Commit Graph

914152 Commits

Author SHA1 Message Date
Gustavo A. R. Silva
51022f8715 lib/ts_kmp.c: replace zero-length array with flexible-array member
The current codebase makes use of the zero-length array language extension
to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertenly introduced[3] to the codebase from now on.

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200211205948.GA26459@embeddedor
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:43 -07:00
Gustavo A. R. Silva
842ae1f52b lib/ts_fsm.c: replace zero-length array with flexible-array member
The current codebase makes use of the zero-length array language extension
to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertenly introduced[3] to the codebase from now on.

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200211205813.GA25602@embeddedor
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:43 -07:00
Gustavo A. R. Silva
c6e2ac3b47 lib/ts_bm.c: replace zero-length array with flexible-array member
The current codebase makes use of the zero-length array language extension
to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertenly introduced[3] to the codebase from now on.

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200211205620.GA24694@embeddedor
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:42 -07:00
Gustavo A. R. Silva
a44ce51370 lib/bch.c: replace zero-length array with flexible-array member
The current codebase makes use of the zero-length array language extension
to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertenly introduced[3] to the codebase from now on.

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200211205119.GA21234@embeddedor
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:42 -07:00
Konstantin Khlebnikov
aecd42df6d lib/test_lockup.c: add parameters for locking generic vfs locks
file_path=<path>	defines file or directory to open
lock_inode=Y		set lock_rwsem_ptr to inode->i_rwsem
lock_mapping=Y		set lock_rwsem_ptr to mapping->i_mmap_rwsem
lock_sb_umount=Y	set lock_rwsem_ptr to sb->s_umount

This gives safe and simple way to see how system reacts to contention of
common vfs locks and how syscalls depend on them directly or indirectly.

For example to block s_umount for 60 seconds:
# modprobe test_lockup file_path=. lock_sb_umount time_secs=60 state=S

This is useful for checking/testing scalability issues like this:
https://lore.kernel.org/lkml/158497590858.7371.9311902565121473436.stgit@buzz/

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/158498153964.5621.83061779039255681.stgit@buzz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:42 -07:00
Colin Ian King
ad3f434b87 lib/test_lockup.c: fix spelling mistake "iteraions" -> "iterations"
There is a spelling mistake in a pr_notice message.  Fix it.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20200221155145.79522-1-colin.king@canonical.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:42 -07:00
Konstantin Khlebnikov
30428ef5d1 lib/test_lockup: test module to generate lockups
CONFIG_TEST_LOCKUP=m adds module "test_lockup" that helps to make sure
that watchdogs and lockup detectors are working properly.

Depending on module parameters test_lockup could emulate soft or hard
lockup, "hung task", hold arbitrary lock, allocate bunch of pages.

Also it could generate series of lockups with cooling-down periods, in
this way it could be used as "ping" for locks or page allocator.  Loop
checks signals between iteration thus could be stopped by ^C.

# modinfo test_lockup
...
parm:           time_secs:lockup time in seconds, default 0 (uint)
parm:           time_nsecs:nanoseconds part of lockup time, default 0 (uint)
parm:           cooldown_secs:cooldown time between iterations in seconds, default 0 (uint)
parm:           cooldown_nsecs:nanoseconds part of cooldown, default 0 (uint)
parm:           iterations:lockup iterations, default 1 (uint)
parm:           all_cpus:trigger lockup at all cpus at once (bool)
parm:           state:wait in 'R' running (default), 'D' uninterruptible, 'K' killable, 'S' interruptible state (charp)
parm:           use_hrtimer:use high-resolution timer for sleeping (bool)
parm:           iowait:account sleep time as iowait (bool)
parm:           lock_read:lock read-write locks for read (bool)
parm:           lock_single:acquire locks only at one cpu (bool)
parm:           reacquire_locks:release and reacquire locks/irq/preempt between iterations (bool)
parm:           touch_softlockup:touch soft-lockup watchdog between iterations (bool)
parm:           touch_hardlockup:touch hard-lockup watchdog between iterations (bool)
parm:           call_cond_resched:call cond_resched() between iterations (bool)
parm:           measure_lock_wait:measure lock wait time (bool)
parm:           lock_wait_threshold:print lock wait time longer than this in nanoseconds, default off (ulong)
parm:           disable_irq:disable interrupts: generate hard-lockups (bool)
parm:           disable_softirq:disable bottom-half irq handlers (bool)
parm:           disable_preempt:disable preemption: generate soft-lockups (bool)
parm:           lock_rcu:grab rcu_read_lock: generate rcu stalls (bool)
parm:           lock_mmap_sem:lock mm->mmap_sem: block procfs interfaces (bool)
parm:           lock_rwsem_ptr:lock rw_semaphore at address (ulong)
parm:           lock_mutex_ptr:lock mutex at address (ulong)
parm:           lock_spinlock_ptr:lock spinlock at address (ulong)
parm:           lock_rwlock_ptr:lock rwlock at address (ulong)
parm:           alloc_pages_nr:allocate and free pages under locks (uint)
parm:           alloc_pages_order:page order to allocate (uint)
parm:           alloc_pages_gfp:allocate pages with this gfp_mask, default GFP_KERNEL (uint)
parm:           alloc_pages_atomic:allocate pages with GFP_ATOMIC (bool)
parm:           reallocate_pages:free and allocate pages between iterations (bool)

