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746,708 commits
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514c603249 |
headers: untangle kmemleak.h from mm.h
Currently <linux/slab.h> #includes <linux/kmemleak.h> for no obvious reason. It looks like it's only a convenience, so remove kmemleak.h from slab.h and add <linux/kmemleak.h> to any users of kmemleak_* that don't already #include it. Also remove <linux/kmemleak.h> from source files that do not use it. This is tested on i386 allmodconfig and x86_64 allmodconfig. It would be good to run it through the 0day bot for other $ARCHes. I have neither the horsepower nor the storage space for the other $ARCHes. Update: This patch has been extensively build-tested by both the 0day bot & kisskb/ozlabs build farms. Both of them reported 2 build failures for which patches are included here (in v2). [ slab.h is the second most used header file after module.h; kernel.h is right there with slab.h. There could be some minor error in the counting due to some #includes having comments after them and I didn't combine all of those. ] [akpm@linux-foundation.org: security/keys/big_key.c needs vmalloc.h, per sfr] Link: http://lkml.kernel.org/r/e4309f98-3749-93e1-4bb7-d9501a39d015@infradead.org Link: http://kisskb.ellerman.id.au/kisskb/head/13396/ Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Reviewed-by: Ingo Molnar <mingo@kernel.org> Reported-by: Michael Ellerman <mpe@ellerman.id.au> [2 build failures] Reported-by: Fengguang Wu <fengguang.wu@intel.com> [2 build failures] Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Wei Yongjun <weiyongjun1@huawei.com> Cc: Luis R. Rodriguez <mcgrof@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Mimi Zohar <zohar@linux.vnet.ibm.com> Cc: John Johansen <john.johansen@canonical.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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91241681c6 |
include/linux/mmdebug.h: make VM_WARN* non-rvals
At present the construct
if (VM_WARN(...))
will compile OK with CONFIG_DEBUG_VM=y and will fail with
CONFIG_DEBUG_VM=n. The reason is that VM_{WARN,BUG}* have always been
special wrt. {WARN/BUG}* and never generate any code when DEBUG_VM is
disabled. So we cannot really use it in conditionals.
We considered changing things so that this construct works in both cases
but that might cause unwanted code generation with CONFIG_DEBUG_VM=n.
It is safer and simpler to make the build fail in both cases.
[akpm@linux-foundation.org: changelog]
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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2c7452a075 |
mm/page_isolation.c: make start_isolate_page_range() fail if already isolated
start_isolate_page_range() is used to set the migrate type of a set of pageblocks to MIGRATE_ISOLATE while attempting to start a migration operation. It assumes that only one thread is calling it for the specified range. This routine is used by CMA, memory hotplug and gigantic huge pages. Each of these users synchronize access to the range within their subsystem. However, two subsystems (CMA and gigantic huge pages for example) could attempt operations on the same range. If this happens, one thread may 'undo' the work another thread is doing. This can result in pageblocks being incorrectly left marked as MIGRATE_ISOLATE and therefore not available for page allocation. What is ideally needed is a way to synchronize access to a set of pageblocks that are undergoing isolation and migration. The only thing we know about these pageblocks is that they are all in the same zone. A per-node mutex is too coarse as we want to allow multiple operations on different ranges within the same zone concurrently. Instead, we will use the migration type of the pageblocks themselves as a form of synchronization. start_isolate_page_range sets the migration type on a set of page- blocks going in order from the one associated with the smallest pfn to the largest pfn. The zone lock is acquired to check and set the migration type. When going through the list of pageblocks check if MIGRATE_ISOLATE is already set. If so, this indicates another thread is working on this pageblock. We know exactly which pageblocks we set, so clean up by undo those and return -EBUSY. This allows start_isolate_page_range to serve as a synchronization mechanism and will allow for more general use of callers making use of these interfaces. Update comments in alloc_contig_range to reflect this new functionality. Each CPU holds the associated zone lock to modify or examine the migration type of a pageblock. And, it will only examine/update a single pageblock per lock acquire/release cycle. Link: http://lkml.kernel.org/r/20180309224731.16978-1-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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1c8f422059 |
mm: change return type to vm_fault_t
The plan for these patches is to introduce the typedef, initially just
as documentation ("These functions should return a VM_FAULT_ status").
We'll trickle the patches to individual drivers/filesystems in through
the maintainers, as far as possible. Then we'll change the typedef to
an unsigned int and break the compilation of any unconverted
drivers/filesystems.
vmf_insert_page(), vmf_insert_mixed() and vmf_insert_pfn() are three
newly added functions. The various drivers/filesystems where return
value of fault(), huge_fault(), page_mkwrite() and pfn_mkwrite() get
converted, will need them. These functions will return correct
VM_FAULT_ code based on err value.
We've had bugs before where drivers returned -EFOO. And we have this
silly inefficiency where vm_insert_xxx() return an errno which (afaict)
every driver then converts into a VM_FAULT code. In many cases drivers
failed to return correct VM_FAULT code value despite of vm_insert_xxx()
fails. We have indentified and clean up all those existing bugs and
silly inefficiencies in driver/filesystems by adding these three new
inline wrappers. As mentioned above, we will trickle those patches to
individual drivers/filesystems in through maintainers after these three
wrapper functions are merged.
Eventually we can convert vm_insert_xxx() into vmf_insert_xxx() and
remove these inline wrappers, but these are a good intermediate step.
