On-disk data corruption could cause a page link to have its i_size set
to PAGE_SIZE (or a multiple thereof) and its contents all non-NUL.
NUL-terminate the link name to ensure this doesn't cause further
problems for the kernel.
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Duane Griffin <duaneg@dghda.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
struct dentry is one of the most critical structures in the kernel. So it's
sad to see it going neglected.
With CONFIG_PROFILING turned on (which is probably the common case at least
for distros and kernel developers), sizeof(struct dcache) == 208 here
(64-bit). This gives 19 objects per slab.
I packed d_mounted into a hole, and took another 4 bytes off the inline
name length to take the padding out from the end of the structure. This
shinks it to 200 bytes. I could have gone the other way and increased the
length to 40, but I'm aiming for a magic number, read on...
I then got rid of the d_cookie pointer. This shrinks it to 192 bytes. Rant:
why was this ever a good idea? The cookie system should increase its hash
size or use a tree or something if lookups are a problem. Also the "fast
dcookie lookups" in oprofile should be moved into the dcookie code -- how
can oprofile possibly care about the dcookie_mutex? It gets dropped after
get_dcookie() returns so it can't be providing any sort of protection.
At 192 bytes, 21 objects fit into a 4K page, saving about 3MB on my system
with ~140 000 entries allocated. 192 is also a multiple of 64, so we get
nice cacheline alignment on 64 and 32 byte line systems -- any given dentry
will now require 3 cachelines to touch all fields wheras previously it
would require 4.
I know the inline name size was chosen quite carefully, however with the
reduction in cacheline footprint, it should actually be just about as fast
to do a name lookup for a 36 character name as it was before the patch (and
faster for other sizes). The memory footprint savings for names which are
<= 32 or > 36 bytes long should more than make up for the memory cost for
33-36 byte names.
Performance is a feature...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Reorder struct inotify_device to remove 8 bytes of padding on 64bit
builds, reducing size to 128 bytes . Therefore allocating from a smaller
slab & using one fewer cachelines.
Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk>
----
Hi,
patch against 2.6.28-rc7.
built & tested on AMDX2 desktop.
I've not been able to send this to the listed inotify maintainers, I
just get mail failures. So I guessed filesystem was the best home for
it, hope that's ok.
regards
Richard
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* 'for-linus' of git://oss.sgi.com/xfs/xfs: (184 commits)
[XFS] Fix race in xfs_write() between direct and buffered I/O with DMAPI
[XFS] handle unaligned data in xfs_bmbt_disk_get_all
[XFS] avoid memory allocations in xfs_fs_vcmn_err
[XFS] Fix speculative allocation beyond eof
[XFS] Remove XFS_BUF_SHUT() and friends
[XFS] Use the incore inode size in xfs_file_readdir()
[XFS] set b_error from bio error in xfs_buf_bio_end_io
[XFS] use inode_change_ok for setattr permission checking
[XFS] add a FMODE flag to make XFS invisible I/O less hacky
[XFS] resync headers with libxfs
[XFS] simplify projid check in xfs_rename
[XFS] replace b_fspriv with b_mount
[XFS] Remove unused tracing code
[XFS] Remove unnecessary assertion
[XFS] Remove unused variable in ktrace_free()
[XFS] Check return value of xfs_buf_get_noaddr()
[XFS] Fix hang after disallowed rename across directory quota domains
[XFS] Fix compile with CONFIG_COMPAT enabled
move inode tracing out of xfs_vnode.
move vn_iowait / vn_iowake into xfs_aops.c
...
* git://git.linux-nfs.org/projects/trondmy/nfs-2.6: (70 commits)
fs/nfs/nfs4proc.c: make nfs4_map_errors() static
rpc: add service field to new upcall
rpc: add target field to new upcall
nfsd: support callbacks with gss flavors
rpc: allow gss callbacks to client
rpc: pass target name down to rpc level on callbacks
nfsd: pass client principal name in rsc downcall
rpc: implement new upcall
rpc: store pointer to pipe inode in gss upcall message
rpc: use count of pipe openers to wait for first open
rpc: track number of users of the gss upcall pipe
rpc: call release_pipe only on last close
rpc: add an rpc_pipe_open method
rpc: minor gss_alloc_msg cleanup
rpc: factor out warning code from gss_pipe_destroy_msg
rpc: remove unnecessary assignment
NFS: remove unused status from encode routines
NFS: increment number of operations in each encode routine
NFS: fix comment placement in nfs4xdr.c
NFS: fix tabs in nfs4xdr.c
...
