Re: [PATCH v2 5/6] mm: Support address range reclaim

Minchan Kim
2013-04-25T00:50:54Z

Hey Namhyung,

On Wed, Apr 24, 2013 at 08:01:48PM +0900, Namhyung Kim wrote:
> Hi Minchan,
>
> On Wed, 24 Apr 2013 10:41:03 +0900, Minchan Kim wrote:
> > 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
> >
> > 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 $((1<<20)) 8192 > /proc/pid/reclaim
> > reclaim pages in (0x100000 - 0x102000)
> >
> > Signed-off-by: Minchan Kim <minchan@kernel.org>
> > ---
> > fs/proc/task_mmu.c | 88 ++++++++++++++++++++++++++++++++++++++++++++----------
> > mm/internal.h | 3 ++
> > 2 files changed, 76 insertions(+), 15 deletions(-)
> >
> > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
> > index 79b674e..dff9756 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 +1263,96 @@ 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) {
> > + int ret;
> > + size_t len;
> > + unsigned long len_in;
> > + char *token;
> > +
> > + token = strsep(&type_buf, " ");
> > + if (!token)
> > + goto out_err;
> > + ret = kstrtoul(token, 10, &start);
>
> Why not using
>
> start = memparse(token, NULL);
>
> to support something like:
>
> # echo 0x100000 8K > /proc/pid/reclaim
>

Because I'm brain-damage. :(
Thanks for noticing useful function.

>
> Thanks,
> Namhyung
>
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--
Kind regards,
Minchan Kim