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2011-03-22smaps: have smaps show transparent huge pagesDave Hansen1-0/+4
Now that the mere act of _looking_ at /proc/$pid/smaps will not destroy transparent huge pages, tell how much of the VMA is actually mapped with them. This way, we can make sure that we're getting THPs where we expect to see them. Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Acked-by: David Rientjes <rientjes@google.com> Reviewed-by: Eric B Munson <emunson@mgebm.net> Tested-by: Eric B Munson <emunson@mgebm.net> Cc: Michael J Wolf <mjwolf@us.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Matt Mackall <mpm@selenic.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-22smaps: teach smaps_pte_range() about THP pmdsDave Hansen1-2/+21
This adds code to explicitly detect and handle pmd_trans_huge() pmds. It then passes HPAGE_SIZE units in to the smap_pte_entry() function instead of PAGE_SIZE. This means that using /proc/$pid/smaps now will no longer cause THPs to be broken down in to small pages. Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com> Reviewed-by: Eric B Munson <emunson@mgebm.net> Tested-by: Eric B Munson <emunson@mgebm.net> Acked-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Michael J Wolf <mjwolf@us.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Matt Mackall <mpm@selenic.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-22smaps: pass pte size argument in to smaps_pte_entry()Dave Hansen1-12/+12
Add an argument to the new smaps_pte_entry() function to let it account in things other than PAGE_SIZE units. I changed all of the PAGE_SIZE sites, even though not all of them can be reached for transparent huge pages, just so this will continue to work without changes as THPs are improved. Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: David Rientjes <rientjes@google.com> Reviewed-by: Eric B Munson <emunson@mgebm.net> Tested-by: Eric B Munson <emunson@mgebm.net> Cc: Michael J Wolf <mjwolf@us.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Matt Mackall <mpm@selenic.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-22smaps: break out smaps_pte_entry() from smaps_pte_range()Dave Hansen1-40/+47
We will use smaps_pte_entry() in a moment to handle both small and transparent large pages. But, we must break it out of smaps_pte_range() first. Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: David Rientjes <rientjes@google.com> Reviewed-by: Eric B Munson <emunson@mgebm.net> Tested-by: Eric B Munson <emunson@mgebm.net> Cc: Michael J Wolf <mjwolf@us.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Matt Mackall <mpm@selenic.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-22pagewalk: only split huge pages when necessaryDave Hansen1-0/+6
Right now, if a mm_walk has either ->pte_entry or ->pmd_entry set, it will unconditionally split any transparent huge pages it runs in to. In practice, that means that anyone doing a cat /proc/$pid/smaps will unconditionally break down every huge page in the process and depend on khugepaged to re-collapse it later. This is fairly suboptimal. This patch changes that behavior. It teaches each ->pmd_entry handler (there are five) that they must break down the THPs themselves. Also, the _generic_ code will never break down a THP unless a ->pte_entry handler is actually set. This means that the ->pmd_entry handlers can now choose to deal with THPs without breaking them down. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Acked-by: David Rientjes <rientjes@google.com> Reviewed-by: Eric B Munson <emunson@mgebm.net> Tested-by: Eric B Munson <emunson@mgebm.net> Cc: Michael J Wolf <mjwolf@us.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Matt Mackall <mpm@selenic.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-16Merge branch 'next' into for-linusJames Morris1-1/+0
2011-03-10/proc/self is never going to be invalidated...Al Viro1-30/+0
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-08unfuck proc_sysctl ->d_compare()Al Viro2-4/+11
a) struct inode is not going to be freed under ->d_compare(); however, the thing PROC_I(inode)->sysctl points to just might. Fortunately, it's enough to make freeing that sucker delayed, provided that we don't step on its ->unregistering, clear the pointer to it in PROC_I(inode) before dropping the reference and check if it's NULL in ->d_compare(). b) I'm not sure that we *can* walk into NULL inode here (we recheck dentry->seq between verifying that it's still hashed / fetching dentry->d_inode and passing it to ->d_compare() and there's no negative hashed dentries in /proc/sys/*), but if we can walk into that, we really should not have ->d_compare() return 0 on it! Said that, I really suspect that this check can be simply killed. Nick? Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-08Merge branch 'master' of git://git.infradead.org/users/eparis/selinux into nextJames Morris1-1/+0
