Commits · ed8fb78d7ecdeb3e2e86df0027e2c2cc55f9908b · github.com / kvm-riscv / linux

Jul 30, 2022

proc: add some (hopefully) insightful comments · ed8fb78d

Alexey Dobriyan authored Jul 23, 2022

* /proc/${pid}/net status
* removing PDE vs last close stuff (again!)
* random small stuff

Link: https://lkml.kernel.org/r/YtwrM6sDC0OQ53YB@localhost.localdomain


Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

ed8fb78d

bdi: remove enum wb_congested_state · fa7d574b

Xiu Jianfeng authored Jul 19, 2022

enum wb_congested_state and the member 'congested' in bdi_writeback are
useless since commit a88f2096 ("remove congestion tracking
framework"), so remove it.

Link: https://lkml.kernel.org/r/20220719083349.87547-1-xiujianfeng@huawei.com


Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: NeilBrown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fa7d574b

kernel/hung_task: fix address space of proc_dohung_task_timeout_secs · 591c32bd

Ben Dooks authored Jul 14, 2022

The proc_dohung_task_timeout_secs() function is incorrectly marked
as having a __user buffer as argument 3. However this is not the
case and it is casing multiple sparse warnings. Fix the following
warnings by removing __user from the argument:

kernel/hung_task.c:237:52: warning: incorrect type in argument 3 (different address spaces)
kernel/hung_task.c:237:52: expected void *
kernel/hung_task.c:237:52: got void [noderef] __user *buffer
kernel/hung_task.c:287:35: warning: incorrect type in initializer (incompatible argument 3 (different address spaces))
kernel/hung_task.c:287:35: expected int ( [usertype] *proc_handler )( ... )
kernel/hung_task.c:287:35: got int ( * )( ... )
kernel/hung_task.c:295:35: warning: incorrect type in initializer (incompatible argument 3 (different address spaces))
kernel/hung_task.c:295:35: expected int ( [usertype] *proc_handler )( ... )
kernel/hung_task.c:295:35: got int ( * )( ... )

Link: https://lkml.kernel.org/r/20220714074744.189017-1-ben.dooks@sifive.com

Signed-off-by: Ben Dooks <ben.dooks@sifive.com>
Cc: <Conor.Dooley@microchip.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

591c32bd

lib/lzo/lzo1x_compress.c: replace ternary operator with min() and min_t() · a10c9ede

Jiangshan Yi authored Jul 14, 2022

Fix the following coccicheck warning:

lib/lzo/lzo1x_compress.c:54: WARNING opportunity for min().
lib/lzo/lzo1x_compress.c:329: WARNING opportunity for min().

min() and min_t() macro is defined in include/linux/minmax.h.  It avoids
multiple evaluations of the arguments when non-constant and performs
strict type-checking.

Link: https://lkml.kernel.org/r/20220714015441.1313036-1-13667453960@163.com


Signed-off-by: Jiangshan Yi <yijiangshan@kylinos.cn>
Tested-by: Dave Rodgman <dave.rodgman@arm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

a10c9ede

squashfs: support reading fragments in readahead call · b09a7a03

Phillip Lougher authored Jun 17, 2022

Add a function which can be used to read fragments in the readahead call.

This function is necessary because filesystems built with the -tailends
(or -always-use-fragments) option may have fragments present which cannot
be currently handled.

Link: https://lkml.kernel.org/r/20220617083810.337573-5-hsinyi@chromium.org


Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
Cc: Hou Tao <houtao1@huawei.com>
Cc: kernel test robot <lkp@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miao Xie <miaoxie@huawei.com>
Cc: Xiongwei Song <Xiongwei.Song@windriver.com>
Cc: Zhang Yi <yi.zhang@huawei.com>
Cc: Zheng Liang <zhengliang6@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

b09a7a03

squashfs: implement readahead · 8fc78b6f

Hsin-Yi Wang authored Jun 17, 2022

Implement readahead callback for squashfs.  It will read datablocks which
cover pages in readahead request.  For a few cases it will not mark page
as uptodate, including:

- file end is 0.
- zero filled blocks.
- current batch of pages isn't in the same datablock.
- decompressor error.

Otherwise pages will be marked as uptodate.  The unhandled pages will be
updated by readpage later.

Link: https://lkml.kernel.org/r/20220617083810.337573-4-hsinyi@chromium.org


Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Reported-by: Matthew Wilcox <willy@infradead.org>
Reported-by: Phillip Lougher <phillip@squashfs.org.uk>
Reported-by: Xiongwei Song <Xiongwei.Song@windriver.com>
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Hou Tao <houtao1@huawei.com>
Cc: kernel test robot <lkp@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Miao Xie <miaoxie@huawei.com>
Cc: Zhang Yi <yi.zhang@huawei.com>
Cc: Zheng Liang <zhengliang6@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

8fc78b6f

squashfs: always build "file direct" version of page actor · db98b430

Phillip Lougher authored Jun 17, 2022

Squashfs_readahead uses the "file direct" version of the page actor, and
so build it unconditionally.

Link: https://lkml.kernel.org/r/20220617083810.337573-3-hsinyi@chromium.org


Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Hou Tao <houtao1@huawei.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miao Xie <miaoxie@huawei.com>
Cc: Xiongwei Song <Xiongwei.Song@windriver.com>
Cc: Zhang Yi <yi.zhang@huawei.com>
Cc: Zheng Liang <zhengliang6@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

db98b430

Revert "squashfs: provide backing_dev_info in order to disable read-ahead" · 0c121857

Hsin-Yi Wang authored Jun 17, 2022

Patch series "Implement readahead for squashfs", v7.

