- 14 Apr, 2015 40 commits
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Shachar Raindel authored
In some cases, do_wp_page had to copy the page suffering a write fault to a new location. If the function logic decided that to do this, it was done by jumping with a "goto" operation to the relevant code block. This made the code really hard to understand. It is also against the kernel coding style guidelines. This patch extracts the page copy and page table update logic to a separate function. It also clean up the naming, from "gotten" to "wp_page_copy", and adds few comments. Signed-off-by:
Shachar Raindel <raindel@mellanox.com> Acked-by:
Linus Torvalds <torvalds@linux-foundation.org> Acked-by:
Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by:
Rik van Riel <riel@redhat.com> Acked-by:
Andi Kleen <ak@linux.intel.com> Acked-by:
Haggai Eran <haggaie@mellanox.com> Acked-by:
Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Matthew Wilcox <matthew.r.wilcox@intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Peter Feiner <pfeiner@google.com> Cc: Michel Lespinasse <walken@google.com> Reviewed-by:
Michal Hocko <mhocko@suse.cz> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
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Shachar Raindel authored
When do_wp_page is ending, in several cases it needs to unlock the pages and ptls it was accessing. Currently, this logic was "called" by using a goto jump. This makes following the control flow of the function harder. Readability was further hampered by the unlock case containing large amount of logic needed only in one of the 3 cases. Using goto for cleanup is generally allowed. However, moving the trivial unlocking flows to the relevant call sites allow deeper refactoring in the next patch. Signed-off-by:
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Shachar Raindel authored
Currently do_wp_page contains 265 code lines. It also contains 9 goto statements, of which 5 are targeting labels which are not cleanup related. This makes the function extremely difficult to understand. The following patches are an attempt at breaking the function to its basic components, and making it easier to understand. The patches are straight forward function extractions from do_wp_page. As we extract functions, we remove unneeded parameters and simplify the code as much as possible. However, the functionality is supposed to remain completely unchanged. The patches also attempt to document the functionality of each extracted function. In patch 2, we split the unlock logic to the contain logic relevant to specific needs of each use case, instead of having huge number of conditional decisions in a single unlock flow. This patch (of 4): When do_wp_page is ending, in several cases it needs to reuse the existing page. This is achieved by making the page table writable, and possibly updating the page-cache state. Currently, this logic was "called" by using a goto jump. This makes following the control flow of the function harder. It is also against the coding style guidelines for using goto. As the code can easily be refactored into a specialized function, refactor it out and simplify the code flow in do_wp_page. Acked-by:
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Kirill A. Shutemov authored
CONFIG_PGTABLE_LEVELS is now available on every architecture and we can use it to check if we need to add nr_pmds into mm_struct. Signed-off-by:
Guenter Roeck <linux@roeck-us.net> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: David Howells <dhowells@redhat.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Richard Weinberger <richard@nod.at> Cc: Russell King <linux@arm.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by:
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Kirill A. Shutemov authored
By this time all architectures which support more than two page table levels should be covered. This patch add default definiton of PGTABLE_LEVELS equal 2. We also add assert to detect inconsistence between CONFIG_PGTABLE_LEVELS and __PAGETABLE_PMD_FOLDED/__PAGETABLE_PUD_FOLDED. Signed-off-by:
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Kirill A. Shutemov authored
We would want to use number of page table level to define mm_struct. Let's expose it as CONFIG_PGTABLE_LEVELS. Signed-off-by:
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Kirill A. Shutemov authored
We would want to use number of page table level to define mm_struct. Let's expose it as CONFIG_PGTABLE_LEVELS. Signed-off-by:
Richard Weinberger <richard@nod.at> Cc: Jeff Dike <jdike@addtoit.com> Tested-by:
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Kirill A. Shutemov authored
We would want to use number of page table level to define mm_struct. Let's expose it as CONFIG_PGTABLE_LEVELS. Signed-off-by:
Chris Metcalf <cmetcalf@ezchip.com> Tested-by:
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Kirill A. Shutemov authored
We would want to use number of page table level to define mm_struct. Let's expose it as CONFIG_PGTABLE_LEVELS. Signed-off-by:
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Kirill A. Shutemov authored
We would want to use number of page table level to define mm_struct. Let's expose it as CONFIG_PGTABLE_LEVELS. Signed-off-by:
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Kirill A. Shutemov authored
We would want to use number of page table level to define mm_struct. Let's expose it as CONFIG_PGTABLE_LEVELS. Core mm expects __PAGETABLE_{PUD,PMD}_FOLDED to be defined if these page table levels folded. Signed-off-by: -
Kirill A. Shutemov authored
