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

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Date:	Mon, 13 Jun 2016 18:07:09 +0800
From:	"Hillf Danton" <hillf.zj@...baba-inc.com>
To:	"'Minchan Kim'" <minchan@...nel.org>
Cc:	"linux-kernel" <linux-kernel@...r.kernel.org>, <linux-mm@...ck.org>
Subject: Re: [PATCH v1 3/3] mm: per-process reclaim

> +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?

> +		}
> +		flush_tlb_mm(mm);
> +		up_read(&mm->mmap_sem);
> +		mmput(mm);
> +	}
> +	put_task_struct(task);
> +
> +	return count;
> +}