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* [PATCH V5 1/2] btrfs: use GFP_NOFS instead of GFP_KERNEL
@ 2011-03-24 11:41 Miao Xie
  2011-03-24 23:07 ` David Sterba
  0 siblings, 1 reply; 3+ messages in thread
From: Miao Xie @ 2011-03-24 11:41 UTC (permalink / raw)
  To: Chris Mason; +Cc: Linux Btrfs, Itaru Kitayama, Ito, David Sterba

In the filesystem context, we must allocate memory by GFP_NOFS,
or we may start another filesystem operation and make kswap thread hang up.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
---
 fs/btrfs/extent-tree.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index f1db57d..42061d2 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -471,7 +471,7 @@ static int cache_block_group(struct btrfs_block_group_cache *cache,
 	if (load_cache_only)
 		return 0;
 
-	caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_KERNEL);
+	caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 	BUG_ON(!caching_ctl);
 
 	INIT_LIST_HEAD(&caching_ctl->list);
@@ -1743,7 +1743,7 @@ static int remove_extent_backref(struct btrfs_trans_handle *trans,
 static void btrfs_issue_discard(struct block_device *bdev,
 				u64 start, u64 len)
 {
-	blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_KERNEL,
+	blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_NOFS,
 			BLKDEV_IFL_WAIT | BLKDEV_IFL_BARRIER);
 }
 
-- 
1.7.3.1

^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [PATCH V5 1/2] btrfs: use GFP_NOFS instead of GFP_KERNEL
  2011-03-24 11:41 [PATCH V5 1/2] btrfs: use GFP_NOFS instead of GFP_KERNEL Miao Xie
@ 2011-03-24 23:07 ` David Sterba
  2011-03-25  1:56   ` Miao Xie
  0 siblings, 1 reply; 3+ messages in thread
From: David Sterba @ 2011-03-24 23:07 UTC (permalink / raw)
  To: Miao Xie; +Cc: Chris Mason, Linux Btrfs, Itaru Kitayama, Ito, David Sterba

Hi,

On Thu, Mar 24, 2011 at 07:41:21PM +0800, Miao Xie wrote:
> In the filesystem context, we must allocate memory by GFP_NOFS,
> or we may start another filesystem operation and make kswap thread hang up.

indeed. Did you check for other GFP_KERNEL allocations? I've found 8 more
them and at least these look like candidates for GFP_NOFS too:

diff --git a/fs/btrfs/acl.c b/fs/btrfs/acl.c
index de34bfa..76b9218 100644
--- a/fs/btrfs/acl.c
+++ b/fs/btrfs/acl.c
@@ -289,7 +289,7 @@ int btrfs_acl_chmod(struct inode *inode)
        if (IS_ERR(acl) || !acl)
                return PTR_ERR(acl);

-       clone = posix_acl_clone(acl, GFP_KERNEL);
+       clone = posix_acl_clone(acl, GFP_NOFS);
        posix_acl_release(acl);
        if (!clone)
                return -ENOMEM;
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index f447b78..eb5c01d 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -998,7 +998,7 @@ static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
        nrptrs = min((iov_iter_count(&i) + PAGE_CACHE_SIZE - 1) /
                     PAGE_CACHE_SIZE, PAGE_CACHE_SIZE /
                     (sizeof(struct page *)));
-       pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
+       pages = kmalloc(nrptrs * sizeof(struct page *), GFP_NOFS);
        if (!pages) {
                ret = -ENOMEM;
                goto out;
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index d1bace3..e9b9648 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1644,7 +1644,7 @@ static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
                        goto out;
                }

-               range = kzalloc(sizeof(*range), GFP_KERNEL);
+               range = kzalloc(sizeof(*range), GFP_NOFS);
                if (!range) {
                        ret = -ENOMEM;
                        goto out;
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index d39a989..5e0fff7 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -399,7 +399,7 @@ static int btrfs_parse_early_options(const char *options, fmode_t flags,
         * strsep changes the string, duplicate it because parse_options
         * gets called twice
         */
-       opts = kstrdup(options, GFP_KERNEL);
+       opts = kstrdup(options, GFP_NOFS);
        if (!opts)
                return -ENOMEM;
        orig = opts;
@@ -446,7 +446,7 @@ static int btrfs_parse_early_options(const char *options, fmode_t flags,
         * mount path doesn't care if it's the default volume or another one.
         */
        if (!*subvol_name) {
-               *subvol_name = kstrdup(".", GFP_KERNEL);
+               *subvol_name = kstrdup(".", GFP_NOFS);
                if (!*subvol_name)
                        return -ENOMEM;
        }


