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2013-08-21drivers: base: use standard device online/offline for state changeSeth Jennings1-10/+3
There are two ways to set the online/offline state for a memory block: echo 0|1 > online and echo online|online_kernel|online_movable|offline > state. The state attribute can online a memory block with extra data, the "online type", where the online attribute uses a default online type of ONLINE_KEEP, same as echo online > state. Currently there is a state_mutex that provides consistency between the memory block state and the underlying memory. The problem is that this code does a lot of things that the common device layer can do for us, such as the serialization of the online/offline handlers using the device lock, setting the dev->offline field, and calling kobject_uevent(). This patch refactors the online/offline code to allow the common device_[online|offline] functions to be used. The result is a simpler and more common code path for the two state setting mechanisms. It also removes the state_mutex from the struct memory_block as the memory block device lock provides the state consistency. No functional change is intended by this patch. Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-08-21drivers: base: reduce add_memory_section() for boot-time onlySeth Jennings1-1/+0
Now that add_memory_section() is only called from boot time, reduce the logic and remove the enum. Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-05-01memory hotplug: fix warningsVincent Stehlé1-1/+1
Fix the following compilation warnings: mm/slab.c: In function `kmem_cache_init_late': mm/slab.c:1778:2: warning: statement with no effect [-Wunused-value] mm/page_cgroup.c: In function `page_cgroup_init': mm/page_cgroup.c:305:2: warning: statement with no effect [-Wunused-value] Signed-off-by: Vincent Stehlé <vincent.stehle@laposte.net> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30mm, hotplug: avoid compiling memory hotremove functions when disabledDavid Rientjes1-1/+2
__remove_pages() is only necessary for CONFIG_MEMORY_HOTREMOVE. PowerPC pseries will return -EOPNOTSUPP if unsupported. Adding an #ifdef causes several other functions it depends on to also become unnecessary, which saves in .text when disabled (it's disabled in most defconfigs besides powerpc, including x86). remove_memory_block() becomes static since it is not referenced outside of drivers/base/memory.c. Build tested on x86 and powerpc with CONFIG_MEMORY_HOTREMOVE both enabled and disabled. Signed-off-by: David Rientjes <rientjes@google.com> Acked-by: Toshi Kani <toshi.kani@hp.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Wen Congyang <wency@cn.fujitsu.com> Cc: Tang Chen <tangchen@cn.fujitsu.com> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30include/linux/memory.h: implement register_hotmemory_notifier()Andrew Morton1-4/+10
When CONFIG_MEMORY_HOTPLUG=n, we don't want the memory-hotplug notifier handlers to be included in the .o files, for space reasons. The existing hotplug_memory_notifier() tries to handle this but testing with gcc-4.4.4 shows that it doesn't work - the hotplug functions are still present in the .o files. So implement a new register_hotmemory_notifier() which is a copy of register_hotcpu_notifier(), and which actually works as desired. hotplug_memory_notifier() and register_memory_notifier() callsites should be converted to use this new register_hotmemory_notifier(). While we're there, let's repair the existing hotplug_memory_notifier(): it simply stomps on the register_memory_notifier() return value, so well-behaved code cannot check for errors. Apparently non of the existing callers were well-behaved :( Cc: Andrew Shewmaker <agshew@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-13hotplug: update nodemasks managementLai Jiangshan1-0/+1
Update nodemasks management for N_MEMORY. [lliubbo@gmail.com: fix build] Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com> Cc: Christoph Lameter <cl@linux.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Lin Feng <linfeng@cn.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Bob Liu <lliubbo@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12memory_hotplug: fix possible incorrect node_states[N_NORMAL_MEMORY]Lai Jiangshan1-0/+1
