path: root/mm/Kconfig
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2010-03-03Merge branch 'x86-bootmem-for-linus' of ↵Linus Torvalds
git:// * 'x86-bootmem-for-linus' of git:// (30 commits) early_res: Need to save the allocation name in drop_range_partial() sparsemem: Fix compilation on PowerPC early_res: Add free_early_partial() x86: Fix non-bootmem compilation on PowerPC core: Move early_res from arch/x86 to kernel/ x86: Add find_fw_memmap_area Move round_up/down to kernel.h x86: Make 32bit support NO_BOOTMEM early_res: Enhance check_and_double_early_res x86: Move back find_e820_area to e820.c x86: Add find_early_area_size x86: Separate early_res related code from e820.c x86: Move bios page reserve early to head32/64.c sparsemem: Put mem map for one node together. sparsemem: Put usemap for one node together x86: Make 64 bit use early_res instead of bootmem before slab x86: Only call dma32_reserve_bootmem 64bit !CONFIG_NUMA x86: Make early_node_mem get mem > 4 GB if possible x86: Dynamically increase early_res array size x86: Introduce max_early_res and early_res_count ...
2010-02-12sparsemem: Put mem map for one node together.Yinghai Lu
Add vmemmap_alloc_block_buf for mem map only. It will fallback to the old way if it cannot get a block that big. Before this patch, when a node have 128g ram installed, memmap are split into two parts or more. [ 0.000000] [ffffea0000000000-ffffea003fffffff] PMD -> [ffff880100600000-ffff88013e9fffff] on node 1 [ 0.000000] [ffffea0040000000-ffffea006fffffff] PMD -> [ffff88013ec00000-ffff88016ebfffff] on node 1 [ 0.000000] [ffffea0070000000-ffffea007fffffff] PMD -> [ffff882000600000-ffff8820105fffff] on node 0 [ 0.000000] [ffffea0080000000-ffffea00bfffffff] PMD -> [ffff882010800000-ffff8820507fffff] on node 0 [ 0.000000] [ffffea00c0000000-ffffea00dfffffff] PMD -> [ffff882050a00000-ffff8820709fffff] on node 0 [ 0.000000] [ffffea00e0000000-ffffea00ffffffff] PMD -> [ffff884000600000-ffff8840205fffff] on node 2 [ 0.000000] [ffffea0100000000-ffffea013fffffff] PMD -> [ffff884020800000-ffff8840607fffff] on node 2 [ 0.000000] [ffffea0140000000-ffffea014fffffff] PMD -> [ffff884060a00000-ffff8840709fffff] on node 2 [ 0.000000] [ffffea0150000000-ffffea017fffffff] PMD -> [ffff886000600000-ffff8860305fffff] on node 3 [ 0.000000] [ffffea0180000000-ffffea01bfffffff] PMD -> [ffff886030800000-ffff8860707fffff] on node 3 [ 0.000000] [ffffea01c0000000-ffffea01ffffffff] PMD -> [ffff888000600000-ffff8880405fffff] on node 4 [ 0.000000] [ffffea0200000000-ffffea022fffffff] PMD -> [ffff888040800000-ffff8880707fffff] on node 4 [ 0.000000] [ffffea0230000000-ffffea023fffffff] PMD -> [ffff88a000600000-ffff88a0105fffff] on node 5 [ 0.000000] [ffffea0240000000-ffffea027fffffff] PMD -> [ffff88a010800000-ffff88a0507fffff] on node 5 [ 0.000000] [ffffea0280000000-ffffea029fffffff] PMD -> [ffff88a050a00000-ffff88a0709fffff] on node 5 [ 0.000000] [ffffea02a0000000-ffffea02bfffffff] PMD -> [ffff88c000600000-ffff88c0205fffff] on node 6 [ 0.000000] [ffffea02c0000000-ffffea02ffffffff] PMD -> [ffff88c020800000-ffff88c0607fffff] on node 6 [ 0.000000] [ffffea0300000000-ffffea030fffffff] PMD -> [ffff88c060a00000-ffff88c0709fffff] on node 6 [ 0.000000] [ffffea0310000000-ffffea033fffffff] PMD -> [ffff88e000600000-ffff88e0305fffff] on node 7 [ 0.000000] [ffffea0340000000-ffffea037fffffff] PMD -> [ffff88e030800000-ffff88e0707fffff] on node 7 after patch will get [ 0.000000] [ffffea0000000000-ffffea006fffffff] PMD -> [ffff880100200000-ffff88016e5fffff] on node 0 [ 0.000000] [ffffea0070000000-ffffea00dfffffff] PMD -> [ffff882000200000-ffff8820701fffff] on node 1 [ 0.000000] [ffffea00e0000000-ffffea014fffffff] PMD -> [ffff884000200000-ffff8840701fffff] on node 2 [ 0.000000] [ffffea0150000000-ffffea01bfffffff] PMD -> [ffff886000200000-ffff8860701fffff] on node 3 [ 0.000000] [ffffea01c0000000-ffffea022fffffff] PMD -> [ffff888000200000-ffff8880701fffff] on node 4 [ 0.000000] [ffffea0230000000-ffffea029fffffff] PMD -> [ffff88a000200000-ffff88a0701fffff] on node 5 [ 0.000000] [ffffea02a0000000-ffffea030fffffff] PMD -> [ffff88c000200000-ffff88c0701fffff] on node 6 [ 0.000000] [ffffea0310000000-ffffea037fffffff] PMD -> [ffff88e000200000-ffff88e0701fffff] on node 7 -v2: change buf to vmemmap_buf instead according to Ingo also add CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER according to Ingo -v3: according to Andrew, use sizeof(name) instead of hard coded 15 Signed-off-by: Yinghai Lu <> LKML-Reference: <> Cc: Christoph Lameter <> Acked-by: Christoph Lameter <> Signed-off-by: H. Peter Anvin <>
2010-01-05sh: Drop down to a single quicklist.Paul Mundt
We previously had 2 quicklists, one for the PGD case and one for PTEs. Now that the PGD/PMD cases are handled through slab caches due to the multi-level configurability, only the PTE quicklist remains. As such, reduce NR_QUICK to its appropriate size and bump down the PTE quicklist index. Signed-off-by: Paul Mundt <>
2009-12-21HWPOISON: Add PROC_FS dependency to hwpoison injector v2Andi Kleen
The injector filter requires stable_page_flags() which is supplied by procfs. So make it dependent on that. Also add ifdefs around the filter code in memory-failure.c so that when the filter is disabled due to missing dependencies the whole code still builds. Reported-by: Ingo Molnar Signed-off-by: Andi Kleen <>
2009-12-17NOMMU: Optimise away the {dac_,}mmap_min_addr testsDavid Howells
In NOMMU mode clamp dac_mmap_min_addr to zero to cause the tests on it to be skipped by the compiler. We do this as the minimum mmap address doesn't make any sense in NOMMU mode. mmap_min_addr and round_hint_to_min() can be discarded entirely in NOMMU mode. Signed-off-by: David Howells <> Acked-by: Eric Paris <> Signed-off-by: James Morris <>
2009-12-16HWPOISON: mention HWPoison in Kconfig entryAndi Kleen
Signed-off-by: Andi Kleen <>
2009-12-16HWPOISON: add page flags filterWu Fengguang