Link: http://lkml.kernel.org/r/20180310162351.GA7422@jordon-HP-15-Notebook-PC
Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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d46078b288 |
mm, oom: remove 3% bonus for CAP_SYS_ADMIN processes
Since the 2.6 kernel, the oom killer has slightly biased away from CAP_SYS_ADMIN processes by discounting some of its memory usage in comparison to other processes. This has always been implicit and nothing exactly relies on the behavior. Gaurav notices that __task_cred() can dereference a potentially freed pointer if the task under consideration is exiting because a reference to the task_struct is not held. Remove the CAP_SYS_ADMIN bias so that all processes are treated equally. If any CAP_SYS_ADMIN process would like to be biased against, it is always allowed to adjust /proc/pid/oom_score_adj. Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1803071548510.6996@chino.kir.corp.google.com Signed-off-by: David Rientjes <rientjes@google.com> Reported-by: Gaurav Kohli <gkohli@codeaurora.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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5ecd9d403a |
mm, page_alloc: wakeup kcompactd even if kswapd cannot free more memory
Kswapd will not wakeup if per-zone watermarks are not failing or if too many previous attempts at background reclaim have failed. This can be true if there is a lot of free memory available. For high- order allocations, kswapd is responsible for waking up kcompactd for background compaction. If the zone is not below its watermarks or reclaim has recently failed (lots of free memory, nothing left to reclaim), kcompactd does not get woken up. When __GFP_DIRECT_RECLAIM is not allowed, allow kcompactd to still be woken up even if kswapd will not reclaim. This allows high-order allocations, such as thp, to still trigger background compaction even when the zone has an abundance of free memory. Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1803111659420.209721@chino.kir.corp.google.com Signed-off-by: David Rientjes <rientjes@google.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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3eda69c92d |
kernel/fork.c: detect early free of a live mm
KASAN splats indicate that in some cases we free a live mm, then continue to access it, with potentially disastrous results. This is likely due to a mismatched mmdrop() somewhere in the kernel, but so far the culprit remains elusive. Let's have __mmdrop() verify that the mm isn't live for the current task, similar to the existing check for init_mm. This way, we can catch this class of issue earlier, and without requiring KASAN. Currently, idle_task_exit() leaves active_mm stale after it switches to init_mm. This isn't harmful, but will trigger the new assertions, so we must adjust idle_task_exit() to update active_mm. Link: http://lkml.kernel.org/r/20180312140103.19235-1-mark.rutland@arm.com Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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0c7c1bed7e |
mm: make counting of list_lru_one::nr_items lockless
During the reclaiming slab of a memcg, shrink_slab iterates over all registered shrinkers in the system, and tries to count and consume objects related to the cgroup. In case of memory pressure, this behaves bad: I observe high system time and time spent in list_lru_count_one() for many processes on RHEL7 kernel. This patch makes list_lru_node::memcg_lrus rcu protected, that allows to skip taking spinlock in list_lru_count_one(). Shakeel Butt with the patch observes significant perf graph change. He says: ======================================================================== Setup: running a fork-bomb in a memcg of 200MiB on a 8GiB and 4 vcpu VM and recording the trace with 'perf record -g -a'. The trace without the patch: + 34.19% fb.sh [kernel.kallsyms] [k] queued_spin_lock_slowpath + 30.77% fb.sh [kernel.kallsyms] [k] _raw_spin_lock + 3.53% fb.sh [kernel.kallsyms] [k] list_lru_count_one + 2.26% fb.sh [kernel.kallsyms] [k] super_cache_count + 1.68% fb.sh [kernel.kallsyms] [k] shrink_slab + 0.59% fb.sh [kernel.kallsyms] [k] down_read_trylock + 0.48% fb.sh [kernel.kallsyms] [k] _raw_spin_unlock_irqrestore + 0.38% fb.sh [kernel.kallsyms] [k] shrink_node_memcg + 0.32% fb.sh [kernel.kallsyms] [k] queue_work_on + 0.26% fb.sh [kernel.kallsyms] [k] count_shadow_nodes With the patch: + 0.16% swapper [kernel.kallsyms] [k] default_idle + 0.13% oom_reaper [kernel.kallsyms] [k] mutex_spin_on_owner + 0.05% perf [kernel.kallsyms] [k] copy_user_generic_string + 0.05% init.real [kernel.kallsyms] [k] wait_consider_task + 0.05% kworker/0:0 [kernel.kallsyms] [k] finish_task_switch + 0.04% kworker/2:1 [kernel.kallsyms] [k] finish_task_switch + 0.04% kworker/3:1 [kernel.kallsyms] [k] finish_task_switch + 0.04% kworker/1:0 [kernel.kallsyms] [k] finish_task_switch + 0.03% binary [kernel.kallsyms] [k] copy_page ======================================================================== Thanks Shakeel for the testing. [ktkhai@virtuozzo.com: v2] Link: http://lkml.kernel.org/r/151203869520.3915.2587549826865799173.stgit@localhost.localdomain Link: http://lkml.kernel.org/r/150583358557.26700.8490036563698102569.stgit@localhost.localdomain Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Tested-by: Shakeel Butt <shakeelb@google.com> Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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f5c754d63d |
mm/swap_state.c: make bool enable_vma_readahead and swap_vma_readahead() static
The bool enable_vma_readahead and swap_vma_readahead() are local to the source and do not need to be in global scope, so make them static. Cleans up sparse warnings: mm/swap_state.c:41:6: warning: symbol 'enable_vma_readahead' was not declared. Should it be static? mm/swap_state.c:742:13: warning: symbol 'swap_vma_readahead' was not declared. Should it be static? Link: http://lkml.kernel.org/r/20180223164852.5159-1-colin.king@canonical.com Signed-off-by: Colin Ian King <colin.king@canonical.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: "Huang, Ying" <ying.huang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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3172485f4f |
block_invalidatepage(): only release page if the full page was invalidated
Prior to commit |
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e8b098fc57 |
mm: kernel-doc: add missing parameter descriptions
Link: http://lkml.kernel.org/r/1519585191-10180-4-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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002843de36 |
mm/swap.c: remove @cold parameter description for release_pages()
The 'cold' parameter was removed from release_pages function by commit
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e48e3c590a |
mm/nommu: remove description of alloc_vm_area
The alloc_mm_area in nommu is a stub, but its description states it allocates kernel address space. Remove the description to make the code and the documentation agree. Link: http://lkml.kernel.org/r/1519585191-10180-2-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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60f5921a9a |
zram: drop max_zpage_size and use zs_huge_class_size()
