linux-kernel - Re: [PATCH v1 3/3] mm: per-process reclaim

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Date:	Wed, 15 Jun 2016 09:46:33 +0900
From:	Minchan Kim <minchan@...nel.org>
To:	Hillf Danton <hillf.zj@...baba-inc.com>
CC:	linux-kernel <linux-kernel@...r.kernel.org>, <linux-mm@...ck.org>
Subject: Re: [PATCH v1 3/3] mm: per-process reclaim

On Mon, Jun 13, 2016 at 06:07:09PM +0800, Hillf Danton wrote:
> > +static ssize_t reclaim_write(struct file *file, const char __user *buf,
> > +				size_t count, loff_t *ppos)
> > +{
> > +	struct task_struct *task;
> > +	char buffer[PROC_NUMBUF];
> > +	struct mm_struct *mm;
> > +	struct vm_area_struct *vma;
> > +	int itype;
> > +	int rv;
> > +	enum reclaim_type type;
> > +
> > +	memset(buffer, 0, sizeof(buffer));
> > +	if (count > sizeof(buffer) - 1)
> > +		count = sizeof(buffer) - 1;
> > +	if (copy_from_user(buffer, buf, count))
> > +		return -EFAULT;
> > +	rv = kstrtoint(strstrip(buffer), 10, &itype);
> > +	if (rv < 0)
> > +		return rv;
> > +	type = (enum reclaim_type)itype;
> > +	if (type < RECLAIM_FILE || type > RECLAIM_ALL)
> > +		return -EINVAL;
> > +
> > +	task = get_proc_task(file->f_path.dentry->d_inode);
> > +	if (!task)
> > +		return -ESRCH;
> > +
> > +	mm = get_task_mm(task);
> > +	if (mm) {
> > +		struct mm_walk reclaim_walk = {
> > +			.pmd_entry = reclaim_pte_range,
> > +			.mm = mm,
> > +		};
> > +
> > +		down_read(&mm->mmap_sem);
> > +		for (vma = mm->mmap; vma; vma = vma->vm_next) {
> > +			reclaim_walk.private = vma;
> > +
> > +			if (is_vm_hugetlb_page(vma))
> > +				continue;
> > +
> > +			if (!vma_is_anonymous(vma) && !(type & RECLAIM_FILE))
> > +				continue;
> > +
> > +			if (vma_is_anonymous(vma) && !(type & RECLAIM_ANON))
> > +				continue;
> > +
> > +			walk_page_range(vma->vm_start, vma->vm_end,
> > +					&reclaim_walk);
> 
> Check fatal signal after reclaiming a mapping?

Yeb, We might need it in page_walker.

Thanks.