Currently memory_hotplug only manages the node_states[N_HIGH_MEMORY], it forgets to manage node_states[N_NORMAL_MEMORY]. This may cause node_states[N_NORMAL_MEMORY] to become incorrect. Example, if a node is empty before online, and we online a memory which is in ZONE_NORMAL. And after online, node_states[N_HIGH_MEMORY] is correct, but node_states[N_NORMAL_MEMORY] is incorrect, the online code doesn't set the new online node to node_states[N_NORMAL_MEMORY]. The same thing will happen when offlining (the offline code doesn't clear the node from node_states[N_NORMAL_MEMORY] when needed). Some memory managment code depends node_states[N_NORMAL_MEMORY], so we have to fix up the node_states[N_NORMAL_MEMORY]. We add node_states_check_changes_online() and node_states_check_changes_offline() to detect whether node_states[N_HIGH_MEMORY] and node_states[N_NORMAL_MEMORY] are changed while hotpluging. Also add @status_change_nid_normal to struct memory_notify, thus the memory hotplug callbacks know whether the node_states[N_NORMAL_MEMORY] are changed. (We can add a @flags and reuse @status_change_nid instead of introducing @status_change_nid_normal, but it will add much more complexity in memory hotplug callback in every subsystem. So introducing @status_change_nid_normal is better and it doesn't change the sematics of @status_change_nid) Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Rob Landley <rob@landley.net> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Greg Kroah-Hartman <gregkh@suse.de> Cc: Mel Gorman <mgorman@suse.de> Cc: Wen Congyang <wency@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-09-18mm/ia64: fix a memory block size bugJianguo Wu1-1/+1
I found following definition in include/linux/memory.h, in my IA64 platform, SECTION_SIZE_BITS is equal to 32, and MIN_MEMORY_BLOCK_SIZE will be 0. #define MIN_MEMORY_BLOCK_SIZE (1 << SECTION_SIZE_BITS) Because MIN_MEMORY_BLOCK_SIZE is int type and length of 32bits, so MIN_MEMORY_BLOCK_SIZE(1 << 32) will will equal to 0. Actually when SECTION_SIZE_BITS >= 31, MIN_MEMORY_BLOCK_SIZE will be wrong. This will cause wrong system memory infomation in sysfs. I think it should be: #define MIN_MEMORY_BLOCK_SIZE (1UL << SECTION_SIZE_BITS) And "echo offline > memory0/state" will cause following call trace: kernel BUG at mm/memory_hotplug.c:885! sh[6455]: bugcheck! 0 [1] Pid: 6455, CPU 0, comm: sh psr : 0000101008526030 ifs : 8000000000000fa4 ip : [<a0000001008c40f0>] Not tainted (3.6.0-rc1) ip is at offline_pages+0x210/0xee0 Call Trace: show_stack+0x80/0xa0 show_regs+0x640/0x920 die+0x190/0x2c0 die_if_kernel+0x50/0x80 ia64_bad_break+0x3d0/0x6e0 ia64_native_leave_kernel+0x0/0x270 offline_pages+0x210/0xee0 alloc_pages_current+0x180/0x2a0 Signed-off-by: Jianguo Wu <wujianguo@huawei.com> Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Cc: "Luck, Tony" <tony.luck@intel.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-12-22convert 'memory' sysdev_class to a regular subsystemKay Sievers1-2/+1
This moves the 'memory sysdev_class' over to a regular 'memory' subsystem and converts the devices to regular devices. The sysdev drivers are implemented as subsystem interfaces now. After all sysdev classes are ported to regular driver core entities, the sysdev implementation will be entirely removed from the kernel. Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-07-12mm: Move definition of MIN_MEMORY_BLOCK_SIZE to a headerBenjamin Herrenschmidt1-0/+2
The macro MIN_MEMORY_BLOCK_SIZE is currently defined twice in two .c files, and I need it in a third one to fix a powerpc bug, so let's first move it into a header Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: Ingo Molnar <mingo@elte.hu>
2011-02-04memory hotplug: Update phys_index to [start|end]_section_nrNathan Fontenot1-1/+2
Update the 'phys_index' property of a the memory_block struct to be called start_section_nr, and add a end_section_nr property. The data tracked here is the same but the updated naming is more in line with what is stored here, namely the first and last section number that the memory block spans. The names presented to userspace remain the same, phys_index for start_section_nr and end_phys_index for end_section_nr, to avoid breaking anything in userspace. This also updates the node sysfs code to be aware of the new capability for a memory block to contain multiple memory sections and be aware of the memory block structure name changes (start_section_nr). This requires an additional parameter to unregister_mem_sect_under_nodes so that we know which memory section of the memory block to unregister. Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Reviewed-by: Robin Holt <holt@sgi.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-10-22Driver core: Add section count to memory_block structNathan Fontenot1-0/+2
