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path: root/Documentation/vm/pagemap.txt
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2013-07-04Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial Pull trivial tree updates from Jiri Kosina: "The usual stuff from trivial tree" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (34 commits) treewide: relase -> release Documentation/cgroups/memory.txt: fix stat file documentation sysctl/net.txt: delete reference to obsolete 2.4.x kernel spinlock_api_smp.h: fix preprocessor comments treewide: Fix typo in printk doc: device tree: clarify stuff in usage-model.txt. open firmware: "/aliasas" -> "/aliases" md: bcache: Fixed a typo with the word 'arithmetic' irq/generic-chip: fix a few kernel-doc entries frv: Convert use of typedef ctl_table to struct ctl_table sgi: xpc: Convert use of typedef ctl_table to struct ctl_table doc: clk: Fix incorrect wording Documentation/arm/IXP4xx fix a typo Documentation/networking/ieee802154 fix a typo Documentation/DocBook/media/v4l fix a typo Documentation/video4linux/si476x.txt fix a typo Documentation/virtual/kvm/api.txt fix a typo Documentation/early-userspace/README fix a typo Documentation/video4linux/soc-camera.txt fix a typo lguest: fix CONFIG_PAE -> CONFIG_x86_PAE in comment ...
2013-07-03pagemap: prepare to reuse constant bits with page-shiftPavel Emelyanov
In order to reuse bits from pagemap entries gracefully, we leave the entries as is but on pagemap open emit a warning in dmesg, that bits 55-60 are about to change in a couple of releases. Next, if a user issues soft-dirty clear command via the clear_refs file (it was disabled before v3.9) we assume that he's aware of the new pagemap format, note that fact and report the bits in pagemap in the new manner. The "migration strategy" looks like this then: 1. existing users are not affected -- they don't touch soft-dirty feature, thus see old bits in pagemap, but are warned and have time to fix themselves 2. those who use soft-dirty know about new pagemap format 3. some time soon we get rid of any signs of page-shift in pagemap as well as this trick with clear-soft-dirty affecting pagemap format. Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Cc: Matt Mackall <mpm@selenic.com> Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Cc: Glauber Costa <glommer@parallels.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-05-28doc: fix misspellings with 'codespell' toolAnatol Pomozov
Signed-off-by: Anatol Pomozov <anatol.pomozov@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2012-05-31proc: report file/anon bit in /proc/pid/pagemapKonstantin Khlebnikov
This is an implementation of Andrew's proposal to extend the pagemap file bits to report what is missing about tasks' working set. The problem with the working set detection is multilateral. In the criu (checkpoint/restore) project we dump the tasks' memory into image files and to do it properly we need to detect which pages inside mappings are really in use. The mincore syscall I though could help with this did not. First, it doesn't report swapped pages, thus we cannot find out which parts of anonymous mappings to dump. Next, it does report pages from page cache as present even if they are not mapped, and it doesn't make that has not been cow-ed. Note, that issue with swap pages is critical -- we must dump swap pages to image file. But the issues with file pages are optimization -- we can take all file pages to image, this would be correct, but if we know that a page is not mapped or not cow-ed, we can remove them from dump file. The dump would still be self-consistent, though significantly smaller in size (up to 10 times smaller on real apps). Andrew noticed, that the proc pagemap file solved 2 of 3 above issues -- it reports whether a page is present or swapped and it doesn't report not mapped page cache pages. But, it doesn't distinguish cow-ed file pages from not cow-ed. I would like to make the last unused bit in this file to report whether the page mapped into respective pte is PageAnon or not. [comment stolen from Pavel Emelyanov's v1 patch] Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Matt Mackall <mpm@selenic.com> Cc: Hugh Dickins <hughd@google.com> Cc: Rik van Riel <riel@redhat.com> Acked-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>
2012-03-21pagemap: document KPF_THP and make page-types aware of itNaoya Horiguchi
page-types, which is a common user of pagemap, gets aware of thp with this patch. This helps system admins and kernel hackers know about how thp works. Here is a sample output of page-types over a thp: $ page-types -p <pid> --raw --list voffset offset len flags ... 7f9d40200 3f8400 1 ___U_lA____Ma_bH______t____________ 7f9d40201 3f8401 1ff ________________T_____t____________ flags page-count MB symbolic-flags long-symbolic-flags 0x0000000000410000 511 1 ________________T_____t____________ compound_tail,thp 0x000000000040d868 1 0 ___U_lA____Ma_bH______t____________ uptodate,lru,active,mmap,anonymous,swapbacked,compound_head,thp Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: Wu Fengguang <fengguang.wu@intel.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-08pagemap: document KPF_KSM and show it in page-typesWu Fengguang
It indicates to the system admin that processes mapping such pages may be eating less physical memory than the reported numbers by legacy tools. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: Izik Eidus <ieidus@redhat.com> Acked-by: Chris Wright <chrisw@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-08pagemap: export KPF_HWPOISONWu Fengguang
This flag indicates a hardware detected memory corruption on the page. Any future access of the page data may bring down the machine. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Andi Kleen <andi@firstfloor.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-16pagemap: document 9 more exported page flagsWu Fengguang
Also add short descriptions for all of the 20 exported page flags. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Matt Mackall <mpm@selenic.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-16pagemap: document clarificationsWu Fengguang
Some bit ranges were inclusive and some not. Fix them to be consistently inclusive. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Matt Mackall <mpm@selenic.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-06-06pagemap: add documentation for pagemapThomas Tuttle
Just a quick explanation of the pagemap interface from a userspace point of view, and an example of how to use it (in English, not code). Signed-off-by: Thomas Tuttle <ttuttle@google.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>