Parameters for locking by address are unsafe and taints kernel. With
CONFIG_DEBUG_SPINLOCK=y they at least check magics for embedded spinlocks.

Examples:

task hang in D-state:
modprobe test_lockup time_secs=1 iterations=60 state=D

task hang in io-wait D-state:
modprobe test_lockup time_secs=1 iterations=60 state=D iowait

softlockup:
modprobe test_lockup time_secs=1 iterations=60 state=R

hardlockup:
modprobe test_lockup time_secs=1 iterations=60 state=R disable_irq

system-wide hardlockup:
modprobe test_lockup time_secs=1 iterations=60 state=R \
 disable_irq all_cpus

rcu stall:
modprobe test_lockup time_secs=1 iterations=60 state=R \
 lock_rcu touch_softlockup

lock mmap_sem / block procfs interfaces:
modprobe test_lockup time_secs=1 iterations=60 state=S lock_mmap_sem

lock tasklist_lock for read / block forks:
TASKLIST_LOCK=$(awk '$3 == "tasklist_lock" {print "0x"$1}' /proc/kallsyms)
modprobe test_lockup time_secs=1 iterations=60 state=R \
 disable_irq lock_read lock_rwlock_ptr=$TASKLIST_LOCK

lock namespace_sem / block vfs mount operations:
NAMESPACE_SEM=$(awk '$3 == "namespace_sem" {print "0x"$1}' /proc/kallsyms)
modprobe test_lockup time_secs=1 iterations=60 state=S \
 lock_rwsem_ptr=$NAMESPACE_SEM

lock cgroup mutex / block cgroup operations:
CGROUP_MUTEX=$(awk '$3 == "cgroup_mutex" {print "0x"$1}' /proc/kallsyms)
modprobe test_lockup time_secs=1 iterations=60 state=S \
 lock_mutex_ptr=$CGROUP_MUTEX

ping cgroup_mutex every second and measure maximum lock wait time:
modprobe test_lockup cooldown_secs=1 iterations=60 state=S \
 lock_mutex_ptr=$CGROUP_MUTEX reacquire_locks measure_lock_wait

[linux@roeck-us.net: rename disable_irq to fix build error]
  Link: http://lkml.kernel.org/r/20200317133614.23152-1-linux@roeck-us.net
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Dmitry Monakhov <dmtrmonakhov@yandex-team.ru
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Link: http://lkml.kernel.org/r/158132859146.2797.525923171323227836.stgit@buzz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:42 -07:00
Josh Poimboeuf
f80ac98a64 bitops: always inline sign extension helpers
With CONFIG_CC_OPTIMIZE_FOR_SIZE, objtool reports:

  drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool: i915_gem_execbuffer2_ioctl()+0x5b7: call to gen8_canonical_addr() with UACCESS enabled

This means i915_gem_execbuffer2_ioctl() is calling gen8_canonical_addr()
from the user_access_begin/end critical region (i.e, with SMAP disabled).

While it's probably harmless in this case, in general we like to avoid
extra function calls in SMAP-disabled regions because it can open up
inadvertent security holes.

Fix the warning by changing the sign extension helpers to __always_inline.
This convinces GCC to inline gen8_canonical_addr().

The sign extension functions are trivial anyway, so it makes sense to
always inline them.  With my test optimize-for-size-based config, this
actually shrinks the text size of i915_gem_execbuffer.o by 45 bytes -- and
no change for vmlinux.

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://lkml.kernel.org/r/740179324b2b18b750b16295c48357f00b5fa9ed.1582982020.git.jpoimboe@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:42 -07:00
Joe Perches
6680125ea5 MAINTAINERS: list the section entries in the preferred order
The MAINTAINERS file header has never shown a preferred order for the
section entries but scripts/parse-maintainers.pl added a preferred order
with commit 61f741645a ("parse-maintainers: Add section pattern
sorting")

Commit 5cdbec108f ("parse-maintainers: Do not sort section content by
default") changed the preferred order to be a bit more sensible.

