From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 14 Mar 2001 21:55:46 +0000 From: Matthew Wilcox Subject: Re: [parisc-linux] [PATCH] Shared mmap [Take 3] Message-ID: <20010314215546.D12200@parcelfarce.linux.theplanet.co.uk> References: <20010312175042.B19848@parcelfarce.linux.theplanet.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20010312175042.B19848@parcelfarce.linux.theplanet.co.uk>; from matthew@wil.cx on Mon, Mar 12, 2001 at 05:50:42PM +0000 Sender: owner-linux-mm@kvack.org Return-Path: To: Matthew Wilcox Cc: linux-mm@kvack.org, parisc-linux@parisc-linux.org List-ID: On Mon, Mar 12, 2001 at 05:50:42PM +0000, Matthew Wilcox wrote: > > This patch changes shared mmaps of files to always be aligned at the > same offset within the processor's d-cache. This fixes PA-RISC & MIPS. > Sparc & IA-64 need some of their support changing, but I don't want to > do that until everyone's had the chance to disagree with my changes :-) What, no comment? no flames, no insults? is this an uncontroversial patch? Anyway, I have some improvements. * use inode->i_mapping->i_mmap_shared to determine whether there are any existing mappings rather than keeping track of it through i_mmap_offset. * take `pgoff' into account. Oops, that was the whole point of the patch. * ensure `offset' is limited to the range [0 .. SHMLBA) this time it's actually tested on PA-RISC. Should work on MIPS too. Sparc & IA-64 will need work. Index: include/linux/fs.h =================================================================== RCS file: /home/cvs/parisc/linux/include/linux/fs.h,v retrieving revision 1.10 diff -u -p -r1.10 fs.h --- fs.h 2001/02/02 03:37:12 1.10 +++ fs.h 2001/03/14 21:11:54 @@ -424,6 +424,7 @@ struct inode { unsigned long i_state; + unsigned int i_mmap_offset; /* Handle L1 d-cache aliasing */ unsigned int i_flags; unsigned char i_sock; Index: include/linux/mm.h =================================================================== RCS file: /home/cvs/parisc/linux/include/linux/mm.h,v retrieving revision 1.16 diff -u -p -r1.16 mm.h --- mm.h 2001/02/08 22:39:19 1.16 +++ mm.h 2001/03/14 21:11:54 @@ -423,6 +423,7 @@ extern void insert_vm_struct(struct mm_s extern void __insert_vm_struct(struct mm_struct *, struct vm_area_struct *); extern void build_mmap_avl(struct mm_struct *); extern void exit_mmap(struct mm_struct *); +extern unsigned long get_shared_area(unsigned long, unsigned long, unsigned int); extern unsigned long get_unmapped_area(unsigned long, unsigned long); extern unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, Index: mm/mmap.c =================================================================== RCS file: /home/cvs/parisc/linux/mm/mmap.c,v retrieving revision 1.19 diff -u -p -r1.19 mmap.c --- mmap.c 2001/02/02 03:37:18 1.19 +++ mmap.c 2001/03/14 21:11:55 @@ -190,6 +190,7 @@ unsigned long do_mmap_pgoff(struct file { struct mm_struct * mm = current->mm; struct vm_area_struct * vma; + struct inode *inode = NULL; int correct_wcount = 0; int error; @@ -223,17 +224,18 @@ unsigned long do_mmap_pgoff(struct file * of the memory object, so we don't do any here. */ if (file != NULL) { + inode = file->f_dentry->d_inode; switch (flags & MAP_TYPE) { case MAP_SHARED: if ((prot & PROT_WRITE) && !