When specified, only poison pages if ((page_flags & mask) == value). - corrupt-filter-flags-mask - corrupt-filter-flags-value This allows stress testing of many kinds of pages. Strictly speaking, the buddy pages requires taking zone lock, to avoid setting PG_hwpoison on a "was buddy but now allocated to someone" page. However we can just do nothing because we set PG_locked in the beginning, this prevents the page allocator from allocating it to someone. (It will BUG() on the unexpected PG_locked, which is fine for hwpoison testing.) [AK: Add select PROC_PAGE_MONITOR to satisfy dependency] CC: Nick Piggin <> Signed-off-by: Wu Fengguang <> Signed-off-by: Andi Kleen <>
2009-12-15ksm: remove unswappable max_kernel_pagesHugh Dickins
Now that ksm pages are swappable, and the known holes plugged, remove mention of unswappable kernel pages from KSM documentation and comments. Remove the totalram_pages/4 initialization of max_kernel_pages. In fact, remove max_kernel_pages altogether - we can reinstate it if removal turns out to break someone's script; but if we later want to limit KSM's memory usage, limiting the stable nodes would not be an effective approach. Signed-off-by: Hugh Dickins <> Cc: Izik Eidus <> Cc: Andrea Arcangeli <> Cc: Chris Wright <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-12-15mm: stop ptlock enlarging struct pageHugh Dickins
CONFIG_DEBUG_SPINLOCK adds 12 or 16 bytes to a 32- or 64-bit spinlock_t, and CONFIG_DEBUG_LOCK_ALLOC adds another 12 or 24 bytes to it: lockdep enables both of those, and CONFIG_LOCK_STAT adds 8 or 16 bytes to that. When 2.6.15 placed the split page table lock inside struct page (usually sized 32 or 56 bytes), only CONFIG_DEBUG_SPINLOCK was a possibility, and we ignored the enlargement (but fitted in CONFIG_GENERIC_LOCKBREAK's 4 by letting the spinlock_t occupy both page->private and page->mapping). Should these debugging options be allowed to double the size of a struct page, when only one minority use of the page (as a page table) needs to fit a spinlock in there? Perhaps not. Take the easy way out: switch off SPLIT_PTLOCK_CPUS when DEBUG_SPINLOCK or DEBUG_LOCK_ALLOC is in force. I've sometimes tried to be cleverer, kmallocing a cacheline for the spinlock when it doesn't fit, but given up each time. Falling back to mm->page_table_lock (as we do when ptlock is not split) lets lockdep check out the strictest path anyway. And now that some arches allow 8192 cpus, use 999999 for infinity. (What has this got to do with KSM swapping? It doesn't care about the size of struct page, but may care about random junk in page->mapping - to be explained separately later.) Signed-off-by: Hugh Dickins <> Cc: Izik Eidus <> Cc: Andrea Arcangeli <> Cc: Nick Piggin <> Cc: KOSAKI Motohiro <> Cc: Rik van Riel <> Cc: Lee Schermerhorn <> Cc: Andi Kleen <> Cc: KAMEZAWA Hiroyuki <> Cc: Wu Fengguang <> Cc: Minchan Kim <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-12-15mm: CONFIG_MMU for PG_mlockedHugh Dickins
Remove three degrees of obfuscation, left over from when we had CONFIG_UNEVICTABLE_LRU. MLOCK_PAGES is CONFIG_HAVE_MLOCKED_PAGE_BIT is CONFIG_HAVE_MLOCK is CONFIG_MMU. rmap.o (and memory-failure.o) are only built when CONFIG_MMU, so don't need such conditions at all. Somehow, I feel no compulsion to remove the CONFIG_HAVE_MLOCK* lines from 169 defconfigs: leave those to evolve in due course. Signed-off-by: Hugh Dickins <> Cc: Izik Eidus <> Cc: Andrea Arcangeli <> Cc: Nick Piggin <> Reviewed-by: KOSAKI Motohiro <> Cc: Rik van Riel <> Cc: Lee Schermerhorn <> Cc: Andi Kleen <> Cc: KAMEZAWA Hiroyuki <> Cc: Wu Fengguang <> Cc: Minchan Kim <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-11-17mm: allow memory hotplug and hibernation in the same kernelAndi Kleen
Allow memory hotplug and hibernation in the same kernel Memory hotplug and hibernation were exclusive in Kconfig. This is obviously a problem for distribution kernels who want to support both in the same image. After some discussions with Rafael and others the only problem is with parallel memory hotadd or removal while a hibernation operation is in process. It was also working for s390 before. This patch removes the Kconfig level exclusion, and simply makes the memory add / remove functions grab the pm_mutex to exclude against hibernation. Fixes a regression - old kernels didn't exclude memory hotadd and hibernation. Signed-off-by: Andi Kleen <> Cc: Gerald Schaefer <> Cc: KOSAKI Motohiro <> Cc: Yasunori Goto <> Acked-by: Rafael J. Wysocki <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-10-29Merge branch 'merge' of ↵Linus Torvalds
git:// * 'merge' of git:// powerpc/ppc64: Use preempt_schedule_irq instead of preempt_schedule powerpc: Minor cleanup to lib/Kconfig.debug powerpc: Minor cleanup to sound/ppc/Kconfig powerpc: Minor cleanup to init/Kconfig powerpc: Limit memory hotplug support to PPC64 Book-3S machines powerpc: Limit hugetlbfs support to PPC64 Book-3S machines powerpc: Fix compile errors found by new ppc64e_defconfig powerpc: Add a Book-3E 64-bit defconfig powerpc/booke: Fix xmon single step on PowerPC Book-E powerpc: Align vDSO base address powerpc: Fix segment mapping in vdso32 powerpc/iseries: Remove compiler version dependent hack powerpc/perf_events: Fix priority of MSR HV vs PR bits powerpc/5200: Update defconfigs drivers/serial/mpc52xx_uart.c: Use UPIO_MEM rather than SERIAL_IO_MEM powerpc/boot/dts: drop obsolete 'fsl5200-clocking' of: Remove nested function mpc5200: support for the MAN mpc5200 based board mucmc52 mpc5200: support for the MAN mpc5200 based board uc101
2009-10-29mm: fix sparsemem configurationRussell King
Currently, sparsemem is only available if EXPERIMENTAL is enabled. However, it hasn't ever been marked experimental. It's been about four years since sparsemem was merged, and we have platforms which depend on it; allow architectures to decide whether sparsemem should be the default memory model. Signed-off-by: Russell King <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-10-27powerpc: Limit memory hotplug support to PPC64 Book-3S machinesKumar Gala
Signed-off-by: Kumar Gala <> Signed-off-by: Benjamin Herrenschmidt <>
2009-10-08ksm: more on default valuesHugh Dickins
