On Tue, 29 Jan 2013, xtu4 wrote:
> Subject: [PATCH] [SEQ_FILE] Avoid high order memory allocating with kmalloc
> when read large seq file
>
> currently, when dumpstate access /proc/xxx/binder , this binder include lots
> of info,
> it will use seq_read in kernel, in this function, it will trigger high order
> memory alloc,
> when read binder info or other large file, this will cause memory presure when
> system
> don't have contious high order memory, it will lead to high kswap workload to
> reclaim the
> page. so change kmalloc to vmalloc, it can avoid contiously high order memory
> allocating.
> [ 4356.532357] dumpstate: page allocation failure: order:4, mode:0x40d0
> [ 4356.532400] Pid: 18256, comm: dumpstate Tainted: G C
> 3.0.34-141128-g4be7088 #1
> [ 4356.532416] Call Trace:
> [ 4356.532443] [<c185c836>] ? printk+0x1d/0x1f
> [ 4356.532467] [<c12cde1f>] warn_alloc_failed+0xbf/0xf0
> [ 4356.532491] [<c12d0aba>] __alloc_pages_nodemask+0x4ba/0x6a0
> [ 4356.532521] [<c12d0d1c>] __get_free_pages+0x1c/0x30
> [ 4356.532541] [<c12f51e1>] kmalloc_order_trace+0x21/0xd0
> [ 4356.532561] [<c131d0f7>] ? seq_read+0x137/0x390
> [ 4356.532579] [<c12f549a>] __kmalloc+0x20a/0x230
> [ 4356.532596] [<c131d0f7>] ? seq_read+0x137/0x390
> [ 4356.532616] [<c12d343c>] ? put_page+0x2c/0x40
> [ 4356.532634] [<c12f4a7d>] ? kfree+0xcd/0x160
> [ 4356.532655] [<c18656cd>] ? mutex_unlock+0xd/0x10
> [ 4356.532675] [<c131d109>] seq_read+0x149/0x390
> [ 4356.532697] [<c130062c>] vfs_read+0x8c/0x160
> [ 4356.532716] [<c131cfc0>] ? seq_lseek+0x180/0x180
> [ 4356.532735] [<c130073d>] sys_read+0x3d/0x70
> [ 4356.532755] [<c1866e91>] syscall_call+0x7/0xb
> [ 4356.532777] [<c1860000>] ? log_dir_items+0x33d/0x40c
> Signed-off-by: xiaobing tu <[email protected]>
> Signed-off-by: linX z chen <[email protected]>
> Signed-off-by: guifang tang <[email protected]>
> Change-Id: I892c97d02cf25e59b23c9bc68dff754ea01c1d56
> ---
> fs/seq_file.c | 18 +++++++++++++++---
> 1 files changed, 15 insertions(+), 3 deletions(-)
>
> diff --git a/fs/seq_file.c b/fs/seq_file.c
> index dba43c3..20b8e36 100644
> --- a/fs/seq_file.c
> +++ b/fs/seq_file.c
> @@ -209,8 +209,17 @@ ssize_t seq_read(struct file *file, char __user *buf,
> size_t size, loff_t *ppos)
> if (m->count < m->size)
> goto Fill;
> m->op->stop(m, p);
> - kfree(m->buf);
> - m->buf = kmalloc(m->size <<= 1, GFP_KERNEL);
> + if (m->size > 2 * PAGE_SIZE) {
> + vfree(m->buf);
> + } else
> + kfree(m->buf);
> + m->size <<= 1;
> + if (m->size > 2 * PAGE_SIZE) {
> + m->buf = vmalloc(m->size);
> + } else
> + m->buf = kmalloc(m->size <<= 1, GFP_KERNEL);
I thought m->size was already shifted.
Your patch is severely mangled, please check out
Documentation/SubmittingPatches and Documentation/email-clients.txt.
> +
> +
> if (!m->buf)
> goto Enomem;
> m->count = 0;
> @@ -325,7 +334,10 @@ EXPORT_SYMBOL(seq_lseek);
> int seq_release(struct inode *inode, struct file *file)
> {
> struct seq_file *m = file->private_data;
> - kfree(m->buf);
> + if (m->size > 2 * PAGE_SIZE) {
> + vfree(m->buf);
> + } else
> + kfree(m->buf);
> kfree(m);
> return 0;
> }
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
