Messages in this thread | | | Date | Fri, 01 Feb 2013 11:31:12 +0800 | From | xtu4 <> | Subject | Re: resend----[PATCH] Avoid high order memory allocating with kmalloc, when read large seq file |
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On 01/31/2013 02:11 PM, xtu4 wrote: > [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 > > the m->size is very huge > <3>[ 1185.457656, 1] xiaobing >> seq_read: m->size 8192 > <3>[ 1185.463462, 1] xiaobing >> seq_read: m->size 16384 > <3>[ 1185.470472, 1] xiaobing >> seq_read: m->size 32768 > <3>[ 1185.481201, 0] xiaobing >> seq_read: m->size 8192 > <3>[ 1185.488071, 0] xiaobing >> seq_read: m->size 16384 > <3>[ 1185.495892, 0] xiaobing >> seq_read: m->size 32768 > <3>[ 1185.504841, 0] xiaobing >> seq_read: m->size 65536 > <3>[ 1185.517180, 0] xiaobing >> seq_read: m->size 131072 > <3>[ 1185.536286, 0] xiaobing >> seq_read: m->size 262144 > > some times even more then 262144 byte > > Signed-off-by: xiaobing tu <xiaobing.tu@intel.com> > Change-Id: I892c97d02cf25e59b23c9bc68dff754ea01c1d56 > --- > fs/seq_file.c | 22 +++++++++++++++++----- > 1 files changed, 17 insertions(+), 5 deletions(-) > > diff --git a/fs/seq_file.c b/fs/seq_file.c > index dba43c3..19df826 100644 > --- a/fs/seq_file.c > +++ b/fs/seq_file.c > @@ -12,7 +12,7 @@ > > #include <asm/uaccess.h> > #include <asm/page.h> > - > +#include <linux/mm.h> > /** > * seq_open - initialize sequential file > * @file: file we initialize > @@ -116,7 +116,13 @@ static int traverse(struct seq_file *m, loff_t > offset) > Eoverflow: > m->op->stop(m, p); > kfree(m->buf); > - m->buf = kmalloc(m->size <<= 1, GFP_KERNEL); > + > + is_vmalloc_addr(m->buf) ? vfree(m->buf) : kfree(m->buf); > + m->size <<= 1; > + if (m->size <= (2 * PAGE_SIZE)) > + m->buf = kmalloc(m->size, GFP_KERNEL); > + else > + m->buf = vmalloc(m->size); > return !m->buf ? -ENOMEM : -EAGAIN; > } > > @@ -209,8 +215,14 @@ 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); > + is_vmalloc_addr(m->buf) ? vfree(m->buf) : kfree(m->buf); > + m->size <<= 1; > + if (m->size > 2 * PAGE_SIZE) > + m->buf = vmalloc(m->size); > + else > + m->buf = kmalloc(m->size, GFP_KERNEL); > + > + > if (!m->buf) > goto Enomem; > m->count = 0; > @@ -325,7 +337,7 @@ EXPORT_SYMBOL(seq_lseek); > int seq_release(struct inode *inode, struct file *file) > { > struct seq_file *m = file->private_data; > - kfree(m->buf); > + is_vmalloc_addr(m->buf) ? vfree(m->buf) : kfree(m->buf); > kfree(m); > return 0; > }
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