Add a section count property to the memory_block struct to track the number of memory sections that have been added/removed from a memory block. This allows us to know when the last memory section of a memory block has been removed so we can remove the memory block. Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Reviewed-by: Robin Holt <holt@sgi.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-10-22driver core: Introduce find_memory_block_hinted which utilizes ↵Robin Holt1-0/+2
kset_find_obj_hinted. Introduce a find_memory_block_hinted() which utilizes the recently added kset_find_obj_hinted(). Signed-off-by: Robin Holt <holt@sgi.com> To: Dave Hansen <haveblue@us.ibm.com> To: Matt Tolentino <matthew.e.tolentino@intel.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-03-18memory hotplug: allow setting of phys_deviceHeiko Carstens1-0/+2
/sys/devices/system/memory/memoryX/phys_device is supposed to contain the number of the physical device that the corresponding piece of memory belongs to. In case a physical device should be replaced or taken offline for whatever reason it is necessary to set all corresponding memory pieces offline. The current implementation always sets phys_device to '0' and there is no way or hook to change that. Seems like there was a plan to implement that but it wasn't finished for whatever reason. So add a weak function which architectures can override to actually set the phys_device from within add_memory_block(). Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-18mm: Add notifier in pageblock isolation for balloon driversRobert Jennings1-0/+27
Memory balloon drivers can allocate a large amount of memory which is not movable but could be freed to accomodate memory hotplug remove. Prior to calling the memory hotplug notifier chain the memory in the pageblock is isolated. Currently, if the migrate type is not MIGRATE_MOVABLE the isolation will not proceed, causing the memory removal for that page range to fail. Rather than failing pageblock isolation if the migrateteype is not MIGRATE_MOVABLE, this patch checks if all of the pages in the pageblock, and not on the LRU, are owned by a registered balloon driver (or other entity) using a notifier chain. If all of the non-movable pages are owned by a balloon, they can be freed later through the memory notifier chain and the range can still be isolated in set_migratetype_isolate(). Signed-off-by: Robert Jennings <rcj@linux.vnet.ibm.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Ingo Molnar <mingo@elte.hu> Cc: Brian King <brking@linux.vnet.ibm.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Gerald Schaefer <geralds@linux.vnet.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-04-05Merge branch 'tracing-for-linus' of ↵Linus Torvalds1-0/+6
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (413 commits) tracing, net: fix net tree and tracing tree merge interaction tracing, powerpc: fix powerpc tree and tracing tree interaction ring-buffer: do not remove reader page from list on ring buffer free function-graph: allow unregistering twice trace: make argument 'mem' of trace_seq_putmem() const tracing: add missing 'extern' keywords to trace_output.h tracing: provide trace_seq_reserve() blktrace: print out BLK_TN_MESSAGE properly blktrace: extract duplidate code blktrace: fix memory leak when freeing struct blk_io_trace blktrace: fix blk_probes_ref chaos blktrace: make classic output more classic blktrace: fix off-by-one bug blktrace: fix the original blktrace blktrace: fix a race when creating blk_tree_root in debugfs blktrace: fix timestamp in binary output tracing, Text Edit Lock: cleanup tracing: filter fix for TRACE_EVENT_FORMAT events ftrace: Using FTRACE_WARN_ON() to check "freed record" in ftrace_release() x86: kretprobe-booster interrupt emulation code fix ... Fix up trivial conflicts in arch/parisc/include/asm/ftrace.h include/linux/memory.h kernel/extable.c kernel/module.c
2009-04-03memory_accessor: new interface for reading/writing persistent memoryKevin Hilman1-0/+11
Add an interface by which other kernel code can read/write persistent memory such as I2C or SPI EEPROMs, or devices which provide NVRAM. Use cases include storage of board-specific configuration data like Ethernet addresses and sensor calibrations. Original idea, review and improvement suggestions by David Brownell. Acked-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com> Cc: Jean Delvare <khali@linux-fr.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-03-06tracing, Text Edit Lock - Architecture Independent CodeMathieu Desnoyers1-0/+6