Update the MAINTAINERS section description block to use this preferred
section entry ordering.

Add a slightly better description for the N: entry too.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: http://lkml.kernel.org/r/5aa5aad6fb1678230c260337dc066cd449a2bf32.camel@perches.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:42 -07:00
Vegard Nossum
af9c5d2e3b compiler.h: fix error in BUILD_BUG_ON() reporting
compiletime_assert() uses __LINE__ to create a unique function name.  This
means that if you have more than one BUILD_BUG_ON() in the same source
line (which can happen if they appear e.g.  in a macro), then the error
message from the compiler might output the wrong condition.

For this source file:

	#include <linux/build_bug.h>

	#define macro() \
		BUILD_BUG_ON(1); \
		BUILD_BUG_ON(0);

	void foo()
	{
		macro();
	}

gcc would output:

./include/linux/compiler.h:350:38: error: call to `__compiletime_assert_9' declared with attribute error: BUILD_BUG_ON failed: 0
  _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)

However, it was not the BUILD_BUG_ON(0) that failed, so it should say 1
instead of 0. With this patch, we use __COUNTER__ instead of __LINE__, so
each BUILD_BUG_ON() gets a different function name and the correct
condition is printed:

./include/linux/compiler.h:350:38: error: call to `__compiletime_assert_0' declared with attribute error: BUILD_BUG_ON failed: 1
  _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)

Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Daniel Santos <daniel.santos@pobox.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Joe Perches <joe@perches.com>
Link: http://lkml.kernel.org/r/20200331112637.25047-1-vegard.nossum@oracle.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:42 -07:00
Masahiro Yamada
889b3c1245 compiler: remove CONFIG_OPTIMIZE_INLINING entirely
Commit ac7c3e4ff4 ("compiler: enable CONFIG_OPTIMIZE_INLINING
forcibly") made this always-on option. We released v5.4 and v5.5
including that commit.

Remove the CONFIG option and clean up the code now.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Miller <davem@davemloft.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200220110807.32534-2-masahiroy@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:42 -07:00
Masahiro Yamada
12a5b00a53 sparc,x86: vdso: remove meaningless undefining CONFIG_OPTIMIZE_INLINING
The code, #undef CONFIG_OPTIMIZE_INLINING, is not working as expected
because <linux/compiler_types.h> is parsed before vclock_gettime.c since
28128c61e0 ("kconfig.h: Include compiler types to avoid missed struct
attributes").

Since then, <linux/compiler_types.h> is included really early by using the
'-include' option.  So, you cannot negate the decision of
<linux/compiler_types.h> in this way.

You can confirm it by checking the pre-processed code, like this:

  $ make arch/x86/entry/vdso/vdso32/vclock_gettime.i

There is no difference with/without CONFIG_CC_OPTIMIZE_FOR_SIZE.

It is about two years since 28128c61e0.  Nobody has reported a problem
(or, nobody has even noticed the fact that this code is not working).

It is ugly and unreliable to attempt to undefine a CONFIG option from C
files, and anyway the inlining heuristic is up to the compiler.

Just remove the broken code.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: David Miller <davem@davemloft.net>
Link: http://lkml.kernel.org/r/20200220110807.32534-1-masahiroy@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:42 -07:00
Nathan Chancellor
63174f61df kernel/extable.c: use address-of operator on section symbols
Clang warns:

../kernel/extable.c:37:52: warning: array comparison always evaluates to
a constant [-Wtautological-compare]
        if (main_extable_sort_needed && __stop___ex_table > __start___ex_table) {
                                                          ^
1 warning generated.

These are not true arrays, they are linker defined symbols, which are just
addresses.  Using the address of operator silences the warning and does
not change the resulting assembly with either clang/ld.lld or gcc/ld
(tested with diff + objdump -Dr).

Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://github.com/ClangBuiltLinux/linux/issues/892
Link: http://lkml.kernel.org/r/20200219202036.45702-1-natechancellor@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:42 -07:00
Michal Simek
06e85c7e9a asm-generic: fix unistd_32.h generation format
Generated files are also checked by sparse that's why add newline to
remove sparse (C=1) warning.

