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The lockdep warning below detects a possible A->B/B->A locking
dependency of mm->mmap_sem and dcookie_mutex. The order in
sync_buffer() is mm->mmap_sem/dcookie_mutex, while in
sys_lookup_dcookie() it is vice versa.
Fixing it in sys_lookup_dcookie() by unlocking dcookie_mutex before
copy_to_user().
oprofiled/4432 is trying to acquire lock:
(&mm->mmap_sem){++++++}, at: [<ffffffff810b444b>] might_fault+0x53/0xa3
but task is already holding lock:
(dcookie_mutex){+.+.+.}, at: [<ffffffff81124d28>] sys_lookup_dcookie+0x45/0x149
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (dcookie_mutex){+.+.+.}:
[<ffffffff8106557f>] lock_acquire+0xf8/0x11e
[<ffffffff814634f0>] mutex_lock_nested+0x63/0x309
[<ffffffff81124e5c>] get_dcookie+0x30/0x144
[<ffffffffa0000fba>] sync_buffer+0x196/0x3ec [oprofile]
[<ffffffffa0001226>] task_exit_notify+0x16/0x1a [oprofile]
[<ffffffff81467b96>] notifier_call_chain+0x37/0x63
[<ffffffff8105803d>] __blocking_notifier_call_chain+0x50/0x67
[<ffffffff81058068>] blocking_notifier_call_chain+0x14/0x16
[<ffffffff8105a718>] profile_task_exit+0x1a/0x1c
[<ffffffff81039e8f>] do_exit+0x2a/0x6fc
[<ffffffff8103a5e4>] do_group_exit+0x83/0xae
[<ffffffff8103a626>] sys_exit_group+0x17/0x1b
[<ffffffff8146ad4b>] system_call_fastpath+0x16/0x1b
-> #0 (&mm->mmap_sem){++++++}:
[<ffffffff81064dfb>] __lock_acquire+0x1085/0x1711
[<ffffffff8106557f>] lock_acquire+0xf8/0x11e
[<ffffffff810b4478>] might_fault+0x80/0xa3
[<ffffffff81124de7>] sys_lookup_dcookie+0x104/0x149
[<ffffffff8146ad4b>] system_call_fastpath+0x16/0x1b
other info that might help us debug this:
1 lock held by oprofiled/4432:
#0: (dcookie_mutex){+.+.+.}, at: [<ffffffff81124d28>] sys_lookup_dcookie+0x45/0x149
stack backtrace:
Pid: 4432, comm: oprofiled Not tainted 2.6.39-00008-ge5a450d #9
Call Trace:
[<ffffffff81063193>] print_circular_bug+0xae/0xbc
[<ffffffff81064dfb>] __lock_acquire+0x1085/0x1711
[<ffffffff8102ef13>] ? get_parent_ip+0x11/0x42
[<ffffffff810b444b>] ? might_fault+0x53/0xa3
[<ffffffff8106557f>] lock_acquire+0xf8/0x11e
[<ffffffff810b444b>] ? might_fault+0x53/0xa3
[<ffffffff810d7d54>] ? path_put+0x22/0x27
[<ffffffff810b4478>] might_fault+0x80/0xa3
[<ffffffff810b444b>] ? might_fault+0x53/0xa3
[<ffffffff81124de7>] sys_lookup_dcookie+0x104/0x149
[<ffffffff8146ad4b>] system_call_fastpath+0x16/0x1b
References: https://bugzilla.kernel.org/show_bug.cgi?id=13809
Cc: <stable@kernel.org> # .27+
Signed-off-by: Robert Richter <robert.richter@amd.com>
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System calls with an unsigned long long argument can't be converted with
the standard wrappers since that would include a cast to long, which in
turn means that we would lose the upper 32 bit on 32 bit architectures.
Also semctl can't use the standard wrapper since it has a 'union'
parameter.
So we handle them as special case and add some extra wrappers instead.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
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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>
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d_path() is used on a <dentry,vfsmount> pair. Lets use a struct path to
reflect this.
[akpm@linux-foundation.org: fix build in mm/memory.c]
Signed-off-by: Jan Blunck <jblunck@suse.de>
Acked-by: Bryan Wu <bryan.wu@analog.com>
Acked-by: Christoph Hellwig <hch@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Neil Brown <neilb@suse.de>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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get_dcookie() is always called with a dentry and a vfsmount from a struct
path. Make get_dcookie() take it directly as an argument.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Jan Blunck <jblunck@suse.de>
Acked-by: Christoph Hellwig <hch@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Remove fs.h from mm.h. For this,
1) Uninline vma_wants_writenotify(). It's pretty huge anyway.
2) Add back fs.h or less bloated headers (err.h) to files that need it.
As result, on x86_64 allyesconfig, fs.h dependencies cut down from 3929 files
rebuilt down to 3444 (-12.3%).