Remove ZRAM's enforced "huge object" value and use zsmalloc huge-class watermark instead, which makes more sense. TEST - I used a 1G zram device, LZO compression back-end, original data set size was 444MB. Looking at zsmalloc classes stats the test ended up to be pretty fair. BASE ZRAM/ZSMALLOC ===================== zram mm_stat 498978816 191482495 199831552 0 199831552 15634 0 zsmalloc classes class size almost_full almost_empty obj_allocated obj_used pages_used pages_per_zspage freeable ... 151 2448 0 0 1240 1240 744 3 0 168 2720 0 0 4200 4200 2800 2 0 190 3072 0 0 10100 10100 7575 3 0 202 3264 0 0 380 380 304 4 0 254 4096 0 0 10620 10620 10620 1 0 Total 7 46 106982 106187 48787 0 PATCHED ZRAM/ZSMALLOC ===================== zram mm_stat 498978816 182579184 194248704 0 194248704 15628 0 zsmalloc classes class size almost_full almost_empty obj_allocated obj_used pages_used pages_per_zspage freeable ... 151 2448 0 0 1240 1240 744 3 0 168 2720 0 0 4200 4200 2800 2 0 190 3072 0 0 10100 10100 7575 3 0 202 3264 0 0 7180 7180 5744 4 0 254 4096 0 0 3820 3820 3820 1 0 Total 8 45 106959 106193 47424 0 As we can see, we reduced the number of objects stored in class-4096, because a huge number of objects which we previously forcibly stored in class-4096 now stored in non-huge class-3264. This results in lower memory consumption: - zsmalloc now uses 47424 physical pages, which is less than 48787 pages zsmalloc used before. - objects that we store in class-3264 share zspages. That's why overall the number of pages that both class-4096 and class-3264 consumed went down from 10924 to 9564. [sergey.senozhatsky.work@gmail.com: add pool param to zs_huge_class_size()] Link: http://lkml.kernel.org/r/20180314081833.1096-3-sergey.senozhatsky@gmail.com Link: http://lkml.kernel.org/r/20180306070639.7389-3-sergey.senozhatsky@gmail.com Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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010b495e2f |
zsmalloc: introduce zs_huge_class_size()
Patch series "zsmalloc/zram: drop zram's max_zpage_size", v3. ZRAM's max_zpage_size is a bad thing. It forces zsmalloc to store normal objects as huge ones, which results in bigger zsmalloc memory usage. Drop it and use actual zsmalloc huge-class value when decide if the object is huge or not. This patch (of 2): Not every object can be share its zspage with other objects, e.g. when the object is as big as zspage or nearly as big a zspage. For such objects zsmalloc has a so called huge class - every object which belongs to huge class consumes the entire zspage (which consists of a physical page). On x86_64, PAGE_SHIFT 12 box, the first non-huge class size is 3264, so starting down from size 3264, objects can share page(-s) and thus minimize memory wastage. ZRAM, however, has its own statically defined watermark for huge objects, namely "3 * PAGE_SIZE / 4 = 3072", and forcibly stores every object larger than this watermark (3072) as a PAGE_SIZE object, in other words, to a huge class, while zsmalloc can keep some of those objects in non-huge classes. This results in increased memory consumption. zsmalloc knows better if the object is huge or not. Introduce zs_huge_class_size() function which tells if the given object can be stored in one of non-huge classes or not. This will let us to drop ZRAM's huge object watermark and fully rely on zsmalloc when we decide if the object is huge. [sergey.senozhatsky.work@gmail.com: add pool param to zs_huge_class_size()] Link: http://lkml.kernel.org/r/20180314081833.1096-2-sergey.senozhatsky@gmail.com Link: http://lkml.kernel.org/r/20180306070639.7389-2-sergey.senozhatsky@gmail.com Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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cb9f753a37 |
mm: fix races between swapoff and flush dcache
Thanks to commit
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1c0ff0f1bd |
fs/direct-io.c: minor cleanups in do_blockdev_direct_IO
We already get the block counts and calculate the end block at the beginning of the function. Let's use the local variables for consistency and readability. No functional changes [akpm@linux-foundation.org: constify the locals to prevent future slipups] Link: http://lkml.kernel.org/r/1519638870-17756-1-git-send-email-nborisov@suse.com Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Jeff Moyer <jmoyer@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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5844a486da |
include/linux/mm.h: provide consistent declaration for num_poisoned_pages
clang reports the following compile warning.
In file included from mm/vmscan.c:56:
./include/linux/swapops.h:327:22: warning:
section attribute is specified on redeclared variable [-Wsection]
extern atomic_long_t num_poisoned_pages __read_mostly;
^
./include/linux/mm.h:2585:22: note: previous declaration is here
extern atomic_long_t num_poisoned_pages;
^
Let's use __read_mostly everywhere.
Link: http://lkml.kernel.org/r/1519686565-8224-1-git-send-email-linux@roeck-us.net
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthias Kaehlcke <mka@chromium.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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c1d53b92b9 |
device-dax: implement ->pagesize() for smaps to report MMUPageSize
Given that device-dax is making similar page mapping size guarantees as hugetlbfs, emit the size in smaps and any other kernel path that requests the mapping size of a vma. Link: http://lkml.kernel.org/r/151996255287.27922.18397777516059080245.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reported-by: Jane Chu <jane.chu@oracle.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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05ea88608d |
mm, hugetlbfs: introduce ->pagesize() to vm_operations_struct
When device-dax is operating in huge-page mode we want it to behave like
hugetlbfs and report the MMU page mapping size that is being enforced by
the vma.
Similar to commit
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09135cc594 |
mm, powerpc: use vma_kernel_pagesize() in vma_mmu_pagesize()
Patch series "mm, smaps: MMUPageSize for device-dax", v3.
Similar to commit
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2923117b71 |
mm/gup.c: fix coding style issues.
- Fixed style error: 8 spaces -> 1 tab. - Fixed style warning: Corrected misleading indentation. Link: http://lkml.kernel.org/r/20180302210254.31888-1-marioleinweber@web.de Signed-off-by: Mario Leinweber <marioleinweber@web.de> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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97334162e4 |
mm/free_pcppages_bulk: prefetch buddy while not holding lock
When a page is freed back to the global pool, its buddy will be checked
to see if it's possible to do a merge. This requires accessing buddy's
page structure and that access could take a long time if it's cache
cold.
This patch adds a prefetch to the to-be-freed page's buddy outside of
zone->lock in hope of accessing buddy's page structure later under
zone->lock will be faster. Since we *always* do buddy merging and check
an order-0 page's buddy to try to merge it when it goes into the main
allocator, the cacheline will always come in, i.e. the prefetched data
will never be unused.
Normally, the number of prefetch will be pcp->batch(default=31 and has
an upper limit of (PAGE_SHIFT * 8)=96 on x86_64) but in the case of
pcp's pages get all drained, it will be pcp->count which has an upper
limit of pcp->high. pcp->high, although has a default value of 186
(pcp->batch=31 * 6), can be changed by user through
/proc/sys/vm/percpu_pagelist_fraction and there is no software upper
limit so could be large, like several thousand. For this reason, only
the first pcp->batch number of page's buddy structure is prefetched to
avoid excessive prefetching.