The issue was found on Microblaze and reported like this:
./arch/microblaze/include/generated/uapi/asm/unistd_32.h:438:45: warning:
no newline at end of file

Mips and PowerPC have it already but let's align with style used by m68k.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Stefan Asserhall <stefan.asserhall@xilinx.com>
Acked-by: Max Filippov <jcmvbkbc@gmail.com> (xtensa)
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Chris Zankel <chris@zankel.net>
Cc: David S. Miller <davem@davemloft.net>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/4d32ab4e1fb2edb691d2e1687e8fb303c09fd023.1581504803.git.michal.simek@xilinx.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:42 -07:00
Matthew Wilcox (Oracle)
fad955009c proc: inline m_next_vma into m_next
It's clearer to just put this inline.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200317193201.9924-5-adobriyan@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:42 -07:00
Matthew Wilcox (Oracle)
b829a0f0f2 seq_file: remove m->version
The process maps file was the only user of version (introduced back in
2005).  Now that it uses ppos instead, we can remove it.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200317193201.9924-4-adobriyan@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:42 -07:00
Matthew Wilcox (Oracle)
4781f2c3ab proc: use ppos instead of m->version
The ppos is a private cursor, just like m->version.  Use the canonical
cursor, not a special one.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200317193201.9924-3-adobriyan@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:42 -07:00
Matthew Wilcox (Oracle)
c2e88d22e8 proc: remove m_cache_vma
Instead of setting m->version in the show method, set it in m_next(),
where it should be.  Also remove the fallback code for failing to find a
vma, or version being zero.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200317193201.9924-2-adobriyan@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:42 -07:00
Matthew Wilcox (Oracle)
d07ded611e proc: inline vma_stop into m_stop
Instead of calling vma_stop() from m_start() and m_next(), do its work
in m_stop().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200317193201.9924-1-adobriyan@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:42 -07:00
Alexey Dobriyan
5c5ab9714c proc: speed up /proc/*/statm
top(1) reads all /proc/*/statm files but kernel threads will always have
zeros.  Print those zeroes directly without going through
seq_put_decimal_ull().

Speed up reading /proc/2/statm (which is kthreadd) is like 3%.

My system has more kernel threads than normal processes after booting KDE.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200307154435.GA2788@avx2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:42 -07:00
Alexey Dobriyan
d919b33daf proc: faster open/read/close with "permanent" files
Now that "struct proc_ops" exist we can start putting there stuff which
could not fly with VFS "struct file_operations"...

Most of fs/proc/inode.c file is dedicated to make open/read/.../close
reliable in the event of disappearing /proc entries which usually happens
if module is getting removed.  Files like /proc/cpuinfo which never
disappear simply do not need such protection.

Save 2 atomic ops, 1 allocation, 1 free per open/read/close sequence for such
"permanent" files.

Enable "permanent" flag for

	/proc/cpuinfo
	/proc/kmsg
	/proc/modules
	/proc/slabinfo
	/proc/stat
	/proc/sysvipc/*
	/proc/swaps

More will come once I figure out foolproof way to prevent out module
authors from marking their stuff "permanent" for performance reasons
when it is not.

This should help with scalability: benchmark is "read /proc/cpuinfo R times
by N threads scattered over the system".

	N	R	t, s (before)	t, s (after)
	-----------------------------------------------------
	64	4096	1.582458	1.530502	-3.2%
	256	4096	6.371926	6.125168	-3.9%
	1024	4096	25.64888	24.47528	-4.6%

Benchmark source:

#include <chrono>
#include <iostream>
#include <thread>
#include <vector>

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

const int NR_CPUS = sysconf(_SC_NPROCESSORS_ONLN);
int N;
const char *filename;
int R;

int xxx = 0;

int glue(int n)
{
	cpu_set_t m;
	CPU_ZERO(&m);
	CPU_SET(n, &m);
	return sched_setaffinity(0, sizeof(cpu_set_t), &m);
}

void f(int n)
{
	glue(n % NR_CPUS);

	while (*(volatile int *)&xxx == 0) {
	}

	for (int i = 0; i < R; i++) {
		int fd = open(filename, O_RDONLY);
		char buf[4096];
		ssize_t rv = read(fd, buf, sizeof(buf));
		asm volatile ("" :: "g" (rv));
		close(fd);
	}
}

int main(int argc, char *argv[])
{
	if (argc < 4) {
		std::cerr << "usage: " << argv[0] << ' ' << "N /proc/filename R
";
		return 1;
	}

	N = atoi(argv[1]);
	filename = argv[2];
	R = atoi(argv[3]);

	for (int i = 0; i < NR_CPUS; i++) {
		if (glue(i) == 0)
			break;
	}

	std::vector<std::thread> T;
	T.reserve(N);
	for (int i = 0; i < N; i++) {
		T.emplace_back(f, i);
	}

	auto t0 = std::chrono::system_clock::now();
	{
		*(volatile int *)&xxx = 1;
		for (auto& t: T) {
			t.join();
		}
	}
	auto t1 = std::chrono::system_clock::now();
	std::chrono::duration<double> dt = t1 - t0;
	std::cout << dt.count() << '
';

	return 0;
}

P.S.:
Explicit randomization marker is added because adding non-function pointer
will silently disable structure layout randomization.