2011-03-02of/flattree: Drop an uninteresting message to pr_debug levelPaul Bolle1-1/+1
This message looks like an error (which it isn't) when booting with a flattened device tree. Remove the message from normal kernel builds. Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2011-02-15s390: remove task_show_regsMartin Schwidefsky1-3/+0
task_show_regs used to be a debugging aid in the early bringup days of Linux on s390. /proc/<pid>/status is a world readable file, it is not a good idea to show the registers of a process. The only correct fix is to remove task_show_regs. Reported-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-01security/selinux: fix /proc/sys/ labelingLucian Adrian Grijincu1-1/+0
This fixes an old (2007) selinux regression: filesystem labeling for /proc/sys returned -r--r--r-- unknown /proc/sys/fs/file-nr instead of -r--r--r-- system_u:object_r:sysctl_fs_t:s0 /proc/sys/fs/file-nr Events that lead to breaking of /proc/sys/ selinux labeling: 1) sysctl was reimplemented to route all calls through /proc/sys/ commit 77b14db502cb85a031fe8fde6c85d52f3e0acb63 [PATCH] sysctl: reimplement the sysctl proc support 2) proc_dir_entry was removed from ctl_table: commit 3fbfa98112fc3962c416452a0baf2214381030e6 [PATCH] sysctl: remove the proc_dir_entry member for the sysctl tables 3) selinux still walked the proc_dir_entry tree to apply labeling. Because ctl_tables don't have a proc_dir_entry, we did not label /proc/sys/ inodes any more. To achieve this the /proc/sys/ inodes were marked private and private inodes were ignored by selinux. commit bbaca6c2e7ef0f663bc31be4dad7cf530f6c4962 [PATCH] selinux: enhance selinux to always ignore private inodes commit 86a71dbd3e81e8870d0f0e56b87875f57e58222b [PATCH] sysctl: hide the sysctl proc inodes from selinux Access control checks have been done by means of a special sysctl hook that was called for read/write accesses to any /proc/sys/ entry. We don't have to do this because, instead of walking the proc_dir_entry tree we can walk the dentry tree (as done in this patch). With this patch: * we don't mark /proc/sys/ inodes as private * we don't need the sysclt security hook * we walk the dentry tree to find the path to the inode. We have to strip the PID in /proc/PID/ entries that have a proc_dir_entry because selinux does not know how to label paths like '/1/net/rpc/nfsd.fh' (and defaults to 'proc_t' labeling). Selinux does know of '/net/rpc/nfsd.fh' (and applies the 'sysctl_rpc_t' label). PID stripping from the path was done implicitly in the previous code because the proc_dir_entry tree had the root in '/net' in the example from above. The dentry tree has the root in '/1'. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Lucian Adrian Grijincu <lucian.grijincu@gmail.com> Signed-off-by: Eric Paris <eparis@redhat.com>
2011-01-26console: rename acquire/release_console_sem() to console_lock/unlock()Torben Hohn1-2/+2
The -rt patches change the console_semaphore to console_mutex. As a result, a quite large chunk of the patches changes all acquire/release_console_sem() to acquire/release_console_mutex() This commit makes things use more neutral function names which dont make implications about the underlying lock. The only real change is the return value of console_trylock which is inverted from try_acquire_console_sem() This patch also paves the way to switching console_sem from a semaphore to a mutex. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: make console_trylock return 1 on success, per Geert] Signed-off-by: Torben Hohn <torbenh@gmx.de> Cc: Thomas Gleixner <tglx@tglx.de> Cc: Greg KH <gregkh@suse.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-20kconfig: rename CONFIG_EMBEDDED to CONFIG_EXPERTDavid Rientjes1-3/+3
The meaning of CONFIG_EMBEDDED has long since been obsoleted; the option is used to configure any non-standard kernel with a much larger scope than only small devices. This patch renames the option to CONFIG_EXPERT in init/Kconfig and fixes references to the option throughout the kernel. A new CONFIG_EMBEDDED option is added that automatically selects CONFIG_EXPERT when enabled and can be used in the future to isolate options that should only be considered for embedded systems (RISC architectures, SLOB, etc). Calling the option "EXPERT" more accurately represents its intention: only expert users who understand the impact of the configuration changes they are making should enable it. Reviewed-by: Ingo Molnar <mingo@elte.hu> Acked-by: David Woodhouse <david.woodhouse@intel.com> Signed-off-by: David Rientjes <rientjes@google.com> Cc: Greg KH <gregkh@suse.de> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jens Axboe <axboe@kernel.dk> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Robin Holt <holt@sgi.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13thp: remove PG_buddyAndrea Arcangeli1-6/+8