This is an architecture independant synchronization around kernel text modifications through use of a global mutex. A mutex has been chosen so that kprobes, the main user of this, can sleep during memory allocation between the memory read of the instructions it must replace and the memory write of the breakpoint. Other user of this interface: immediate values. Paravirt and alternatives are always done when SMP is inactive, so there is no need to use locks. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> LKML-Reference: <49B142D8.7020601@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-07mm: show node to memory section relationship with symlinks in sysfsGary Hade1-3/+3
Show node to memory section relationship with symlinks in sysfs Add /sys/devices/system/node/nodeX/memoryY symlinks for all the memory sections located on nodeX. For example: /sys/devices/system/node/node1/memory135 -> ../../memory/memory135 indicates that memory section 135 resides on node1. Also revises documentation to cover this change as well as updating Documentation/ABI/testing/sysfs-devices-memory to include descriptions of memory hotremove files 'phys_device', 'phys_index', and 'state' that were previously not described there. In addition to it always being a good policy to provide users with the maximum possible amount of physical location information for resources that can be hot-added and/or hot-removed, the following are some (but likely not all) of the user benefits provided by this change. Immediate: - Provides information needed to determine the specific node on which a defective DIMM is located. This will reduce system downtime when the node or defective DIMM is swapped out. - Prevents unintended onlining of a memory section that was previously offlined due to a defective DIMM. This could happen during node hot-add when the user or node hot-add assist script onlines _all_ offlined sections due to user or script inability to identify the specific memory sections located on the hot-added node. The consequences of reintroducing the defective memory could be ugly. - Provides information needed to vary the amount and distribution of memory on specific nodes for testing or debugging purposes. Future: - Will provide information needed to identify the memory sections that need to be offlined prior to physical removal of a specific node. Symlink creation during boot was tested on 2-node x86_64, 2-node ppc64, and 2-node ia64 systems. Symlink creation during physical memory hot-add tested on a 2-node x86_64 system. Signed-off-by: Gary Hade <garyhade@us.ibm.com> Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-11-30hotplug_memory_notifier section annotationAl Viro1-1/+1
Same as for hotplug_cpu - we want static notifier_block in there in meminitdata, to avoid false positives whenever it's used. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29ipc: recompute msgmni on memory add / removeNadia Derbey1-0/+1
Introduce the registration of a callback routine that recomputes msg_ctlmni upon memory add / remove. A single notifier block is registered in the hotplug memory chain for all the ipc namespaces. Since the ipc namespaces are not linked together, they have their own notification chain: one notifier_block is defined per ipc namespace. Each time an ipc namespace is created (removed) it registers (unregisters) its notifier block in (from) the ipcns chain. The callback routine registered in the memory chain invokes the ipcns notifier chain with the IPCNS_LOWMEM event. Each callback routine registered in the ipcns namespace, in turn, recomputes msgmni for the owning namespace. Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net> Cc: Yasunori Goto <y-goto@jp.fujitsu.com> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: Mingming Cao <cmm@us.ibm.com> Cc: Pierre Peiffer <pierre.peiffer@bull.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29ipc: define the slab_memory_callback priority as a constantNadia Derbey1-0/+6
This is a trivial patch that defines the priority of slab_memory_callback in the callback chain as a constant. This is to prepare for next patch in the series. Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net> Cc: Yasunori Goto <y-goto@jp.fujitsu.com> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: Mingming Cao <cmm@us.ibm.com> Cc: Pierre Peiffer <pierre.peiffer@bull.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-20driver core: memory: semaphore to mutexDaniel Walker1-3/+2