Cross-compile tested without regressions on my two usual configs and (sigh):
alpha arm-mx1ads mips-bigsur powerpc-ebony
alpha-allnoconfig arm-neponset mips-capcella powerpc-g5
alpha-defconfig arm-netwinder mips-cobalt powerpc-holly
alpha-up arm-netx mips-db1000 powerpc-iseries
arm arm-ns9xxx mips-db1100 powerpc-linkstation
arm-assabet arm-omap_h2_1610 mips-db1200 powerpc-lite5200
arm-at91rm9200dk arm-onearm mips-db1500 powerpc-maple
arm-at91rm9200ek arm-picotux200 mips-db1550 powerpc-mpc7448_hpc2
arm-at91sam9260ek arm-pleb mips-ddb5477 powerpc-mpc8272_ads
arm-at91sam9261ek arm-pnx4008 mips-decstation powerpc-mpc8313_rdb
arm-at91sam9263ek arm-pxa255-idp mips-e55 powerpc-mpc832x_mds
arm-at91sam9rlek arm-realview mips-emma2rh powerpc-mpc832x_rdb
arm-ateb9200 arm-realview-smp mips-excite powerpc-mpc834x_itx
arm-badge4 arm-rpc mips-fulong powerpc-mpc834x_itxgp
arm-carmeva arm-s3c2410 mips-ip22 powerpc-mpc834x_mds
arm-cerfcube arm-shannon mips-ip27 powerpc-mpc836x_mds
arm-clps7500 arm-shark mips-ip32 powerpc-mpc8540_ads
arm-collie arm-simpad mips-jazz powerpc-mpc8544_ds
arm-corgi arm-spitz mips-jmr3927 powerpc-mpc8560_ads
arm-csb337 arm-trizeps4 mips-malta powerpc-mpc8568mds
arm-csb637 arm-versatile mips-mipssim powerpc-mpc85xx_cds
arm-ebsa110 i386 mips-mpc30x powerpc-mpc8641_hpcn
arm-edb7211 i386-allnoconfig mips-msp71xx powerpc-mpc866_ads
arm-em_x270 i386-defconfig mips-ocelot powerpc-mpc885_ads
arm-ep93xx i386-up mips-pb1100 powerpc-pasemi
arm-footbridge ia64 mips-pb1500 powerpc-pmac32
arm-fortunet ia64-allnoconfig mips-pb1550 powerpc-ppc64
arm-h3600 ia64-bigsur mips-pnx8550-jbs powerpc-prpmc2800
arm-h7201 ia64-defconfig mips-pnx8550-stb810 powerpc-ps3
arm-h7202 ia64-gensparse mips-qemu powerpc-pseries
arm-hackkit ia64-sim mips-rbhma4200 powerpc-up
arm-integrator ia64-sn2 mips-rbhma4500 s390
arm-iop13xx ia64-tiger mips-rm200 s390-allnoconfig
arm-iop32x ia64-up mips-sb1250-swarm s390-defconfig
arm-iop33x ia64-zx1 mips-sead s390-up
arm-ixp2000 m68k mips-tb0219 sparc
arm-ixp23xx m68k-amiga mips-tb0226 sparc-allnoconfig
arm-ixp4xx m68k-apollo mips-tb0287 sparc-defconfig
arm-jornada720 m68k-atari mips-workpad sparc-up
arm-kafa m68k-bvme6000 mips-wrppmc sparc64
arm-kb9202 m68k-hp300 mips-yosemite sparc64-allnoconfig
arm-ks8695 m68k-mac parisc sparc64-defconfig
arm-lart m68k-mvme147 parisc-allnoconfig sparc64-up
arm-lpd270 m68k-mvme16x parisc-defconfig um-x86_64
arm-lpd7a400 m68k-q40 parisc-up x86_64
arm-lpd7a404 m68k-sun3 powerpc x86_64-allnoconfig
arm-lubbock m68k-sun3x powerpc-cell x86_64-defconfig
arm-lusl7200 mips powerpc-celleb x86_64-up
arm-mainstone mips-atlas powerpc-chrp32
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Slab destructors were no longer supported after Christoph's
c59def9f222d44bb7e2f0a559f2906191a0862d7 change. They've been
BUGs for both slab and slub, and slob never supported them
either.
This rips out support for the dtor pointer from kmem_cache_create()
completely and fixes up every single callsite in the kernel (there were
about 224, not including the slab allocator definitions themselves,
or the documentation references).
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
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Replace all uses of kmem_cache_t with struct kmem_cache.
The patch was generated using the following script:
#!/bin/sh
#
# Replace one string by another in all the kernel sources.
#
set -e
for file in `find * -name "*.c" -o -name "*.h"|xargs grep -l $1`; do
quilt add $file
sed -e "1,\$s/$1/$2/g" $file >/tmp/$$
mv /tmp/$$ $file
quilt refresh
done
The script was run like this
sh replace kmem_cache_t "struct kmem_cache"
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
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I discovered on oprofile hunting on a SMP platform that dentry lookups were
slowed down because d_hash_mask, d_hash_shift and dentry_hashtable were in
a cache line that contained inodes_stat. So each time inodes_stats is
changed by a cpu, other cpus have to refill their cache line.
This patch moves some variables to the __read_mostly section, in order to
avoid false sharing. RCU dentry lookups can go full speed.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Semaphore to mutex conversion.
The conversion was generated via scripts, and the result was validated
automatically via a script as well.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Eric Van Hensbergen <ericvh@ericvh.myip.org>
Cc: Robert Love <rml@tech9.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Dave Kleikamp <shaggy@austin.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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fs: Use <linux/capability.h> where capable() is used.
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Acked-by: Tim Schmielau <tim@physik3.uni-rostock.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Dcookies shouldn't play with the internals of dentry and vfsmnt
refcounting. It defeats grepping, and is prone to break if implementation
details change.
In addition the function doesn't even seem to be performance critical: it
calls kmem_cache_alloc().
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
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