Messages in this thread Patch in this message | | | Subject | [patch 2/3] only allow nonlinear vmas for ram backed filesystems | From | Miklos Szeredi <> | Date | Sat, 24 Mar 2007 23:09:19 +0100 |
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From: Miklos Szeredi <mszeredi@suse.cz>
Dirty page accounting/limiting doesn't work for nonlinear mappings, so for non-ram backed filesystems emulate with linear mappings. This retains ABI compatibility with previous kernels at minimal code cost.
All known users of nonlinear mappings actually use tmpfs, so this shouldn't have any negative effect.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> ---
Index: linux-2.6.21-rc4-mm1/mm/fremap.c =================================================================== --- linux-2.6.21-rc4-mm1.orig/mm/fremap.c 2007-03-24 22:30:05.000000000 +0100 +++ linux-2.6.21-rc4-mm1/mm/fremap.c 2007-03-24 22:37:59.000000000 +0100 @@ -181,6 +181,24 @@ asmlinkage long sys_remap_file_pages(uns goto retry; } mapping = vma->vm_file->f_mapping; + /* + * page_mkclean doesn't work on nonlinear vmas, so if dirty + * pages need to be accounted, emulate with linear vmas. + */ + if (mapping_cap_account_dirty(mapping)) { + unsigned long addr; + + flags &= MAP_NONBLOCK; + addr = mmap_region(vma->vm_file, start, size, flags, + vma->vm_flags, pgoff, 1); + if (IS_ERR_VALUE(addr)) + err = addr; + else { + BUG_ON(addr != start); + err = 0; + } + goto out; + } spin_lock(&mapping->i_mmap_lock); flush_dcache_mmap_lock(mapping); vma->vm_flags |= VM_NONLINEAR; - 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/
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