<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/fs/hfs/super.c, branch v3.4.54</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>switch open-coded instances of d_make_root() to new helper</title>
<updated>2012-03-21T01:29:35+00:00</updated>
<author>
<name>Al Viro</name>
<email>viro@zeniv.linux.org.uk</email>
</author>
<published>2012-01-09T03:15:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=48fde701aff662559b38d9a609574068f22d00fe'/>
<id>48fde701aff662559b38d9a609574068f22d00fe</id>
<content type='text'>
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>vfs: switch -&gt;show_options() to struct dentry *</title>
<updated>2012-01-07T04:19:54+00:00</updated>
<author>
<name>Al Viro</name>
<email>viro@zeniv.linux.org.uk</email>
</author>
<published>2011-12-09T02:32:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=34c80b1d93e6e20ca9dea0baf583a5b5510d92d4'/>
<id>34c80b1d93e6e20ca9dea0baf583a5b5510d92d4</id>
<content type='text'>
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>vfs: fix the stupidity with i_dentry in inode destructors</title>
<updated>2012-01-04T03:52:40+00:00</updated>
<author>
<name>Al Viro</name>
<email>viro@zeniv.linux.org.uk</email>
</author>
<published>2011-12-12T20:51:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=6b520e0565422966cdf1c3759bd73df77b0f248c'/>
<id>6b520e0565422966cdf1c3759bd73df77b0f248c</id>
<content type='text'>
Seeing that just about every destructor got that INIT_LIST_HEAD() copied into
it, there is no point whatsoever keeping this INIT_LIST_HEAD in inode_init_once();
the cost of taking it into inode_init_always() will be negligible for pipes
and sockets and negative for everything else.  Not to mention the removal of
boilerplate code from -&gt;destroy_inode() instances...

Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Seeing that just about every destructor got that INIT_LIST_HEAD() copied into
it, there is no point whatsoever keeping this INIT_LIST_HEAD in inode_init_once();
the cost of taking it into inode_init_always() will be negligible for pipes
and sockets and negative for everything else.  Not to mention the removal of
boilerplate code from -&gt;destroy_inode() instances...

Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>switch hfs</title>
<updated>2011-01-13T01:02:45+00:00</updated>
<author>
<name>Al Viro</name>
<email>viro@zeniv.linux.org.uk</email>
</author>
<published>2010-12-18T16:19:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=518c79d28e22f657fec399ef5bf0d50b13f7e9b0'/>
<id>518c79d28e22f657fec399ef5bf0d50b13f7e9b0</id>
<content type='text'>
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>fs: dcache reduce branches in lookup path</title>
<updated>2011-01-07T06:50:28+00:00</updated>
<author>
<name>Nick Piggin</name>
<email>npiggin@kernel.dk</email>
</author>
<published>2011-01-07T06:49:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=fb045adb99d9b7c562dc7fef834857f78249daa1'/>
<id>fb045adb99d9b7c562dc7fef834857f78249daa1</id>
<content type='text'>
Reduce some branches and memory accesses in dcache lookup by adding dentry
flags to indicate common d_ops are set, rather than having to check them.
This saves a pointer memory access (dentry-&gt;d_op) in common path lookup
situations, and saves another pointer load and branch in cases where we
have d_op but not the particular operation.

Patched with:

git grep -E '[.&gt;]([[:space:]])*d_op([[:space:]])*=' | xargs sed -e 's/\([^\t ]*\)-&gt;d_op = \(.*\);/d_set_d_op(\1, \2);/' -e 's/\([^\t ]*\)\.d_op = \(.*\);/d_set_d_op(\&amp;\1, \2);/' -i

Signed-off-by: Nick Piggin &lt;npiggin@kernel.dk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Reduce some branches and memory accesses in dcache lookup by adding dentry
flags to indicate common d_ops are set, rather than having to check them.
This saves a pointer memory access (dentry-&gt;d_op) in common path lookup
situations, and saves another pointer load and branch in cases where we
have d_op but not the particular operation.

