Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932065AbXHQCPf (ORCPT ); Thu, 16 Aug 2007 22:15:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759888AbXHQCP0 (ORCPT ); Thu, 16 Aug 2007 22:15:26 -0400 Received: from waste.org ([66.93.16.53]:35274 "EHLO waste.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758846AbXHQCPY (ORCPT ); Thu, 16 Aug 2007 22:15:24 -0400 Date: Thu, 16 Aug 2007 21:16:17 -0500 From: Matt Mackall To: Fengguang Wu Cc: Andrew Morton , Al Viro , John Berthels , linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/4] maps: address based vma walking Message-ID: <20070817021617.GI30556@waste.org> References: <20070816220516.782145952@mail.ustc.edu.cn> <20070816220849.192029043@mail.ustc.edu.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070816220849.192029043@mail.ustc.edu.cn> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5974 Lines: 204 On Fri, Aug 17, 2007 at 06:05:18AM +0800, Fengguang Wu wrote: > Split large vmas into page groups of proc_maps_private.batch_size bytes, and > iterate them one by one for seqfile->show. This allows us to export large scale > process address space information via the seqfile interface. The old behavior > of walking one vma at a time can be achieved by setting the batching size to > ~0UL. > > Cc: Matt Mackall > Cc: Al Viro > Signed-off-by: Fengguang Wu > --- > fs/proc/task_mmu.c | 105 ++++++++++++-------------------------- > include/linux/proc_fs.h | 6 +- > mm/mempolicy.c | 2 > 3 files changed, 38 insertions(+), 75 deletions(-) > > --- linux-2.6.23-rc2-mm2.orig/include/linux/proc_fs.h > +++ linux-2.6.23-rc2-mm2/include/linux/proc_fs.h > @@ -283,9 +283,9 @@ static inline struct proc_dir_entry *PDE > struct proc_maps_private { > struct pid *pid; > struct task_struct *task; > -#ifdef CONFIG_MMU > - struct vm_area_struct *tail_vma; > -#endif > + struct mm_struct *mm; > + /* walk min(batch_size, remaining_size_of(vma)) bytes at a time */ > + unsigned long batch_size; > }; > > #endif /* _LINUX_PROC_FS_H */ > --- linux-2.6.23-rc2-mm2.orig/mm/mempolicy.c > +++ linux-2.6.23-rc2-mm2/mm/mempolicy.c > @@ -1937,7 +1937,5 @@ out: > seq_putc(m, '\n'); > kfree(md); > > - if (m->count < m->size) > - m->version = (vma != priv->tail_vma) ? vma->vm_start : 0; > return 0; > } What's this bit for? > --- linux-2.6.23-rc2-mm2.orig/fs/proc/task_mmu.c > +++ linux-2.6.23-rc2-mm2/fs/proc/task_mmu.c > @@ -115,99 +115,65 @@ static void pad_len_spaces(struct seq_fi > seq_printf(m, "%*c", len, ' '); > } > > -static void vma_stop(struct proc_maps_private *priv, struct vm_area_struct *vma) > +static void *seek_vma_addr(struct seq_file *m, > + struct vm_area_struct *vma, loff_t *pos) > { > - if (vma && vma != priv->tail_vma) { > - struct mm_struct *mm = vma->vm_mm; > - up_read(&mm->mmap_sem); > - mmput(mm); > - } > + struct proc_maps_private *priv = m->private; > + unsigned long addr = *pos; > + > + if (addr & ~PAGE_MASK) { /* time for next batch */ > + if (vma->vm_end - addr < priv->batch_size) { > + vma = vma->vm_next; > + if (!vma || vma == get_gate_vma(priv->task)) > + goto done; > + } else > + addr = (addr + priv->batch_size) & PAGE_MASK; > + } > + if (addr < vma->vm_start) > + addr = vma->vm_start; > + > + m->version = *pos = addr; > + return vma; > +done: > + return NULL; > } > > static void *m_start(struct seq_file *m, loff_t *pos) > { > struct proc_maps_private *priv = m->private; > - unsigned long last_addr = m->version; > - struct mm_struct *mm; > - struct vm_area_struct *vma, *tail_vma = NULL; > - loff_t l = *pos; > - > - /* Clear the per syscall fields in priv */ > - priv->task = NULL; > - priv->tail_vma = NULL; > - > - /* > - * We remember last_addr rather than next_addr to hit with > - * mmap_cache most of the time. We have zero last_addr at > - * the beginning and also after lseek. We will have -1 last_addr > - * after the end of the vmas. > - */ > - > - if (last_addr == -1UL) > - return NULL; > + struct vm_area_struct *vma; > > + priv->mm = NULL; > priv->task = get_pid_task(priv->pid, PIDTYPE_PID); > if (!priv->task) > return NULL; > > - mm = get_task_mm(priv->task); > - if (!mm) > + priv->mm = get_task_mm(priv->task); > + if (!priv->mm) > return NULL; > > - priv->tail_vma = tail_vma = get_gate_vma(priv->task); > - down_read(&mm->mmap_sem); > + down_read(&priv->mm->mmap_sem); > > - /* Start with last addr hint */ > - if (last_addr && (vma = find_vma(mm, last_addr))) { > - vma = vma->vm_next; > - goto out; > - } > - > - /* > - * Check the vma index is within the range and do > - * sequential scan until m_index. > - */ > - vma = NULL; > - if ((unsigned long)l < mm->map_count) { > - vma = mm->mmap; > - while (l-- && vma) > - vma = vma->vm_next; > - goto out; > - } > - > - if (l != mm->map_count) > - tail_vma = NULL; /* After gate vma */ > - > -out: > - if (vma) > - return vma; > + vma = find_vma(priv->mm, *pos); > + if (!vma || vma == get_gate_vma(priv->task)) > + return NULL; > > - /* End of vmas has been reached */ > - m->version = (tail_vma != NULL)? 0: -1UL; > - up_read(&mm->mmap_sem); > - mmput(mm); > - return tail_vma; > + return seek_vma_addr(m, vma, pos); > } > > static void *m_next(struct seq_file *m, void *v, loff_t *pos) > { > - struct proc_maps_private *priv = m->private; > - struct vm_area_struct *vma = v; > - struct vm_area_struct *tail_vma = priv->tail_vma; > - > (*pos)++; > - if (vma && (vma != tail_vma) && vma->vm_next) > - return vma->vm_next; > - vma_stop(priv, vma); > - return (vma != tail_vma)? tail_vma: NULL; > + return seek_vma_addr(m, v, pos); > } > > static void m_stop(struct seq_file *m, void *v) > { > struct proc_maps_private *priv = m->private; > - struct vm_area_struct *vma = v; > - > - vma_stop(priv, vma); > + if (priv->mm) { > + up_read(&priv->mm->mmap_sem); > + mmput(priv->mm); > + } > if (priv->task) > put_task_struct(priv->task); > } > @@ -220,6 +186,7 @@ static int do_maps_open(struct inode *in > priv = kzalloc(sizeof(*priv), GFP_KERNEL); > if (priv) { > priv->pid = proc_pid(inode); > + priv->batch_size = ~0; > ret = seq_open(file, ops); > if (!ret) { > struct seq_file *m = file->private_data; > @@ -291,8 +258,6 @@ static int show_map(struct seq_file *m, > } > seq_putc(m, '\n'); > > - if (m->count < m->size) /* vma is copied successfully */ > - m->version = (vma != get_gate_vma(task))? vma->vm_start: 0; > return 0; > } -- Mathematics is the supreme nostalgia of our time. - 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/