(file->f_mode & FMODE_WRITE)) return -EACCES; /* Make sure we don't allow writing to an append-only file.. */ - if (IS_APPEND(file->f_dentry->d_inode) && (file->f_mode & FMODE_WRITE)) + if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE)) return -EACCES; /* make sure there are no mandatory locks on the file. */ - if (locks_verify_locked(file->f_dentry->d_inode)) + if (locks_verify_locked(inode)) return -EAGAIN; /* fall through */ @@ -253,11 +255,20 @@ unsigned long do_mmap_pgoff(struct file if (flags & MAP_FIXED) { if (addr & ~PAGE_MASK) return -EINVAL; + } else if (inode && (flags & MAP_SHARED)) { + if (inode->i_mapping->i_mmap_shared) { + addr = get_shared_area(addr, len, inode->i_mmap_offset + (pgoff << PAGE_SHIFT)); + } else { + addr = get_unmapped_area(addr, len); + if (addr) { + inode->i_mmap_offset = (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1); + } + } } else { addr = get_unmapped_area(addr, len); - if (!addr) - return -ENOMEM; } + if (!addr) + return -ENOMEM; /* Determine the object being mapped and call the appropriate * specific mapper. the address has already been validated, but @@ -348,7 +359,7 @@ unsigned long do_mmap_pgoff(struct file insert_vm_struct(mm, vma); if (correct_wcount) - atomic_inc(&file->f_dentry->d_inode->i_writecount); + atomic_inc(&inode->i_writecount); mm->total_vm += len >> PAGE_SHIFT; if (flags & VM_LOCKED) { @@ -359,7 +370,7 @@ unsigned long do_mmap_pgoff(struct file unmap_and_free_vma: if (correct_wcount) - atomic_inc(&file->f_dentry->d_inode->i_writecount); + atomic_inc(&inode->i_writecount); vma->vm_file = NULL; fput(file); /* Undo any partial mapping done by a device driver. */ @@ -376,6 +387,30 @@ free_vma: * Return value 0 means ENOMEM. */ #ifndef HAVE_ARCH_UNMAPPED_AREA + +#define DCACHE_ALIGN(addr) ((addr) &~ (SHMLBA - 1)) + +unsigned long get_shared_area(unsigned long addr, unsigned long len, unsigned int offset) +{ + struct vm_area_struct *vmm; + offset &= SHMLBA - 1; + + if (len > TASK_SIZE) + return 0; + if (!addr) + addr = TASK_UNMAPPED_BASE; + addr = DCACHE_ALIGN(addr - offset) + offset; + + for (vmm = find_vma(current->mm, addr); ; vmm = vmm->vm_next) { + /* At this point: (!vmm || addr < vmm->vm_end). */ + if (TASK_SIZE - len < addr) + return 0; + if (!vmm || addr + len <= vmm->vm_start) + return addr; + addr = DCACHE_ALIGN(vmm->vm_end - offset) + offset; + } +} + unsigned long get_unmapped_area(unsigned long addr, unsigned long len) { struct vm_area_struct * vmm; Index: mm/mremap.c =================================================================== RCS file: /home/cvs/parisc/linux/mm/mremap.c,v retrieving revision 1.7 diff -u -p -r1.7 mremap.c --- mremap.c 2001/01/25 00:03:36 1.7 +++ mremap.c 2001/03/14 21:11:55 @@ -276,7 +276,11 @@ unsigned long do_mremap(unsigned long ad ret = -ENOMEM; if (flags & MREMAP_MAYMOVE) { if (!(flags & MREMAP_FIXED)) { - new_addr = get_unmapped_area(0, new_len); + if (vma->vm_file && (vma->vm_flags & VM_SHARED)) { + new_addr = get_shared_area(0, new_len, vma->vm_file->f_dentry->d_inode->i_mmap_offset + (vma->vm_pgoff << PAGE_SHIFT)); + } else { + new_addr = get_unmapped_area(0, new_len); + } if (!new_addr) goto out; } _______________________________________________ parisc-linux-cvs mailing list parisc-linux-cvs@lists.parisc-linux.org http://lists.parisc-linux.org/cgi-bin/mailman/listinfo/parisc-linux-cvs -- Revolutions do not require corporate support. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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