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Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
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irq_time_read() returns the irqtime minus the ksoftirqd time. This
is necessary because irq_time_read() is used to substract the IRQ time
from the sum_exec_runtime of a task. If we were to include the softirq
time of ksoftirqd, this task would substract its own CPU time everytime
it updates ksoftirqd->sum_exec_runtime which would therefore never
progress.
But this behaviour got broken by:
a499a5a14db ("sched/cputime: Increment kcpustat directly on irqtime account")
... which now includes ksoftirqd softirq time in the time returned by
irq_time_read().
This has resulted in wrong ksoftirqd cputime reported to userspace
through /proc/stat and thus "top" not showing ksoftirqd when it should
after intense networking load.
ksoftirqd->stime happens to be correct but it gets scaled down by
sum_exec_runtime through task_cputime_adjusted().
To fix this, just account the strict IRQ time in a separate counter and
use it to report the IRQ time.
Reported-and-tested-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1493129448-5356-1-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull ARC fix from Vineet Gupta:
"Last minute fixes for ARC:
- build error in Mellanox nps platform
- addressing lack of saving FPU regs in releavnt configs"
* tag 'arc-4.11-final' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
ARCv2: entry: save Accumulator register pair (r58:59) if present
ARC: [plat-eznps] Fix build error
Pull SCSI fix from James Bottomley:
"Our final fix before the 4.12 release (hopefully).
It's an error leg again: the fix to not bug on empty DMA transfers is
returning the wrong code and confusing the block layer"
* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
scsi: return correct blkprep status code in case scsi_init_io() fails.
Accumulator is present in configs with FPU and/or DSP MPY (mpy > 6)
Instead of doing this in pt_regs (and thus every kernel entry/exit),
this could have been done in context switch (and for user task only) as
currently kernel doesn't clobber these registers for its own accord.
However we will soon start using 64-bit multiply instructions for kernel
which can clobber these. Also gcc folks also plan to start using these
as GPRs, hence better to always save/restore them
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Pull MIPS fixes from Ralf Baechle:
"Another round of 4.11 for the MIPS architecture. This time around it's
mostly arch but little platforms-specific code.
- PCI: Register controllers in the right order to aoid a PCI error
- KGDB: Use kernel context for sleeping threads
- smp-cps: Fix potentially uninitialised value of core
- KASLR: Fix build
- ELF: Fix BUG() warning in arch_check_elf
- Fix modversioning of _mcount symbol
- fix out-of-tree defconfig target builds
- cevt-r4k: Fix out-of-bounds array access
- perf: fix deadlock
- Malta: Fix i8259 irqchip setup"
* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
MIPS: PCI: add controllers before the specified head
MIPS: KGDB: Use kernel context for sleeping threads
MIPS: smp-cps: Fix potentially uninitialised value of core
MIPS: KASLR: Add missing header files
MIPS: Avoid BUG warning in arch_check_elf
MIPS: Fix modversioning of _mcount symbol
MIPS: generic: fix out-of-tree defconfig target builds
MIPS: cevt-r4k: Fix out-of-bounds array access
MIPS: perf: fix deadlock
MIPS: Malta: Fix i8259 irqchip setup
Make ATOMIC_INIT available for all ARC platforms (including plat-eznps)
Cc: <stable@vger.kernel.org> # 4.9+
Signed-off-by: Noam Camus <noamca@mellanox.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
With commit 23dac14d058f ("MIPS: PCI: Use struct list_head lists") new
controllers are added after the specified head where they where added
before the specified head previously.
Use list_add_tail to restore the former order.
This patches fixes the following PCI error on lantiq:
pci 0000:01:00.0: BAR 0: error updating (0x1c000004 != 0x000000)
Fixes: 23dac14d058f ("MIPS: PCI: Use struct list_head lists")
Signed-off-by: Mathias Kresin <dev@kresin.me>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/15808/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
When instrumenting the SCSI layer to run into the
!blk_rq_nr_phys_segments(rq) case the following warning emitted from the
block layer:
blk_peek_request: bad return=-22
This happens because since commit fd3fc0b4d730 ("scsi: don't BUG_ON()
empty DMA transfers") we return the wrong error value from
scsi_prep_fn() back to the block layer.
[mkp: silenced checkpatch]
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Fixes: fd3fc0b4d730 scsi: don't BUG_ON() empty DMA transfers
Cc: <stable@vger.kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Pull UBI/UBIFS fixes from Richard Weinberger:
"This contains fixes for issues in both UBI and UBIFS:
- more O_TMPFILE fallout
- RENAME_WHITEOUT regression due to a mis-merge
- memory leak in ubifs_mknod()
- power-cut problem in UBI's update volume feature"
* tag 'upstream-4.11-rc7' of git://git.infradead.org/linux-ubifs:
ubifs: Fix O_TMPFILE corner case in ubifs_link()
ubifs: Fix RENAME_WHITEOUT support
ubifs: Fix debug messages for an invalid filename in ubifs_dump_inode
ubifs: Fix debug messages for an invalid filename in ubifs_dump_node
ubifs: Remove filename from debug messages in ubifs_readdir
ubifs: Fix memory leak in error path in ubifs_mknod
ubi/upd: Always flush after prepared for an update
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