[PATCH] - GRU Driver V3 fixes to resolve code review comments

From: Jack Steiner
Date: Mon Jul 28 2008 - 16:06:18 EST

Fixes problems identified in a code review:
- add comment with high level dscription of the GRU
- prepend "gru_" to all global names
- delete unused function
- couple of trivial bug fixes

Signed-off-by: Jack Steiner <steiner@xxxxxxx>

---
drivers/misc/sgi-gru/gru_instructions.h | 10 ----
drivers/misc/sgi-gru/grufile.c | 8 ++-
drivers/misc/sgi-gru/grukservices.c | 6 +-
drivers/misc/sgi-gru/grumain.c | 16 ++++--
drivers/misc/sgi-gru/gruprocfs.c | 4 -
drivers/misc/sgi-gru/grutables.h | 74 +++++++++++++++++++++++++++++---
drivers/misc/sgi-gru/grutlbpurge.c | 4 +
7 files changed, 93 insertions(+), 29 deletions(-)

Index: linux/drivers/misc/sgi-gru/gru_instructions.h
===================================================================
--- linux.orig/drivers/misc/sgi-gru/gru_instructions.h 2008-07-28 14:52:26.000000000 -0500
+++ linux/drivers/misc/sgi-gru/gru_instructions.h 2008-07-28 14:52:54.000000000 -0500
@@ -285,16 +285,6 @@ __opword(unsigned char opcode, unsigned
}

/*
- * Prefetch a cacheline. Fetch is unconditional. Must page fault if
- * no valid TLB entry is found.
- * ??? should I use actual "load" or hardware prefetch???
- */
-static inline void gru_prefetch(void *p)
-{
- *(volatile char *)p;
-}
-
-/*
* Architecture specific intrinsics
*/
static inline void gru_flush_cache(void *p)
Index: linux/drivers/misc/sgi-gru/grufile.c
===================================================================
--- linux.orig/drivers/misc/sgi-gru/grufile.c 2008-07-28 14:52:26.000000000 -0500
+++ linux/drivers/misc/sgi-gru/grufile.c 2008-07-28 14:52:54.000000000 -0500
@@ -112,6 +112,10 @@ static int gru_file_mmap(struct file *fi
if ((vma->vm_flags & (VM_SHARED | VM_WRITE)) != (VM_SHARED | VM_WRITE))
return -EPERM;

+ if (vma->vm_start & (GRU_GSEG_PAGESIZE - 1) ||
+ vma->vm_end & (GRU_GSEG_PAGESIZE - 1))
+ return -EINVAL;
+
vma->vm_flags |=
(VM_IO | VM_DONTCOPY | VM_LOCKED | VM_DONTEXPAND | VM_PFNMAP |
VM_RESERVED);
@@ -471,8 +475,8 @@ struct vm_operations_struct gru_vm_ops =
module_init(gru_init);
module_exit(gru_exit);

-module_param(options, ulong, 0644);
-MODULE_PARM_DESC(options, "Various debug options");
+module_param(gru_options, ulong, 0644);
+MODULE_PARM_DESC(gru_options, "Various debug options");

MODULE_AUTHOR("Silicon Graphics, Inc.");
MODULE_LICENSE("GPL");
Index: linux/drivers/misc/sgi-gru/grukservices.c
===================================================================
--- linux.orig/drivers/misc/sgi-gru/grukservices.c 2008-07-28 14:52:26.000000000 -0500
+++ linux/drivers/misc/sgi-gru/grukservices.c 2008-07-28 14:52:54.000000000 -0500
@@ -638,11 +638,11 @@ int gru_kservices_init(struct gru_state
cpus_possible = uv_blade_nr_possible_cpus(gru->gs_blade_id);

num = GRU_NUM_KERNEL_CBR * cpus_possible;
- cbr_map = reserve_gru_cb_resources(gru, GRU_CB_COUNT_TO_AU(num), NULL);
+ cbr_map = gru_reserve_cb_resources(gru, GRU_CB_COUNT_TO_AU(num), NULL);
gru->gs_reserved_cbrs += num;

num = GRU_NUM_KERNEL_DSR_BYTES * cpus_possible;
- dsr_map = reserve_gru_ds_resources(gru, GRU_DS_BYTES_TO_AU(num), NULL);
+ dsr_map = gru_reserve_ds_resources(gru, GRU_DS_BYTES_TO_AU(num), NULL);
gru->gs_reserved_dsr_bytes += num;

gru->gs_active_contexts++;
@@ -673,7 +673,7 @@ int gru_kservices_init(struct gru_state
}
unlock_cch_handle(cch);