PG_buddy can be converted to _mapcount == -2. So the PG_compound_lock can be added to page->flags without overflowing (because of the sparse section bits increasing) with CONFIG_X86_PAE=y and CONFIG_X86_PAT=y. This also has to move the memory hotplug code from _mapcount to lru.next to avoid any risk of clashes. We can't use lru.next for PG_buddy removal, but memory hotplug can use lru.next even more easily than the mapcount instead. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13thp: transparent hugepage vmstatAndrea Arcangeli1-1/+13
Add hugepage stat information to /proc/vmstat and /proc/meminfo. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13oom: allow a non-CAP_SYS_RESOURCE proces to oom_score_adj downMandeep Singh Baines1-1/+3
We'd like to be able to oom_score_adj a process up/down as it enters/leaves the foreground. Currently, it is not possible to oom_adj down without CAP_SYS_RESOURCE. This patch allows a task to decrease its oom_score_adj back to the value that a CAP_SYS_RESOURCE thread set it to or its inherited value at fork. Assuming the thread that has forked it has oom_score_adj of 0, each process could decrease it back from 0 upon activation unless a CAP_SYS_RESOURCE thread elevated it to something higher. Alternative considered: * a setuid binary * a daemon with CAP_SYS_RESOURCE Since you don't wan't all processes to be able to reduce their oom_adj, a setuid or daemon implementation would be complex. The alternatives also have much higher overhead. This patch updated from original patch based on feedback from David Rientjes. Signed-off-by: Mandeep Singh Baines <msb@chromium.org> Acked-by: David Rientjes <rientjes@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Cc: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13mm: smaps: export mlock informationNikanth Karthikesan1-2/+5
Currently there is no way to find whether a process has locked its pages in memory or not. And which of the memory regions are locked in memory. Add a new field "Locked" to export this information via the smaps file. Signed-off-by: Nikanth Karthikesan <knikanth@suse.de> Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com> Acked-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Matt Mackall <mpm@selenic.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13/proc/kcore: fix seekingDave Anderson1-1/+1
Commit 34aacb2920 ("procfs: Use generic_file_llseek in /proc/kcore") broke seeking on /proc/kcore. This changes it back to use default_llseek in order to restore the original behavior. The problem with generic_file_llseek is that it only allows seeks up to inode->i_sb->s_maxbytes, which is 2GB-1 on procfs, where the memory file offset values in the /proc/kcore PT_LOAD segments may exceed or start beyond that offset value. A similar revert was made for /proc/vmcore. Signed-off-by: Dave Anderson <anderson@redhat.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13proc: move proc_console.c to fs/proc/consoles.cAlexey Dobriyan2-3/+3
Filename is supposed to match procfile name for random junk. Add __init while I'm at it. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13proc: less LOCK/UNLOCK in remove_proc_entry()Alexey Dobriyan1-4/+1
For the common case where a proc entry is being removed and nobody is in the process of using it, save a LOCK/UNLOCK pair. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13kpagecount: add slab page checking because _mapcount is in a unionPetr Holasek1-1/+1
Add a PageSlab() check before adding the _mapcount value to /kpagecount. page->_mapcount is in a union with the SLAB structure so for pages controlled by SLAB, page_mapcount() returns nonsense. Signed-off-by: Petr Holasek <pholasek@redhat.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Matt Mackall <mpm@selenic.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13proc: use single_open() correctlyJovi Zhang1-26/+3
single_open()'s third argument is for copying into seq_file->private. Use that, rather than open-coding it. Signed-off-by: Jovi Zhang <bookjovi@gmail.com> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13proc: ->low_ino cleanupAlexey Dobriyan3-15/+6
- ->low_ino is write-once field -- reading it under locks is unnecessary. - /proc/$PID stuff never reaches pde_put()/free_proc_entry() -- PROC_DYNAMIC_FIRST check never triggers. - in proc_get_inode(), inode number always matches proc dir entry, so save one parameter. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13proc: use seq_puts()/seq_putc() where possibleAlexey Dobriyan6-31/+31