Adjust the max_kernel_pages default to a quarter of totalram_pages, instead of nr_free_buffer_pages() / 4: the KSM pages themselves come from highmem, and even on a 16GB PAE machine, 4GB of KSM pages would only be pinning 32MB of lowmem with their rmap_items, so no need for the more obscure calculation (nor for its own special init function). There is no way for the user to switch KSM on if CONFIG_SYSFS is not enabled, so in that case default run to KSM_RUN_MERGE. Update KSM Documentation and Kconfig to reflect the new defaults. Signed-off-by: Hugh Dickins <> Cc: Izik Eidus <> Cc: Andrea Arcangeli <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-09-27x86: Fix hwpoison code related build failure on 32-bit NUMAQLinus Torvalds
This build failure triggers: In file included from include/linux/suspend.h:8, from arch/x86/kernel/asm-offsets_32.c:11, from arch/x86/kernel/asm-offsets.c:2: include/linux/mm.h:503:2: error: #error SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS Because due to the hwpoison page flag we ran out of page flags on 32-bit. Dont turn on hwpoison on 32-bit NUMA (it's rare in any case). Also clean up the Kconfig dependencies in the generic MM code by introducing ARCH_SUPPORTS_MEMORY_FAILURE. Signed-off-by: Linus Torvalds <> Signed-off-by: Ingo Molnar <>
2009-09-24Merge branch 'hwpoison' of ↵Linus Torvalds
git:// * 'hwpoison' of git:// (21 commits) HWPOISON: Enable error_remove_page on btrfs HWPOISON: Add simple debugfs interface to inject hwpoison on arbitary PFNs HWPOISON: Add madvise() based injector for hardware poisoned pages v4 HWPOISON: Enable error_remove_page for NFS HWPOISON: Enable .remove_error_page for migration aware file systems HWPOISON: The high level memory error handler in the VM v7 HWPOISON: Add PR_MCE_KILL prctl to control early kill behaviour per process HWPOISON: shmem: call set_page_dirty() with locked page HWPOISON: Define a new error_remove_page address space op for async truncation HWPOISON: Add invalidate_inode_page HWPOISON: Refactor truncate to allow direct truncating of page v2 HWPOISON: check and isolate corrupted free pages v2 HWPOISON: Handle hardware poisoned pages in try_to_unmap HWPOISON: Use bitmask/action code for try_to_unmap behaviour HWPOISON: x86: Add VM_FAULT_HWPOISON handling to x86 page fault handler v2 HWPOISON: Add poison check to page fault handling HWPOISON: Add basic support for poisoned pages in fault handler v3 HWPOISON: Add new SIGBUS error codes for hardware poison signals HWPOISON: Add support for poison swap entries v2 HWPOISON: Export some rmap vma locking to outside world ...
2009-09-22ksm: add some documentationHugh Dickins
Add Documentation/vm/ksm.txt: how to use the Kernel Samepage Merging feature Signed-off-by: Hugh Dickins <> Cc: Michael Kerrisk <> Cc: Randy Dunlap <> Acked-by: Izik Eidus <> Cc: Andrea Arcangeli <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-09-22ksm: the mm interface to ksmHugh Dickins
This patch presents the mm interface to a dummy version of ksm.c, for better scrutiny of that interface: the real ksm.c follows later. When CONFIG_KSM is not set, madvise(2) reject MADV_MERGEABLE and MADV_UNMERGEABLE with EINVAL, since that seems more helpful than pretending that they can be serviced. But when CONFIG_KSM=y, accept them even if KSM is not currently running, and even on areas which KSM will not touch (e.g. hugetlb or shared file or special driver mappings). Like other madvices, report ENOMEM despite success if any area in the range is unmapped, and use EAGAIN to report out of memory. Define vma flag VM_MERGEABLE to identify an area on which KSM may try merging pages: leave it to ksm_madvise() to decide whether to set it. Define mm flag MMF_VM_MERGEABLE to identify an mm which might contain VM_MERGEABLE areas, to minimize callouts when forking or exiting. Based upon earlier patches by Chris Wright and Izik Eidus. Signed-off-by: Hugh Dickins <> Signed-off-by: Chris Wright <> Signed-off-by: Izik Eidus <> Cc: Michael Kerrisk <> Cc: Andrea Arcangeli <> Cc: Rik van Riel <> Cc: Wu Fengguang <> Cc: Balbir Singh <> Cc: Hugh Dickins <> Cc: KAMEZAWA Hiroyuki <> Cc: Lee Schermerhorn <> Cc: Avi Kivity <> Cc: Nick Piggin <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-09-16HWPOISON: Add simple debugfs interface to inject hwpoison on arbitary PFNsAndi Kleen
Useful for some testing scenarios, although specific testing is often done better through MADV_POISON This can be done with the x86 level MCE injector too, but this interface allows it to do independently from low level x86 changes. v2: Add module license (Haicheng Li) Signed-off-by: Andi Kleen <>
2009-09-16HWPOISON: The high level memory error handler in the VM v7Andi Kleen
Add the high level memory handler that poisons pages that got corrupted by hardware (typically by a two bit flip in a DIMM or a cache) on the Linux level. The goal is to prevent everyone from accessing these pages in the future. This done at the VM level by marking a page hwpoisoned and doing the appropriate action based on the type of page it is. The code that does this is portable and lives in mm/memory-failure.c To quote the overview comment: High level machine check handler. Handles pages reported by the hardware as being corrupted usually due to a 2bit ECC memory or cache failure. This focuses on pages detected as corrupted in the background. When the current CPU tries to consume corruption the currently running process can just be killed directly instead. This implies that if the error cannot be handled for some reason it's safe to just ignore it because no corruption has been consumed yet. Instead when that happens another machine check will happen. Handles page cache pages in various states. The tricky part here is that we can access any page asynchronous to other VM users, because memory failures could happen anytime and anywhere, possibly violating some of their assumptions. This is why this code has to be extremely careful. Generally it tries to use normal locking rules, as in get the standard locks, even if that means the error handling takes potentially a long time. Some of the operations here are somewhat inefficient and have non linear algorithmic complexity, because the data structures have not been optimized for this case. This is in particular the case for the mapping from a vma to a process. Since this case is expected to be rare we hope we can get away with this. There are in principle two strategies to kill processes on poison: - just unmap the data and wait for an actual reference before killing - kill as soon as corruption is detected. Both have advantages and disadvantages and should be used in different situations. Right now both are implemented and can be switched with a new sysctl vm.memory_failure_early_kill The default is early kill. The patch does some rmap data structure walking on its own to collect processes to kill. This is unusual because normally all rmap data structure knowledge is in rmap.c only. I put it here for now to keep everything together and rmap knowledge has been seeping out anyways Includes contributions from Johannes Weiner, Chris Mason, Fengguang Wu, Nick Piggin (who did a lot of great work) and others. Cc: Cc: Signed-off-by: Andi Kleen <> Acked-by: Rik van Riel <> Reviewed-by: Hidehiro Kawai <>