- if (options & GRU_QUICKLOOK)
+ if (gru_options & GRU_QUICKLOOK)
quicktest(gru);
return 0;
}
Index: linux/drivers/misc/sgi-gru/grumain.c
===================================================================
--- linux.orig/drivers/misc/sgi-gru/grumain.c 2008-07-28 14:52:26.000000000 -0500
+++ linux/drivers/misc/sgi-gru/grumain.c 2008-07-28 14:52:54.000000000 -0500
@@ -22,7 +22,7 @@
#include "grutables.h"
#include "gruhandles.h"

-unsigned long options __read_mostly;
+unsigned long gru_options __read_mostly;

static struct device_driver gru_driver = {
.name = "gru"
@@ -163,14 +163,14 @@ static unsigned long reserve_resources(u
return bits;
}

-unsigned long reserve_gru_cb_resources(struct gru_state *gru, int cbr_au_count,
+unsigned long gru_reserve_cb_resources(struct gru_state *gru, int cbr_au_count,
char *cbmap)
{
return reserve_resources(&gru->gs_cbr_map, cbr_au_count, GRU_CBR_AU,
cbmap);
}

-unsigned long reserve_gru_ds_resources(struct gru_state *gru, int dsr_au_count,
+unsigned long gru_reserve_ds_resources(struct gru_state *gru, int dsr_au_count,
char *dsmap)
{
return reserve_resources(&gru->gs_dsr_map, dsr_au_count, GRU_DSR_AU,
@@ -182,10 +182,10 @@ static void reserve_gru_resources(struct
{
gru->gs_active_contexts++;
gts->ts_cbr_map =
- reserve_gru_cb_resources(gru, gts->ts_cbr_au_count,
+ gru_reserve_cb_resources(gru, gts->ts_cbr_au_count,
gts->ts_cbr_idx);
gts->ts_dsr_map =
- reserve_gru_ds_resources(gru, gts->ts_dsr_au_count, NULL);
+ gru_reserve_ds_resources(gru, gts->ts_dsr_au_count, NULL);
}

static void free_gru_resources(struct gru_state *gru,
@@ -416,6 +416,7 @@ static void gru_free_gru_context(struct

/*
* Prefetching cachelines help hardware performance.
+ * (Strictly a performance enhancement. Not functionally required).
*/
static void prefetch_data(void *p, int num, int stride)
{
@@ -746,6 +747,8 @@ again:
* gru_nopage
*
* Map the user's GRU segment
+ *
+ * Note: gru segments alway mmaped on GRU_GSEG_PAGESIZE boundaries.
*/
int gru_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
@@ -757,6 +760,7 @@ int gru_fault(struct vm_area_struct *vma
vma, vaddr, GSEG_BASE(vaddr));
STAT(nopfn);

+ /* The following check ensures vaddr is a valid address in the VMA */
gts = gru_find_thread_state(vma, TSID(vaddr, vma));
if (!gts)
return VM_FAULT_SIGBUS;
@@ -775,7 +779,7 @@ again:
}

if (!gts->ts_gru) {
- while (!gru_assign_gru_context(gts)) {
+ if (!gru_assign_gru_context(gts)) {
mutex_unlock(&gts->ts_ctxlock);
preempt_enable();
schedule_timeout(GRU_ASSIGN_DELAY); /* true hack ZZZ */
Index: linux/drivers/misc/sgi-gru/gruprocfs.c
===================================================================
--- linux.orig/drivers/misc/sgi-gru/gruprocfs.c 2008-07-28 14:52:26.000000000 -0500
+++ linux/drivers/misc/sgi-gru/gruprocfs.c 2008-07-28 14:52:54.000000000 -0500
@@ -122,7 +122,7 @@ static ssize_t statistics_write(struct f

static int options_show(struct seq_file *s, void *p)
{
- seq_printf(s, "0x%lx\n", options);
+ seq_printf(s, "0x%lx\n", gru_options);
return 0;
}

@@ -136,7 +136,7 @@ static ssize_t options_write(struct file
(buf, userbuf, count < sizeof(buf) ? count : sizeof(buf)))
return -EFAULT;
if (!strict_strtoul(buf, 10, &val))
- options = val;
+ gru_options = val;

return count;
}
Index: linux/drivers/misc/sgi-gru/grutables.h
===================================================================
--- linux.orig/drivers/misc/sgi-gru/grutables.h 2008-07-28 14:52:26.000000000 -0500
+++ linux/drivers/misc/sgi-gru/grutables.h 2008-07-28 14:52:54.000000000 -0500
@@ -24,6 +24,70 @@
#define __GRUTABLES_H__

