From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764974AbXJZQk5 (ORCPT ); Fri, 26 Oct 2007 12:40:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1763927AbXJZQgo (ORCPT ); Fri, 26 Oct 2007 12:36:44 -0400 Received: from waste.org ([66.93.16.53]:56591 "EHLO cinder.waste.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1763369AbXJZQgi (ORCPT ); Fri, 26 Oct 2007 12:36:38 -0400 From: Matt Mackall To: Andrew Morton , linux-kernel@vger.kernel.org X-PatchBomber: http://selenic.com/scripts/mailpatches Cc: Dave Hansen , Rusty Russell , Jeremy Fitzhardinge , David Rientjes , Fengguang Wu In-Reply-To: <1.430487409@selenic.com> Message-Id: <12.430487409@selenic.com> Subject: [PATCH 11/12] maps4: add /proc/kpageflags interface Date: Fri, 26 Oct 2007 11:36:37 -0500 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org From: Matt Mackall This makes a subset of physical page flags available to userspace. Together with /proc/pid/kpagemap, this allows tracking of a wide variety of VM behaviors. Exported flags are decoupled from the kernel's internal flags. This allows us to reorder flag bits, and synthesize any bits that get redefined in terms of other bits. Signed-off-by: Matt Mackall --- Index: l/fs/proc/proc_misc.c =================================================================== --- l.orig/fs/proc/proc_misc.c 2007-10-22 17:53:48.000000000 -0500 +++ l/fs/proc/proc_misc.c 2007-10-22 18:55:25.000000000 -0500 @@ -708,6 +708,84 @@ static struct file_operations proc_kpage .read = kpagecount_read, }; +/* /proc/kpageflags - an array exposing page flags + * + * Each entry is a u64 representing the corresponding + * physical page flags. + */ + +/* These macros are used to decouple internal flags from exported ones */ + +#define KPF_LOCKED 0 +#define KPF_ERROR 1 +#define KPF_REFERENCED 2 +#define KPF_UPTODATE 3 +#define KPF_DIRTY 4 +#define KPF_LRU 5 +#define KPF_ACTIVE 6 +#define KPF_SLAB 7 +#define KPF_WRITEBACK 8 +#define KPF_RECLAIM 9 +#define KPF_BUDDY 10 + +#define kpf_copy_bit(flags, srcpos, dstpos) (((flags >> srcpos) & 1) << dstpos) + +static ssize_t kpageflags_read(struct file *file, char __user *buf, + size_t count, loff_t *ppos) +{ + u64 __user *out = (u64 __user *)buf; + struct page *ppage; + unsigned long src = *ppos; + unsigned long pfn; + ssize_t ret = 0; + u64 kflags, uflags; + + if (!access_ok(VERIFY_WRITE, buf, count)) + return -EFAULT; + + pfn = src / KPMSIZE; + count = min_t(unsigned long, count, (max_pfn * KPMSIZE) - src); + if (src & KPMMASK || count & KPMMASK) + return -EIO; + + while (count > 0) { + ppage = pfn_to_page(pfn++); + if (!ppage) + kflags = 0; + else + kflags = ppage->flags; + + uflags = kpf_copy_bit(KPF_LOCKED, PG_locked, kflags) | + kpf_copy_bit(kflags, KPF_ERROR, PG_error) | + kpf_copy_bit(kflags, KPF_REFERENCED, PG_referenced) | + kpf_copy_bit(kflags, KPF_UPTODATE, PG_uptodate) | + kpf_copy_bit(kflags, KPF_DIRTY, PG_dirty) | + kpf_copy_bit(kflags, KPF_LRU, PG_lru) | + kpf_copy_bit(kflags, KPF_ACTIVE, PG_active) | + kpf_copy_bit(kflags, KPF_SLAB, PG_slab) | + kpf_copy_bit(kflags, KPF_WRITEBACK, PG_writeback) | + kpf_copy_bit(kflags, KPF_RECLAIM, PG_reclaim) | + kpf_copy_bit(kflags, KPF_BUDDY, PG_buddy); + + if (put_user(uflags, out++)) { + ret = -EFAULT; + break; + } + + count -= KPMSIZE; + } + + *ppos += (char __user *)out - buf; + if (!ret) + ret = (char __user *)out - buf; + return ret; +} + +static struct file_operations proc_kpageflags_operations = { + .llseek = mem_lseek, + .read = kpageflags_read, +}; + struct proc_dir_entry *proc_root_kcore; void create_seq_entry(char *name, mode_t mode, const struct file_operations *f) @@ -788,6 +866,7 @@ void __init proc_misc_init(void) } #endif create_seq_entry("kpagecount", S_IRUSR, &proc_kpagecount_operations); + create_seq_entry("kpageflags", S_IRUSR, &proc_kpageflags_operations); #ifdef CONFIG_PROC_VMCORE proc_vmcore = create_proc_entry("vmcore", S_IRUSR, NULL); if (proc_vmcore)