Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750725AbVKLA0Q (ORCPT ); Fri, 11 Nov 2005 19:26:16 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750745AbVKLA0Q (ORCPT ); Fri, 11 Nov 2005 19:26:16 -0500 Received: from smtp.osdl.org ([65.172.181.4]:41688 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S1750725AbVKLA0P (ORCPT ); Fri, 11 Nov 2005 19:26:15 -0500 Date: Fri, 11 Nov 2005 16:25:11 -0800 From: Andrew Morton To: Badari Pulavarty Cc: andrea@suse.de, linux-kernel@vger.kernel.org, hugh@veritas.com, dvhltc@us.ibm.com, linux-mm@kvack.org, blaisorblade@yahoo.it, jdike@addtoit.com Subject: Re: [PATCH] 2.6.14 patch for supporting madvise(MADV_REMOVE) Message-Id: <20051111162511.57ee1af3.akpm@osdl.org> In-Reply-To: <1130947957.24503.70.camel@localhost.localdomain> References: <1130366995.23729.38.camel@localhost.localdomain> <20051028034616.GA14511@ccure.user-mode-linux.org> <43624F82.6080003@us.ibm.com> <20051028184235.GC8514@ccure.user-mode-linux.org> <1130544201.23729.167.camel@localhost.localdomain> <20051029025119.GA14998@ccure.user-mode-linux.org> <1130788176.24503.19.camel@localhost.localdomain> <20051101000509.GA11847@ccure.user-mode-linux.org> <1130894101.24503.64.camel@localhost.localdomain> <20051102014321.GG24051@opteron.random> <1130947957.24503.70.camel@localhost.localdomain> X-Mailer: Sylpheed version 1.0.4 (GTK+ 1.2.10; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3677 Lines: 109 Badari Pulavarty wrote: > > +/* > + * Application wants to free up the pages and associated backing store. > + * This is effectively punching a hole into the middle of a file. > + * > + * NOTE: Currently, only shmfs/tmpfs is supported for this operation. > + * Other filesystems return -ENOSYS. > + */ > +static long madvise_remove(struct vm_area_struct * vma, > + unsigned long start, unsigned long end) > +{ > + struct address_space *mapping; > + loff_t offset, endoff; > + > + if (vma->vm_flags & (VM_LOCKED|VM_NONLINEAR|VM_HUGETLB)) > + return -EINVAL; > + > + if (!vma->vm_file || !vma->vm_file->f_mapping > + || !vma->vm_file->f_mapping->host) { > + return -EINVAL; > + } > + > + mapping = vma->vm_file->f_mapping; > + if (mapping == &swapper_space) { > + return -EINVAL; > + } > + > + offset = (loff_t)(start - vma->vm_start) > + + (vma->vm_pgoff << PAGE_SHIFT); > + endoff = (loff_t)(end - vma->vm_start - 1) > + + (vma->vm_pgoff << PAGE_SHIFT); > + return vmtruncate_range(mapping->host, offset, endoff); > +} > + I'm suspecting you tested this on a 64-bit machine, yes? On 32-bit that vm_pgoff shift is going to overflow. Fixes-thus-far below. Please rerun all tests on x86? Why does madvise_remove() have an explicit check for swapper_space? In your testing, how are you determining that the code is successfully removing the correct number of pages, from the correct file offset? diff -puN mm/madvise.c~madvise-remove-remove-pages-from-tmpfs-shm-backing-store-tidy mm/madvise.c --- devel/mm/madvise.c~madvise-remove-remove-pages-from-tmpfs-shm-backing-store-tidy 2005-11-11 16:12:43.000000000 -0800 +++ devel-akpm/mm/madvise.c 2005-11-11 16:16:50.000000000 -0800 @@ -147,8 +147,8 @@ static long madvise_dontneed(struct vm_a * NOTE: Currently, only shmfs/tmpfs is supported for this operation. * Other filesystems return -ENOSYS. */ -static long madvise_remove(struct vm_area_struct * vma, - unsigned long start, unsigned long end) +static long madvise_remove(struct vm_area_struct *vma, + unsigned long start, unsigned long end) { struct address_space *mapping; loff_t offset, endoff; @@ -162,14 +162,13 @@ static long madvise_remove(struct vm_are } mapping = vma->vm_file->f_mapping; - if (mapping == &swapper_space) { + if (mapping == &swapper_space) return -EINVAL; - } offset = (loff_t)(start - vma->vm_start) - + (vma->vm_pgoff << PAGE_SHIFT); + + ((loff_t)vma->vm_pgoff << PAGE_SHIFT); endoff = (loff_t)(end - vma->vm_start - 1) - + (vma->vm_pgoff << PAGE_SHIFT); + + ((loff_t)vma->vm_pgoff << PAGE_SHIFT); return vmtruncate_range(mapping->host, offset, endoff); } diff -puN mm/memory.c~madvise-remove-remove-pages-from-tmpfs-shm-backing-store-tidy mm/memory.c --- devel/mm/memory.c~madvise-remove-remove-pages-from-tmpfs-shm-backing-store-tidy 2005-11-11 16:16:54.000000000 -0800 +++ devel-akpm/mm/memory.c 2005-11-11 16:17:59.000000000 -0800 @@ -1608,10 +1608,9 @@ out_big: out_busy: return -ETXTBSY; } - EXPORT_SYMBOL(vmtruncate); -int vmtruncate_range(struct inode * inode, loff_t offset, loff_t end) +int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end) { struct address_space *mapping = inode->i_mapping; @@ -1634,7 +1633,6 @@ int vmtruncate_range(struct inode * inod return 0; } - EXPORT_SYMBOL(vmtruncate_range); /* _ - 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/