- 09 May, 2017 40 commits
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Kirill Tkhai authored
alloc_pidmap() advances pid_namespace::last_pid. When first pid allocation fails, then next created process will have pid 2 and pid_ns_prepare_proc() won't be called. So, pid_namespace::proc_mnt will never be initialized (not to mention that there won't be a child reaper). I saw crash stack of such case on kernel 3.10: BUG: unable to handle kernel NULL pointer dereference at (null) IP: proc_flush_task+0x8f/0x1b0 Call Trace: release_task+0x3f/0x490 wait_consider_task.part.10+0x7ff/0xb00 do_wait+0x11f/0x280 SyS_wait4+0x7d/0x110 We may fix this by restore of last_pid in 0 or by prohibiting of futher allocations. Since there was a similar issue in Oleg Nesterov's commit 314a8ad0 ("pidns: fix free_pid() to handle the first fork failure"). and it was fixed via prohibiting allocation, let's follow this way, and do the same. Link: http://lkml.kernel.org/r/149201021004.4863.6762095011554287922.stgit@localhost.localdomainSigned-off-by:Kirill Tkhai <ktkhai@virtuozzo.com> Acked-by:
Cyrill Gorcunov <gorcunov@openvz.org> Cc: Andrei Vagin <avagin@virtuozzo.com> Cc: Andreas Gruenbacher <agruenba@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Paul Moore <paul@paul-moore.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Ingo Molnar <mingo@kernel.org> Cc: Serge Hallyn <serge@hallyn.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Hari Bathini authored
As we are reusing crashkernel parameter instead of fadump_reserve_mem parameter to specify the memory to reserve for fadump's crash kernel, update the documentation accordingly. Link: http://lkml.kernel.org/r/149035347559.6881.14224829694291758581.stgit@hbathini.in.ibm.comSigned-off-by:
Hari Bathini <hbathini@linux.vnet.ibm.com> Acked-by:
Michael Ellerman <mpe@ellerman.id.au> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Dave Young <dyoung@redhat.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by:
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Hari Bathini authored
fadump supports specifying memory to reserve for fadump's crash kernel with fadump_reserve_mem kernel parameter. This parameter currently supports passing a fixed memory size, like fadump_reserve_mem=<size> only. This patch aims to add support for other syntaxes like range-based memory size <range1>:<size1>[,<range2>:<size2>,<range3>:<size3>,...] which allows using the same parameter to boot the kernel with different system RAM sizes. As crashkernel parameter already supports the above mentioned syntaxes, this patch deprecates fadump_reserve_mem parameter and reuses crashkernel parameter instead, to specify memory for fadump's crash kernel memory reservation as well. If any offset is provided in crashkernel parameter, it will be ignored in case of fadump, as fadump reserves memory at end of RAM. Advantages using crashkernel parameter instead of fadump_reserve_mem parameter are one less kernel parameter overall, code reuse and support for multiple syntaxes to specify memory. Suggested-by:
Dave Young <dyoung@redhat.com> Link: http://lkml.kernel.org/r/149035346749.6881.911095631212975718.stgit@hbathini.in.ibm.comSigned-off-by:
Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Acked-by:
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Hari Bathini authored
Now that crashkernel parameter parsing and vmcoreinfo related code is moved under CONFIG_CRASH_CORE instead of CONFIG_KEXEC_CORE, remove dependency with CONFIG_KEXEC for CONFIG_FA_DUMP. While here, get rid of definitions of fadump_append_elf_note() & fadump_final_note() functions to reuse similar functions compiled under CONFIG_CRASH_CORE. Link: http://lkml.kernel.org/r/149035343956.6881.1536459326017709354.stgit@hbathini.in.ibm.comSigned-off-by:
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Hari Bathini authored
Get rid of multiple definitions of append_elf_note() & final_note() functions. Reuse these functions compiled under CONFIG_CRASH_CORE Also, define Elf_Word and use it instead of generic u32 or the more specific Elf64_Word. Link: http://lkml.kernel.org/r/149035342324.6881.11667840929850361402.stgit@hbathini.in.ibm.comSigned-off-by:
Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by:
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Hari Bathini authored
