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)
Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
---
fs/proc/task_mmu.c | 85 ++++++++++++++++++++++++++++++++++++++++++++----------
mm/Kconfig | 3 ++
2 files changed, 73 insertions(+), 15 deletions(-)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index ccc97b1..61b6bde 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -12,6 +12,7 @@
#include <linux/swap.h>
#include <linux/swapops.h>
#include <linux/mm_inline.h>
+#include <linux/ctype.h>
#include <asm/elf.h>
#include <asm/uaccess.h>
@@ -1239,11 +1240,14 @@ 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)
@@ -1259,42 +1263,93 @@ 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;
- down_read(&mm->mmap_sem);
- for (vma = mm->mmap; vma; vma = vma->vm_next) {
- reclaim_walk.private = vma;
+ reclaim_walk.mm = mm;
+ reclaim_walk.pmd_entry = reclaim_pte_range;
+ down_read(&mm->mmap_sem);
+ 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);
+ &reclaim_walk);
}
- flush_tlb_mm(mm);
- up_read(&mm->mmap_sem);
- mmput(mm);
}
- put_task_struct(task);
+ 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 = {
diff --git a/mm/Kconfig b/mm/Kconfig
index d119b5b..3460da4 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -501,4 +501,7 @@ 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 vaule is ignored.
--
1.8.2.1
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