For string without format specifiers, use seq_puts(). For seq_printf("\n"), use seq_putc('\n'). text data bss dec hex filename 61866 488 112 62466 f402 fs/proc/proc.o 61729 488 112 62329 f379 fs/proc/proc.o ---------------------------------------------------- -139 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13proc: use unsigned long inside /proc/*/statmAlexey Dobriyan4-9/+12
/proc/*/statm code needlessly truncates data from unsigned long to int. One needs only 8+ TB of RAM to make truncation visible. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13fs/proc/base.c, kernel/latencytop.c: convert sprintf_symbol() to %psJoe Perches1-14/+8
Use temporary lr for struct latency_record for improved readability and fewer columns used. Removed trailing space from output. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Joe Perches <joe@perches.com> Cc: Jiri Kosina <trivial@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-07Merge branch 'tty-next' of ↵Linus Torvalds2-0/+115
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6 * 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6: (36 commits) serial: apbuart: Fixup apbuart_console_init() TTY: Add tty ioctl to figure device node of the system console. tty: add 'active' sysfs attribute to tty0 and console device drivers: serial: apbuart: Handle OF failures gracefully Serial: Avoid unbalanced IRQ wake disable during resume tty: fix typos/errors in tty_driver.h comments pch_uart : fix warnings for 64bit compile 8250: fix uninitialized FIFOs ip2: fix compiler warning on ip2main_pci_tbl specialix: fix compiler warning on specialix_pci_tbl rocket: fix compiler warning on rocket_pci_ids 8250: add a UPIO_DWAPB32 for 32 bit accesses 8250: use container_of() instead of casting serial: omap-serial: Add support for kernel debugger serial: fix pch_uart kconfig & build drivers: char: hvc: add arm JTAG DCC console support RS485 documentation: add 16C950 UART description serial: ifx6x60: fix memory leak serial: ifx6x60: free IRQ on error Serial: EG20T: add PCH_UART driver ... Fixed up conflicts in drivers/serial/apbuart.c with evil merge that makes the code look fairly sane (unlike either side).
2011-01-07Merge branch 'vfs-scale-working' of ↵Linus Torvalds4-29/+68
git://git.kernel.org/pub/scm/linux/kernel/git/npiggin/linux-npiggin * 'vfs-scale-working' of git://git.kernel.org/pub/scm/linux/kernel/git/npiggin/linux-npiggin: (57 commits) fs: scale mntget/mntput fs: rename vfsmount counter helpers fs: implement faster dentry memcmp fs: prefetch inode data in dcache lookup fs: improve scalability of pseudo filesystems fs: dcache per-inode inode alias locking fs: dcache per-bucket dcache hash locking bit_spinlock: add required includes kernel: add bl_list xfs: provide simple rcu-walk ACL implementation btrfs: provide simple rcu-walk ACL implementation ext2,3,4: provide simple rcu-walk ACL implementation fs: provide simple rcu-walk generic_check_acl implementation fs: provide rcu-walk aware permission i_ops fs: rcu-walk aware d_revalidate method fs: cache optimise dentry and inode for rcu-walk fs: dcache reduce branches in lookup path fs: dcache remove d_mounted fs: fs_struct use seqlock fs: rcu-walk for path lookup ...
2011-01-07fs: provide rcu-walk aware permission i_opsNick Piggin2-3/+8
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07fs: rcu-walk aware d_revalidate methodNick Piggin2-7/+29
Require filesystems be aware of .d_revalidate being called in rcu-walk mode (nd->flags & LOOKUP_RCU). For now do a simple push down, returning -ECHILD from all implementations. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07fs: dcache reduce branches in lookup pathNick Piggin3-9/+9
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->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 '[.>]([[:space:]])*d_op([[:space:]])*=' | xargs sed -e 's/\([^\t ]*\)->d_op = \(.*\);/d_set_d_op(\1, \2);/' -e 's/\([^\t ]*\)\.d_op = \(.*\);/d_set_d_op(\&\1, \2);/' -i Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07fs: rcu-walk for path lookupNick Piggin1-0/+4