In the meantime, there are two concerns:
1. the prefetch could potentially evict existing cachelines, especially
for L1D cache since it is not huge
2. there is some additional instruction overhead, namely calculating
buddy pfn twice
For 1, it's hard to say, this microbenchmark though shows good result
but the actual benefit of this patch will be workload/CPU dependant;
For 2, since the calculation is a XOR on two local variables, it's
expected in many cases that cycles spent will be offset by reduced
memory latency later. This is especially true for NUMA machines where
multiple CPUs are contending on zone->lock and the most time consuming
part under zone->lock is the wait of 'struct page' cacheline of the
to-be-freed pages and their buddies.
Test with will-it-scale/page_fault1 full load:
kernel Broadwell(2S) Skylake(2S) Broadwell(4S) Skylake(4S)
v4.16-rc2+ 9034215 7971818 13667135 15677465
patch2/3
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0a5f4e5b45 |
mm/free_pcppages_bulk: do not hold lock when picking pages to free
When freeing a batch of pages from Per-CPU-Pages(PCP) back to buddy, the
zone->lock is held and then pages are chosen from PCP's migratetype
list. While there is actually no need to do this 'choose part' under
lock since it's PCP pages, the only CPU that can touch them is us and
irq is also disabled.
Moving this part outside could reduce lock held time and improve
performance. Test with will-it-scale/page_fault1 full load:
kernel Broadwell(2S) Skylake(2S) Broadwell(4S) Skylake(4S)
v4.16-rc2+ 9034215 7971818 13667135 15677465
this patch
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77ba9062e4 |
mm/free_pcppages_bulk: update pcp->count inside
Matthew Wilcox found that all callers of free_pcppages_bulk() currently update pcp->count immediately after so it's natural to do it inside free_pcppages_bulk(). No functionality or performance change is expected from this patch. Link: http://lkml.kernel.org/r/20180301062845.26038-2-aaron.lu@intel.com Signed-off-by: Aaron Lu <aaron.lu@intel.com> Suggested-by: Matthew Wilcox <willy@infradead.org> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Huang Ying <ying.huang@intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Kemi Wang <kemi.wang@intel.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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bc3106b26c |
mm, compaction: drain pcps for zone when kcompactd fails
It's possible for free pages to become stranded on per-cpu pagesets
(pcps) that, if drained, could be merged with buddy pages on the zone's
free area to form large order pages, including up to MAX_ORDER.
Consider a verbose example using the tools/vm/page-types tool at the
beginning of a ZONE_NORMAL ('B' indicates a buddy page and 'S' indicates
a slab page). Pages on pcps do not have any page flags set.
109954 1 _______S________________________________________________________
109955 2 __________B_____________________________________________________
109957 1 ________________________________________________________________
109958 1 __________B_____________________________________________________
109959 7 ________________________________________________________________
109960 1 __________B_____________________________________________________
109961 9 ________________________________________________________________
10996a 1 __________B_____________________________________________________
10996b 3 ________________________________________________________________
10996e 1 __________B_____________________________________________________
10996f 1 ________________________________________________________________
...
109f8c 1 __________B_____________________________________________________
109f8d 2 ________________________________________________________________
109f8f 2 __________B_____________________________________________________
109f91 f ________________________________________________________________
109fa0 1 __________B_____________________________________________________
109fa1 7 ________________________________________________________________
109fa8 1 __________B_____________________________________________________
109fa9 1 ________________________________________________________________
109faa 1 __________B_____________________________________________________
109fab 1 _______S________________________________________________________
The compaction migration scanner is attempting to defragment this memory
since it is at the beginning of the zone. It has done so quite well,
all movable pages have been migrated. From pfn [0x109955, 0x109fab),
there are only buddy pages and pages without flags set.
These pages may be stranded on pcps that could otherwise allow this
memory to be coalesced if freed back to the zone free area. It is
possible that some of these pages may not be on pcps and that something
has called alloc_pages() and used the memory directly, but we rely on
the absence of __GFP_MOVABLE in these cases to allocate from
MIGATE_UNMOVABLE pageblocks to try to keep these MIGRATE_MOVABLE
pageblocks as free as possible.
These buddy and pcp pages, spanning 1,621 pages, could be coalesced and
allow for three transparent hugepages to be dynamically allocated.
Running the numbers for all such spans on the system, it was found that
there were over 400 such spans of only buddy pages and pages without
flags set at the time this /proc/kpageflags sample was collected.
Without this support, there were _no_ order-9 or order-10 pages free.
When kcompactd fails to defragment memory such that a cc.order page can
be allocated, drain all pcps for the zone back to the buddy allocator so
this stranding cannot occur. Compaction for that order will
subsequently be deferred, which acts as a ratelimit on this drain.
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1803010340100.88270@chino.kir.corp.google.com
Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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4f6923fbb3 |
mm: make should_failslab always available for fault injection
should_failslab() is a convenient function to hook into for directed
error injection into kmalloc(). However, it is only available if a
config flag is set.
The following BCC script, for example, fails kmalloc() calls after a
btrfs umount:
from bcc import BPF
prog = r"""
BPF_HASH(flag);
#include <linux/mm.h>
int kprobe__btrfs_close_devices(void *ctx) {
u64 key = 1;
flag.update(&key, &key);
return 0;
}
int kprobe__should_failslab(struct pt_regs *ctx) {
u64 key = 1;
u64 *res;
res = flag.lookup(&key);
if (res != 0) {
bpf_override_return(ctx, -ENOMEM);
}
return 0;
}
"""
b = BPF(text=prog)
while 1:
b.kprobe_poll()
This patch refactors the should_failslab implementation so that the
function is always available for error injection, independent of flags.
This change would be similar in nature to commit f5490d3ec921 ("block:
Add should_fail_bio() for bpf error injection").