[akpm@linux-foundation.org: coding style fixes]
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Joe Perches <joe@perches.com>
Link: http://lkml.kernel.org/r/20200222201539.GA22576@avx2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:42 -07:00
Jules Irenge
904f394e2e fs/proc/inode.c: annotate close_pdeo() for sparse
Fix sparse locking imbalance warning:

	warning: context imbalance in close_pdeo() - unexpected unlock

Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200227201538.GA30462@avx2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:42 -07:00
Waiman Long
6218d740ac mm: remove dummy struct bootmem_data/bootmem_data_t
Both bootmem_data and bootmem_data_t structures are no longer defined.
Remove the dummy forward declarations.

Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Baoquan He <bhe@redhat.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Link: http://lkml.kernel.org/r/20200326022617.26208-1-longman@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:42 -07:00
Mateusz Nosek
1386f7a3bf mm/dmapool.c: micro-optimisation remove unnecessary branch
Previously there was a check if 'size' is aligned to 'align' and if not
then it was aligned.  This check was expensive as both branch and division
are expensive instructions in most architectures.  'ALIGN' function on
already aligned value will not change it, and as it is cheaper than branch
+ division it can be executed all the time and branch can be removed.

Signed-off-by: Mateusz Nosek <mateusznosek0@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200320173317.26408-1-mateusznosek0@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:42 -07:00
Ira Weiny
1d90b64910 include/linux/memremap.h: remove stale comments
Fixes: 80a72d0af0 ("memremap: remove the data field in struct dev_pagemap")
Fixes: fdc029b19d ("memremap: remove the dev field in struct dev_pagemap")
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Dan Williams <dan.j.williams@intel.com>
Link: http://lkml.kernel.org/r/20200316213205.145333-1-ira.weiny@intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:41 -07:00
Steven Price
3f3673d7d3 include/linux/swapops.h: correct guards for non_swap_entry()
If CONFIG_DEVICE_PRIVATE is defined, but neither CONFIG_MEMORY_FAILURE nor
CONFIG_MIGRATION, then non_swap_entry() will return 0, meaning that the
condition (non_swap_entry(entry) && is_device_private_entry(entry)) in
zap_pte_range() will never be true even if the entry is a device private
one.

Equally any other code depending on non_swap_entry() will not function as
expected.

I originally spotted this just by looking at the code, I haven't actually
observed any problems.

Looking a bit more closely it appears that actually this situation
(currently at least) cannot occur:

DEVICE_PRIVATE depends on ZONE_DEVICE
ZONE_DEVICE depends on MEMORY_HOTREMOVE
MEMORY_HOTREMOVE depends on MIGRATION

Fixes: 5042db43cc ("mm/ZONE_DEVICE: new type of ZONE_DEVICE for unaddressable memory")
Signed-off-by: Steven Price <steven.price@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Link: http://lkml.kernel.org/r/20200305130550.22693-1-steven.price@arm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:41 -07:00
Joe Perches
e4a9bc5896 mm: use fallthrough;
Convert the various /* fallthrough */ comments to the pseudo-keyword
fallthrough;

Done via script:
https://lore.kernel.org/lkml/b56602fcf79f849e733e7b521bb0e17895d390fa.1582230379.git.joe@perches.com/

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Link: http://lkml.kernel.org/r/f62fea5d10eb0ccfc05d87c242a620c261219b66.camel@perches.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:41 -07:00
Mateusz Nosek
e46b893dd1 mm/mm_init.c: clean code. Use BUILD_BUG_ON when comparing compile time constant
MAX_ZONELISTS is a compile time constant, so it should be compared using
BUILD_BUG_ON not BUG_ON.

Signed-off-by: Mateusz Nosek <mateusznosek0@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Link: http://lkml.kernel.org/r/20200228224617.11343-1-mateusznosek0@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:41 -07:00
chenqiwu
552657b7b3 mm: fix ambiguous comments for better code readability
The parameter of remap_pfn_range() @pfn passed from the caller is actually
a page-frame number converted by corresponding physical address of kernel
memory, the original comment is ambiguous that may mislead the users.

Meanwhile, there is an ambiguous typo "VMM" in the comment of
vm_area_struct.  So fixing them will make the code more readable.

