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Subject[PATCH v9 27/60] PCI: Optimize bus align/size calculation for optional during sizing
Date
Current add_align always use max align, that make required+optional
to get allocated more than needed in some cases.

Now we have new calculate_mem_align(), so we could use it for
add_align calculation.

Need to create separated list for required+optional align/size info.

After that we can get smaller add_align/size, and we have more chance
to make required+optional to get allocated sucessfully.

The result for bridge that have Intel 4x10g card installed:

pci 0000:20:03.2: bridge window [mem 0x00000000-0x000fffff 64bit pref]
to [bus 2a-31] calculate_mem for required
align/size:
00800000/00800000, 00800000/00800000, 00800000/00800000,
00800000/00800000, 00008000/00008000, 00008000/00008000,
00008000/00008000, 00008000/00008000
original min_align/min_size: 00400000/02400000
new min_align/min_size: 00400000/02400000

pci 0000:20:03.2: bridge window [mem 0x00000000-0x000fffff 64bit pref]
to [bus 2a-31] calculate_mem for required+optional
align/size:
00800000/00800000, 00800000/00800000, 00800000/00800000,
00800000/00800000, 00010000/00200000, 00010000/00200000,
00010000/00200000, 00010000/00200000, 00008000/00008000,
00008000/00008000, 00008000/00008000, 00008000/00008000,
00004000/00080000, 00004000/00080000, 00004000/00080000,
00004000/00080000
original code min_align/min_size: 00800000/03000000
new min_align/min_size: 00100000/02b00000

so required align/size: 0x400000/0x2400000, and
new required+optional align/size: 0x100000/0x2b00000, and it is much better
than original required+optional align/size: 0x800000/0x3000000
and even have smaller min_align than required.

-v2: remove not used size1 in calculate_memsize

Link: https://bugzilla.kernel.org/show_bug.cgi?id=81431
Reported-by: TJ <linux@iam.tj>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>


drivers/pci/setup-bus.c | 82 +++++++++++++++++++++++++++++-------------------
1 file changed, 51 insertions(+), 31 deletions(-)
---
drivers/pci/setup-bus.c | 82 ++++++++++++++++++++++++++++++-------------------
1 file changed, 51 insertions(+), 31 deletions(-)

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 6e67608..d8db9e3 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -944,7 +944,6 @@ static resource_size_t calculate_iosize(resource_size_t size,

static resource_size_t calculate_memsize(resource_size_t size,
resource_size_t min_size,
- resource_size_t size1,
resource_size_t old_size,
resource_size_t align)
{
@@ -954,7 +953,7 @@ static resource_size_t calculate_memsize(resource_size_t size,
old_size = 0;
if (size < old_size)
size = old_size;
- size = ALIGN(size + size1, align);
+ size = ALIGN(size, align);
return size;
}

@@ -1217,26 +1216,23 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
struct list_head *realloc_head)
{
struct pci_dev *dev;
- resource_size_t min_align, align, size, size0, size1;
- resource_size_t max_align = 0;
+ resource_size_t min_align = 0, min_add_align = 0;
+ resource_size_t max_align = 0, max_add_align = 0;
+ resource_size_t size = 0, size0 = 0, size1 = 0, sum_add_size = 0;
struct resource *b_res = find_free_bus_resource(bus,
mask | IORESOURCE_PREFETCH, type);
- resource_size_t children_add_size = 0;
- resource_size_t children_add_align = 0;
- resource_size_t add_align = 0;
LIST_HEAD(align_test_list);
+ LIST_HEAD(align_test_add_list);

if (!b_res)
return -ENOSPC;