Patched with:

git grep -E '[.&gt;]([[:space:]])*d_op([[:space:]])*=' | xargs sed -e 's/\([^\t ]*\)-&gt;d_op = \(.*\);/d_set_d_op(\1, \2);/' -e 's/\([^\t ]*\)\.d_op = \(.*\);/d_set_d_op(\&amp;\1, \2);/' -i

Signed-off-by: Nick Piggin &lt;npiggin@kernel.dk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>fs: icache RCU free inodes</title>
<updated>2011-01-07T06:50:26+00:00</updated>
<author>
<name>Nick Piggin</name>
<email>npiggin@kernel.dk</email>
</author>
<published>2011-01-07T06:49:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=fa0d7e3de6d6fc5004ad9dea0dd6b286af8f03e9'/>
<id>fa0d7e3de6d6fc5004ad9dea0dd6b286af8f03e9</id>
<content type='text'>
RCU free the struct inode. This will allow:

- Subsequent store-free path walking patch. The inode must be consulted for
  permissions when walking, so an RCU inode reference is a must.
- sb_inode_list_lock to be moved inside i_lock because sb list walkers who want
  to take i_lock no longer need to take sb_inode_list_lock to walk the list in
  the first place. This will simplify and optimize locking.
- Could remove some nested trylock loops in dcache code
- Could potentially simplify things a bit in VM land. Do not need to take the
  page lock to follow page-&gt;mapping.

The downsides of this is the performance cost of using RCU. In a simple
creat/unlink microbenchmark, performance drops by about 10% due to inability to
reuse cache-hot slab objects. As iterations increase and RCU freeing starts
kicking over, this increases to about 20%.

In cases where inode lifetimes are longer (ie. many inodes may be allocated
during the average life span of a single inode), a lot of this cache reuse is
not applicable, so the regression caused by this patch is smaller.

The cache-hot regression could largely be avoided by using SLAB_DESTROY_BY_RCU,
however this adds some complexity to list walking and store-free path walking,
so I prefer to implement this at a later date, if it is shown to be a win in
real situations. I haven't found a regression in any non-micro benchmark so I
doubt it will be a problem.

Signed-off-by: Nick Piggin &lt;npiggin@kernel.dk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
RCU free the struct inode. This will allow:

- Subsequent store-free path walking patch. The inode must be consulted for
  permissions when walking, so an RCU inode reference is a must.
- sb_inode_list_lock to be moved inside i_lock because sb list walkers who want
  to take i_lock no longer need to take sb_inode_list_lock to walk the list in
  the first place. This will simplify and optimize locking.
- Could remove some nested trylock loops in dcache code
- Could potentially simplify things a bit in VM land. Do not need to take the
  page lock to follow page-&gt;mapping.

The downsides of this is the performance cost of using RCU. In a simple
creat/unlink microbenchmark, performance drops by about 10% due to inability to
reuse cache-hot slab objects. As iterations increase and RCU freeing starts
kicking over, this increases to about 20%.

In cases where inode lifetimes are longer (ie. many inodes may be allocated
during the average life span of a single inode), a lot of this cache reuse is
not applicable, so the regression caused by this patch is smaller.

The cache-hot regression could largely be avoided by using SLAB_DESTROY_BY_RCU,
however this adds some complexity to list walking and store-free path walking,
so I prefer to implement this at a later date, if it is shown to be a win in
real situations. I haven't found a regression in any non-micro benchmark so I
doubt it will be a problem.

Signed-off-by: Nick Piggin &lt;npiggin@kernel.dk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>new helper: mount_bdev()</title>
<updated>2010-10-29T08:16:13+00:00</updated>
<author>
<name>Al Viro</name>
<email>viro@zeniv.linux.org.uk</email>
</author>
<published>2010-07-24T20:46:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=152a08366671080f27b32e0c411ad620c5f88b57'/>
<id>152a08366671080f27b32e0c411ad620c5f88b57</id>
<content type='text'>
... and switch of the obvious get_sb_bdev() users to -&gt;mount()

Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
... and switch of the obvious get_sb_bdev() users to -&gt;mount()

Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>switch hfs to hlist_add_fake()</title>
<updated>2010-10-26T01:24:16+00:00</updated>
<author>
<name>Al Viro</name>
<email>viro@zeniv.linux.org.uk</email>
</author>
<published>2010-10-23T19:26:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=89b0fc38cca4e6c92a90b58960881ffc5dddd89c'/>
<id>89b0fc38cca4e6c92a90b58960881ffc5dddd89c</id>
<content type='text'>
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>BKL: Remove BKL from HFS</title>
<updated>2010-10-04T19:10:39+00:00</updated>
<author>
<name>Jan Blunck</name>
<email>jblunck@infradead.org</email>
</author>
<published>2010-02-24T12:25:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=8526fb37c907f8f4eb9965367af6aeec76aedbce'/>
<id>8526fb37c907f8f4eb9965367af6aeec76aedbce</id>
<content type='text'>
The BKL is only used in put_super and fill_super that are both protected by
the superblocks s_umount rw_semaphore. Therefore it is safe to remove the
BKL entirely.

Signed-off-by: Jan Blunck &lt;jblunck@infradead.org&gt;
Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The BKL is only used in put_super and fill_super that are both protected by
the superblocks s_umount rw_semaphore. Therefore it is safe to remove the
BKL entirely.

Signed-off-by: Jan Blunck &lt;jblunck@infradead.org&gt;
Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>BKL: Explicitly add BKL around get_sb/fill_super</title>
<updated>2010-10-04T19:10:10+00:00</updated>
<author>
<name>Jan Blunck</name>
<email>jblunck@infradead.org</email>
</author>
<published>2010-08-15T20:51:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=db71922217a214e5c9268448e537b54fc1f301ea'/>
<id>db71922217a214e5c9268448e537b54fc1f301ea</id>
<content type='text'>
This patch is a preparation necessary to remove the BKL from do_new_mount().
It explicitly adds calls to lock_kernel()/unlock_kernel() around
get_sb/fill_super operations for filesystems that still uses the BKL.

I've read through all the code formerly covered by the BKL inside
do_kern_mount() and have satisfied myself that it doesn't need the BKL
any more.

do_kern_mount() is already called without the BKL when mounting the rootfs
and in nfsctl. do_kern_mount() calls vfs_kern_mount(), which is called
from various places without BKL: simple_pin_fs(), nfs_do_clone_mount()
through nfs_follow_mountpoint(), afs_mntpt_do_automount() through
afs_mntpt_follow_link(). Both later functions are actually the filesystems
follow_link inode operation. vfs_kern_mount() is calling the specified
get_sb function and lets the filesystem do its job by calling the given
fill_super function.

Therefore I think it is safe to push down the BKL from the VFS to the
low-level filesystems get_sb/fill_super operation.

[arnd: do not add the BKL to those file systems that already
       don't use it elsewhere]

Signed-off-by: Jan Blunck &lt;jblunck@infradead.org&gt;
Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Cc: Matthew Wilcox &lt;matthew@wil.cx&gt;
Cc: Christoph Hellwig &lt;hch@infradead.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This patch is a preparation necessary to remove the BKL from do_new_mount().
It explicitly adds calls to lock_kernel()/unlock_kernel() around
get_sb/fill_super operations for filesystems that still uses the BKL.

I've read through all the code formerly covered by the BKL inside
do_kern_mount() and have satisfied myself that it doesn't need the BKL
any more.

do_kern_mount() is already called without the BKL when mounting the rootfs
and in nfsctl. do_kern_mount() calls vfs_kern_mount(), which is called
from various places without BKL: simple_pin_fs(), nfs_do_clone_mount()
through nfs_follow_mountpoint(), afs_mntpt_do_automount() through
afs_mntpt_follow_link(). Both later functions are actually the filesystems
follow_link inode operation. vfs_kern_mount() is calling the specified
get_sb function and lets the filesystem do its job by calling the given
fill_super function.

Therefore I think it is safe to push down the BKL from the VFS to the
low-level filesystems get_sb/fill_super operation.

[arnd: do not add the BKL to those file systems that already
       don't use it elsewhere]

Signed-off-by: Jan Blunck &lt;jblunck@infradead.org&gt;
Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Cc: Matthew Wilcox &lt;matthew@wil.cx&gt;
Cc: Christoph Hellwig &lt;hch@infradead.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