Patch series "kexec/fadump: remove dependency with CONFIG_KEXEC and reuse crashkernel parameter for fadump", v4. Traditionally, kdump is used to save vmcore in case of a crash. Some architectures like powerpc can save vmcore using architecture specific support instead of kexec/kdump mechanism. Such architecture specific support also needs to reserve memory, to be used by dump capture kernel. crashkernel parameter can be a reused, for memory reservation, by such architecture specific infrastructure. This patchset removes dependency with CONFIG_KEXEC for crashkernel parameter and vmcoreinfo related code as it can be reused without kexec support. Also, crashkernel parameter is reused instead of fadump_reserve_mem to reserve memory for fadump. The first patch moves crashkernel parameter parsing and vmcoreinfo related code under CONFIG_CRASH_CORE instead of CONFIG_KEXEC_CORE. The second patch reuses the definitions of append_elf_note() & final_note() functions under CONFIG_CRASH_CORE in IA64 arch code. The third patch removes dependency on CONFIG_KEXEC for firmware-assisted dump (fadump) in powerpc. The next patch reuses crashkernel parameter for reserving memory for fadump, instead of the fadump_reserve_mem parameter. This has the advantage of using all syntaxes crashkernel parameter supports, for fadump as well. The last patch updates fadump kernel documentation about use of crashkernel parameter. This patch (of 5): Traditionally, kdump is used to save vmcore in case of a crash. Some architectures like powerpc can save vmcore using architecture specific support instead of kexec/kdump mechanism. Such architecture specific support also needs to reserve memory, to be used by dump capture kernel. crashkernel parameter can be a reused, for memory reservation, by such architecture specific infrastructure. But currently, code related to vmcoreinfo and parsing of crashkernel parameter is built under CONFIG_KEXEC_CORE. This patch introduces CONFIG_CRASH_CORE and moves the above mentioned code under this config, allowing code reuse without dependency on CONFIG_KEXEC. There is no functional change with this patch. Link: http://lkml.kernel.org/r/149035338104.6881.4550894432615189948.stgit@hbathini.in.ibm.comSigned-off-by:
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Alexey Dobriyan authored
Bit searching functions accept "unsigned long" indices but "nr_cpumask_bits" is "int" which is signed, so inevitable sign extensions occur on x86_64. Those MOVSX are #1 MOVSX bloat by number of uses across whole kernel. Change "nr_cpumask_bits" to unsigned, this number can't be negative after all. It allows to do implicit zero-extension on x86_64 without MOVSX. Change signed comparisons into unsigned comparisons where necessary. Other uses looks fine because it is either argument passed to a function or comparison is already unsigned. Net win on allyesconfig type of kernel: ~2.8 KB (!) add/remove: 0/0 grow/shrink: 8/725 up/down: 93/-2926 (-2833) function old new delta xen_exit_mmap 691 735 +44 qstat_read 426 440 +14 __cpufreq_cooling_register 1678 1687 +9 trace_rb_cpu_prepare 447 455 +8 vermagic 54 60 +6 nfp_driver_version 54 60 +6 rcu_torture_stats_print 1147 1151 +4 find_next_push_cpu 267 269 +2 xen_irq_resume 961 960 -1 ... init_vp_index 946 906 -40 od_set_powersave_bias 328 281 -47 power_cpu_exit 193 139 -54 arch_show_interrupts 3538 3484 -54 select_idle_sibling 1558 1471 -87 Total: Before=158358910, After=158356077, chg -0.00% Same arguments apply to "nr_cpu_ids" but I haven't yet found enough courage to delve into this issue (and proper fix may require new type "cpu_t" which is whole separate story). Link: http://lkml.kernel.org/r/20170309205322.GA1728@avx2Signed-off-by:
Alexey Dobriyan <adobriyan@gmail.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by:
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Hoeun Ryu authored
Using virtually mapped stack, kernel stacks are allocated via vmalloc. In the current implementation, two stacks per cpu can be cached when tasks are freed and the cached stacks are used again in task duplications. But the cached stacks may remain unfreed even when cpu are offline. By adding a cpu hotplug callback to free the cached stacks when a cpu goes offline, the pages of the cached stacks are not wasted. Link: http://lkml.kernel.org/r/1487076043-17802-1-git-send-email-hoeun.ryu@gmail.comSigned-off-by:
Hoeun Ryu <hoeun.ryu@gmail.com> Reviewed-by:
Thomas Gleixner <tglx@linutronix.de> Acked-by:
Michal Hocko <mhocko@suse.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Mateusz Guzik <mguzik@redhat.com> Signed-off-by:
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Kees Cook authored