Signed-off-by: chenqiwu <chenqiwu@xiaomi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1583026921-15279-1-git-send-email-qiwuchen55@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:41 -07:00
Jules Irenge
bc22b18b1f mm/zsmalloc: add missing annotation for unpin_tag()
Sparse reports a warning at unpin_tag()()

warning: context imbalance in unpin_tag() - unexpected unlock

The root cause is the missing annotation at unpin_tag()
Add the missing __releases(bitlock) annotation

Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Link: http://lkml.kernel.org/r/20200214204741.94112-14-jbi.octave@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:41 -07:00
Jules Irenge
70c7ec95be mm/zsmalloc: add missing annotation for pin_tag()
Sparse reports a warning at pin_tag()()

warning: context imbalance in pin_tag() - wrong count at exit

The root cause is the missing annotation at pin_tag()
Add the missing __acquires(bitlock) annotation

Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Link: http://lkml.kernel.org/r/20200214204741.94112-13-jbi.octave@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:41 -07:00
Jules Irenge
8a374cccee mm/zsmalloc: add missing annotation for migrate_read_unlock()
Sparse reports a warning at migrate_read_unlock()()

 warning: context imbalance in migrate_read_unlock() - unexpected unlock

The root cause is the missing annotation at migrate_read_unlock()
Add the missing __releases(&zspage->lock) annotation

Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Link: http://lkml.kernel.org/r/20200214204741.94112-12-jbi.octave@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:41 -07:00
Jules Irenge
cfc451cfdf mm/zsmalloc: add missing annotation for migrate_read_lock()
Sparse reports a warning at migrate_read_lock()()

 warning: context imbalance in migrate_read_lock() - wrong count at exit

The root cause is the missing annotation at migrate_read_lock()
Add the missing __acquires(&zspage->lock) annotation

Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Link: http://lkml.kernel.org/r/20200214204741.94112-11-jbi.octave@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:41 -07:00
Jules Irenge
81aba9e06b mm/slub: add missing annotation for put_map()
Sparse reports a warning at put_map()()

 warning: context imbalance in put_map() - unexpected unlock

The root cause is the missing annotation at put_map()
Add the missing __releases(&object_map_lock) annotation

Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200214204741.94112-10-jbi.octave@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:41 -07:00
Jules Irenge
31364c2e16 mm/slub: add missing annotation for get_map()
Sparse reports a warning at get_map()()

 warning: context imbalance in get_map() - wrong count at exit

The root cause is the missing annotation at get_map()
Add the missing __acquires(&object_map_lock) annotation

Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200214204741.94112-9-jbi.octave@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:41 -07:00
Jules Irenge
959a7e136d mm/mempolicy: add missing annotation for queue_pages_pmd()
Sparse reports a warning at queue_pages_pmd()

context imbalance in queue_pages_pmd() - unexpected unlock

The root cause is the missing annotation at queue_pages_pmd()
Add the missing __releases(ptl)

Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200214204741.94112-8-jbi.octave@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:41 -07:00
Jules Irenge
1b2a1e7bb9 mm/hugetlb: add missing annotation for gather_surplus_pages()
Sparse reports a warning at gather_surplus_pages()

warning: context imbalance in hugetlb_cow() - unexpected unlock

The root cause is the missing annotation at gather_surplus_pages()
Add the missing __must_hold(&hugetlb_lock)

Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Link: http://lkml.kernel.org/r/20200214204741.94112-7-jbi.octave@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:41 -07:00
Jules Irenge
77337edee7 mm/compaction: add missing annotation for compact_lock_irqsave
Sparse reports a warning at compact_lock_irqsave()

warning: context imbalance in compact_lock_irqsave() - wrong count at exit

The root cause is the missing annotation at compact_lock_irqsave()
Add the missing __acquires(lock) annotation.

Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200214204741.94112-6-jbi.octave@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:41 -07:00
Maciej S. Szmigiero
bb8b93b5b6 mm/zswap: allow setting default status, compressor and allocator in Kconfig
The compressed cache for swap pages (zswap) currently needs from 1 to 3
extra kernel command line parameters in order to make it work: it has to
be enabled by adding a "zswap.enabled=1" command line parameter and if one
wants a different compressor or pool allocator than the default lzo / zbud
combination then these choices also need to be specified on the kernel
command line in additional parameters.

Using a different compressor and allocator for zswap is actually pretty
common as guides often recommend using the lz4 / z3fold pair instead of
the default one.  In such case it is also necessary to remember to enable
the appropriate compression algorithm and pool allocator in the kernel
config manually.

Let's avoid the need for adding these kernel command line parameters and
automatically pull in the dependencies for the selected compressor
algorithm and pool allocator by adding an appropriate default switches to
Kconfig.