Perform common cases of path lookups without any stores or locking in the ancestor dentry elements. This is called rcu-walk, as opposed to the current algorithm which is a refcount based walk, or ref-walk. This results in far fewer atomic operations on every path element, significantly improving path lookup performance. It also avoids cacheline bouncing on common dentries, significantly improving scalability. The overall design is like this: * LOOKUP_RCU is set in nd->flags, which distinguishes rcu-walk from ref-walk. * Take the RCU lock for the entire path walk, starting with the acquiring of the starting path (eg. root/cwd/fd-path). So now dentry refcounts are not required for dentry persistence. * synchronize_rcu is called when unregistering a filesystem, so we can access d_ops and i_ops during rcu-walk. * Similarly take the vfsmount lock for the entire path walk. So now mnt refcounts are not required for persistence. Also we are free to perform mount lookups, and to assume dentry mount points and mount roots are stable up and down the path. * Have a per-dentry seqlock to protect the dentry name, parent, and inode, so we can load this tuple atomically, and also check whether any of its members have changed. * Dentry lookups (based on parent, candidate string tuple) recheck the parent sequence after the child is found in case anything changed in the parent during the path walk. * inode is also RCU protected so we can load d_inode and use the inode for limited things. * i_mode, i_uid, i_gid can be tested for exec permissions during path walk. * i_op can be loaded. When we reach the destination dentry, we lock it, recheck lookup sequence, and increment its refcount and mountpoint refcount. RCU and vfsmount locks are dropped. This is termed "dropping rcu-walk". If the dentry refcount does not match, we can not drop rcu-walk gracefully at the current point in the lokup, so instead return -ECHILD (for want of a better errno). This signals the path walking code to re-do the entire lookup with a ref-walk. Aside from the final dentry, there are other situations that may be encounted where we cannot continue rcu-walk. In that case, we drop rcu-walk (ie. take a reference on the last good dentry) and continue with a ref-walk. Again, if we can drop rcu-walk gracefully, we return -ECHILD and do the whole lookup using ref-walk. But it is very important that we can continue with ref-walk for most cases, particularly to avoid the overhead of double lookups, and to gain the scalability advantages on common path elements (like cwd and root). The cases where rcu-walk cannot continue are: * NULL dentry (ie. any uncached path element) * parent with d_inode->i_op->permission or ACLs * dentries with d_revalidate * Following links In future patches, permission checks and d_revalidate become rcu-walk aware. It may be possible eventually to make following links rcu-walk aware. Uncached path elements will always require dropping to ref-walk mode, at the very least because i_mutex needs to be grabbed, and objects allocated. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07fs: icache RCU free inodesNick Piggin1-1/+8
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->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 <npiggin@kernel.dk>
2011-01-07fs: change d_compare for rcu-walkNick Piggin1-6/+7
Change d_compare so it may be called from lock-free RCU lookups. This does put significant restrictions on what may be done from the callback, however there don't seem to have been any problems with in-tree fses. If some strange use case pops up that _really_ cannot cope with the rcu-walk rules, we can just add new rcu-unaware callbacks, which would cause name lookup to drop out of rcu-walk mode. For in-tree filesystems, this is just a mechanical change. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07fs: change d_delete semanticsNick Piggin3-3/+3
Change d_delete from a dentry deletion notification to a dentry caching advise, more like ->drop_inode. Require it to be constant and idempotent, and not take d_lock. This is how all existing filesystems use the callback anyway. This makes fine grained dentry locking of dput and dentry lru scanning much simpler. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-06Merge branch 'devel' of master.kernel.org:/home/rmk/linux-2.6-armLinus Torvalds1-1/+1
* 'devel' of master.kernel.org:/home/rmk/linux-2.6-arm: (416 commits) ARM: DMA: add support for DMA debugging ARM: PL011: add DMA burst threshold support for ST variants ARM: PL011: Add support for transmit DMA ARM: PL011: Ensure IRQs are disabled in UART interrupt handler ARM: PL011: Separate hardware FIFO size from TTY FIFO size ARM: PL011: Allow better handling of vendor data ARM: PL011: Ensure error flags are clear at startup ARM: PL011: include revision number in boot-time port printk ARM: vexpress: add sched_clock() for Versatile Express ARM i.MX53: Make MX53 EVK bootable ARM i.MX53: Some bug fix about MX53 MSL code ARM: 6607/1: sa1100: Update platform device registration ARM: 6606/1: sa1100: Fix platform device registration ARM i.MX51: rename IPU irqs ARM i.MX51: Add ipu clock support ARM: imx/mx27_3ds: Add PMIC support ARM: DMA: Replace page_to_dma()/dma_to_page() with pfn_to_dma()/dma_to_pfn() mx51: fix usb clock support MX51: Add support for usb host 2 arch/arm/plat-mxc/ehci.c: fix errors/typos ...