Prepare to mark sensitive kernel structures for randomization by making sure they're using designated initializers. These were identified during allyesconfig builds of x86, arm, and arm64, with most initializer fixes extracted from grsecurity. Link: http://lkml.kernel.org/r/20170329210419.GA40066@beastSigned-off-by:
Kees Cook <keescook@chromium.org> Cc: Jan Kara <jack@suse.cz> Signed-off-by:
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Joe Perches authored
The current SUSPECT_CODE_INDENT test does not recognize several defective code style defects where code following a logical test is inappropriately indented. Before this patch, for code like: if (foo) bar(); checkpatch would not emit a warning. Improve the test to warn when code after a logical test has the same indentation as the logical test. Perform the same indentation test for "else" blocks too. Link: http://lkml.kernel.org/r/df2374b68c4a68af2b7ef08afe486584811f610a.1493683942.git.joe@perches.comSigned-off-by:
Joe Perches <joe@perches.com> Signed-off-by:
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Joe Perches authored
The current test works only for a single patch context as it is done in the foreach ($rawlines) loop that precedes the loop where the actual $context_function variable is used. Move the set of $context_function into the foreach (@lines) loop where it is useful for each patch context. Link: http://lkml.kernel.org/r/6c675a31c74fbfad4fc45b9f462303d60ca2a283.1493486091.git.joe@perches.comSigned-off-by:
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Jerome Forissier authored
When using checkpatch on out-of-tree code, it may occur that some project-specific types are used, which will cause spurious warnings. Add the --typedefsfile option as a way to extend the known types and deal with this issue. This was developed for OP-TEE [1]. We run a Travis job on all pull requests [2], and checkpatch is part of that. The typical false warning we get on a regular basis is with some pointers to functions returning TEE_Result [3], which is a typedef from the GlobalPlatform APIs. We consider it is acceptable to use GP types in the OP-TEE core implementation, that's why this patch would be helpful for us. [1] https://github.com/OP-TEE/optee_os [2] https://travis-ci.org/OP-TEE/optee_os/builds [3] https://travis-ci.org/OP-TEE/optee_os/builds/193355335#L1733 Link: http://lkml.kernel.org/r/ba1124d6dfa599bb0dd1d8919dd45dd09ce541a4.1492702192.git.jerome.forissier@linaro.orgSigned-off-by:
Jerome Forissier <jerome.forissier@linaro.org> Cc: Joe Perches <joe@perches.com> Cc: Andy Whitcroft <apw@canonical.com> Signed-off-by:
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Joe Perches authored
Find multi-line uses of k.alloc by using the $stat variable and not the $line variable. This can still --fix only the single line variant though. Link: http://lkml.kernel.org/r/3f4b23d37cd4c7d8628eefc25afe83ba8fb3ab55.1493167076.git.joe@perches.comSigned-off-by:
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Wei Wang authored
Currently checkpatch.pl does not recognize git's default commit revert message and will complain about the hash format. Add special audit for revert commit message line to fix it. Link: http://lkml.kernel.org/r/20170411191532.74381-1-wvw@google.comSigned-off-by:
Wei Wang <wvw@google.com> Acked-by:
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Joe Perches authored
Try to make the conversion of embedded function names to "%s: ", __func__ a bit clearer. Add a bit more information to the comment describing the test too. Link: http://lkml.kernel.org/r/38f5d32f0aec1cd98cb9ceeedd6a736cc9a802db.1491759835.git.joe@perches.comSigned-off-by:
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Joe Perches authored
The logic currrently misses macros that start with an if statement. e.g.: #define foo(bar) if (bar) baz; Add a test for macro content that starts with if Link: http://lkml.kernel.org/r/a9d41aafe1673889caf1a9850208fb7fd74107a0.1491783914.git.joe@perches.comSigned-off-by:
Andreas Mohr <andi@lisas.de> Original-patch-by:
Alfonso Lima <alfonsolimaastor@gmail.com> Signed-off-by:
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Joe Perches authored
Many structs are generally used const and there is a known list of these structs. struct definitions should not be generally be declared const. Add a test for the lack of an open brace immediately after the struct to avoid definitions. This avoids the false positive "struct foo should normally be const" message only when the open brace is on the same line as the definition. Link: http://lkml.kernel.org/r/0dce709150d712e66f1b90b03827634b53b28085.1491845946.git.joe@perches.comSigned-off-by:
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Joe Perches authored
Allow a leading space and otherwise blank link in the email headers as it can be a line wrapped Spamassassin multiple line string or any other valid rfc 2822/5322 email header. The line with space causes checkpatch to erroneously think that it's in the content body, as opposed to headers and thus flag a mail header as an unwrapped long comment line. Link: http://lkml.kernel.org/r/d75a9f0b78b3488078429f4037d9fff3bdfa3b78.1490247180.git.joe@perches.comSigned-off-by:
Joe Perches <joe@perches.com>Reported-by: Darren Hart (VMware) <dvhart@infradead.org> Tested-by:
Darren Hart (VMware) <dvhart@vmware.com> Original-patch-by:
John 'Warthog9' Hawley (VMware) <warthog9@eaglescrag.net> Signed-off-by:
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Joe Perches authored
The existing behavior relies on patch context to identify function declarations. Add the ability to find function declarations when there is an open brace in column 1. This finds function declarations only in specific single line forms where the function name is on a single line like: int foo(args...) { and int foo(args...) { It does not recognize function declarations like: int foo(int bar, int baz) { Link: http://lkml.kernel.org/r/738d74bbbe1a06b80f11ed504818107c68903095.1488155636.git.joe@perches.comSigned-off-by: -
Joe Perches authored
%pK was at least once misused at %pk in an out-of-tree module. This lead to some security concerns. Add the ability to track single and multiple line statements for misuses of %p<foo>. [akpm@linux-foundation.org: add helpful comment into lib/vsprintf.c] [akpm@linux-foundation.org: text tweak] Link: http://lkml.kernel.org/r/163a690510e636a23187c0dc9caa09ddac6d4cde.1488228427.git.joe@perches.comSigned-off-by:
William Roberts <william.c.roberts@intel.com> Signed-off-by:
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Ruslan Bilovol authored
Config EXPERIMENTAL has been removed from kernel in 2013 (see commit 3d374d09: "final removal of CONFIG_EXPERIMENTAL"), there is no any reason to do these checks now. Link: http://lkml.kernel.org/r/1488234097-20119-1-git-send-email-ruslan.bilovol@gmail.comSigned-off-by:
Ruslan Bilovol <ruslan.bilovol@gmail.com> Acked-by:
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Luis R. Rodriguez authored
If you modify the target asm we currently do not force the recompilation of the firmware files. The target asm is in the firmware/Makefile, peg this file as a dependency to require re-compilation of firmware targets when the asm changes. Link: http://lkml.kernel.org/r/20170123150727.4883-1-mcgrof@kernel.orgSigned-off-by:
Luis R. Rodriguez <mcgrof@kernel.org> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Michal Marek <mmarek@suse.com> Cc: Ming Lei <ming.lei@canonical.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Tom Gundersen <teg@jklm.no> Cc: David Woodhouse <dwmw2@infradead.org> Signed-off-by:
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Geert Uytterhoeven authored
Extract the linked list sorting test code into its own source file, to allow to compile it either to a loadable module, or builtin into the kernel. Link: http://lkml.kernel.org/r/1488287219-15832-4-git-send-email-geert@linux-m68k.orgSigned-off-by:
Geert Uytterhoeven <geert@linux-m68k.org> Reviewed-by:
Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by:
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Geert Uytterhoeven authored
Allow to compile the array-based sort test code either to a loadable module, or builtin into the kernel. Link: http://lkml.kernel.org/r/1488287219-15832-3-git-send-email-geert@linux-m68k.orgSigned-off-by:
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Geert Uytterhoeven authored
Patch series "lib: add module support to sort tests". This patch series allows to compile the array-based and linked list sort test code either to loadable modules, or builtin into the kernel. It's very valuable to have modular tests, so you can run them just by insmodding the test modules, instead of needing a separate kernel that runs them at boot. This patch (of 3): This reverts commit 8893f519. It's very valuable to have modular tests, so you can run them just by insmodding the test modules, instead of needing a separate kernel that runs them at boot. Link: http://lkml.kernel.org/r/1488287219-15832-2-git-send-email-geert@linux-m68k.orgSigned-off-by:
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Dan Carpenter authored
c2port_device_register() never returns NULL, it uses error pointers. Link: http://lkml.kernel.org/r/20170412083321.GC3250@mwanda Fixes: 65131cd5 ("c2port: add c2port support for Eurotech Duramar 2150") Signed-off-by:
Dan Carpenter <dan.carpenter@oracle.com> Acked-by:
Rodolfo Giometti <giometti@linux.it> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by:
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Dan Carpenter authored
The "DIV_ROUND_UP(size, PAGE_SIZE)" operation can overflow if "size" is more than ULLONG_MAX - PAGE_SIZE. Link: http://lkml.kernel.org/r/20170322111950.GA11279@mwandaSigned-off-by:
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Tetsuo Handa authored
When I was running my testcase which may block hundreds of threads on fs locks, I got lockup due to output from debug_show_all_locks() added by commit b2d4c2ed ("locking/hung_task: Show all locks"). For example, if 1000 threads were blocked in TASK_UNINTERRUPTIBLE state and 500 out of 1000 threads hold some lock, debug_show_all_locks() from for_each_process_thread() loop will report locks held by 500 threads for 1000 times. This is a too much noise. In order to make sure rcu_lock_break() is called frequently, we should avoid calling debug_show_all_locks() from for_each_process_thread() loop because debug_show_all_locks() effectively calls for_each_process_thread() loop. Let's defer calling debug_show_all_locks() till before panic() or leaving for_each_process_thread() loop. Link: http://lkml.kernel.org/r/1489296834-60436-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jpSigned-off-by:
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by:
Vegard Nossum <vegard.nossum@oracle.com> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by:
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Randy Dunlap authored
Add a top-level Makefile help target for Userspace tools. Also make each help "heading" end with a colon ':'. Link: http://lkml.kernel.org/r/55c986ff-3966-3e47-2984-7349da2cce51@infradead.orgSigned-off-by:
Randy Dunlap <rdunlap@infradead.org> Signed-off-by:
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Matthias Kaehlcke authored
jiffies_64 is defined in kernel/time/timer.c with ____cacheline_aligned_in_smp, however this macro is not part of the declaration of jiffies and jiffies_64 in jiffies.h. As a result clang generates the following warning: kernel/time/timer.c:57:26: error: section does not match previous declaration [-Werror,-Wsection] __visible u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES; ^ include/linux/cache.h:39:36: note: expanded from macro '__cacheline_aligned_in_smp' ^ include/linux/cache.h:34:4: note: expanded from macro '__cacheline_aligned' __section__(".data..cacheline_aligned"))) ^ include/linux/jiffies.h:77:12: note: previous attribute is here extern u64 __jiffy_data jiffies_64; ^ include/linux/jiffies.h:70:38: note: expanded from macro '__jiffy_data' Link: http://lkml.kernel.org/r/20170403190200.70273-1-mka@chromium.orgSigned-off-by:Matthias Kaehlcke <mka@chromium.org> Cc: "Jason A . Donenfeld" <Jason@zx2c4.com> Cc: Grant Grundler <grundler@chromium.org> Cc: Michael Davidson <md@google.com> Cc: Greg Hackmann <ghackmann@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by:
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Lorenzo Stoakes authored
Moving from get_user_pages() to get_user_pages_unlocked() simplifies the code and takes advantage of VM_FAULT_RETRY functionality when faulting in pages. Link: http://lkml.kernel.org/r/20161101194332.23961-1-lstoakes@gmail.comSigned-off-by:
Lorenzo Stoakes <lstoakes@gmail.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Kumar Gala <galak@kernel.crashing.org> Cc: Mihai Caraman <mihai.caraman@freescale.com> Cc: Greg KH <gregkh@linuxfoundation.org> Signed-off-by:
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Gao Feng authored
do_proc_dointvec_jiffies_conv() uses LONG_MAX/HZ as the max value to avoid overflow. But actually the *valp is int type, so it still causes overflow. For example, echo 2147483647 > ./sys/net/ipv4/tcp_keepalive_time Then, cat ./sys/net/ipv4/tcp_keepalive_time The output is "-1", it is not expected. Now use INT_MAX/HZ as the max value instead LONG_MAX/HZ to fix it. Link: http://lkml.kernel.org/r/1490109532-9228-1-git-send-email-fgao@ikuai8.comSigned-off-by:
Gao Feng <fgao@ikuai8.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by:
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Tobin C. Harding authored
Coccinelle emits this warning: WARNING: casting value returned by memory allocation function to (struct proc_inode *) is useless. Remove unnecessary cast. Link: http://lkml.kernel.org/r/1487745720-16967-1-git-send-email-me@tobin.ccSigned-off-by:
Tobin C. Harding <me@tobin.cc> Signed-off-by:
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Vlastimil Babka authored
The main goal of direct compaction is to form a high-order page for allocation, but it should also help against long-term fragmentation when possible. Most lower-than-pageblock-order compactions are for non-movable allocations, which means that if we compact in a movable pageblock and terminate as soon as we create the high-order page, it's unlikely that the fallback heuristics will claim the whole block. Instead there might be a single unmovable page in a pageblock full of movable pages, and the next unmovable allocation might pick another pageblock and increase long-term fragmentation. To help against such scenarios, this patch changes the termination criteria for compaction so that the current pageblock is finished even though the high-order page already exists. Note that it might be possible that the high-order page formed elsewhere in the zone due to parallel activity, but this patch doesn't try to detect that. This is only done with sync compaction, because async compaction is limited to pageblock of the same migratetype, where it cannot result in a migratetype fallback. (Async compaction also eagerly skips order-aligned blocks where isolation fails, which is against the goal of migrating away as much of the pageblock as possible.) As a result of this patch, long-term memory fragmentation should be reduced. In testing based on 4.9 kernel with stress-highalloc from mmtests configured for order-4 GFP_KERNEL allocations, this patch has reduced the number of unmovable allocations falling back to movable pageblocks by 20%. The number Link: http://lkml.kernel.org/r/20170307131545.28577-9-vbabka@suse.czSigned-off-by:
Vlastimil Babka <vbabka@suse.cz> Acked-by:
Mel Gorman <mgorman@techsingularity.net> Acked-by:
Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by:
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Vlastimil Babka authored
The migrate scanner in async compaction is currently limited to MIGRATE_MOVABLE pageblocks. This is a heuristic intended to reduce latency, based on the assumption that non-MOVABLE pageblocks are unlikely to contain movable pages. However, with the exception of THP's, most high-order allocations are not movable. Should the async compaction succeed, this increases the chance that the non-MOVABLE allocations will fallback to a MOVABLE pageblock, making the long-term fragmentation worse. This patch attempts to help the situation by changing async direct compaction so that the migrate scanner only scans the pageblocks of the requested migratetype. If it's a non-MOVABLE type and there are such pageblocks that do contain movable pages, chances are that the allocation can succeed within one of such pageblocks, removing the need for a fallback. If that fails, the subsequent sync attempt will ignore this restriction. In testing based on 4.9 kernel with stress-highalloc from mmtests configured for order-4 GFP_KERNEL allocations, this patch has reduced the number of unmovable allocations falling back to movable pageblocks by 30%. The number of movable allocations falling back is reduced by 12%. Link: http://lkml.kernel.org/r/20170307131545.28577-8-vbabka@suse.czSigned-off-by:
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Vlastimil Babka authored
Preparation patch. We are going to need migratetype at lower layers than compact_zone() and compact_finished(). Link: http://lkml.kernel.org/r/20170307131545.28577-7-vbabka@suse.czSigned-off-by:
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Vlastimil Babka authored
Preparation for making the decisions more complex and depending on compact_control flags. No functional change. Link: http://lkml.kernel.org/r/20170307131545.28577-6-vbabka@suse.czSigned-off-by:
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Vlastimil Babka authored
