From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx122.postini.com [74.125.245.122]) by kanga.kvack.org (Postfix) with SMTP id CCFF16B0083 for ; Tue, 14 May 2013 12:43:16 -0400 (EDT) Date: Tue, 14 May 2013 12:42:55 -0400 From: Vivek Goyal Subject: Re: [PATCH v5 6/8] vmcore: treat memory chunks referenced by PT_LOAD program header entries in page-size boundary in vmcore_list Message-ID: <20130514164255.GI13674@redhat.com> References: <20130514015622.18697.77191.stgit@localhost6.localdomain6> <20130514015740.18697.67638.stgit@localhost6.localdomain6> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130514015740.18697.67638.stgit@localhost6.localdomain6> Sender: owner-linux-mm@kvack.org List-ID: To: HATAYAMA Daisuke Cc: ebiederm@xmission.com, akpm@linux-foundation.org, cpw@sgi.com, kumagai-atsushi@mxc.nes.nec.co.jp, lisa.mitchell@hp.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, zhangyanfei@cn.fujitsu.com, jingbai.ma@hp.com, linux-mm@kvack.org On Tue, May 14, 2013 at 10:57:40AM +0900, HATAYAMA Daisuke wrote: > Treat memory chunks referenced by PT_LOAD program header entries in > page-size boundary in vmcore_list. Formally, for each range [start, > end], we set up the corresponding vmcore object in vmcore_list to > [rounddown(start, PAGE_SIZE), roundup(end, PAGE_SIZE)]. > > This change affects layout of /proc/vmcore. The gaps generated by the > rearrangement are newly made visible to applications as > holes. Concretely, they are two ranges [rounddown(start, PAGE_SIZE), > start] and [end, roundup(end, PAGE_SIZE)]. > > Suppose variable m points at a vmcore object in vmcore_list, and > variable phdr points at the program header of PT_LOAD type the > variable m corresponds to. Then, pictorially: > > m->offset +---------------+ > | hole | > phdr->p_offset = +---------------+ > m->offset + (paddr - start) | |\ > | kernel memory | phdr->p_memsz > | |/ > +---------------+ > | hole | > m->offset + m->size +---------------+ > > where m->offset and m->offset + m->size are always page-size aligned. > > Signed-off-by: HATAYAMA Daisuke Looks good to me. I think this patch could be higher up in the series. Acked-by: Vivek Goyal Vivek > --- > > fs/proc/vmcore.c | 30 ++++++++++++++++++++++-------- > 1 files changed, 22 insertions(+), 8 deletions(-) > > diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c > index 795efd2..eb7ff29 100644 > --- a/fs/proc/vmcore.c > +++ b/fs/proc/vmcore.c > @@ -504,20 +504,27 @@ static int __init process_ptload_program_headers_elf64(char *elfptr, > vmcore_off = elfsz + elfnotesegsz; > > for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) { > + u64 paddr, start, end, size; > + > if (phdr_ptr->p_type != PT_LOAD) > continue; > > + paddr = phdr_ptr->p_offset; > + start = rounddown(paddr, PAGE_SIZE); > + end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE); > + size = end - start; > + > /* Add this contiguous chunk of memory to vmcore list.*/ > new = get_new_element(); > if (!new) > return -ENOMEM; > - new->paddr = phdr_ptr->p_offset; > - new->size = phdr_ptr->p_memsz; > + new->paddr = start; > + new->size = size; > list_add_tail(&new->list, vc_list); > > /* Update the program header offset. */ > - phdr_ptr->p_offset = vmcore_off; > - vmcore_off = vmcore_off + phdr_ptr->p_memsz; > + phdr_ptr->p_offset = vmcore_off + (paddr - start); > + vmcore_off = vmcore_off + size; > } > return 0; > } > @@ -540,20 +547,27 @@ static int __init process_ptload_program_headers_elf32(char *elfptr, > vmcore_off = elfsz + elfnotesegsz; > > for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) { > + u64 paddr, start, end, size; > + > if (phdr_ptr->p_type != PT_LOAD) > continue; > > + paddr = phdr_ptr->p_offset; > + start = rounddown(paddr, PAGE_SIZE); > + end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE); > + size = end - start; > + > /* Add this contiguous chunk of memory to vmcore list.*/ > new = get_new_element(); > if (!new) > return -ENOMEM; > - new->paddr = phdr_ptr->p_offset; > - new->size = phdr_ptr->p_memsz; > + new->paddr = start; > + new->size = size; > list_add_tail(&new->list, vc_list); > > /* Update the program header offset */ > - phdr_ptr->p_offset = vmcore_off; > - vmcore_off = vmcore_off + phdr_ptr->p_memsz; > + phdr_ptr->p_offset = vmcore_off + (paddr - start); > + vmcore_off = vmcore_off + size; > } > return 0; > } -- 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