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Commit 635a7edf authored by Minchan Kim's avatar Minchan Kim Committed by Gerrit - the friendly Code Review server
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mm: Support address range reclaim 



This patch adds address range reclaim of a process.
The requirement is following as,

Like webkit1, it uses a address space for handling multi tabs.
IOW, it uses *one* process model so all tabs shares address space
of the process. In such scenario, per-process reclaim is rather
coarse-grained so this patch supports more fine-grained reclaim
for being able to reclaim target address range of the process.
For reclaim target range, you should use following format.

	echo [addr] [size-byte] > /proc/pid/reclaim
The addr should be page-aligned.

So now reclaim konb's interface is following as.

echo file > /proc/pid/reclaim
	reclaim file-backed pages only
echo anon > /proc/pid/reclaim
	reclaim anonymous pages only
echo all > /proc/pid/reclaim
	reclaim all pages
echo 0x100000 8K > /proc/pid/reclaim
	reclaim pages in (0x100000 - 0x102000)

Change-Id: I111131d31be1cfcfa246617b634a9a8bc4078098
Signed-off-by: default avatarMinchan Kim <minchan@kernel.org>
Patch-mainline: linux-mm @ 9 May 2013 08:39:01
[vinmenon@codeaurora.org: trivial merge conflict fixes]
Signed-off-by: default avatarVinayak Menon <vinmenon@codeaurora.org>
parent 5a83f94a

fs/proc/task_mmu.c

+71 −15
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ 
#include <linux/uaccess.h>

#include <linux/pkeys.h>

#include <linux/mm_inline.h>

#include <linux/ctype.h>



#include <asm/elf.h>

#include <asm/tlb.h>
@@ -1689,11 +1690,14 @@ 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];

	char buffer[200];

	struct mm_struct *mm;

	struct vm_area_struct *vma;

	enum reclaim_type type;

	char *type_buf;

	struct mm_walk reclaim_walk = {};

	unsigned long start = 0;

	unsigned long end = 0;



	memset(buffer, 0, sizeof(buffer));

	if (count > sizeof(buffer) - 1)
@@ -1709,42 +1713,94 @@ static ssize_t reclaim_write(struct file *file, const char __user *buf, 
		type = RECLAIM_ANON;

	else if (!strcmp(type_buf, "all"))

		type = RECLAIM_ALL;

	else if (isdigit(*type_buf))

		type = RECLAIM_RANGE;

	else

		return -EINVAL;

		goto out_err;



	if (type == RECLAIM_RANGE) {

		char *token;

		unsigned long long len, len_in, tmp;



		token = strsep(&type_buf, " ");

		if (!token)

			goto out_err;

		tmp = memparse(token, &token);

		if (tmp & ~PAGE_MASK || tmp > ULONG_MAX)

			goto out_err;

		start = tmp;



		token = strsep(&type_buf, " ");

		if (!token)

			goto out_err;

		len_in = memparse(token, &token);

		len = (len_in + ~PAGE_MASK) & PAGE_MASK;

		if (len > ULONG_MAX)

			goto out_err;

		/*

		 * Check to see whether len was rounded up from small -ve

		 * to zero.

		 */

		if (len_in && !len)

			goto out_err;



		end = start + len;

		if (end < start)

			goto out_err;

	}



	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,

		};

	if (!mm)

		goto out;



	reclaim_walk.mm = mm;

	reclaim_walk.pmd_entry = reclaim_pte_range;



	down_read(&mm->mmap_sem);

		for (vma = mm->mmap; vma; vma = vma->vm_next) {

			reclaim_walk.private = vma;

	if (type == RECLAIM_RANGE) {

		vma = find_vma(mm, start);

		while (vma) {

			if (vma->vm_start > end)

				break;

			if (is_vm_hugetlb_page(vma))

				continue;



			reclaim_walk.private = vma;

			walk_page_range(max(vma->vm_start, start),

					min(vma->vm_end, end),

					&reclaim_walk);

			vma = vma->vm_next;

		}

	} else {

		for (vma = mm->mmap; vma; vma = vma->vm_next) {

			if (is_vm_hugetlb_page(vma))

				continue;



			if (type == RECLAIM_ANON && vma->vm_file)

				continue;



			if (type == RECLAIM_FILE && !vma->vm_file)

				continue;



			reclaim_walk.private = vma;

			walk_page_range(vma->vm_start, vma->vm_end,

				&reclaim_walk);

		}

	}



	flush_tlb_mm(mm);

	up_read(&mm->mmap_sem);

	mmput(mm);

	}

out:

	put_task_struct(task);



	return count;



out_err:

	return -EINVAL;

}



const struct file_operations proc_reclaim_operations = {

mm/Kconfig

+3 −0
Original line number Diff line number Diff line
@@ -828,4 +828,7 @@ config PROCESS_RECLAIM 
	 (echo anon > /proc/PID/reclaim) reclaims anonymous pages only.

	 (echo all > /proc/PID/reclaim) reclaims all pages.



	 (echo addr size-byte > /proc/PID/reclaim) reclaims pages in

	 (addr, addr + size-bytes) of the process.



	 Any other value is ignored.