2011-01-05Merge branches 'ftrace', 'gic', 'io', 'kexec', 'mod', 'sa11x0', 'sh' and ↵Russell King1-1/+1
'versatile' into devel
2010-12-08Merge branch 'linus' into sched/coreIngo Molnar2-2/+3
Merge reason: we want to queue up dependent cleanup Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-12-05Revert "vfs: show unreachable paths in getcwd and proc"Eric W. Biederman1-1/+1
Because it caused a chroot ttyname regression in 2.6.36. As of 2.6.36 ttyname does not work in a chroot. It has already been reported that screen breaks, and for me this breaks an automated distribution testsuite, that I need to preserve the ability to run the existing binaries on for several more years. glibc 2.11.3 which has a fix for this is not an option. The root cause of this breakage is: commit 8df9d1a4142311c084ffeeacb67cd34d190eff74 Author: Miklos Szeredi <mszeredi@suse.cz> Date: Tue Aug 10 11:41:41 2010 +0200 vfs: show unreachable paths in getcwd and proc Prepend "(unreachable)" to path strings if the path is not reachable from the current root. Two places updated are - the return string from getcwd() - and symlinks under /proc/$PID. Other uses of d_path() are left unchanged (we know that some old software crashes if /proc/mounts is changed). Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> So remove the nice sounding, but ultimately ill advised change to how /proc/fd symlinks work. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-11-30sched: Add 'autogroup' scheduling feature: automated per session task groupsMike Galbraith1-0/+79
A recurring complaint from CFS users is that parallel kbuild has a negative impact on desktop interactivity. This patch implements an idea from Linus, to automatically create task groups. Currently, only per session autogroups are implemented, but the patch leaves the way open for enhancement. Implementation: each task's signal struct contains an inherited pointer to a refcounted autogroup struct containing a task group pointer, the default for all tasks pointing to the init_task_group. When a task calls setsid(), a new task group is created, the process is moved into the new task group, and a reference to the preveious task group is dropped. Child processes inherit this task group thereafter, and increase it's refcount. When the last thread of a process exits, the process's reference is dropped, such that when the last process referencing an autogroup exits, the autogroup is destroyed. At runqueue selection time, IFF a task has no cgroup assignment, its current autogroup is used. Autogroup bandwidth is controllable via setting it's nice level through the proc filesystem: cat /proc/<pid>/autogroup Displays the task's group and the group's nice level. echo <nice level> > /proc/<pid>/autogroup Sets the task group's shares to the weight of nice <level> task. Setting nice level is rate limited for !admin users due to the abuse risk of task group locking. The feature is enabled from boot by default if CONFIG_SCHED_AUTOGROUP=y is selected, but can be disabled via the boot option noautogroup, and can also be turned on/off on the fly via: echo [01] > /proc/sys/kernel/sched_autogroup_enabled ... which will automatically move tasks to/from the root task group. Signed-off-by: Mike Galbraith <efault@gmx.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Markus Trippelsdorf <markus@trippelsdorf.de> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Paul Turner <pjt@google.com> Cc: Oleg Nesterov <oleg@redhat.com> [ Removed the task_group_path() debug code, and fixed !EVENTFD build failure. ] Signed-off-by: Ingo Molnar <mingo@elte.hu> LKML-Reference: <1290281700.28711.9.camel@maggy.simson.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-30ARM: 6485/5: proc/vmcore - allow archs to override vmcore_elf_check_arch()Mika Westerberg1-1/+1
Allow architectures to redefine this macro if needed. This is useful for example in architectures where 64-bit ELF vmcores are not supported. Specifying zero vmcore_elf64_check_arch() allows compiler to optimize away unnecessary parts of parse_crash_elf64_headers(). We also rename the macro to vmcore_elf64_check_arch() to reflect that it is used for 64-bit vmcores only. Signed-off-by: Mika Westerberg <mika.westerberg@iki.fi> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-11-25pagemap: set pagemap walk limit to PMD boundaryNaoya Horiguchi1-1/+2