Commit 9eec1d89("squashfs: provide backing_dev_info in order to
disable read-ahead") mitigates the performance drop issue for squashfs by
closing readahead for it.

This series implements readahead callback for squashfs.


This patch (of 4):

This reverts 9eec1d89 ("squashfs: provide backing_dev_info in order
to disable read-ahead").

Revert closing the readahead to squashfs since the readahead callback for
squashfs is implemented.

Link: https://lkml.kernel.org/r/20220617083810.337573-1-hsinyi@chromium.org
Link: https://lkml.kernel.org/r/20220617083810.337573-2-hsinyi@chromium.org


Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
Suggested-by: Xiongwei Song <Xiongwei.Song@windriver.com>
Cc: Phillip Lougher <phillip@squashfs.org.uk>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Zheng Liang <zhengliang6@huawei.com>
Cc: Zhang Yi <yi.zhang@huawei.com>
Cc: Hou Tao <houtao1@huawei.com>
Cc: Miao Xie <miaoxie@huawei.com>

Cc: kernel test robot <lkp@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

0c121857

Jul 18, 2022

fs/ocfs2: Fix spelling typo in comment · 233eb8d6

Jiangshan Yi authored Jul 15, 2022

Fix spelling typo in comment.

Link: https://lkml.kernel.org/r/20220715060035.632903-1-13667453960@163.com


Signed-off-by: Jiangshan Yi <yijiangshan@kylinos.cn>
Reported-by: k2ci <kernel-bot@kylinos.cn>
Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

233eb8d6

ia64: old_rr4 added under CONFIG_HUGETLB_PAGE · 1298f83b

Souptick Joarder (HPE) authored Jun 26, 2022

kernel test robot throws below warning ->

arch/ia64/include/asm/mmu_context.h: In function 'reload_context':
   arch/ia64/include/asm/mmu_context.h:127:48: warning: variable
'old_rr4' set but not used [-Wunused-but-set-variable]
     127 |         unsigned long rr0, rr1, rr2, rr3, rr4, old_rr4;

Add it under CONFIG_HUGETLB_PAGE

Link: https://lkml.kernel.org/r/20220626022114.4020-1-jrdr.linux@gmail.com


Signed-off-by: Souptick Joarder (HPE) <jrdr.linux@gmail.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1298f83b

proc: fix test for "vsyscall=xonly" boot option · 3adb2d87

Alexey Dobriyan authored Jul 12, 2022

Booting with vsyscall=xonly results in the following vsyscall VMA:

	ffffffffff600000-ffffffffff601000 --xp ... [vsyscall]


Test does read from fixed vsyscall address to determine if kernel
supports vsyscall page but it doesn't work because, well, vsyscall
page is execute only.

Fix test by trying to execute from the first byte of the page which
contains gettimeofday() stub. This should work because vsyscall
entry points have stable addresses by design.

	Alexey, avoiding parsing .config, /proc/config.gz and
	/proc/cmdline at all costs.

Link: https://lkml.kernel.org/r/Ys2KgeiEMboU8Ytu@localhost.localdomain


Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: <dylanbhatch@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

3adb2d87

proc: fix a dentry lock race between release_task and lookup · d919a1e7

Zhihao Cheng authored Jul 13, 2022

Commit 7bc3e6e5 ("proc: Use a list of inodes to flush from proc")
moved proc_flush_task() behind __exit_signal().  Then, process systemd can
take long period high cpu usage during releasing task in following
concurrent processes:

  systemd                                 ps
kernel_waitid                 stat(/proc/tgid)
  do_wait                       filename_lookup
    wait_consider_task            lookup_fast
      release_task
        __exit_signal
          __unhash_process
            detach_pid
              __change_pid // remove task->pid_links
                                     d_revalidate -> pid_revalidate  // 0
                                     d_invalidate(/proc/tgid)
                                       shrink_dcache_parent(/proc/tgid)
                                         d_walk(/proc/tgid)
                                           spin_lock_nested(/proc/tgid/fd)
                                           // iterating opened fd
        proc_flush_pid                                    |
           d_invalidate (/proc/tgid/fd)                   |
              shrink_dcache_parent(/proc/tgid/fd)         |
                shrink_dentry_list(subdirs)               ↓
                  shrink_lock_dentry(/proc/tgid/fd) --> race on dentry lock

Function d_invalidate() will remove dentry from hash firstly, but why does
proc_flush_pid() process dentry '/proc/tgid/fd' before dentry
'/proc/tgid'?  That's because proc_pid_make_inode() adds proc inode in
reverse order by invoking hlist_add_head_rcu().  But proc should not add
any inodes under '/proc/tgid' except '/proc/tgid/task/pid', fix it by
adding inode into 'pid->inodes' only if the inode is /proc/tgid or
/proc/tgid/task/pid.

Performance regression:
Create 200 tasks, each task open one file for 50,000 times. Kill all
tasks when opened files exceed 10,000,000 (cat /proc/sys/fs/file-nr).

Before fix:
$ time killall -wq aa
  real    4m40.946s   # During this period, we can see 'ps' and 'systemd'
			taking high cpu usage.

After fix:
$ time killall -wq aa
  real    1m20.732s   # During this period, we can see 'systemd' taking
			high cpu usage.

Link: https://lkml.kernel.org/r/20220713130029.4133533-1-chengzhihao1@huawei.com
Fixes: 7bc3e6e5 ("proc: Use a list of inodes to flush from proc")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216054


Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Suggested-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>