Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932065AbbHUGhG (ORCPT ); Fri, 21 Aug 2015 02:37:06 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:51227 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753133AbbHUGhC (ORCPT ); Fri, 21 Aug 2015 02:37:02 -0400 From: Yinghai Lu To: Bjorn Helgaas , David Miller , Benjamin Herrenschmidt , Wei Yang , TJ , Yijing Wang Cc: Andrew Morton , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Yinghai Lu Subject: [PATCH v4 04/52] PCI: Optimize bus min_align/size calculation during sizing Date: Thu, 20 Aug 2015 23:20:19 -0700 Message-Id: <1440138067-4314-5-git-send-email-yinghai@kernel.org> X-Mailer: git-send-email 1.8.4.5 In-Reply-To: <1440138067-4314-1-git-send-email-yinghai@kernel.org> References: <1440138067-4314-1-git-send-email-yinghai@kernel.org> X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8926 Lines: 322 Current code try to get align as small as possible and use that to align final size. But it does not handle resource that size is bigger than align in optimal way, kernel only use max align for them. For example: when we have resources with align/size: 1M/2M, 512M/512M, bus resource min_align/size0 will be 512M/1024M, but optimal value should be 256M/768M. For following cases that we have resource size that is bigger than resource alignment: 1. SRIOV bar. 2. PCI bridges with children that need several MMIOs that are more than 1M. We can keep on trying to allocate children devices resources under range [offset, offset + aligned_size) and offset is aligned with half_align. If sucesses, we can use that half_align as new min_align. After this patch, we get: align/size: 1M/2M, 2M/4M, 4M/8M, 8M/16M new min_align/min_size: 4M/32M, and old is 8M/32M align/size: 1M/2M, 2M/4M, 4M/8M new min_align/min_size: 2M/14M, and old is 4M/16M align/size: 1M/2M, 512M/512M new min_align/min_size: 256M/768M, and old is 512M/1024M The real result from one system with one pcie card that has four functions that support sriov: children resources with 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 the for the bridge with orig code we have min_align/min_size: 00400000/02c00000 and with this patch we have min_align/min_size: 00100000/02b00000 So align will be 1M instead of 4M and even have smaller size. Link: https://bugzilla.kernel.org/show_bug.cgi?id=81431 Reported-by: TJ Signed-off-by: Yinghai Lu --- drivers/pci/setup-bus.c | 195 ++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 157 insertions(+), 38 deletions(-) diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index aea35b6..861fe68 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -30,6 +30,34 @@ unsigned int pci_flags; +static inline bool is_before(resource_size_t align1, resource_size_t size1, + resource_size_t align2, resource_size_t size2) +{ + resource_size_t size1_left, size2_left; + + /* big align is before small align */ + if (align1 > align2) + return true; + + /* + * for same align: + * aligned is before not aligned + * for not aligned, big remainder is before small remainder + */ + if (align1 == align2) { + size1_left = size1 & (align1 - 1); + if (!size1_left) + size1_left = align1; + size2_left = size2 & (align2 - 1); + if (!size2_left) + size2_left = align2; + if (size1_left > size2_left) + return true; + } + + return false; +} + struct pci_dev_resource { struct list_head list; struct resource *res; @@ -998,26 +1026,125 @@ static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size, } } -static inline resource_size_t calculate_mem_align(resource_size_t *aligns, - int max_order) +struct align_test_res { + struct list_head list; + struct resource res; + resource_size_t size; + resource_size_t align; +}; + +static void free_align_test_list(struct list_head *head) { - resource_size_t align = 0; - resource_size_t min_align = 0; - int order; + struct align_test_res *p, *tmp; - for (order = 0; order <= max_order; order++) { - resource_size_t align1 = 1; + list_for_each_entry_safe(p, tmp, head, list) { + list_del(&p->list); + kfree(p); + } +} - align1 <<= (order + 20); +static int add_to_align_test_list(struct list_head *head, + resource_size_t align, resource_size_t size) +{ + struct