2009-09-15Merge branch 'x86-pat-for-linus' of ↵Linus Torvalds
git:// * 'x86-pat-for-linus' of git:// x86, pat: Fix cacheflush address in change_page_attr_set_clr() mm: remove !NUMA condition from PAGEFLAGS_EXTENDED condition set x86: Fix earlyprintk=dbgp for machines without NX x86, pat: Sanity check remap_pfn_range for RAM region x86, pat: Lookup the protection from memtype list on vm_insert_pfn() x86, pat: Add lookup_memtype to get the current memtype of a paddr x86, pat: Use page flags to track memtypes of RAM pages x86, pat: Generalize the use of page flag PG_uncached x86, pat: Add rbtree to do quick lookup in memtype tracking x86, pat: Add PAT reserve free to io_mapping* APIs x86, pat: New i/f for driver to request memtype for IO regions x86, pat: ioremap to follow same PAT restrictions as other PAT users x86, pat: Keep identity maps consistent with mmaps even when pat_disabled x86, mtrr: make mtrr_aps_delayed_init static bool x86, pat/mtrr: Rendezvous all the cpus for MTRR/PAT init generic-ipi: Allow cpus not yet online to call smp_call_function with irqs disabled x86: Fix an incorrect argument of reserve_bootmem() x86: Fix system crash when loading with "reservetop" parameter
2009-08-31mm: remove !NUMA condition from PAGEFLAGS_EXTENDED condition setH. Peter Anvin
CONFIG_PAGEFLAGS_EXTENDED disables a trick to conserve pageflags. This trick is indended to be enabled when the pressure on page flags is very high. The previous condition was: - depends on 64BIT || SPARSEMEM_VMEMMAP || !NUMA || !SPARSEMEM ... however, the sparsemem code already has a way to crowd out the node number from the pageflags, which means that !NUMA actually doesn't contribute to hard pageflags exhaustion. This is required for the new PG_uncached flag to not cause pageflags exhaustion on x86_32 + PAE + SPARSEMEM + !NUMA. Signed-off-by: H. Peter Anvin <> LKML-Reference: <> Cc: Venkatesh Pallipadi <> Cc: Suresh Siddha <>
2009-08-17Security/SELinux: seperate lsm specific mmap_min_addrEric Paris
Currently SELinux enforcement of controls on the ability to map low memory is determined by the mmap_min_addr tunable. This patch causes SELinux to ignore the tunable and instead use a seperate Kconfig option specific to how much space the LSM should protect. The tunable will now only control the need for CAP_SYS_RAWIO and SELinux permissions will always protect the amount of low memory designated by CONFIG_LSM_MMAP_MIN_ADDR. This allows users who need to disable the mmap_min_addr controls (usual reason being they run WINE as a non-root user) to do so and still have SELinux controls preventing confined domains (like a web server) from being able to map some area of low memory. Signed-off-by: Eric Paris <> Signed-off-by: James Morris <>
2009-06-16Merge branch 'akpm'Linus Torvalds
* akpm: (182 commits) fbdev: bf54x-lq043fb: use kzalloc over kmalloc/memset fbdev: *bfin*: fix __dev{init,exit} markings fbdev: *bfin*: drop unnecessary calls to memset fbdev: bfin-t350mcqb-fb: drop unused local variables fbdev: blackfin has __raw I/O accessors, so use them in fb.h fbdev: s1d13xxxfb: add accelerated bitblt functions tcx: use standard fields for framebuffer physical address and length fbdev: add support for handoff from firmware to hw framebuffers intelfb: fix a bug when changing video timing fbdev: use framebuffer_release() for freeing fb_info structures radeon: P2G2CLK_ALWAYS_ONb tested twice, should 2nd be P2G2CLK_DAC_ALWAYS_ONb? s3c-fb: CPUFREQ frequency scaling support s3c-fb: fix resource releasing on error during probing carminefb: fix possible access beyond end of carmine_modedb[] acornfb: remove fb_mmap function mb862xxfb: use CONFIG_OF instead of CONFIG_PPC_OF mb862xxfb: restrict compliation of platform driver to PPC Samsung SoC Framebuffer driver: add Alpha Channel support atmel-lcdc: fix pixclock upper bound detection offb: use framebuffer_alloc() to allocate fb_info struct ... Manually fix up conflicts due to kmemcheck in mm/slab.c
2009-06-16mm: remove CONFIG_UNEVICTABLE_LRU config optionKOSAKI Motohiro
Currently, nobody wants to turn UNEVICTABLE_LRU off. Thus this configurability is unnecessary. Signed-off-by: KOSAKI Motohiro <> Cc: Johannes Weiner <> Cc: Andi Kleen <> Acked-by: Minchan Kim <> Cc: David Woodhouse <> Cc: Matt Mackall <> Cc: Rik van Riel <> Cc: Lee Schermerhorn <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-06-16[S390] pm: memory hotplug power management callbacksGerald Schaefer
Signed-off-by: Gerald Schaefer <> Signed-off-by: Martin Schwidefsky <>
2009-06-04security: use mmap_min_addr indepedently of security modelsChristoph Lameter
This patch removes the dependency of mmap_min_addr on CONFIG_SECURITY. It also sets a default mmap_min_addr of 4096. mmapping of addresses below 4096 will only be possible for processes with CAP_SYS_RAWIO. Signed-off-by: Christoph Lameter <> Acked-by: Eric Paris <> Looks-ok-by: Linus Torvalds <> Signed-off-by: James Morris <>
2009-05-06nommu: make the initial mmap allocation excess behaviour Kconfig configurableDavid Howells