We would want to use number of page table level to define mm_struct. Let's expose it as CONFIG_PGTABLE_LEVELS. Signed-off-by:
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Kirill A. Shutemov authored
We would want to use number of page table level to define mm_struct. Let's expose it as CONFIG_PGTABLE_LEVELS. Signed-off-by:
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Kirill A. Shutemov authored
We would want to use number of page table level to define mm_struct. Let's expose it as CONFIG_PGTABLE_LEVELS. Signed-off-by:
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Kirill A. Shutemov authored
We would want to use number of page table level to define mm_struct. Let's expose it as CONFIG_PGTABLE_LEVELS. Core mm expects __PAGETABLE_{PUD,PMD}_FOLDED to be defined if these page table levels folded. Signed-off-by: -
Kirill A. Shutemov authored
We would want to use number of page table level to define mm_struct. Let's expose it as CONFIG_PGTABLE_LEVELS. We need to define PGTABLE_LEVELS before sourcing init/Kconfig: arch/Kconfig will define default value and it's sourced from init/Kconfig. Signed-off-by:
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Kirill A. Shutemov authored
We would want to use number of page table level to define mm_struct. Let's expose it as CONFIG_PGTABLE_LEVELS. Signed-off-by:
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Kirill A. Shutemov authored
We would want to use number of page table level to define mm_struct. Let's expose it as CONFIG_PGTABLE_LEVELS. ARM64_PGTABLE_LEVELS is renamed to PGTABLE_LEVELS and defined before sourcing init/Kconfig: arch/Kconfig will define default value and it's sourced from init/Kconfig. Signed-off-by:
Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Tested-by:
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Kirill A. Shutemov authored
I've implemented accounting for pmd page tables as we have for pte (see mm->nr_ptes). It's requires a new counter in mm_struct: mm->nr_pmds. But the feature doesn't make any sense if an architecture has PMD level folded and it would be nice get rid of the counter in this case. The problem is that we cannot use __PAGETABLE_PMD_FOLDED in <linux/mm_types.h> due to circular dependencies: <linux/mm_types> -> <asm/pgtable.h> -> <linux/mm_types.h> In most cases <asm/pgtable.h> wants <linux/mm_types.h> to get definition of struct page and struct vm_area_struct. I've tried to split mm_struct into separate header file to be able to user <asm/pgtable.h> there. But it doesn't fly on some architectures, like ARM: it wants mm_struct <asm/pgtable.h> to implement tlb flushing. I don't see how to fix it without massive de-inlining or coverting a lot for inline functions to macros. This is other approach: expose number of page tables in use via Kconfig and use it in <linux/mm_types.h> instead of __PAGETABLE_PMD_FOLDED from <asm/pgtable.h>. This patch (of 19): We would want to use number of page table level to define mm_struct. Let's expose it as CONFIG_PGTABLE_LEVELS. Signed-off-by:
Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Tested-by:
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Konstantin Khlebnikov authored
It seems nobody needs this. Signed-off-by:
Konstantin Khlebnikov <koct9i@gmail.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: David Rientjes <rientjes@google.com> Signed-off-by:
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Konstantin Khlebnikov authored
This makes show_mem() much less verbose on huge machines. Instead of huge and almost useless dump of counters for each per-zone per-cpu lists this patch prints the sum of these counters for each zone (free_pcp) and size of per-cpu list for current cpu (local_pcp). The filter flag SHOW_MEM_PERCPU_LISTS reverts to the old verbose mode. [akpm@linux-foundation.org: update show_free_areas comment] Signed-off-by:
Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Acked-by:
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Konstantin Khlebnikov authored
This patch replaces cancel_dirty_page() with a helper function account_page_cleaned() which only updates counters. It's called from truncate_complete_page() and from try_to_free_buffers() (hack for ext3). Page is locked in both cases, page-lock protects against concurrent dirtiers: see commit 2d6d7f98 ("mm: protect set_page_dirty() from ongoing truncation"). Delete_from_page_cache() shouldn't be called for dirty pages, they must be handled by caller (either written or truncated). This patch treats final dirty accounting fixup at the end of __delete_from_page_cache() as a debug check and adds WARN_ON_ONCE() around it. If something removes dirty pages without proper handling that might be a bug and unwritten data might be lost. Hugetlbfs has no dirty pages accounting, ClearPageDirty() is enough here. cancel_dirty_page() in nfs_wb_page_cancel() is redundant. This is helper for nfs_invalidate_page() and it's called only in case complete invalidation. The mess was started in v2.6.20 after commits 46d2277c ("Clean up and make try_to_free_buffers() not race with dirty pages") and 3e67c098 ("truncate: clear page dirtiness before running try_to_free_buffers()") first was reverted right in v2.6.20 in commit ecdfc978 ("Resurrect 'try_to_free_buffers()' VM hackery"), second in v2.6.25 commit a2b34564 ("Fix dirty page accounting leak with ext3 data=journal"). Custom fixes were introduced between these points. NFS in v2.6.23, commit 1b3b4a1a ("NFS: Fix a write request leak in nfs_invalidate_page()"). Kludge in __delete_from_page_cache() in v2.6.24, commit 3a692790 ("Do dirty page accounting when removing a page from the page cache"). Since v2.6.25 all of them are redundant. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by:
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Ebru Akagunduz authored
This patch improves THP collapse rates, by allowing zero pages. Currently THP can collapse 4kB pages into a THP when there are up to khugepaged_max_ptes_none pte_none ptes in a 2MB range. This patch counts pte none and mapped zero pages with the same variable. The patch was tested with a program that allocates 800MB of memory, and performs interleaved reads and writes, in a pattern that causes some 2MB areas to first see read accesses, resulting in the zero pfn being mapped there. To simulate memory fragmentation at allocation time, I modified do_huge_pmd_anonymous_page to return VM_FAULT_FALLBACK for read faults. Without the patch, only %50 of the program was collapsed into THP and the percentage did not increase over time. With this patch after 10 minutes of waiting khugepaged had collapsed %99 of the program's memory. [aarcange@redhat.com: fix bogus BUG()] Signed-off-by:
Ebru Akagunduz <ebru.akagunduz@gmail.com> Reviewed-by:
Andrea Arcangeli <aarcange@redhat.com> Acked-by:
Vlastimil Babka <vbabka@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: David Rientjes <rientjes@google.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by:
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Joonsoo Kim authored
Compaction has anti fragmentation algorithm. It is that freepage should be more than pageblock order to finish the compaction if we don't find any freepage in requested migratetype buddy list. This is for mitigating fragmentation, but, there is a lack of migratetype consideration and it is too excessive compared to page allocator's anti fragmentation algorithm. Not considering migratetype would cause premature finish of compaction. For example, if allocation request is for unmovable migratetype, freepage with CMA migratetype doesn't help that allocation and compaction should not be stopped. But, current logic regards this situation as compaction is no longer needed, so finish the compaction. Secondly, condition is too excessive compared to page allocator's logic. We can steal freepage from other migratetype and change pageblock migratetype on more relaxed conditions in page allocator. This is designed to prevent fragmentation and we can use it here. Imposing hard constraint only to the compaction doesn't help much in this case since page allocator would cause fragmentation again. To solve these problems, this patch borrows anti fragmentation logic from page allocator. It will reduce premature compaction finish in some cases and reduce excessive compaction work. stress-highalloc test in mmtests with non movable order 7 allocation shows considerable increase of compaction success rate. Compaction success rate (Compaction success * 100 / Compaction stalls, %) 31.82 : 42.20 I tested it on non-reboot 5 runs stress-highalloc benchmark and found that there is no more degradation on allocation success rate than before. That roughly means that this patch doesn't result in more fragmentations. Vlastimil suggests additional idea that we only test for fallbacks when migration scanner has scanned a whole pageblock. It looked good for fragmentation because chance of stealing increase due to making more free pages in certain pageblock. So, I tested it, but, it results in decreased compaction success rate, roughly 38.00. I guess the reason that if system is low memory condition, watermark check could be failed due to not enough order 0 free page and so, sometimes, we can't reach a fallback check although migrate_pfn is aligned to pageblock_nr_pages. I can insert code to cope with this situation but it makes code more complicated so I don't include his idea at this patch. [akpm@linux-foundation.org: fix CONFIG_CMA=n build] Signed-off-by:
Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by:
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Joonsoo Kim authored
This is preparation step to use page allocator's anti fragmentation logic in compaction. This patch just separates fallback freepage checking part from fallback freepage management part. Therefore, there is no functional change. Signed-off-by:
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Joonsoo Kim authored
Freepage with MIGRATE_CMA can be used only for MIGRATE_MOVABLE and they should not be expanded to other migratetype buddy list to protect them from unmovable/reclaimable allocation. Implementing these requirements in __rmqueue_fallback(), that is, finding largest possible block of freepage has bad effect that high order freepage with MIGRATE_CMA are broken continually although there are suitable order CMA freepage. Reason is that they are not be expanded to other migratetype buddy list and next __rmqueue_fallback() invocation try to finds another largest block of freepage and break it again. So, MIGRATE_CMA fallback should be handled separately. This patch introduces __rmqueue_cma_fallback(), that just wrapper of __rmqueue_smallest() and call it before __rmqueue_fallback() if migratetype == MIGRATE_MOVABLE. This results in unintended behaviour change that MIGRATE_CMA freepage is always used first rather than other migratetype as movable allocation's fallback. But, as already mentioned above, MIGRATE_CMA can be used only for MIGRATE_MOVABLE, so it is better to use MIGRATE_CMA freepage first as much as possible. Otherwise, we needlessly take up precious freepages with other migratetype and increase chance of fragmentation. Signed-off-by:
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David Rientjes authored