Signed-off-by: Daniel Walker <dwalker@mvista.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-22memory hotplug: make kmem_cache_node for SLUB on memory online avoid panicYasunori Goto1-0/+4
Fix a panic due to access NULL pointer of kmem_cache_node at discard_slab() after memory online. When memory online is called, kmem_cache_nodes are created for all SLUBs for new node whose memory are available. slab_mem_going_online_callback() is called to make kmem_cache_node() in callback of memory online event. If it (or other callbacks) fails, then slab_mem_offline_callback() is called for rollback. In memory offline, slab_mem_going_offline_callback() is called to shrink all slub cache, then slab_mem_offline_callback() is called later. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: locking fix] [akpm@linux-foundation.org: build fix] Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-22memory hotplug: rearrange memory hotplug notifierYasunori Goto1-12/+15
Current memory notifier has some defects yet. (Fortunately, nothing uses it.) This patch is to fix and rearrange for them. - Add information of start_pfn, nr_pages, and node id if node status is changes from/to memoryless node for callback functions. Callbacks can't do anything without those information. - Add notification going-online status. It is necessary for creating per node structure before the node's pages are available. - Move GOING_OFFLINE status notification after page isolation. It is good place for return memory like cache for callback, because returned page is not used again. - Make CANCEL events for rollingback when error occurs. - Delete MEM_MAPPING_INVALID notification. It will be not used. - Fix compile error of (un)register_memory_notifier(). Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2006-10-01[PATCH] hot-add-mem x86_64: use CONFIG_MEMORY_HOTPLUG_SPARSEKeith Mannthey1-2/+2
Migate CONFIG_MEMORY_HOTPLUG to CONFIG_MEMORY_HOTPLUG_SPARSE where needed. Signed-off-by: Keith Mannthey <kmannth@us.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Andi Kleen <ak@muc.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27[PATCH] Notifier chain update: API changesAlan Stern1-1/+0
The kernel's implementation of notifier chains is unsafe. There is no protection against entries being added to or removed from a chain while the chain is in use. The issues were discussed in this thread: http://marc.theaimsgroup.com/?l=linux-kernel&m=113018709002036&w=2 We noticed that notifier chains in the kernel fall into two basic usage classes: "Blocking" chains are always called from a process context and the callout routines are allowed to sleep; "Atomic" chains can be called from an atomic context and the callout routines are not allowed to sleep. We decided to codify this distinction and make it part of the API. Therefore this set of patches introduces three new, parallel APIs: one for blocking notifiers, one for atomic notifiers, and one for "raw" notifiers (which is really just the old API under a new name). New kinds of data structures are used for the heads of the chains, and new routines are defined for registration, unregistration, and calling a chain. The three APIs are explained in include/linux/notifier.h and their implementation is in kernel/sys.c. With atomic and blocking chains, the implementation guarantees that the chain links will not be corrupted and that chain callers will not get messed up by entries being added or removed. For raw chains the implementation provides no guarantees at all; users of this API must provide their own protections. (The idea was that situations may come up where the assumptions of the atomic and blocking APIs are not appropriate, so it should be possible for users to handle these things in their own way.) There are some limitations, which should not be too hard to live with. For atomic/blocking chains, registration and unregistration must always be done in a process context since the chain is protected by a mutex/rwsem. Also, a callout routine for a non-raw chain must not try to register or unregister entries on its own chain. (This did happen in a couple of places and the code had to be changed to avoid it.) Since atomic chains may be called from within an NMI handler, they cannot use spinlocks for synchronization. Instead we use RCU. The overhead falls almost entirely in the unregister routine, which is okay since unregistration is much less frequent that calling a chain. Here is the list of chains that we adjusted and their classifications. None of them