Link: http://lkml.kernel.org/r/20180222020320.6944-1-hmclauchlan@fb.com
Signed-off-by: Howard McLauchlan <hmclauchlan@fb.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
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>
Cc: Josef Bacik <jbacik@fb.com>
Cc: Johannes Weiner <jweiner@fb.com>
Cc: Alexei Starovoitov <ast@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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14298d3663 |
mm/page_poison.c: make early_page_poison_param() __init
The early_param() is only called during kernel initialization, So Linux marks the function of it with __init macro to save memory. But it forgot to mark the early_page_poison_param(). So, Make it __init as well. Link: http://lkml.kernel.org/r/20180117034757.27024-1-douly.fnst@cn.fujitsu.com Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Philippe Ombredanne <pombredanne@nexb.com> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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1173194e1e |
mm/page_owner.c: make early_page_owner_param() __init
The early_param() is only called during kernel initialization, So Linux marks the functions of it with __init macro to save memory. But it forgot to mark the early_page_owner_param(). So, Make it __init as well. Link: http://lkml.kernel.org/r/20180117034736.26963-1-douly.fnst@cn.fujitsu.com Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Michal Hocko <mhocko@suse.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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8bd30c1090 |
mm/kmemleak.c: make kmemleak_boot_config() __init
The early_param() is only called during kernel initialization, So Linux marks the functions of it with __init macro to save memory. But it forgot to mark the kmemleak_boot_config(). So, Make it __init as well. Link: http://lkml.kernel.org/r/20180117034720.26897-1-douly.fnst@cn.fujitsu.com Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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e9e9b7ecee |
mm: swap: unify cluster-based and vma-based swap readahead
This patch makes do_swap_page() not need to be aware of two different swap readahead algorithms. Just unify cluster-based and vma-based readahead function call. Link: http://lkml.kernel.org/r/1509520520-32367-3-git-send-email-minchan@kernel.org Link: http://lkml.kernel.org/r/20180220085249.151400-3-minchan@kernel.org Signed-off-by: Minchan Kim <minchan@kernel.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Hugh Dickins <hughd@google.com> Cc: Huang Ying <ying.huang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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eaf649ebc3 |
mm: swap: clean up swap readahead
When I see recent change of swap readahead, I am very unhappy about current code structure which diverges two swap readahead algorithm in do_swap_page. This patch is to clean it up. Main motivation is that fault handler doesn't need to be aware of readahead algorithms but just should call swapin_readahead. As first step, this patch cleans up a little bit but not perfect (I just separate for review easier) so next patch will make the goal complete. [minchan@kernel.org: do not check readahead flag with THP anon] Link: http://lkml.kernel.org/r/874lm83zho.fsf@yhuang-dev.intel.com Link: http://lkml.kernel.org/r/20180227232611.169883-1-minchan@kernel.org Link: http://lkml.kernel.org/r/1509520520-32367-2-git-send-email-minchan@kernel.org Link: http://lkml.kernel.org/r/20180220085249.151400-2-minchan@kernel.org Signed-off-by: Minchan Kim <minchan@kernel.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Hugh Dickins <hughd@google.com> Cc: Huang Ying <ying.huang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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e830c63a62 |
mm,vmscan: don't pretend forward progress upon shrinker_rwsem contention
Since we no longer use return value of shrink_slab() for normal reclaim, the comment is no longer true. If some do_shrink_slab() call takes unexpectedly long (root cause of stall is currently unknown) when register_shrinker()/unregister_shrinker() is pending, trying to drop caches via /proc/sys/vm/drop_caches could become infinite cond_resched() loop if many mem_cgroup are defined. For safety, let's not pretend forward progress. Link: http://lkml.kernel.org/r/201802202229.GGF26507.LVFtMSOOHFJOQF@I-love.SAKURA.ne.jp Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Dave Chinner <dchinner@redhat.com> Cc: Glauber Costa <glommer@gmail.com> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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5c9bab592f |
z3fold: limit use of stale list for allocation
Currently if z3fold couldn't find an unbuddied page it would first try to pull a page off the stale list. The problem with this approach is that we can't 100% guarantee that the page is not processed by the workqueue thread at the same time unless we run cancel_work_sync() on it, which we can't do if we're in an atomic context. So let's just limit stale list usage to non-atomic contexts only. Link: http://lkml.kernel.org/r/47ab51e7-e9c1-d30e-ab17-f734dbc3abce@gmail.com Signed-off-by: Vitaly Vul <vitaly.vul@sony.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: <Oleksiy.Avramchenko@sony.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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605ca5ede7 |
mm/huge_memory.c: reorder operations in __split_huge_page_tail()
THP split makes non-atomic change of tail page flags. This is almost ok because tail pages are locked and isolated but this breaks recent changes in page locking: non-atomic operation could clear bit PG_waiters. As a result concurrent sequence get_page_unless_zero() -> lock_page() might block forever. Especially if this page was truncated later. Fix is trivial: clone flags before unfreezing page reference counter. This race exists since commit |
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03f5d58fa4 |
mm/page_ref: use atomic_set_release in page_ref_unfreeze
page_ref_unfreeze() has exactly that semantic. No functional changes: just minus one barrier and proper handling of PPro errata. Link: http://lkml.kernel.org/r/151844393004.210639.4672319312617954272.stgit@buzz Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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e92bb4dd96 |
mm: fix races between address_space dereference and free in page_evicatable
When page_mapping() is called and the mapping is dereferenced in
page_evicatable() through shrink_active_list(), it is possible for the
inode to be truncated and the embedded address space to be freed at the
same time. This may lead to the following race.
CPU1 CPU2
truncate(inode) shrink_active_list()
... page_evictable(page)
truncate_inode_page(mapping, page);
delete_from_page_cache(page)
spin_lock_irqsave(&mapping->tree_lock, flags);
__delete_from_page_cache(page, NULL)
page_cache_tree_delete(..)
... mapping = page_mapping(page);
page->mapping = NULL;
...
spin_unlock_irqrestore(&mapping->tree_lock, flags);
page_cache_free_page(mapping, page)
put_page(page)
if (put_page_testzero(page)) -> false
- inode now has no pages and can be freed including embedded address_space
mapping_unevictable(mapping)
test_bit(AS_UNEVICTABLE, &mapping->flags);
- we've dereferenced mapping which is potentially already free.
Similar race exists between swap cache freeing and page_evicatable()
too.
The address_space in inode and swap cache will be freed after a RCU
grace period. So the races are fixed via enclosing the page_mapping()
and address_space usage in rcu_read_lock/unlock(). Some comments are
added in code to make it clear what is protected by the RCU read lock.