The default values for these options match what the code was using
previously as its defaults.

Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com>
Link: http://lkml.kernel.org/r/20200202000112.456103-1-mail@maciej.szmigiero.name
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:41 -07:00
Palmer Dabbelt
4708f31885 mm: prevent a warning when casting void* -> enum
I recently build the RISC-V port with LLVM trunk, which has introduced a
new warning when casting from a pointer to an enum of a smaller size.
This patch simply casts to a long in the middle to stop the warning.  I'd
be surprised this is the only one in the kernel, but it's the only one I
saw.

Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200227211741.83165-1-palmer@dabbelt.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:41 -07:00
Hugh Dickins
71725ed10c mm: huge tmpfs: try to split_huge_page() when punching hole
Yang Shi writes:

Currently, when truncating a shmem file, if the range is partly in a THP
(start or end is in the middle of THP), the pages actually will just get
cleared rather than being freed, unless the range covers the whole THP.
Even though all the subpages are truncated (randomly or sequentially), the
THP may still be kept in page cache.

This might be fine for some usecases which prefer preserving THP, but
balloon inflation is handled in base page size.  So when using shmem THP
as memory backend, QEMU inflation actually doesn't work as expected since
it doesn't free memory.  But the inflation usecase really needs to get the
memory freed.  (Anonymous THP will also not get freed right away, but will
be freed eventually when all subpages are unmapped: whereas shmem THP
still stays in page cache.)

Split THP right away when doing partial hole punch, and if split fails
just clear the page so that read of the punched area will return zeroes.

Hugh Dickins adds:

Our earlier "team of pages" huge tmpfs implementation worked in the way
that Yang Shi proposes; and we have been using this patch to continue to
split the huge page when hole-punched or truncated, since converting over
to the compound page implementation.  Although huge tmpfs gives out huge
pages when available, if the user specifically asks to truncate or punch a
hole (perhaps to free memory, perhaps to reduce the memcg charge), then
the filesystem should do so as best it can, splitting the huge page.

That is not always possible: any additional reference to the huge page
prevents split_huge_page() from succeeding, so the result can be flaky.
But in practice it works successfully enough that we've not seen any
problem from that.

Add shmem_punch_compound() to encapsulate the decision of when a split is
needed, and doing the split if so.  Using this simplifies the flow in
shmem_undo_range(); and the first (trylock) pass does not need to do any
page clearing on failure, because the second pass will either succeed or
do that clearing.  Following the example of zero_user_segment() when
clearing a partial page, add flush_dcache_page() and set_page_dirty() when
clearing a hole - though I'm not certain that either is needed.

But: split_huge_page() would be sure to fail if shmem_undo_range()'s
pagevec holds further references to the huge page.  The easiest way to fix
that is for find_get_entries() to return early, as soon as it has put one
compound head or tail into the pagevec.  At first this felt like a hack;
but on examination, this convention better suits all its callers - or will
do, if the slight one-page-per-pagevec slowdown in shmem_unlock_mapping()
and shmem_seek_hole_data() is transformed into a 512-page-per-pagevec
speedup by checking for compound pages there.

Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Alexander Duyck <alexander.duyck@gmail.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2002261959020.10801@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:41 -07:00
Mateusz Nosek
343c3d7f09 mm/shmem.c: clean code by removing unnecessary assignment
Previously 0 was assigned to variable 'error' but the variable was never
read before reassignemnt later.  So the assignment can be removed.

Signed-off-by: Mateusz Nosek <mateusznosek0@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Link: http://lkml.kernel.org/r/20200301152832.24595-1-mateusznosek0@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:41 -07:00
Kees Cook
27d80fa243 mm/shmem.c: distribute switch variables for initialization
Variables declared in a switch statement before any case statements cannot
be automatically initialized with compiler instrumentation (as they are
not part of any execution flow).  With GCC's proposed automatic stack
variable initialization feature, this triggers a warning (and they don't
get initialized).  Clang's automatic stack variable initialization (via
CONFIG_INIT_STACK_ALL=y) doesn't throw a warning, but it also doesn't
initialize such variables[1].  Note that these warnings (or silent
skipping) happen before the dead-store elimination optimization phase, so
even when the automatic initializations are later elided in favor of
direct initializations, the warnings remain.