NOMMU mmap() has an option controlled by a sysctl variable that determines whether the allocations made by do_mmap_private() should have the excess space trimmed off and returned to the allocator. Make the initial setting of this variable a Kconfig configuration option. The reason there can be excess space is that the allocator only allocates in power-of-2 size chunks, but mmap()'s can be made in sizes that aren't a power of 2. There are two alternatives: (1) Keep the excess as dead space. The dead space then remains unused for the lifetime of the mapping. Mappings of shared objects such as libc, or busybox's text segment may retain their dead space forever. (2) Return the excess to the allocator. This means that the dead space is limited to less than a page per mapping, but it means that for a transient process, there's more chance of fragmentation as the excess space may be reused fairly quickly. During the boot process, a lot of transient processes are created, and this can cause a lot of fragmentation as the pagecache and various slabs grow greatly during this time. By turning off the trimming of excess space during boot and disabling batching of frees, Coldfire can manage to boot. A better way of doing things might be to have /sbin/init turn this option off. By that point libc, and init - which are all long-duration processes - have all been loaded and trimmed. Reported-by: Lanttor Guo <> Signed-off-by: David Howells <> Tested-by: Lanttor Guo <> Cc: Greg Ungerer <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-04-13mm: point the UNEVICTABLE_LRU config option at the documentationDavid Howells
Point the UNEVICTABLE_LRU config option at the documentation describing the option. Signed-off-by: David Howells <> Cc: Lee Schermerhorn <> Cc: Rik van Riel <> Cc: KOSAKI Motohiro <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-04-01nommu: make CONFIG_UNEVICTABLE_LRU available when CONFIG_MMU=nDavid Howells
Make CONFIG_UNEVICTABLE_LRU available when CONFIG_MMU=n. There's no logical reason it shouldn't be available, and it can be used for ramfs. Signed-off-by: David Howells <> Reviewed-by: KOSAKI Motohiro <> Cc: Peter Zijlstra <> Cc: Greg Ungerer <> Cc: Johannes Weiner <> Cc: Rik van Riel <> Cc: Lee Schermerhorn <> Cc: Enrik Berkhan <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-04-01nommu: there is no mlock() for NOMMU, so don't provide the bitsDavid Howells
The mlock() facility does not exist for NOMMU since all mappings are effectively locked anyway, so we don't make the bits available when they're not useful. Signed-off-by: David Howells <> Reviewed-by: KOSAKI Motohiro <> Cc: Peter Zijlstra <> Cc: Greg Ungerer <> Cc: Johannes Weiner <> Cc: Rik van Riel <> Cc: Lee Schermerhorn <> Cc: Enrik Berkhan <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-01-06Remove obsolete CONFIG_RESOURCES_64BITGeert Uytterhoeven
commit 8308c54d7e312f7a03e2ce2057d0837e6fe3843f ("generic: redefine resource_size_t as phys_addr_t") made CONFIG_RESOURCES_64BIT obsolete, but didn't remove it. Remove it. Signed-off-by: Geert Uytterhoeven <> Cc: Jeremy Fitzhardinge <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2008-10-20Unevictable LRU InfrastructureLee Schermerhorn
When the system contains lots of mlocked or otherwise unevictable pages, the pageout code (kswapd) can spend lots of time scanning over these pages. Worse still, the presence of lots of unevictable pages can confuse kswapd into thinking that more aggressive pageout modes are required, resulting in all kinds of bad behaviour. Infrastructure to manage pages excluded from reclaim--i.e., hidden from vmscan. Based on a patch by Larry Woodman of Red Hat. Reworked to maintain "unevictable" pages on a separate per-zone LRU list, to "hide" them from vmscan. Kosaki Motohiro added the support for the memory controller unevictable lru list. Pages on the unevictable list have both PG_unevictable and PG_lru set. Thus, PG_unevictable is analogous to and mutually exclusive with PG_active--it specifies which LRU list the page is on. The unevictable infrastructure is enabled by a new mm Kconfig option [CONFIG_]UNEVICTABLE_LRU. A new function 'page_evictable(page, vma)' in vmscan.c tests whether or not a page may be evictable. Subsequent patches will add the various !evictable tests. We'll want to keep these tests light-weight for use in shrink_active_list() and, possibly, the fault path. To avoid races between tasks putting pages [back] onto an LRU list and tasks that might be moving the page from non-evictable to evictable state, the new function 'putback_lru_page()' -- inverse to 'isolate_lru_page()' -- tests the "evictability" of a page after placing it on the LRU, before dropping the reference. If the page has become unevictable, putback_lru_page() will redo the 'putback', thus moving the page to the unevictable list. This way, we avoid "stranding" evictable pages on the unevictable list. [ fix fallout from out-of-order merge] [ fix UNEVICTABLE_LRU and !PROC_PAGE_MONITOR build] [ remove redundant mapping check] [ unevictable-lru-infrastructure: putback_lru_page()/unevictable page handling rework] [ kill unnecessary lock_page() in vmscan.c] [ revert migration change of unevictable lru infrastructure] [ revert to unevictable-lru-infrastructure-kconfig-fix.patch] [ restore patch failure of vmstat-unevictable-and-mlocked-pages-vm-events.patch] Signed-off-by: Lee Schermerhorn <> Signed-off-by: Rik van Riel <> Signed-off-by: KOSAKI Motohiro <> Debugged-by: Benjamin Kidwell <> Signed-off-by: Daisuke Nishimura <> Signed-off-by: KAMEZAWA Hiroyuki <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2008-10-16Merge branch 'core-v28-for-linus' of ↵Linus Torvalds
git:// * 'core-v28-for-linus' of git:// do_generic_file_read: s/EINTR/EIO/ if lock_page_killable() fails softirq, warning fix: correct a format to avoid a warning softirqs, debug: preemption check x86, pci-hotplug, calgary / rio: fix EBDA ioremap() IO resources, x86: ioremap sanity check to catch mapping requests exceeding, fix IO resources, x86: ioremap sanity check to catch mapping requests exceeding the BAR sizes softlockup: Documentation/sysctl/kernel.txt: fix softlockup_thresh description dmi scan: warn about too early calls to dmi_check_system() generic: redefine resource_size_t as phys_addr_t generic: make PFN_PHYS explicitly return phys_addr_t generic: add phys_addr_t for holding physical addresses softirq: allocate less vectors IO resources: fix/remove printk printk: robustify printk, update comment printk: robustify printk, fix #2 printk: robustify printk, fix printk: robustify printk Fixed up conflicts in: arch/powerpc/include/asm/types.h arch/powerpc/platforms/Kconfig.cputype manually.