Link: http://lkml.kernel.org/r/20180212081227.1940-1-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Minchan Kim <minchan@kernel.org>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
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5ad3509364 |
mm: reuse DEFINE_SHOW_ATTRIBUTE() macro
...instead of open coding file operations followed by custom ->open() callbacks per each attribute. [andriy.shevchenko@linux.intel.com: add tags, fix compilation issue] Link: http://lkml.kernel.org/r/20180217144253.58604-1-andriy.shevchenko@linux.intel.com Link: http://lkml.kernel.org/r/20180214154644.54505-1-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Christoph Lameter <cl@linux.com> Cc: Tejun Heo <tj@kernel.org> Cc: Dennis Zhou <dennisszhou@gmail.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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7f16f91fdf |
mm, page_alloc: move mirrored_kernelcore to __meminitdata
mirrored_kernelcore can be in __meminitdata, so move it there. At the same time, fixup section specifiers to be after the name of the variable per checkpatch. Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1802121623280.179479@chino.kir.corp.google.com Signed-off-by: David Rientjes <rientjes@google.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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a5c6d65093 |
mm, page_alloc: extend kernelcore and movablecore for percent
Both kernelcore= and movablecore= can be used to define the amount of ZONE_NORMAL and ZONE_MOVABLE on a system, respectively. This requires the system memory capacity to be known when specifying the command line, however. This introduces the ability to define both kernelcore= and movablecore= as a percentage of total system memory. This is convenient for systems software that wants to define the amount of ZONE_MOVABLE, for example, as a proportion of a system's memory rather than a hardcoded byte value. To define the percentage, the final character of the parameter should be a '%'. mhocko: "why is anyone using these options nowadays?" rientjes: : : Fragmentation of non-__GFP_MOVABLE pages due to low on memory : situations can pollute most pageblocks on the system, as much as 1GB of : slab being fragmented over 128GB of memory, for example. When the : amount of kernel memory is well bounded for certain systems, it is : better to aggressively reclaim from existing MIGRATE_UNMOVABLE : pageblocks rather than eagerly fallback to others. : : We have additional patches that help with this fragmentation if you're : interested, specifically kcompactd compaction of MIGRATE_UNMOVABLE : pageblocks triggered by fallback of non-__GFP_MOVABLE allocations and : draining of pcp lists back to the zone free area to prevent stranding. [rientjes@google.com: updates] Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1802131700160.71590@chino.kir.corp.google.com Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1802121622470.179479@chino.kir.corp.google.com Signed-off-by: David Rientjes <rientjes@google.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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|
31286a8484 |
mm: hwpoison: disable memory error handling on 1GB hugepage
Recently the following BUG was reported:
Injecting memory failure for pfn 0x3c0000 at process virtual address 0x7fe300000000
Memory failure: 0x3c0000: recovery action for huge page: Recovered
BUG: unable to handle kernel paging request at ffff8dfcc0003000
IP: gup_pgd_range+0x1f0/0xc20
PGD 17ae72067 P4D 17ae72067 PUD 0
Oops: 0000 [#1] SMP PTI
...
CPU: 3 PID: 5467 Comm: hugetlb_1gb Not tainted 4.15.0-rc8-mm1-abc+ #3
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.3-1.fc25 04/01/2014
You can easily reproduce this by calling madvise(MADV_HWPOISON) twice on
a 1GB hugepage. This happens because get_user_pages_fast() is not aware
of a migration entry on pud that was created in the 1st madvise() event.
I think that conversion to pud-aligned migration entry is working, but
other MM code walking over page table isn't prepared for it. We need
some time and effort to make all this work properly, so this patch
avoids the reported bug by just disabling error handling for 1GB
hugepage.
[n-horiguchi@ah.jp.nec.com: v2]
Link: http://lkml.kernel.org/r/1517284444-18149-1-git-send-email-n-horiguchi@ah.jp.nec.com
Link: http://lkml.kernel.org/r/1517207283-15769-1-git-send-email-n-horiguchi@ah.jp.nec.com
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Punit Agrawal <punit.agrawal@arm.com>
Tested-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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d0dc12e86b |
mm/memory_hotplug: optimize memory hotplug
During memory hotplugging we traverse struct pages three times: 1. memset(0) in sparse_add_one_section() 2. loop in __add_section() to set do: set_page_node(page, nid); and SetPageReserved(page); 3. loop in memmap_init_zone() to call __init_single_pfn() This patch removes the first two loops, and leaves only loop 3. All struct pages are initialized in one place, the same as it is done during boot. The benefits: - We improve memory hotplug performance because we are not evicting the cache several times and also reduce loop branching overhead. - Remove condition from hotpath in __init_single_pfn(), that was added in order to fix the problem that was reported by Bharata in the above email thread, thus also improve performance during normal boot. - Make memory hotplug more similar to the boot memory initialization path because we zero and initialize struct pages only in one function. - Simplifies memory hotplug struct page initialization code, and thus enables future improvements, such as multi-threading the initialization of struct pages in order to improve hotplug performance even further on larger machines. [pasha.tatashin@oracle.com: v5] Link: http://lkml.kernel.org/r/20180228030308.1116-7-pasha.tatashin@oracle.com Link: http://lkml.kernel.org/r/20180215165920.8570-7-pasha.tatashin@oracle.com Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Baoquan He <bhe@redhat.com> Cc: Bharata B Rao <bharata@linux.vnet.ibm.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Steven Sistare <steven.sistare@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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fc44f7f923 |
mm/memory_hotplug: don't read nid from struct page during hotplug
During memory hotplugging the probe routine will leave struct pages uninitialized, the same as it is currently done during boot. Therefore, we do not want to access the inside of struct pages before __init_single_page() is called during onlining. Because during hotplug we know that pages in one memory block belong to the same numa node, we can skip the checking. We should keep checking for the boot case. [pasha.tatashin@oracle.com: s/register_new_memory()/hotplug_memory_register()] Link: http://lkml.kernel.org/r/20180228030308.1116-6-pasha.tatashin@oracle.com Link: http://lkml.kernel.org/r/20180215165920.8570-6-pasha.tatashin@oracle.com Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Bharata B Rao <bharata@linux.vnet.ibm.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Steven Sistare <steven.sistare@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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b77eab7079 |
