From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx188.postini.com [74.125.245.188]) by kanga.kvack.org (Postfix) with SMTP id 1B8566B003A for ; Wed, 3 Apr 2013 15:58:27 -0400 (EDT) Message-ID: <1365018417.11159.107.camel@misato.fc.hp.com> Subject: Re: [PATCH 2/3] resource: Add release_mem_region_adjustable() From: Toshi Kani Date: Wed, 03 Apr 2013 13:46:57 -0600 In-Reply-To: <515B853D.4060003@jp.fujitsu.com> References: <1364919450-8741-1-git-send-email-toshi.kani@hp.com> <1364919450-8741-3-git-send-email-toshi.kani@hp.com> <515B853D.4060003@jp.fujitsu.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Yasuaki Ishimatsu Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linuxram@us.ibm.com, tmac@hp.com, wency@cn.fujitsu.com, tangchen@cn.fujitsu.com, jiang.liu@huawei.com On Wed, 2013-04-03 at 10:26 +0900, Yasuaki Ishimatsu wrote: > 2013/04/03 1:17, Toshi Kani wrote: > > Added release_mem_region_adjustable(), which releases a requested > > region from a currently busy memory resource. This interface > > adjusts the matched memory resource accordingly if the requested > > region does not match exactly but still fits into. > > > > This new interface is intended for memory hot-delete. During > > bootup, memory resources are inserted from the boot descriptor > > table, such as EFI Memory Table and e820. Each memory resource > > entry usually covers the whole contigous memory range. Memory > > hot-delete request, on the other hand, may target to a particular > > range of memory resource, and its size can be much smaller than > > the whole contiguous memory. Since the existing release interfaces > > like __release_region() require a requested region to be exactly > > matched to a resource entry, they do not allow a partial resource > > to be released. > > > > There is no change to the existing interfaces since their restriction > > is valid for I/O resources. > > > > Signed-off-by: Toshi Kani > > The patch looks mostly good. One nitpick below. Thanks for reviewing all 3 patches! > > --- > > include/linux/ioport.h | 2 + > > kernel/resource.c | 87 ++++++++++++++++++++++++++++++++++++++++++++++++ > > 2 files changed, 89 insertions(+) > > > > diff --git a/include/linux/ioport.h b/include/linux/ioport.h > > index 85ac9b9b..0fe1a82 100644 > > --- a/include/linux/ioport.h > > +++ b/include/linux/ioport.h > > @@ -192,6 +192,8 @@ extern struct resource * __request_region(struct resource *, > > extern int __check_region(struct resource *, resource_size_t, resource_size_t); > > extern void __release_region(struct resource *, resource_size_t, > > resource_size_t); > > +extern int release_mem_region_adjustable(struct resource *, resource_size_t, > > + resource_size_t); > > > > static inline int __deprecated check_region(resource_size_t s, > > resource_size_t n) > > diff --git a/kernel/resource.c b/kernel/resource.c > > index ae246f9..789f160 100644 > > --- a/kernel/resource.c > > +++ b/kernel/resource.c > > @@ -1021,6 +1021,93 @@ void __release_region(struct resource *parent, resource_size_t start, > > } > > EXPORT_SYMBOL(__release_region); > > > > +/** > > + * release_mem_region_adjustable - release a previously reserved memory region > > + * @parent: parent resource descriptor > > + * @start: resource start address > > + * @size: resource region size > > + * > > + * The requested region is released from a currently busy memory resource. > > + * It adjusts the matched busy memory resource accordingly if the requested > > + * region does not match exactly but still fits into. Existing children of > > + * the busy memory resource must be immutable in this request. > > + * > > + * Note, when the busy memory resource gets split into two entries, the code > > + * assumes that all children remain in the lower address entry for simplicity. > > + * Enhance this logic when necessary. > > + */ > > +int release_mem_region_adjustable(struct resource *parent, > > + resource_size_t start, resource_size_t size) > > +{ > > + struct resource **p; > > + struct resource *res, *new; > > + resource_size_t end; > > + int ret = 0; > > + > > + p = &parent->child; > > + end = start + size - 1; > > + > > + write_lock(&resource_lock); > > + > > + while ((res = *p)) { > > + if (res->start > start || res->end < end) { > > + p = &res->sibling; > > + continue; > > + } > > + > > + if (!(res->flags & IORESOURCE_MEM)) { > > + ret = -EINVAL; > > + break; > > + } > > + > > + if (!(res->flags & IORESOURCE_BUSY)) { > > + p = &res->child; > > + continue; > > + } > > + > > + if (res->start == start && res->end == end) { > > + /* free the whole entry */ > > + *p = res->sibling; > > + kfree(res); > > + } else if (res->start == start && res->end != end) { > > + /* adjust the start */ > > + ret = __adjust_resource(res, end+1, > end + 1, Yes, I will update as you suggested. Thanks, -Toshi -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org