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband:
IB/mlx4: Fix reading SL field out of cqe->sl_vid
RDMA/addr: Fix build breakage when IPv6 is disabled
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6: (583 commits)
V4L/DVB (10130): use USB API functions rather than constants
V4L/DVB (10129): dvb: remove deprecated use of RW_LOCK_UNLOCKED in frontends
V4L/DVB (10128): modify V4L documentation to be a valid XHTML
V4L/DVB (10127): stv06xx: Avoid having y unitialized
V4L/DVB (10125): em28xx: Don't do AC97 vendor detection for i2s audio devices
V4L/DVB (10124): em28xx: expand output formats available
V4L/DVB (10123): em28xx: fix reversed definitions of I2S audio modes
V4L/DVB (10122): em28xx: don't load em28xx-alsa for em2870 based devices
V4L/DVB (10121): em28xx: remove worthless Pinnacle PCTV HD Mini 80e device profile
V4L/DVB (10120): em28xx: remove redundant Pinnacle Dazzle DVC 100 profile
V4L/DVB (10119): em28xx: fix corrupted XCLK value
V4L/DVB (10118): zoran: fix warning for a variable not used
V4L/DVB (10116): af9013: Fix gcc false warnings
V4L/DVB (10111a): usbvideo.h: remove an useless blank line
V4L/DVB (10111): quickcam_messenger.c: fix a warning
V4L/DVB (10110): v4l2-ioctl: Fix warnings when using .unlocked_ioctl = __video_ioctl2
V4L/DVB (10109): anysee: Fix usage of an unitialized function
V4L/DVB (10104): uvcvideo: Add support for video output devices
V4L/DVB (10102): uvcvideo: Ignore interrupt endpoint for built-in iSight webcams.
V4L/DVB (10101): uvcvideo: Fix bulk URB processing when the header is erroneous
...
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6:
net: Fix percpu counters deadlock
cpumask: prepare for iterators to only go to nr_cpu_ids/nr_cpumask_bits: net
drivers/net/usb: use USB API functions rather than constants
cls_cgroup: clean up Kconfig
cls_cgroup: clean up for cgroup part
cls_cgroup: fix an oops when removing a cgroup
EtherExpress16: fix printing timed out status
mlx4_en: Added "set_ringparam" Ethtool interface implementation
mlx4_en: Always allocate RX ring for each interrupt vector
mlx4_en: Verify number of RX rings doesn't exceed MAX_RX_RINGS
IPVS: Make "no destination available" message more consistent between schedulers
net: KS8695: removed duplicated #include
tun: Fix SIOCSIFHWADDR error.
smsc911x: compile fix re netif_rx signature changes
netns: foreach_netdev_safe is insufficient in default_device_exit
net: make xfrm_statistics_seq_show use generic snmp_fold_field
net: Fix more NAPI interface netdev argument drop fallout.
net: Fix unused variable warnings in pasemi_mac.c and spider_net.c
* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
lguest: struct device - replace bus_id with dev_name()
lguest: move the initial guest page table creation code to the host
kvm-s390: implement config_changed for virtio on s390
virtio_console: support console resizing
virtio: add PCI device release() function
virtio_blk: fix type warning
virtio: block: dynamic maximum segments
virtio: set max_segment_size and max_sectors to infinite.
virtio: avoid implicit use of Linux page size in balloon interface
virtio: hand virtio ring alignment as argument to vring_new_virtqueue
virtio: use KVM_S390_VIRTIO_RING_ALIGN instead of relying on pagesize
virtio: use LGUEST_VRING_ALIGN instead of relying on pagesize
virtio: Don't use PAGE_SIZE for vring alignment in virtio_pci.
virtio: rename 'pagesize' arg to vring_init/vring_size
virtio: Don't use PAGE_SIZE in virtio_pci.c
virtio: struct device - replace bus_id with dev_name(), dev_set_name()
virtio-pci queue allocation not page-aligned
* 'devel' of master.kernel.org:/home/rmk/linux-2.6-arm: (407 commits)
[ARM] pxafb: add support for overlay1 and overlay2 as framebuffer devices
[ARM] pxafb: cleanup of the timing checking code
[ARM] pxafb: cleanup of the color format manipulation code
[ARM] pxafb: add palette format support for LCCR4_PAL_FOR_3
[ARM] pxafb: add support for FBIOPAN_DISPLAY by dma braching
[ARM] pxafb: allow pxafb_set_par() to start from arbitrary yoffset
[ARM] pxafb: allow video memory size to be configurable
[ARM] pxa: add document on the MFP design and how to use it
[ARM] sa1100_wdt: don't assume CLOCK_TICK_RATE to be a constant
[ARM] rtc-sa1100: don't assume CLOCK_TICK_RATE to be a constant
[ARM] pxa/tavorevb: update board support (smartpanel LCD + keypad)
[ARM] pxa: Update eseries defconfig
[ARM] 5352/1: add w90p910-plat config file
[ARM] s3c: S3C options should depend on PLAT_S3C
[ARM] mv78xx0: implement GPIO and GPIO interrupt support
[ARM] Kirkwood: implement GPIO and GPIO interrupt support
[ARM] Orion: share GPIO IRQ handling code
[ARM] Orion: share GPIO handling code
[ARM] s3c: define __io using the typesafe version
[ARM] S3C64XX: Ensure CPU_V6 is selected
...
Zhaolei
Al Viro
Duane Griffin
Julia Lawall
Jan Engelhardt
Nick Piggin
Richard Kennedy
Kentaro Takeda
Linus Torvalds
Huang Weiyi