mm/memory_hotplug: optimize probe routine
When memory is hotplugged pages_correctly_reserved() is called to verify that the added memory is present, this routine traverses through every struct page and verifies that PageReserved() is set. This is a slow operation especially if a large amount of memory is added. Instead of checking every page, it is enough to simply check that the section is present, has mapping (struct page array is allocated), and the mapping is online. In addition, we should not excpect that probe routine sets flags in struct page, as the struct pages have not yet been initialized. The initialization should be done in __init_single_page(), the same as during boot. Link: http://lkml.kernel.org/r/20180215165920.8570-5-pasha.tatashin@oracle.com Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Bharata B Rao <bharata@linux.vnet.ibm.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Steven Sistare <steven.sistare@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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f165b378bb |
mm: uninitialized struct page poisoning sanity checking
During boot we poison struct page memory in order to ensure that no one is accessing this memory until the struct pages are initialized in __init_single_page(). This patch adds more scrutiny to this checking by making sure that flags do not equal the poison pattern when they are accessed. The pattern is all ones. Since node id is also stored in struct page, and may be accessed quite early, we add this enforcement into page_to_nid() function as well. Note, this is applicable only when NODE_NOT_IN_PAGE_FLAGS=n [pasha.tatashin@oracle.com: v4] Link: http://lkml.kernel.org/r/20180215165920.8570-4-pasha.tatashin@oracle.com Link: http://lkml.kernel.org/r/20180213193159.14606-4-pasha.tatashin@oracle.com Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Baoquan He <bhe@redhat.com> Cc: Bharata B Rao <bharata@linux.vnet.ibm.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Steven Sistare <steven.sistare@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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078eb6aa50 |
x86/mm/memory_hotplug: determine block size based on the end of boot memory
Memory sections are combined into "memory block" chunks. These chunks are the units upon which memory can be added and removed. On x86, the new memory may be added after the end of the boot memory, therefore, if block size does not align with end of boot memory, memory hot-plugging/hot-removing can be broken. Memory sections are combined into "memory block" chunks. These chunks are the units upon which memory can be added and removed. On x86 the new memory may be added after the end of the boot memory, therefore, if block size does not align with end of boot memory, memory hotplugging/hotremoving can be broken. Currently, whenever machine is booted with more than 64G the block size is unconditionally increased to 2G from the base 128M. This is done in order to reduce number of memory device files in sysfs: /sys/devices/system/memory/memoryXXX We must use the largest allowed block size that aligns to the next address to be able to hotplug the next block of memory. So, when memory is larger or equal to 64G, we check the end address and find the largest block size that is still power of two but smaller or equal to 2G. Before, the fix: Run qemu with: -m 64G,slots=2,maxmem=66G -object memory-backend-ram,id=mem1,size=2G (qemu) device_add pc-dimm,id=dimm1,memdev=mem1 Block size [0x80000000] unaligned hotplug range: start 0x1040000000, size 0x80000000 acpi PNP0C80:00: add_memory failed acpi PNP0C80:00: acpi_memory_enable_device() error acpi PNP0C80:00: Enumeration failure With the fix memory is added successfully as the block size is set to 1G, and therefore aligns with start address 0x1040000000. [pasha.tatashin@oracle.com: v4] Link: http://lkml.kernel.org/r/20180215165920.8570-3-pasha.tatashin@oracle.com Link: http://lkml.kernel.org/r/20180213193159.14606-3-pasha.tatashin@oracle.com Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Steven Sistare <steven.sistare@oracle.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@suse.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Bharata B Rao <bharata@linux.vnet.ibm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Baoquan He <bhe@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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ba32558523 |
mm/memory_hotplug: enforce block size aligned range check
Patch series "optimize memory hotplug", v3.
This patchset:
- Improves hotplug performance by eliminating a number of struct page
traverses during memory hotplug.
- Fixes some issues with hotplugging, where boundaries were not
properly checked. And on x86 block size was not properly aligned with
end of memory
- Also, potentially improves boot performance by eliminating condition
from __init_single_page().
- Adds robustness by verifying that that struct pages are correctly
poisoned when flags are accessed.
The following experiments were performed on Xeon(R) CPU E7-8895 v3 @
2.60GHz with 1T RAM:
booting in qemu with 960G of memory, time to initialize struct pages:
no-kvm:
TRY1 TRY2
BEFORE: 39.433668 39.39705
AFTER: 36.903781 36.989329
with-kvm:
BEFORE: 10.977447 11.103164
AFTER: 10.929072 10.751885
Hotplug 896G memory:
no-kvm:
TRY1 TRY2
BEFORE: 848.740000 846.910000
AFTER: 783.070000 786.560000
with-kvm:
TRY1 TRY2
BEFORE: 34.410000 33.57
AFTER: 29.810000 29.580000
This patch (of 6):
Start qemu with the following arguments:
-m 64G,slots=2,maxmem=66G -object memory-backend-ram,id=mem1,size=2G
Which: boots machine with 64G, and adds a device mem1 with 2G which can
be hotplugged later.
Also make sure that config has the following turned on:
CONFIG_MEMORY_HOTPLUG
CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE
CONFIG_ACPI_HOTPLUG_MEMORY
Using the qemu monitor hotplug the memory (make sure config has (qemu)
device_add pc-dimm,id=dimm1,memdev=mem1
The operation will fail with the following trace:
WARNING: CPU: 0 PID: 91 at drivers/base/memory.c:205
pages_correctly_reserved+0xe6/0x110
Modules linked in:
CPU: 0 PID: 91 Comm: systemd-udevd Not tainted 4.16.0-rc1_pt_master #29
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS rel-1.11.0-0-g63451fca13-prebuilt.qemu-project.org 04/01/2014
RIP: 0010:pages_correctly_reserved+0xe6/0x110
Call Trace:
memory_subsys_online+0x44/0xa0
device_online+0x51/0x80
store_mem_state+0x5e/0xe0
kernfs_fop_write+0xfa/0x170
__vfs_write+0x2e/0x150
vfs_write+0xa8/0x1a0
SyS_write+0x4d/0xb0
do_syscall_64+0x5d/0x110
entry_SYSCALL_64_after_hwframe+0x21/0x86
---[ end trace 6203bc4f1a5d30e8 ]---
The problem is detected in: drivers/base/memory.c
static bool pages_correctly_reserved(unsigned long start_pfn)
205 if (WARN_ON_ONCE(!pfn_valid(pfn)))
This function loops through every section in the newly added memory
block and verifies that the first pfn is valid, meaning section exists,
has mapping (struct page array), and is online.