align_test_res *tmp; + + tmp = kzalloc(sizeof(*tmp), GFP_KERNEL); + if (!tmp) + return -ENOMEM; + + tmp->align = align; + tmp->size = size; + + list_add_tail(&tmp->list, head); + + return 0; +} + +static void sort_align_test(struct list_head *head) +{ + struct align_test_res *res1, *tmp_res, *res2; - if (!align) - min_align = align1; - else if (ALIGN(align + min_align, min_align) < align1) - min_align = align1 >> 1; - align += aligns[order]; + list_for_each_entry_safe(res1, tmp_res, head, list) { + /* reorder it */ + list_for_each_entry(res2, head, list) { + if (res2 == res1) + break; + + if (is_before(res1->align, res1->size, + res2->align, res2->size)) { + list_move_tail(&res1->list, &res2->list); + break; + } + } + } +} + +static bool is_align_size_good(struct list_head *head, + resource_size_t min_align, resource_size_t size, + resource_size_t start) +{ + struct align_test_res *p; + struct resource root; + + memset(&root, 0, sizeof(root)); + root.start = start; + root.end = start + size - 1; + + list_for_each_entry(p, head, list) + memset(&p->res, 0, sizeof(p->res)); + + list_for_each_entry(p, head, list) + if (allocate_resource(&root, &p->res, p->size, + 0, (resource_size_t)-1ULL, + p->align, NULL, NULL)) + return false; + + return true; +} + +static resource_size_t calculate_mem_align(struct list_head *head, + resource_size_t max_align, resource_size_t size, + resource_size_t align_low) +{ + struct align_test_res *p; + resource_size_t min_align, good_align, aligned_size, start; + int count = 0; + + if (max_align <= align_low) { + good_align = align_low; + goto out; } - return min_align; + good_align = max_align; + + list_for_each_entry(p, head, list) + count++; + + if (count <= 1) + goto out; + + sort_align_test(head); + + do { + /* check if we can use smaller align */ + min_align = good_align >> 1; + aligned_size = ALIGN(size, min_align); + + /* need to make sure every offset work */ + for (start = min_align; start < max_align; start += min_align) { + /* checked already with last align ? */ + if (!(start & (good_align - 1))) + continue; + + if (!is_align_size_good(head, min_align, aligned_size, + start)) + goto out; + } + good_align = min_align; + } while (min_align > align_low); + +out: + return good_align; } /** @@ -1047,19 +1174,17 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask, { struct pci_dev *dev; resource_size_t min_align, align, size, size0, size1; - resource_size_t aligns[18]; /* Alignments from 1Mb to 128Gb */ - int order, max_order; + resource_size_t max_align = 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); if (!b_res) return -ENOSPC; - memset(aligns, 0, sizeof(aligns)); - max_order = 0; size = 0; list_for_each_entry(dev, &bus->devices, bus_list) { @@ -1085,29 +1210,20 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask, continue; } #endif - /* - * aligns[0] is for 1MB (since bridge memory - * windows are always at least 1MB aligned), so - * keep "order" from being negative for smaller - * resources. - */ align = pci_resource_alignment(dev, r); - order = __ffs(align) - 20; - if (order < 0) - order = 0; - if (order >= ARRAY_SIZE(aligns)) { + if (align > (1ULL<<37)) { /*128 Gb*/ dev_warn(&dev->dev, "disabling BAR %d: %pR (bad alignment %#llx)\n", - i, r, (unsigned long long) align); + i, r, (unsigned long long) align); r->flags = 0; continue; } + + if (r_size > 1) + add_to_align_test_list(&align_test_list, + align, r_size); size += r_size; - /* Exclude ranges with size > align from - calculation of the alignment. */ - if (r_size == align) - aligns[order] += align; - if (order > max_order) - max_order = order; + if (align > max_align) + max_align = align; if (realloc_head) { children_add_size += get_res_add_size(realloc_head, r); @@ -1117,9 +1233,12 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask, } } - min_align = calculate_mem_align(aligns, max_order); - min_align = max(min_align, window_alignment(bus, b_res->flags)); - size0 = calculate_memsize(size, min_size, 0, resource_size(b_res), min_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, + 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; -- 1.8.4.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/