use the raw API, so for the moment it is only a placeholder. ATOMIC CHAINS ------------- arch/i386/kernel/traps.c: i386die_chain arch/ia64/kernel/traps.c: ia64die_chain arch/powerpc/kernel/traps.c: powerpc_die_chain arch/sparc64/kernel/traps.c: sparc64die_chain arch/x86_64/kernel/traps.c: die_chain drivers/char/ipmi/ipmi_si_intf.c: xaction_notifier_list kernel/panic.c: panic_notifier_list kernel/profile.c: task_free_notifier net/bluetooth/hci_core.c: hci_notifier net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_chain net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_expect_chain net/ipv6/addrconf.c: inet6addr_chain net/netfilter/nf_conntrack_core.c: nf_conntrack_chain net/netfilter/nf_conntrack_core.c: nf_conntrack_expect_chain net/netlink/af_netlink.c: netlink_chain BLOCKING CHAINS --------------- arch/powerpc/platforms/pseries/reconfig.c: pSeries_reconfig_chain arch/s390/kernel/process.c: idle_chain arch/x86_64/kernel/process.c idle_notifier drivers/base/memory.c: memory_chain drivers/cpufreq/cpufreq.c cpufreq_policy_notifier_list drivers/cpufreq/cpufreq.c cpufreq_transition_notifier_list drivers/macintosh/adb.c: adb_client_list drivers/macintosh/via-pmu.c sleep_notifier_list drivers/macintosh/via-pmu68k.c sleep_notifier_list drivers/macintosh/windfarm_core.c wf_client_list drivers/usb/core/notify.c usb_notifier_list drivers/video/fbmem.c fb_notifier_list kernel/cpu.c cpu_chain kernel/module.c module_notify_list kernel/profile.c munmap_notifier kernel/profile.c task_exit_notifier kernel/sys.c reboot_notifier_list net/core/dev.c netdev_chain net/decnet/dn_dev.c: dnaddr_chain net/ipv4/devinet.c: inetaddr_chain It's possible that some of these classifications are wrong. If they are, please let us know or submit a patch to fix them. Note that any chain that gets called very frequently should be atomic, because the rwsem read-locking used for blocking chains is very likely to incur cache misses on SMP systems. (However, if the chain's callout routines may sleep then the chain cannot be atomic.) The patch set was written by Alan Stern and Chandra Seetharaman, incorporating material written by Keith Owens and suggestions from Paul McKenney and Andrew Morton. [jes@sgi.com: restructure the notifier chain initialization macros] Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Signed-off-by: Jes Sorensen <jes@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-09[PATCH] Fix compilation with CONFIG_MEMORY_HOTPLUG=y and gcc41.Olaf Hering1-7/+1
Fix compilation with CONFIG_MEMORY_HOTPLUG=y and gcc41. Also remove unneeded declations, add a public function. drivers/base/memory.c:53: error: static declaration of 'register_memory_notifier' follows non-static declaration include/linux/memory.h:85: error: previous declaration of 'register_memory_notifier' was here drivers/base/memory.c:58: error: static declaration of 'unregister_memory_notifier' follows non-static declaration include/linux/memory.h:86: error: previous declaration of 'unregister_memory_notifier' was here drivers/base/memory.c:68: error: static declaration of 'register_memory' follows non-static declaration include/linux/memory.h:73: error: previous declaration of 'register_memory' was here Signed-off-by: Olaf Hering <olh@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-29[PATCH] memory_sysdev_class is staticAndrew Morton1-1/+0
So don't define it as extern in the header file. drivers/base/memory.c:28: error: static declaration of 'memory_sysdev_class' follows non-static declaration include/linux/memory.h:88: error: previous declaration of 'memory_sysdev_class' was here Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07[PATCH] fix remaining missing includesTim Schmielau1-0/+3
Fix more include file problems that surfaced since I submitted the previous fix-missing-includes.patch. This should now allow not to include sched.h from module.h, which is done by a followup patch. Signed-off-by: Tim Schmielau <tim@physik3.uni-rostock.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30[PATCH] memory hotplug: sysfs and add/remove functionsDave Hansen1-0/+94
This adds generic memory add/remove and supporting functions for memory hotplug into a new file as well as a memory hotplug kernel config option. Individual architecture patches will follow. For now, disable memory hotplug when swsusp is enabled. There's a lot of churn there right now. We'll fix it up properly once it calms down. Signed-off-by: Matt Tolentino <matthew.e.tolentino@intel.com> Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>