There's a deadlock when concurrently hot-adding memory through the probe interface and switching a memory block from offline to online. When hot-adding memory via the probe interface, add_memory() first takes mem_hotplug_begin() and then device_lock() is later taken when registering the newly initialized memory block. This creates a lock dependency of (1) mem_hotplug.lock (2) dev->mutex. When switching a memory block from offline to online, dev->mutex is first grabbed in device_online() when the write(2) transitions an existing memory block from offline to online, and then online_pages() will take mem_hotplug_begin(). This creates a lock inversion between mem_hotplug.lock and dev->mutex. Vitaly reports that this deadlock can happen when kworker handling a probe event races with systemd-udevd switching a memory block's state. This patch requires the state transition to take mem_hotplug_begin() before dev->mutex. Hot-adding memory via the probe interface creates a memory block while holding mem_hotplug_begin(), there is no way to take dev->mutex first in this case. online_pages() and offline_pages() are only called when transitioning memory block state. We now require that mem_hotplug_begin() is taken before calling them -- this requires exporting the mem_hotplug_begin() and mem_hotplug_done() to generic code. In all hot-add and hot-remove cases, mem_hotplug_begin() is done prior to device_online(). This is all that is needed to avoid the deadlock. Signed-off-by:
David Rientjes <rientjes@google.com> Reported-by:
Vitaly Kuznetsov <vkuznets@redhat.com> Tested-by:
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Sasha Levin authored
Document the structure and files under the new debugfs interface. Signed-off-by:
Sasha Levin <sasha.levin@oracle.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Laura Abbott <lauraa@codeaurora.org> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by:
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Andrew Morton authored
s/CONFIG_CMA_ALIGNMENT/0/, per Joonsoo Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Laura Abbott <lauraa@codeaurora.org> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Sasha Levin <sasha.levin@oracle.com> Signed-off-by:
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Sasha Levin authored
Provides a userspace interface to trigger a CMA release. Usage: echo [pages] > free This would provide testing/fuzzing access to the CMA release paths. [akpm@linux-foundation.org: coding-style fixes] [mhocko@suse.cz: fix build] Signed-off-by: -
Sasha Levin authored
Provides a userspace interface to trigger a CMA allocation. Usage: echo [pages] > alloc This would provide testing/fuzzing access to the CMA allocation paths. Signed-off-by: -
Sasha Levin authored
I've noticed that there is no interfaces exposed by CMA which would let me fuzz what's going on in there. This small patchset exposes some information out to userspace, plus adds the ability to trigger allocation and freeing from userspace. This patch (of 3): Implement a simple debugfs interface to expose information about CMA areas in the system. Useful for testing/sanity checks for CMA since it was impossible to previously retrieve this information in userspace. Signed-off-by:
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Sheng Yong authored
Use macro section_nr_to_pfn() to switch between section and pfn, instead of open-coding it. No semantic changes. Signed-off-by:
Sheng Yong <shengyong1@huawei.com> Signed-off-by:
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Johannes Weiner authored
Add myself to the list of copyright holders. Signed-off-by:
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Baoquan He authored
A small cleanup. Seems in e3239ff9 ("memblock: Rename memblock_region to memblock_type and memblock_property to memblock_region") this one was missed. Signed-off-by:
Baoquan He <bhe@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by:
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Kirill A. Shutemov authored
It's odd that we have populate_vma_page_range() and __mm_populate() in mm/mlock.c. It's implementation of generic memory population and mlocking is one of possible side effect, if VM_LOCKED is set. __get_user_pages() is core of the implementation. Let's move the code into mm/gup.c. Signed-off-by:
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Kirill A. Shutemov authored
This is praparation to moving mm_populate()-related code out of mm/mlock.c. Signed-off-by:
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Kirill A. Shutemov authored
__mlock_vma_pages_range() doesn't necessarily mlock pages. It depends on vma flags. The same codepath is used for MAP_POPULATE. Let's rename __mlock_vma_pages_range() to populate_vma_page_range(). This patch also drops mlock_vma_pages_range() references from documentation. It has gone in cea10a19 ("mm: directly use __mlock_vma_pages_range() in find_extend_vma()"). Signed-off-by:
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Kirill A. Shutemov authored
After commit a1fde08c ("VM: skip the stack guard page lookup in get_user_pages only for mlock") FOLL_MLOCK has lost its original meaning: we don't necessarily mlock the page if the flags is set -- we also take VM_LOCKED into consideration. Since we use the same codepath for __mm_populate(), let's rename FOLL_MLOCK to FOLL_POPULATE. Signed-off-by:
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Fabian Frederick authored
slob_alloc_node() is only used in slob.c. Remove the EXPORT_SYMBOL and make slob_alloc_node() static. Signed-off-by:
Fabian Frederick <fabf@skynet.be> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by:
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