2008-10-16Kconfig: eliminate "def_bool n" constructsJan Beulich
Using "def_bool n" is pointless, simply using bool here appears more appropriate. Further, retaining such options that don't have a prompt and aren't selected by anything seems also at least questionable. Signed-off-by: Jan Beulich <> Cc: Ingo Molnar <> Cc: Tony Luck <> Cc: Thomas Gleixner <> Cc: Bartlomiej Zolnierkiewicz <> Cc: Sam Ravnborg <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2008-09-14generic: add phys_addr_t for holding physical addressesJeremy Fitzhardinge
Add a kernel-wide "phys_addr_t" which is guaranteed to be able to hold any physical address. By default it equals the word size of the architecture, but a 32-bit architecture can set ARCH_PHYS_ADDR_T_64BIT if it needs a 64-bit phys_addr_t. Signed-off-by: Jeremy Fitzhardinge <> Signed-off-by: Ingo Molnar <>
2008-08-12mm: Make generic weak get_user_pages_fast and EXPORT_GPL itRusty Russell
Out of line get_user_pages_fast fallback implementation, make it a weak symbol, get rid of CONFIG_HAVE_GET_USER_PAGES_FAST. Export the symbol to modules so lguest can use it. Signed-off-by: Nick Piggin <> Signed-off-by: Rusty Russell <>
2008-07-28mmu-notifiers: coreAndrea Arcangeli
With KVM/GFP/XPMEM there isn't just the primary CPU MMU pointing to pages. There are secondary MMUs (with secondary sptes and secondary tlbs) too. sptes in the kvm case are shadow pagetables, but when I say spte in mmu-notifier context, I mean "secondary pte". In GRU case there's no actual secondary pte and there's only a secondary tlb because the GRU secondary MMU has no knowledge about sptes and every secondary tlb miss event in the MMU always generates a page fault that has to be resolved by the CPU (this is not the case of KVM where the a secondary tlb miss will walk sptes in hardware and it will refill the secondary tlb transparently to software if the corresponding spte is present). The same way zap_page_range has to invalidate the pte before freeing the page, the spte (and secondary tlb) must also be invalidated before any page is freed and reused. Currently we take a page_count pin on every page mapped by sptes, but that means the pages can't be swapped whenever they're mapped by any spte because they're part of the guest working set. Furthermore a spte unmap event can immediately lead to a page to be freed when the pin is released (so requiring the same complex and relatively slow tlb_gather smp safe logic we have in zap_page_range and that can be avoided completely if the spte unmap event doesn't require an unpin of the page previously mapped in the secondary MMU). The mmu notifiers allow kvm/GRU/XPMEM to attach to the tsk->mm and know when the VM is swapping or freeing or doing anything on the primary MMU so that the secondary MMU code can drop sptes before the pages are freed, avoiding all page pinning and allowing 100% reliable swapping of guest physical address space. Furthermore it avoids the code that teardown the mappings of the secondary MMU, to implement a logic like tlb_gather in zap_page_range that would require many IPI to flush other cpu tlbs, for each fixed number of spte unmapped. To make an example: if what happens on the primary MMU is a protection downgrade (from writeable to wrprotect) the secondary MMU mappings will be invalidated, and the next secondary-mmu-page-fault will call get_user_pages and trigger a do_wp_page through get_user_pages if it called get_user_pages with write=1, and it'll re-establishing an updated spte or secondary-tlb-mapping on the copied page. Or it will setup a readonly spte or readonly tlb mapping if it's a guest-read, if it calls get_user_pages with write=0. This is just an example. This allows to map any page pointed by any pte (and in turn visible in the primary CPU MMU), into a secondary MMU (be it a pure tlb like GRU, or an full MMU with both sptes and secondary-tlb like the shadow-pagetable layer with kvm), or a remote DMA in software like XPMEM (hence needing of schedule in XPMEM code to send the invalidate to the remote node, while no need to schedule in kvm/gru as it's an immediate event like invalidating primary-mmu pte). At least for KVM without this patch it's impossible to swap guests reliably. And having this feature and removing the page pin allows several other optimizations that simplify life considerably. Dependencies: 1) mm_take_all_locks() to register the mmu notifier when the whole VM isn't doing anything with "mm". This allows mmu notifier users to keep track if the VM is in the middle of the invalidate_range_begin/end critical section with an atomic counter incraese in range_begin and decreased in range_end. No secondary MMU page fault is allowed to map any spte or secondary tlb reference, while the VM is in the middle of range_begin/end as any page returned by get_user_pages in that critical section could later immediately be freed without any further ->invalidate_page notification (invalidate_range_begin/end works on ranges and ->invalidate_page isn't called immediately before freeing the page). To stop all page freeing and pagetable overwrites the mmap_sem must be taken in write mode and all other anon_vma/i_mmap locks must be taken too. 2) It'd be a waste to add branches in the VM if nobody could possibly run KVM/GRU/XPMEM on the kernel, so mmu notifiers will only enabled if CONFIG_KVM=m/y. In the current kernel kvm won't yet take advantage of mmu notifiers, but this already allows to compile a KVM external module against a kernel with mmu notifiers enabled and from the next pull from kvm.git we'll start using them. And GRU/XPMEM will also be able to continue the development by enabling KVM=m in their config, until they submit all GRU/XPMEM GPLv2 code to the mainline kernel. Then they can also enable MMU_NOTIFIERS in the same way KVM does it (even if KVM=n). This guarantees nobody selects MMU_NOTIFIER=y if KVM and GRU and XPMEM are all =n. The mmu_notifier_register call can fail because mm_take_all_locks may be interrupted by a signal and return -EINTR. Because mmu_notifier_reigster is used when a driver startup, a failure can be gracefully handled. Here an example of the change applied to kvm to register the mmu notifiers. Usually when a driver startups other allocations are required anyway and -ENOMEM failure paths exists already. struct kvm *kvm_arch_create_vm(void) { struct kvm *kvm = kzalloc(sizeof(struct kvm), GFP_KERNEL); + int err; if (!kvm) return ERR_PTR(-ENOMEM); INIT_LIST_HEAD(&kvm->arch.active_mmu_pages); + kvm->arch.mmu_notifier.ops = &kvm_mmu_notifier_ops; + err = mmu_notifier_register(&kvm->arch.mmu_notifier, current->mm); + if (err) { + kfree(kvm); + return ERR_PTR(err); + } + return kvm; } mmu_notifier_unregister returns void and it's reliable. The patch also adds a few needed but missing includes that would prevent kernel to compile after these changes on non-x86 archs (x86 didn't need them by luck). [ coding-style fixes] [ fix mm/filemap_xip.c build] [ fix mm/mmu_notifier.c build] Signed-off-by: Andrea Arcangeli <> Signed-off-by: Nick Piggin <> Signed-off-by: Christoph Lameter <> Cc: Jack Steiner <> Cc: Robin Holt <> Cc: Nick Piggin <> Cc: Peter Zijlstra <> Cc: Kanoj Sarcar <> Cc: Roland Dreier <> Cc: Steve Wise <> Cc: Avi Kivity <> Cc: Hugh Dickins <> Cc: Rusty Russell <> Cc: Anthony Liguori <> Cc: Chris Wright <> Cc: Marcelo Tosatti <> Cc: Eric Dumazet <> Cc: "Paul E. McKenney" <> Cc: Izik Eidus <> Cc: Anthony Liguori <> Cc: Rik van Riel <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2008-07-26x86: lockless get_user_pages_fast()Nick Piggin
Implement get_user_pages_fast without locking in the fastpath on x86. Do an optimistic lockless pagetable walk, without taking mmap_sem or any page table locks or even mmap_sem. Page table existence is guaranteed by turning interrupts off (combined with the fact that we're always looking up the current mm, means we can do the lockless page table walk within the constraints of the TLB shootdown design). Basically we can do this lockless pagetable walk in a similar manner to the way the CPU's pagetable walker does not have to take any locks to find present ptes. This patch (combined with the subsequent ones to convert direct IO to use it) was found to give about 10% performance improvement on a 2 socket 8 core Intel Xeon system running an OLTP workload on DB2 v9.5 "To test the effects of the patch, an OLTP workload was run on an IBM x3850 M2 server with 2 processors (quad-core Intel Xeon processors at 2.93 GHz) using IBM DB2 v9.5 running Linux 2.6.24rc7 kernel. Comparing runs with and without the patch resulted in an overall performance benefit of ~9.8%. Correspondingly, oprofiles showed that samples from __up_read and __down_read routines that is seen during thread contention for system resources was reduced from 2.8% down to .05%. Monitoring the /proc/vmstat output from the patched run showed that the counter for fast_gup contained a very high number while the fast_gup_slow value was zero." (fast_gup is the old name for get_user_pages_fast, fast_gup_slow is a counter we had for the number of times the slowpath was invoked). The main reason for the improvement is that DB2 has multiple threads each issuing direct-IO. Direct-IO uses get_user_pages, and thus the threads contend the mmap_sem cacheline, and can also contend on page table locks. I would anticipate larger performance gains on larger systems, however I think DB2 uses an adaptive mix of threads and processes, so it could be that thread contention remains pretty constant as machine size increases. In which case, we stuck with "only" a 10% gain. The downside of using get_user_pages_fast is that if there is not a pte with the correct permissions for the access, we end up falling back to get_user_pages and so the get_user_pages_fast is a bit of extra work. However this should not be the common case in most performance critical code. [ coding-style fixes] [ build fix] [ Kconfig fix] [ Makefile fix/cleanup] [ warning fix] Signed-off-by: Nick Piggin <> Cc: Dave Kleikamp <> Cc: Andy Whitcroft <> Cc: Ingo Molnar <> Cc: Thomas Gleixner <> Cc: Andi Kleen <> Cc: Dave Kleikamp <> Cc: Badari Pulavarty <> Cc: Zach Brown <> Cc: Jens Axboe <> Reviewed-by: Peter Zijlstra <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2008-07-24mm: make CONFIG_MIGRATION available w/o CONFIG_NUMAGerald Schaefer
We'd like to support CONFIG_MEMORY_HOTREMOVE on s390, which depends on CONFIG_MIGRATION. So far, CONFIG_MIGRATION is only available with NUMA support. This patch makes CONFIG_MIGRATION selectable for architectures that define ARCH_ENABLE_MEMORY_HOTREMOVE. When MIGRATION is enabled w/o NUMA, the kernel won't compile because migrate_vmas() does not know about vm_ops->migrate() and vma_migratable() does not know about policy_zone. To fix this, those two functions can be restricted to '#ifdef CONFIG_NUMA' because they are not being used w/o NUMA. vma_migratable() is moved over from migrate.h to mempolicy.h. [ build fix] Acked-by: Christoph Lameter <> Signed-off-by: Gerald Schaefer <> Cc: Martin Schwidefsky <> Cc: Heiko Carstens <> Signed-off-by: KOSAKI Motorhiro <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2008-07-14Merge git:// Torvalds
* git:// (31 commits) avr32: Fix typo of IFSR in a comment in the PIO header file avr32: Power Management support ("standby" and "mem" modes) avr32: Add system device for the internal interrupt controller (intc) avr32: Add simple SRAM allocator avr32: Enable SDRAMC clock at startup rtc-at32ap700x: Enable wakeup macb: Basic suspend/resume support atmel_serial: Drain console TX shifter before suspending atmel_serial: Fix build on avr32 with CONFIG_PM enabled avr32: Use a quicklist for PTE allocation as well avr32: Use a quicklist for PGD allocation avr32: Cover the kernel page tables in the user PGDs avr32: Store virtual addresses in the PGD avr32: Remove useless zeroing of swapper_pg_dir at startup avr32: Clean up and optimize the TLB operations avr32: Rename at32ap.c -> pdc.c avr32: Move setup_platform() into chip-specific file avr32: Kill special exception handler sections avr32: Kill unneeded #include <asm/pgalloc.h> from asm/mmu_context.h avr32: Clean up time.c #includes ...
