Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753499AbbHUGWY (ORCPT ); Fri, 21 Aug 2015 02:22:24 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:46243 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752435AbbHUGWU (ORCPT ); Fri, 21 Aug 2015 02:22:20 -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 34/52] resources: Make allocate_resource() return best fit resource Date: Thu, 20 Aug 2015 23:20:49 -0700 Message-Id: <1440138067-4314-35-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: userv0021.oracle.com [156.151.31.71] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6119 Lines: 192 Find all suitable empty slots and pick one with smallest size, so we could save the big slot for needed ones later when we have several pci bridges under parent bridge and some bridges get assigned from bios and we need to assign others in kernel. For examples: we have window [0xc0000000, 0xd0000000), and [0xe0000000,0xe1000000) and we try allocate 0x200000 size resource. in this patch will reserve [0xc0000000, 0xd0000000) and [0xe0000000,0xe1000000) at first, then pick [0xe0000000,0xe1000000) to allocate 0x200000 size. -v2: updated after __allocate_resource change, and add field in constraint instead of passing it directly. -v3: Use best fit instead of just fit according to Bjorn. Signed-off-by: Yinghai Lu --- kernel/resource.c | 81 ++++++++++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 68 insertions(+), 13 deletions(-) diff --git a/kernel/resource.c b/kernel/resource.c index 67b58a5..697b8ca 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -48,6 +48,7 @@ struct resource_constraint { resource_size_t (*alignf)(void *, const struct resource *, resource_size_t, resource_size_t); void *alignf_data; + bool fit; }; static DEFINE_RWLOCK(resource_lock); @@ -554,12 +555,15 @@ static void resource_clip(struct resource *res, resource_size_t min, * alignment constraints */ static int __find_resource(struct resource *root, struct resource *old, - struct resource *new, + struct resource *new, struct resource *avail, resource_size_t size, struct resource_constraint *constraint) { struct resource *this = root->child; - struct resource tmp = *new, avail, alloc; + struct resource tmp = *new, availx, alloc; + + if (!avail || avail == new) + avail = &availx; tmp.start = root->start; /* @@ -583,15 +587,16 @@ static int __find_resource(struct resource *root, struct resource *old, arch_remove_reservations(&tmp); /* Check for overflow after ALIGN() */ - avail.start = ALIGN(tmp.start, constraint->align); - avail.end = tmp.end; - avail.flags = new->flags & ~IORESOURCE_UNSET; - if (avail.start >= tmp.start) { - alloc.flags = avail.flags; - alloc.start = constraint->alignf(constraint->alignf_data, &avail, + avail->start = ALIGN(tmp.start, constraint->align); + avail->end = tmp.end; + avail->flags = new->flags & ~IORESOURCE_UNSET; + if (avail->start >= tmp.start) { + alloc.flags = avail->flags; + alloc.start = constraint->alignf( + constraint->alignf_data, avail, size, constraint->align); alloc.end = alloc.start + size - 1; - if (resource_contains(&avail, &alloc)) { + if (resource_contains(avail, &alloc)) { new->start = alloc.start; new->end = alloc.end; return 0; @@ -608,6 +613,11 @@ next: if (!this || this->end == root->end) return -EBUSY; } +struct good_resource { + struct list_head list; + struct resource avail; + struct resource new; +}; /* * Find empty slot in the resource tree given range and alignment. */ @@ -615,7 +625,49 @@ static int find_resource(struct resource *root, struct resource *new, resource_size_t size, struct resource_constraint *constraint) { - return __find_resource(root, NULL, new, size, constraint); + int ret = -1; + LIST_HEAD(head); + struct good_resource *good, *tmp; + resource_size_t avail_size = (resource_size_t)-1ULL; + + if (!constraint->fit) + return __find_resource(root, NULL, new, NULL, size, + constraint); + + /* find all suitable ones and add to the list */ + for (;;) { + good = kzalloc(sizeof(*good), GFP_KERNEL); + if (!good) + break; + + good->new.start = new->start; + good->new.end = new->end; + good->new.flags = new->flags; + ret = __find_resource(root, NULL, &good->new, &good->avail, + size, constraint); + if (ret || __request_resource(root, &good->avail)) { + ret = -EBUSY; + kfree(good); + break; + } + + list_add(&good->list, &head); + } + + /* pick up the smallest one and delete the list */ + list_for_each_entry_safe(good, tmp, &head, list) { + if (resource_size(&good->avail) < avail_size) { + avail_size = resource_size(&good->avail); + new->start = good->new.start; + new->end = good->new.end; + ret = 0; + } + list_del(&good->list); + __release_resource(&good->avail); + kfree(good); + } + + return ret; } /** @@ -636,7 +688,8 @@ static int __reallocate_resource(struct resource *root, struct resource *old, struct resource new = *old; struct resource *conflict; - if ((err = __find_resource(root, old, &new, newsize, constraint))) + err = __find_resource(root, old, &new, NULL, newsize, constraint); + if (err) goto out; if (resource_contains(&new, old)) { @@ -675,6 +728,7 @@ out: * @align: alignment requested, in bytes * @alignf: alignment function, optional, called if not NULL * @alignf_data: arbitrary data to pass to the @alignf function + * @fit: only allocate fit range. * * Caller need to hold resource_lock if needed. */ @@ -685,7 +739,7 @@ static int __allocate_resource(struct resource *root, struct resource *new, const struct resource *, resource_size_t, resource_size_t), - void *alignf_data) + void *alignf_data, bool fit) { int err; struct resource_constraint constraint; @@ -698,6 +752,7 @@ static int __allocate_resource(struct resource *root, struct resource *new, constraint.align = align; constraint.alignf = alignf; constraint.alignf_data = alignf_data; + constraint.fit = fit; if (new->parent) { /* resource is already allocated, try reallocating with @@ -738,7 +793,7 @@ int allocate_resource(struct resource *root, struct resource *new, write_lock(&resource_lock); ret = __allocate_resource(root, new, size, min, max, align, - alignf, alignf_data); + alignf, alignf_data, true); write_unlock(&resource_lock); return ret; -- 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/