When stealing pages from pageblock of a different migratetype, we count how many free pages were stolen, and change the pageblock's migratetype if more than half of the pageblock was free. This might be too conservative, as there might be other pages that are not free, but were allocated with the same migratetype as our allocation requested. While we cannot determine the migratetype of allocated pages precisely (at least without the page_owner functionality enabled), we can count pages that compaction would try to isolate for migration - those are either on LRU or __PageMovable(). The rest can be assumed to be MIGRATE_RECLAIMABLE or MIGRATE_UNMOVABLE, which we cannot easily distinguish. This counting can be done as part of free page stealing with little additional overhead. The page stealing code is changed so that it considers free pages plus pages of the "good" migratetype for the decision whether to change pageblock's migratetype. The result should be more accurate migratetype of pageblocks wrt the actual pages in the pageblocks, when stealing from semi-occupied pageblocks. This should help the efficiency of page grouping by mobility. In testing based on 4.9 kernel with stress-highalloc from mmtests configured for order-4 GFP_KERNEL allocations, this patch has reduced the number of unmovable allocations falling back to movable pageblocks by 47%. The number of movable allocations falling back to other pageblocks are increased by 55%, but these events don't cause permanent fragmentation, so the tradeoff should be positive. Later patches also offset the movable fallback increase to some extent. [akpm@linux-foundation.org: merge fix] Link: http://lkml.kernel.org/r/20170307131545.28577-5-vbabka@suse.czSigned-off-by:
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Vlastimil Babka authored
The __rmqueue_fallback() function is called when there's no free page of requested migratetype, and we need to steal from a different one. There are various heuristics to make this event infrequent and reduce permanent fragmentation. The main one is to try stealing from a pageblock that has the most free pages, and possibly steal them all at once and convert the whole pageblock. Precise searching for such pageblock would be expensive, so instead the heuristics walks the free lists from MAX_ORDER down to requested order and assumes that the block with highest-order free page is likely to also have the most free pages in total. Chances are that together with the highest-order page, we steal also pages of lower orders from the same block. But then we still split the highest order page. This is wasteful and can contribute to fragmentation instead of avoiding it. This patch thus changes __rmqueue_fallback() to just steal the page(s) and put them on the freelist of the requested migratetype, and only report whether it was successful. Then we pick (and eventually split) the smallest page with __rmqueue_smallest(). This all happens under zone lock, so nobody can steal it from us in the process. This should reduce fragmentation due to fallbacks. At worst we are only stealing a single highest-order page and waste some cycles by moving it between lists and then removing it, but fallback is not exactly hot path so that should not be a concern. As a side benefit the patch removes some duplicate code by reusing __rmqueue_smallest(). [vbabka@suse.cz: fix endless loop in the modified __rmqueue()] Link: http://lkml.kernel.org/r/59d71b35-d556-4fc9-ee2e-1574259282fd@suse.cz Link: http://lkml.kernel.org/r/20170307131545.28577-4-vbabka@suse.czSigned-off-by:
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Vlastimil Babka authored
When detecting whether compaction has succeeded in forming a high-order page, __compact_finished() employs a watermark check, followed by an own search for a suitable page in the freelists. This is not ideal for two reasons: - The watermark check also searches high-order freelists, but has a less strict criteria wrt fallback. It's therefore redundant and waste of cycles. This was different in the past when high-order watermark check attempted to apply reserves to high-order pages. - The watermark check might actually fail due to lack of order-0 pages. Compaction can't help with that, so there's no point in continuing because of that. It's possible that high-order page still exists and it terminates. This patch therefore removes the watermark check. This should save some cycles and terminate compaction sooner in some cases. Link: http://lkml.kernel.org/r/20170307131545.28577-3-vbabka@suse.czSigned-off-by:
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