From: Miles Chen <miles.chen@mediatek.com>
To: Joe Perches <joe@perches.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>,
<linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>,
<wsd_upstream@mediatek.com>, <linux-mediatek@lists.infradead.org>,
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] mm/page_owner: use vmalloc instead of kmalloc
Date: Fri, 26 Oct 2018 16:01:07 +0800 [thread overview]
Message-ID: <1540540867.21297.2.camel@mtkswgap22> (raw)
In-Reply-To: <e0cd65fdd6afc17b2be9b3ac64d50b95b2c2f32e.camel@perches.com>
On Thu, 2018-10-25 at 11:44 -0700, Joe Perches wrote:
> On Fri, 2018-10-26 at 02:34 +0800, miles.chen@mediatek.com wrote:
> > From: Miles Chen <miles.chen@mediatek.com>
> >
> > The kbuf used by page owner is allocated by kmalloc(),
> > which means it can use only normal memory and there might
> > be a "out of memory" issue when we're out of normal memory.
> >
> > Use vmalloc() so we can also allocate kbuf from highmem
> > on 32bit kernel.
>
> If this is really necessary, using kvmalloc/kvfree would
> be better as the vmalloc space is also limited.
thanks for the advise.
kvmalloc/kvfree is better here.
>
> > diff --git a/mm/page_owner.c b/mm/page_owner.c
> []
> > @@ -1,7 +1,6 @@
> > // SPDX-License-Identifier: GPL-2.0
> > #include <linux/debugfs.h>
> > #include <linux/mm.h>
> > -#include <linux/slab.h>
> > #include <linux/uaccess.h>
> > #include <linux/bootmem.h>
> > #include <linux/stacktrace.h>
> > @@ -10,6 +9,7 @@
> > #include <linux/migrate.h>
> > #include <linux/stackdepot.h>
> > #include <linux/seq_file.h>
> > +#include <linux/vmalloc.h>
> >
> > #include "internal.h"
> >
> > @@ -351,7 +351,7 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn,
> > .skip = 0
> > };
> >
> > - kbuf = kmalloc(count, GFP_KERNEL);
> > + kbuf = vmalloc(count);
> > if (!kbuf)
> > return -ENOMEM;
> >
> > @@ -397,11 +397,11 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn,
> > if (copy_to_user(buf, kbuf, ret))
> > ret = -EFAULT;
> >
> > - kfree(kbuf);
> > + vfree(kbuf);
> > return ret;
> >
> > err:
> > - kfree(kbuf);
> > + vfree(kbuf);
> > return -ENOMEM;
> > }
> >
>
next prev parent reply other threads:[~2018-10-26 8:01 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-25 18:34 [PATCH] mm/page_owner: use vmalloc instead of kmalloc miles.chen
2018-10-25 18:44 ` Joe Perches
2018-10-26 8:01 ` Miles Chen [this message]
2018-10-25 19:27 ` Matthew Wilcox
2018-10-26 8:50 ` Miles Chen
2018-10-26 10:56 ` Michal Hocko
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