2008-07-14[S390] Add support for memory hot-add.Heiko Carstens
Cc: Gerald Schaefer <> Signed-off-by: Heiko Carstens <> Signed-off-by: Martin Schwidefsky <>
2008-07-02avr32: Use a quicklist for PTE allocation as wellHaavard Skinnemoen
Using a quicklist to allocate PTEs might be slightly faster than using the page allocator directly since we might avoid zeroing the page after each allocation. Signed-off-by: Haavard Skinnemoen <>
2008-04-28PAGEFLAGS_EXTENDED and separate page flags for Head and TailChristoph Lameter
Having separate page flags for the head and the tail of a compound page allows the compiler to use bitops instead of operations on a word to check for a tail page. That is f.e. important for virt_to_head_page() which is used in various critical code paths (kfree for example): Code for PageTail(page) Before: mov (%rdi),%rdx page->flags mov %rdx,%rax 3 bytes and $0x12000,%eax 5 bytes cmp $0x12000,%rax 6 bytes je 897 <kfree+0xa7> After: mov (%rdi),%rax test $0x40,%ah (3 bytes) jne 887 <kfree+0x97> So we go from 14 bytes to 3 bytes and from 3 instructions to one. From the use of 2 registers we go to none. We can only use page flags for this if we have page flags available. This patch introduces CONFIG_PAGEFLAGS_EXTENDED that is set if pageflags are not scarce due to SPARSEMEM using page flags for its sectionid on 32 bit NUMA platforms. Additional page flag definitions can be added to the CONFIG_PAGEFLAGS_EXTENDED section in page-flags.h if the functionality depends on PAGEFLAGS_EXTENDED or if more page flag overlapping tricks are used for the !PAGEFLAGS_EXTENDED fallback (the upcoming virtual compound patch may hook in here and Rik's/Lee's additional page flags to solve the reclaim issues could also be added there [hint... hint... where are these patchsets?]). Avoiding the overlaying of Pg_reclaim also clears the way for possible use of compound pages for the pagecache or on the LRU. Signed-off-by: Christoph Lameter <> Cc: Nick Piggin <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2008-01-28sh: Bump number of quicklists for SH-5.Paul Mundt
Sync up with the SH definitions. Signed-off-by: Paul Mundt <>
2007-12-17sparsemem: make SPARSEMEM_VMEMMAP selectableGeoff Levand
SPARSEMEM_VMEMMAP needs to be a selectable config option to support building the kernel both with and without sparsemem vmemmap support. This selection is desirable for platforms which could be configured one way for platform specific builds and the other for multi-platform builds. Signed-off-by: Miguel Botón <> Signed-off-by: Geoff Levand <> Acked-by: Yasunori Goto <> Cc: Christoph Lameter <> Cc: Andy Whitcroft <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2007-10-20small documentation fixesPhilipp Marek
Signed-off-by: Adrian Bunk <>
2007-10-17Merge branch 'xen-upstream' of ↵Linus Torvalds
git:// * 'xen-upstream' of git:// xfs: eagerly remove vmap mappings to avoid upsetting Xen xen: add some debug output for failed multicalls xen: fix incorrect vcpu_register_vcpu_info hypercall argument xen: ask the hypervisor how much space it needs reserved xen: lock pte pages while pinning/unpinning xen: deal with stale cr3 values when unpinning pagetables xen: add batch completion callbacks xen: yield to IPI target if necessary Clean up duplicate includes in arch/i386/xen/ remove dead code in pgtable_cache_init paravirt: clean up lazy mode handling paravirt: refactor struct paravirt_ops into smaller pv_*_ops
2007-10-16xen: lock pte pages while pinning/unpinningJeremy Fitzhardinge
When a pagetable is created, it is made globally visible in the rmap prio tree before it is pinned via arch_dup_mmap(), and remains in the rmap tree while it is unpinned with arch_exit_mmap(). This means that other CPUs may race with the pinning/unpinning process, and see a pte between when it gets marked RO and actually pinned, causing any pte updates to fail with write-protect faults. As a result, all pte pages must be properly locked, and only unlocked once the pinning/unpinning process has finished. In order to avoid taking spinlocks for the whole pagetable - which may overflow the PREEMPT_BITS portion of preempt counter - it locks and pins each pte page individually, and then finally pins the whole pagetable. Signed-off-by: Jeremy Fitzhardinge <> Cc: Rik van Riel <> Cc: Hugh Dickens <> Cc: David Rientjes <> Cc: Andrew Morton <> Cc: Andi Kleen <> Cc: Keir Fraser <> Cc: Jan Beulich <>