dave

^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [PATCH V5 1/2] btrfs: use GFP_NOFS instead of GFP_KERNEL
  2011-03-24 23:07 ` David Sterba
@ 2011-03-25  1:56   ` Miao Xie
  0 siblings, 0 replies; 3+ messages in thread
From: Miao Xie @ 2011-03-25  1:56 UTC (permalink / raw)
  To: Chris Mason, Linux Btrfs, Itaru Kitayama, Ito, David Sterba

On Fri, 25 Mar 2011 00:07:59 +0100, David Sterba wrote:
> On Thu, Mar 24, 2011 at 07:41:21PM +0800, Miao Xie wrote:
>> In the filesystem context, we must allocate memory by GFP_NOFS,
>> or we may start another filesystem operation and make kswap thread hang up.
> 
> indeed. Did you check for other GFP_KERNEL allocations? I've found 8 more
> them and at least these look like candidates for GFP_NOFS too:

I just fix the ones, which should use GFP_NOFS.

I think not all of the GFP_KERNEL allocations are wrong, if we don't hold
any btrfs's lock except relative inode's i_mutex and not in the context of
the transaction, we can use GFP_KERNEL. So the following GFP_KERNEL allocations
are right, I think.

Thanks
Miao

> 
> diff --git a/fs/btrfs/acl.c b/fs/btrfs/acl.c
> index de34bfa..76b9218 100644
> --- a/fs/btrfs/acl.c
> +++ b/fs/btrfs/acl.c
> @@ -289,7 +289,7 @@ int btrfs_acl_chmod(struct inode *inode)
>         if (IS_ERR(acl) || !acl)
>                 return PTR_ERR(acl);
> 
> -       clone = posix_acl_clone(acl, GFP_KERNEL);
> +       clone = posix_acl_clone(acl, GFP_NOFS);
>         posix_acl_release(acl);
>         if (!clone)
>                 return -ENOMEM;
> diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
> index f447b78..eb5c01d 100644
> --- a/fs/btrfs/file.c
> +++ b/fs/btrfs/file.c
> @@ -998,7 +998,7 @@ static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
>         nrptrs = min((iov_iter_count(&i) + PAGE_CACHE_SIZE - 1) /
>                      PAGE_CACHE_SIZE, PAGE_CACHE_SIZE /
>                      (sizeof(struct page *)));
> -       pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
> +       pages = kmalloc(nrptrs * sizeof(struct page *), GFP_NOFS);
>         if (!pages) {
>                 ret = -ENOMEM;
>                 goto out;
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index d1bace3..e9b9648 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -1644,7 +1644,7 @@ static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
>                         goto out;
>                 }
> 
> -               range = kzalloc(sizeof(*range), GFP_KERNEL);
> +               range = kzalloc(sizeof(*range), GFP_NOFS);
>                 if (!range) {
>                         ret = -ENOMEM;
>                         goto out;
> diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
> index d39a989..5e0fff7 100644
> --- a/fs/btrfs/super.c
> +++ b/fs/btrfs/super.c
> @@ -399,7 +399,7 @@ static int btrfs_parse_early_options(const char *options, fmode_t flags,
>          * strsep changes the string, duplicate it because parse_options
>          * gets called twice
>          */
> -       opts = kstrdup(options, GFP_KERNEL);
> +       opts = kstrdup(options, GFP_NOFS);
>         if (!opts)
>                 return -ENOMEM;
>         orig = opts;
> @@ -446,7 +446,7 @@ static int btrfs_parse_early_options(const char *options, fmode_t flags,
>          * mount path doesn't care if it's the default volume or another one.
>          */
>         if (!*subvol_name) {
> -               *subvol_name = kstrdup(".", GFP_KERNEL);
> +               *subvol_name = kstrdup(".", GFP_NOFS);
>                 if (!*subvol_name)
>                         return -ENOMEM;
>         }
> 
> 
> dave
> 


^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2011-03-25  1:56 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2011-03-24 11:41 [PATCH V5 1/2] btrfs: use GFP_NOFS instead of GFP_KERNEL Miao Xie
2011-03-24 23:07 ` David Sterba
2011-03-25  1:56   ` Miao Xie

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