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2013-11-13mm: do not walk all of system memory during show_memMel Gorman
It has been reported on very large machines that show_mem is taking almost 5 minutes to display information. This is a serious problem if there is an OOM storm. The bulk of the cost is in show_mem doing a very expensive PFN walk to give us the following information Total RAM: Also available as totalram_pages Highmem pages: Also available as totalhigh_pages Reserved pages: Can be inferred from the zone structure Shared pages: PFN walk required Unshared pages: PFN walk required Quick pages: Per-cpu walk required Only the shared/unshared pages requires a full PFN walk but that information is useless. It is also inaccurate as page pins of unshared pages would be accounted for as shared. Even if the information was accurate, I'm struggling to think how the shared/unshared information could be useful for debugging OOM conditions. Maybe it was useful before rmap existed when reclaiming shared pages was costly but it is less relevant today. The PFN walk could be optimised a bit but why bother as the information is useless. This patch deletes the PFN walker and infers the total RAM, highmem and reserved pages count from struct zone. It omits the shared/unshared page usage on the grounds that it is useless. It also corrects the reporting of HighMem as HighMem/MovableOnly as ZONE_MOVABLE has similar problems to HighMem with respect to lowmem/highmem exhaustion. Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: David Rientjes <rientjes@google.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>
2013-04-29mm, show_mem: suppress page counts in non-blockable contextsDavid Rientjes
On large systems with a lot of memory, walking all RAM to determine page types may take a half second or even more. In non-blockable contexts, the page allocator will emit a page allocation failure warning unless __GFP_NOWARN is specified. In such contexts, irqs are typically disabled and such a lengthy delay may even result in NMI watchdog timeouts. To fix this, suppress the page walk in such contexts when printing the page allocation failure warning. Signed-off-by: David Rientjes <rientjes@google.com> Cc: Mel Gorman <mgorman@suse.de> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25arch, mm: filter disallowed nodes from arch specific show_mem functionsDavid Rientjes
Architectures that implement their own show_mem() function did not pass the filter argument to show_free_areas() to appropriately avoid emitting the state of nodes that are disallowed in the current context. This patch now passes the filter argument to show_free_areas() so those nodes are now avoided. This patch also removes the show_free_areas() wrapper around __show_free_areas() and converts existing callers to pass an empty filter. ia64 emits additional information for each node, so skip_free_areas_zone() must be made global to filter disallowed nodes and it is converted to use a nid argument rather than a zone for this use case. Signed-off-by: David Rientjes <rientjes@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Helge Deller <deller@gmx.de> Cc: James Bottomley <jejb@parisc-linux.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-24lib, arch: add filter argument to show_mem and fix private implementationsDavid Rientjes
Commit ddd588b5dd55 ("oom: suppress nodes that are not allowed from meminfo on oom kill") moved lib/show_mem.o out of lib/lib.a, which resulted in build warnings on all architectures that implement their own versions of show_mem(): lib/lib.a(show_mem.o): In function `show_mem': show_mem.c:(.text+0x1f4): multiple definition of `show_mem' arch/sparc/mm/built-in.o:(.text+0xd70): first defined here The fix is to remove __show_mem() and add its argument to show_mem() in all implementations to prevent this breakage. Architectures that implement their own show_mem() actually don't do anything with the argument yet, but they could be made to filter nodes that aren't allowed in the current context in the future just like the generic implementation. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Reported-by: James Bottomley <James.Bottomley@hansenpartnership.com> Suggested-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-22oom: suppress nodes that are not allowed from meminfo on oom killDavid Rientjes
The oom killer is extremely verbose for machines with a large number of cpus and/or nodes. This verbosity can often be harmful if it causes other important messages to be scrolled from the kernel log and incurs a signicant time delay, specifically for kernels with CONFIG_NODES_SHIFT > 8. This patch causes only memory information to be displayed for nodes that are allowed by current's cpuset when dumping the VM state. Information for all other nodes is irrelevant to the oom condition; we don't care if there's an abundance of memory elsewhere if we can't access it. This only affects the behavior of dumping memory information when an oom is triggered. Other dumps, such as for sysrq+m, still display the unfiltered form when using the existing show_mem() interface. Additionally, the per-cpu pageset statistics are extremely verbose in oom killer output, so it is now suppressed. This removes nodes_weight(current->mems_allowed) * (1 + nr_cpus) lines from the oom killer output. Callers may use __show_mem(SHOW_MEM_FILTER_NODES) to filter disallowed nodes. Signed-off-by: David Rientjes <rientjes@google.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: 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>
2010-03-06mm: use the same log level for show_mem()Amerigo Wang
Use the same log level for printk's in show_mem(), so that those messages can be shown completely when using log level 6. Signed-off-by: WANG Cong <amwang@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-26lib: generic show_mem()Johannes Weiner
This implements a platform-independent version of show_mem(). Signed-off-by: Johannes Weiner <hannes@saeurebad.de> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Haavard Skinnemoen <hskinnemoen@atmel.com> Cc: Bryan Wu <cooloney@kernel.org> Cc: Chris Zankel <chris@zankel.net> Cc: Ingo Molnar <mingo@elte.hu> Cc: Jeff Dike <jdike@addtoit.com> Cc: David S. Miller <davem@davemloft.net> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: David Howells <dhowells@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Greg Ungerer <gerg@uclinux.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Hirokazu Takata <takata@linux-m32r.org> Cc: Mikael Starvik <starvik@axis.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>