To avoid these problems, move such variables into the "case" where they're
used or lift them up into the main function body.

mm/shmem.c: In function `shmem_getpage_gfp':
mm/shmem.c:1816:10: warning: statement will never be executed [-Wswitch-unreachable]
 1816 |   loff_t i_size;
      |          ^~~~~~

[1] https://bugs.llvm.org/show_bug.cgi?id=44916

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Alexander Potapenko <glider@google.com>
Link: http://lkml.kernel.org/r/20200220062312.69165-1-keescook@chromium.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:41 -07:00
chenqiwu
104049017b mm/memory_hotplug.c: use __pfn_to_section() instead of open-coding
Use __pfn_to_section() API instead of open-coding for better code
readability.

Signed-off-by: chenqiwu <chenqiwu@xiaomi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Hildenbrand <david@redhat.com>
Link: http://lkml.kernel.org/r/1584345134-16671-1-git-send-email-qiwuchen55@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:41 -07:00
David Hildenbrand
5f47adf762 mm/memory_hotplug: allow to specify a default online_type
For now, distributions implement advanced udev rules to essentially
- Don't online any hotplugged memory (s390x)
- Online all memory to ZONE_NORMAL (e.g., most virt environments like
  hyperv)
- Online all memory to ZONE_MOVABLE in case the zone imbalance is taken
  care of (e.g., bare metal, special virt environments)

In summary: All memory is usually onlined the same way, however, the
kernel always has to ask user space to come up with the same answer.
E.g., Hyper-V always waits for a memory block to get onlined before
continuing, otherwise it might end up adding memory faster than
onlining it, which can result in strange OOM situations.  This waiting
slows down adding of a bigger amount of memory.

Let's allow to specify a default online_type, not just "online" and
"offline".  This allows distributions to configure the default online_type
when booting up and be done with it.

We can now specify "offline", "online", "online_movable" and
"online_kernel" via
- "memhp_default_state=" on the kernel cmdline
- /sys/devices/system/memory/auto_online_blocks
just like we are able to specify for a single memory block via
/sys/devices/system/memory/memoryX/state

Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Yumei Huang <yuhuang@redhat.com>
Link: http://lkml.kernel.org/r/20200317104942.11178-9-david@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:41 -07:00
David Hildenbrand
862919e568 mm/memory_hotplug: convert memhp_auto_online to store an online_type
...  and rename it to memhp_default_online_type.  This is a preparation
for more detailed default online behavior.

Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Yumei Huang <yuhuang@redhat.com>
Link: http://lkml.kernel.org/r/20200317104942.11178-8-david@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:40 -07:00
David Hildenbrand
5a04af1322 mm/memory_hotplug: unexport memhp_auto_online
All in-tree users except the mm-core are gone. Let's drop the export.

Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Yumei Huang <yuhuang@redhat.com>
Link: http://lkml.kernel.org/r/20200317104942.11178-7-david@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:40 -07:00
David Hildenbrand
bc58ebd506 hv_balloon: don't check for memhp_auto_online manually
We get the MEM_ONLINE notifier call if memory is added right from the
kernel via add_memory() or later from user space.

Let's get rid of the "ha_waiting" flag - the wait event has an inbuilt
mechanism (->done) for that.  Initialize the wait event only once and
reinitialize before adding memory.  Unconditionally call complete() and
wait_for_completion_timeout().

If there are no waiters, complete() will only increment ->done - which
will be reset by reinit_completion().  If complete() has already been
called, wait_for_completion_timeout() will not wait.

There is still the chance for a small race between concurrent
reinit_completion() and complete().  If complete() wins, we would not wait
- which is tolerable (and the race exists in current code as well).

Note: We only wait for "some" memory to get onlined, which seems to be
      good enough for now.

[akpm@linux-foundation.org: register_memory_notifier() after init_completion(), per David]
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Yumei Huang <yuhuang@redhat.com>
Link: http://lkml.kernel.org/r/20200317104942.11178-6-david@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:40 -07:00
David Hildenbrand
ed7f9fec8c powernv/memtrace: always online added memory blocks
Let's always try to online the re-added memory blocks.  In case
add_memory() already onlined the added memory blocks, the first
device_online() call will fail and stop processing the remaining memory
blocks.

This avoids manually having to check memhp_auto_online.

Note: PPC always onlines all hotplugged memory directly from the kernel as
well - something that is handled by user space on other architectures.

Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Yumei Huang <yuhuang@redhat.com>
Link: http://lkml.kernel.org/r/20200317104942.11178-5-david@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:40 -07:00
David Hildenbrand
4dc8207bfd drivers/base/memory: store mapping between MMOP_* and string in an array
Let's use a simple array which we can reuse soon.  While at it, move the
string->mmop conversion out of the device hotplug lock.

Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Yumei Huang <yuhuang@redhat.com>
Link: http://lkml.kernel.org/r/20200317104942.11178-4-david@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:40 -07:00