
 
 	MKSSTAT_KERN_COUNT /* Reserved entry; always last */
 } mksstat_kern_stats_t;

drivers/gpu/drm/vmwgfx/vmwgfx_msg.c

···
 	u32 cookie_low;
 };
 
-
+#if IS_ENABLED(CONFIG_DRM_VMWGFX_MKSSTATS)
+/* Kernel mksGuestStats counter names and desciptions; same order as enum mksstat_kern_stats_t */
+static const char* const mksstat_kern_name_desc[MKSSTAT_KERN_COUNT][2] =
+{
+	{ "vmw_execbuf_ioctl", "vmw_execbuf_ioctl" },
+	{ "vmw_cotable_resize", "vmw_cotable_resize" },
+};
+#endif
 
 /**
  * vmw_open_channel
···
 /* Header to the text description of mksGuestStat instance descriptor */
 #define MKSSTAT_KERNEL_DESCRIPTION "vmwgfx"
 
-/* Kernel mksGuestStats counter names and desciptions; same order as enum mksstat_kern_stats_t */
-static const char* const mksstat_kern_name_desc[MKSSTAT_KERN_COUNT][2] =
-{
-	{ "vmw_execbuf_ioctl", "vmw_execbuf_ioctl" },
-};
-
 /**
  * mksstat_init_record: Initializes an MKSGuestStatCounter-based record
  * for the respective mksGuestStat index.
···
 	/* Set up all kernel-internal counters and corresponding structures */
 	pstrs_acc = pstrs;
 	pstrs_acc = mksstat_init_record_time(MKSSTAT_KERN_EXECBUF, pstat, pinfo, pstrs_acc);
+	pstrs_acc = mksstat_init_record_time(MKSSTAT_KERN_COTABLE_RESIZE, pstat, pinfo, pstrs_acc);
 
 	/* Add new counters above, in their order of appearance in mksstat_kern_stats_t */