/*
+ * GRU Chiplet:
+ * The GRU is a user addressible memory accelerator. It provides
+ * several forms of load, store, memset, bcopy instructions. In addition, it
+ * contains special instructions for AMOs, sending messages to message
+ * queues, etc.
+ *
+ * The GRU is an integral part of the node controller. It connects
+ * directly to the cpu socket. In its current implementation, there are 2
+ * GRU chiplets in the node controller on each blade (~node).
+ *
+ * The entire GRU memory space is fully coherent and cacheable by the cpus.
+ *
+ * Each GRU chiplet has a physical memory map that looks like the following:
+ *
+ * +-----------------+
+ * |/////////////////|
+ * |/////////////////|
+ * |/////////////////|
+ * |/////////////////|
+ * |/////////////////|
+ * |/////////////////|
+ * |/////////////////|
+ * |/////////////////|
+ * +-----------------+
+ * | system control |
+ * +-----------------+ _______ +-------------+
+ * |/////////////////| / | |
+ * |/////////////////| / | |
+ * |/////////////////| / | instructions|
+ * |/////////////////| / | |
+ * |/////////////////| / | |
+ * |/////////////////| / |-------------|
+ * |/////////////////| / | |
+ * +-----------------+ | |
+ * | context 15 | | data |
+ * +-----------------+ | |
+ * | ...... | \ | |
+ * +-----------------+ \____________ +-------------+
+ * | context 1 |
+ * +-----------------+
+ * | context 0 |
+ * +-----------------+
+ *
+ * Each of the "contexts" is a chunk of memory that can be mmaped into user
+ * space. The context consists of 2 parts:
+ *
+ * - an instruction space that can be directly accessed by the user
+ * to issue GRU instructions and to check instruction status.
+ *
+ * - a data area that acts as normal RAM.
+ *
+ * User instructions contain virtual addresses of data to be accessed by the
+ * GRU. The GRU contains a TLB that is used to convert these user virtual
+ * addresses to physical addresses.
+ *
+ * The "system control" area of the GRU chiplet is used by the kernel driver
+ * to manage user contexts and to perform functions such as TLB dropin and
+ * purging.
+ *
+ * One context may be reserved for the kernel and used for cross-partition
+ * communication. The GRU will also be used to asynchronously zero out
+ * large blocks of memory (not currently implemented).
+ *
+ *
* Tables:
*
* VDATA-VMA Data - Holds a few parameters. Head of linked list of
@@ -190,14 +254,14 @@ struct gru_stats_s {
#define GRU_STEAL_DELAY ((HZ * 200) / 1000)

#define STAT(id) do { \
- if (options & OPT_STATS) \
+ if (gru_options & OPT_STATS) \
atomic_long_inc(&gru_stats.id); \
} while (0)

#ifdef CONFIG_SGI_GRU_DEBUG
#define gru_dbg(dev, fmt, x...) \
do { \
- if (options & OPT_DPRINT) \
+ if (gru_options & OPT_DPRINT) \
dev_dbg(dev, "%s: " fmt, __func__, x); \
} while (0)
#else
@@ -529,9 +593,9 @@ extern void gru_flush_all_tlb(struct gru
extern int gru_proc_init(void);
extern void gru_proc_exit(void);

-extern unsigned long reserve_gru_cb_resources(struct gru_state *gru,
+extern unsigned long gru_reserve_cb_resources(struct gru_state *gru,
int cbr_au_count, char *cbmap);
-extern unsigned long reserve_gru_ds_resources(struct gru_state *gru,
+extern unsigned long gru_reserve_ds_resources(struct gru_state *gru,
int dsr_au_count, char *dsmap);
extern int gru_fault(struct vm_area_struct *, struct vm_fault *vmf);
extern struct gru_mm_struct *gru_register_mmu_notifier(void);
@@ -540,6 +604,6 @@ extern void gru_drop_mmu_notifier(struct
extern void gru_flush_tlb_range(struct gru_mm_struct *gms, unsigned long start,
unsigned long len);

-extern unsigned long options;
+extern unsigned long gru_options;

#endif /* __GRUTABLES_H__ */
Index: linux/drivers/misc/sgi-gru/grutlbpurge.c
===================================================================
--- linux.orig/drivers/misc/sgi-gru/grutlbpurge.c 2008-07-28 14:52:26.000000000 -0500
+++ linux/drivers/misc/sgi-gru/grutlbpurge.c 2008-07-28 14:52:54.000000000 -0500
@@ -242,7 +242,9 @@ static void gru_invalidate_range_end(str
struct gru_mm_struct *gms = container_of(mn, struct gru_mm_struct,
ms_notifier);

- atomic_dec(&gms->ms_range_active);
+ /* ..._and_test() provides needed barrier */
+ (void)atomic_dec_and_test(&gms->ms_range_active);
+
wake_up_all(&gms->ms_wait_queue);
gru_dbg(grudev, "gms %p, start 0x%lx, end 0x%lx\n", gms, start, end);
}
--
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