Currently one pagemap_read() call walks in PAGEMAP_WALK_SIZE bytes (== 512 pages.) But there is a corner case where walk_pmd_range() accidentally runs over a VMA associated with a hugetlbfs file. For example, when a process has mappings to VMAs as shown below: # cat /proc/<pid>/maps ... 3a58f6d000-3a58f72000 rw-p 00000000 00:00 0 7fbd51853000-7fbd51855000 rw-p 00000000 00:00 0 7fbd5186c000-7fbd5186e000 rw-p 00000000 00:00 0 7fbd51a00000-7fbd51c00000 rw-s 00000000 00:12 8614 /hugepages/test then pagemap_read() goes into walk_pmd_range() path and walks in the range 0x7fbd51853000-0x7fbd51a53000, but the hugetlbfs VMA should be handled by walk_hugetlb_range(). Otherwise PMD for the hugepage is considered bad and cleared, which causes undesirable results. This patch fixes it by separating pagemap walk range into one PMD. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Matt Mackall <mpm@selenic.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-11-17BKL: remove extraneous #include <smp_lock.h>Arnd Bergmann1-1/+0
The big kernel lock has been removed from all these files at some point, leaving only the #include. Remove this too as a cleanup. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-11-16console: add /proc/consolesJiri Slaby2-0/+115
It allows users to see what consoles are currently known to the system and with what flags. It is based on Werner's patch, the part about traversing fds was removed, the code was moved to kernel/printk.c, where consoles are handled and it makes more sense to me. Signed-off-by: Jiri Slaby <jslaby@suse.cz> [cleanups] Signed-off-by: "Dr. Werner Fink" <werner@suse.de> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-10-29switch procfs to ->mount()Al Viro1-7/+6
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-10-29setting ->proc_mnt doesn't belong in proc_get_sb()Al Viro1-1/+2
take that to kern_mount_data()-using callers Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-10-27/proc/stat: fix scalability of irq sum of all cpuKAMEZAWA Hiroyuki1-8/+2
In /proc/stat, the number of per-IRQ event is shown by making a sum each irq's events on all cpus. But we can make use of kstat_irqs(). kstat_irqs() do the same calculation, If !CONFIG_GENERIC_HARDIRQ, it's not a big cost. (Both of the number of cpus and irqs are small.) If a system is very big and CONFIG_GENERIC_HARDIRQ, it does for_each_irq() for_each_cpu() - look up a radix tree - read desc->irq_stat[cpu] This seems not efficient. This patch adds kstat_irqs() for CONFIG_GENRIC_HARDIRQ and change the calculation as for_each_irq() look up radix tree for_each_cpu() - read desc->irq_stat[cpu] This reduces cost. A test on (4096cpusp, 256 nodes, 4592 irqs) host (by Jack Steiner) %time cat /proc/stat > /dev/null Before Patch: 2.459 sec After Patch : .561 sec [akpm@linux-foundation.org: unexport kstat_irqs, coding-style tweaks] [akpm@linux-foundation.org: fix unused variable 'per_irq_sum'] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Tested-by: Jack Steiner <steiner@sgi.com> Acked-by: Jack Steiner <steiner@sgi.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-27/proc/stat: scalability of irq num per cpuKAMEZAWA Hiroyuki1-3/+1
/proc/stat shows the total number of all interrupts to each cpu. But when the number of IRQs are very large, it take very long time and 'cat /proc/stat' takes more than 10 secs. This is because sum of all irq events are counted when /proc/stat is read. This patch adds "sum of all irq" counter percpu and reduce read costs. The cost of reading /proc/stat is important because it's used by major applications as 'top', 'ps', 'w', etc.... A test on a mechin (4096cpu, 256 nodes, 4592 irqs) shows %time cat /proc/stat > /dev/null Before Patch: 12.627 sec After Patch: 2.459 sec Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Tested-by: Jack Steiner <steiner@sgi.com> Acked-by: Jack Steiner <steiner@sgi.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-27procfs: fix /proc/softirqs formattingDavidlohr Bueso1-2/+2
The length of the BLOCK_IPOLL string is making i's value be printed too far to the right. This patch fixes this and makes the output a bit neater. Currently: CPU0 HI: 0 TIMER: 599792 NET_TX: 2 NET_RX: 6 BLOCK: 80807 BLOCK_IOPOLL: 0 TASKLET: 20012 SCHED: 0 HRTIMER: 63 RCU: 619279 With patch: CPU0 HI: 0 TIMER: 585582 NET_TX: 2 NET_RX: 6 BLOCK: 80320 BLOCK_IOPOLL: 0 TASKLET: 19287 SCHED: 0 HRTIMER: 62 RCU: 604441 Signed-off-by: Davidlohr Bueso <dave@gnu.org> Acked-by: Keika Kobayashi <kobayashi.kk@ncos.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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