- size = 0;
-
list_for_each_entry(dev, &bus->devices, bus_list) {
int i;

for (i = 0; i < PCI_NUM_RESOURCES; i++) {
struct resource *r = &dev->resource[i];
- resource_size_t r_size;
+ resource_size_t r_size, align;
int flags = pci_resource_pref_compatible(dev, r);

if (r->parent || (flags & IORESOURCE_PCI_FIXED) ||
@@ -1244,19 +1240,23 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
(flags & mask) != type2 &&
(flags & mask) != type3))
continue;
+
r_size = resource_size(r);
+ align = pci_resource_alignment(dev, r);
#ifdef CONFIG_PCI_IOV
/* put SRIOV requested res to the optional list */
if (realloc_head && i >= PCI_IOV_RESOURCES &&
i <= PCI_IOV_RESOURCE_END) {
- add_align = max(pci_resource_alignment(dev, r), add_align);
+ add_to_align_test_list(&align_test_add_list,
+ align, r_size);
r->end = r->start - 1;
add_to_list(realloc_head, dev, r, r_size, 0/* don't care */);
- children_add_size += r_size;
+ sum_add_size += r_size;
+ if (align > max_add_align)
+ max_add_align = align;
continue;
}
#endif
- align = pci_resource_alignment(dev, r);
if (align > (1ULL<<37)) { /*128 Gb*/
dev_warn(&dev->dev, "disabling BAR %d: %pR (bad alignment %#llx)\n",
i, r, (unsigned long long) align);
@@ -1264,33 +1264,52 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
continue;
}

- if (r_size > 1)
+ if (r_size > 1) {
add_to_align_test_list(&align_test_list,
align, r_size);
- size += r_size;
- if (align > max_align)
- max_align = align;
+ size += r_size;
+ if (align > max_align)
+ max_align = align;
+ }

if (realloc_head) {
- children_add_size += get_res_add_size(realloc_head, r);
- children_add_align = get_res_add_align(realloc_head, r);
- add_align = max(add_align, children_add_align);
+ resource_size_t add_r_size, add_align;
+
+ add_r_size = get_res_add_size(realloc_head, r);
+ add_align = get_res_add_align(realloc_head, r);
+ /* no add on ? */
+ if (add_align < align)
+ add_align = align;
+ add_to_align_test_list(&align_test_add_list,
+ add_align,
+ r_size + add_r_size);
+ sum_add_size += r_size + add_r_size;
+ if (add_align > max_add_align)
+ max_add_align = add_align;
}
}
}

max_align = max(max_align, window_alignment(bus, b_res->flags));
- min_align = calculate_mem_align(&align_test_list, max_align, size,
- window_alignment(bus, b_res->flags));
- size0 = calculate_memsize(size, min_size, 0,
+ if (size || min_size) {
+ min_align = calculate_mem_align(&align_test_list, max_align,
+ size, window_alignment(bus, b_res->flags));
+ size0 = calculate_memsize(size, min_size,
resource_size(b_res), min_align);
+ }
free_align_test_list(&align_test_list);
- add_align = max(min_align, add_align);
- if (children_add_size > add_size)
- add_size = children_add_size;
- size1 = (!realloc_head || (realloc_head && !add_size)) ? size0 :
- calculate_memsize(size, min_size, add_size,
- resource_size(b_res), add_align);
+
+ if ((sum_add_size - size) < add_size)
+ sum_add_size = size + add_size;
+ if (sum_add_size > size && realloc_head) {
+ min_add_align = calculate_mem_align(&align_test_add_list,
+ max_add_align, sum_add_size,
+ window_alignment(bus, b_res->flags));
+ size1 = calculate_memsize(sum_add_size, min_size,
+ resource_size(b_res), min_add_align);
+ }
+ free_align_test_list(&align_test_add_list);
+
if (!size0 && !size1) {
if (b_res->start || b_res->end)
dev_info(&bus->self->dev, "disabling bridge window %pR to %pR (unused)\n",
@@ -1302,11 +1321,12 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
b_res->end = size0 + min_align - 1;
b_res->flags |= IORESOURCE_STARTALIGN;
if (size1 > size0 && realloc_head) {
- add_to_list(realloc_head, bus->self, b_res, size1-size0, add_align);
+ add_to_list(realloc_head, bus->self, b_res, size1 - size0,
+ min_add_align);
dev_printk(KERN_DEBUG, &bus->self->dev, "bridge window %pR to %pR add_size %llx add_align %llx\n",
b_res, &bus->busn_res,
(unsigned long long) (size1 - size0),
- (unsigned long long) add_align);
+ (unsigned long long) min_add_align);
}
return 0;
}
--
1.8.4.5


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