The block size on x86 is usually 128M, but when machine is booted with
more than 64G of memory, the block size is changed to 2G: $ cat
/sys/devices/system/memory/block_size_bytes 80000000
or
$ dmesg | grep "block size"
[ 0.086469] x86/mm: Memory block size: 2048MB
During memory hotplug, and hotremove we verify that the range is section
size aligned, but we actually must verify that it is block size aligned,
because that is the proper unit for hotplug operations. See:
Documentation/memory-hotplug.txt
So, when the start_pfn of newly added memory is not block size aligned,
we can get a memory block that has only part of it with properly
populated sections.
In our case the start_pfn starts from the last_pfn (end of physical
memory).
$ dmesg | grep last_pfn
[ 0.000000] e820: last_pfn = 0x1040000 max_arch_pfn = 0x400000000
0x1040000 == 65G, and so is not 2G aligned!
The fix is to enforce that memory that is hotplugged and hotremoved is
block size aligned.
With this fix, running the above sequence yield to the following result:
(qemu) device_add pc-dimm,id=dimm1,memdev=mem1
Block size [0x80000000] unaligned hotplug range: start 0x1040000000,
size 0x80000000
acpi PNP0C80:00: add_memory failed
acpi PNP0C80:00: acpi_memory_enable_device() error
acpi PNP0C80:00: Enumeration failure
Link: http://lkml.kernel.org/r/20180213193159.14606-2-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Bharata B Rao <bharata@linux.vnet.ibm.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Steven Sistare <steven.sistare@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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f0849ac0b8 |
mm: thp: fix potential clearing to referenced flag in page_idle_clear_pte_refs_one()
For PTE-mapped THP, the compound THP has not been split to normal 4K
pages yet, the whole THP is considered referenced if any one of sub page
is referenced.
When walking PTE-mapped THP by pvmw, all relevant PTEs will be checked
to retrieve referenced bit. But, the current code just returns the
result of the last PTE. If the last PTE has not referenced, the
referenced flag will be cleared.
Just set referenced when ptep{pmdp}_clear_young_notify() returns true.
Link: http://lkml.kernel.org/r/1518212451-87134-1-git-send-email-yang.shi@linux.alibaba.com
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Reported-by: Gang Deng <gavin.dg@linux.alibaba.com>
Suggested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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c9e97a1997 |
mm: initialize pages on demand during boot
Deferred page initialization allows the boot cpu to initialize a small subset of the system's pages early in boot, with other cpus doing the rest later on. It is, however, problematic to know how many pages the kernel needs during boot. Different modules and kernel parameters may change the requirement, so the boot cpu either initializes too many pages or runs out of memory. To fix that, initialize early pages on demand. This ensures the kernel does the minimum amount of work to initialize pages during boot and leaves the rest to be divided in the multithreaded initialization path (deferred_init_memmap). The on-demand code is permanently disabled using static branching once deferred pages are initialized. After the static branch is changed to false, the overhead is up-to two branch-always instructions if the zone watermark check fails or if rmqueue fails. Sergey Senozhatsky noticed that while deferred pages currently make sense only on NUMA machines (we start one thread per latency node), CONFIG_NUMA is not a requirement for CONFIG_DEFERRED_STRUCT_PAGE_INIT, so that is also must be addressed in the patch. [akpm@linux-foundation.org: fix typo in comment, make deferred_pages static] [pasha.tatashin@oracle.com: fix min() type mismatch warning] Link: http://lkml.kernel.org/r/20180212164543.26592-1-pasha.tatashin@oracle.com [pasha.tatashin@oracle.com: use zone_to_nid() in deferred_grow_zone()] Link: http://lkml.kernel.org/r/20180214163343.21234-2-pasha.tatashin@oracle.com [pasha.tatashin@oracle.com: might_sleep warning] Link: http://lkml.kernel.org/r/20180306192022.28289-1-pasha.tatashin@oracle.com [akpm@linux-foundation.org: s/spin_lock/spin_lock_irq/ in page_alloc_init_late()] [pasha.tatashin@oracle.com: v5] Link: http://lkml.kernel.org/r/20180309220807.24961-3-pasha.tatashin@oracle.com [akpm@linux-foundation.org: tweak comments] [pasha.tatashin@oracle.com: v6] Link: http://lkml.kernel.org/r/20180313182355.17669-3-pasha.tatashin@oracle.com [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/20180209192216.20509-2-pasha.tatashin@oracle.com Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Steven Sistare <steven.sistare@oracle.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: AKASHI Takahiro <takahiro.akashi@linaro.org> Cc: Gioh Kim <gi-oh.kim@profitbricks.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Paul Burton <paul.burton@mips.com> Cc: Miles Chen <miles.chen@mediatek.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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3a2d7fa8a3 |
mm: disable interrupts while initializing deferred pages
Vlastimil Babka reported about a window issue during which when deferred pages are initialized, and the current version of on-demand initialization is finished, allocations may fail. While this is highly unlikely scenario, since this kind of allocation request must be large, and must come from interrupt handler, we still want to cover it. We solve this by initializing deferred pages with interrupts disabled, and holding node_size_lock spin lock while pages in the node are being initialized. The on-demand deferred page initialization that comes later will use the same lock, and thus synchronize with deferred_init_memmap(). It is unlikely for threads that initialize deferred pages to be interrupted. They run soon after smp_init(), but before modules are initialized, and long before user space programs. This is why there is no adverse effect of having these threads running with interrupts disabled. [pasha.tatashin@oracle.com: v6] Link: http://lkml.kernel.org/r/20180313182355.17669-2-pasha.tatashin@oracle.com Link: http://lkml.kernel.org/r/20180309220807.24961-2-pasha.tatashin@oracle.com Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Steven Sistare <steven.sistare@oracle.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: AKASHI Takahiro <takahiro.akashi@linaro.org> Cc: Gioh Kim <gi-oh.kim@profitbricks.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Paul Burton <paul.burton@mips.com> Cc: Miles Chen <miles.chen@mediatek.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |