linux/arch/um/kernel
Peter Xu a2beb5f1ef mm: clean up the last pieces of page fault accountings
Here're the last pieces of page fault accounting that were still done
outside handle_mm_fault() where we still have regs==NULL when calling
handle_mm_fault():

arch/powerpc/mm/copro_fault.c:   copro_handle_mm_fault
arch/sparc/mm/fault_32.c:        force_user_fault
arch/um/kernel/trap.c:           handle_page_fault
mm/gup.c:                        faultin_page
                                 fixup_user_fault
mm/hmm.c:                        hmm_vma_fault
mm/ksm.c:                        break_ksm

Some of them has the issue of duplicated accounting for page fault
retries.  Some of them didn't do the accounting at all.

This patch cleans all these up by letting handle_mm_fault() to do per-task
page fault accounting even if regs==NULL (though we'll still skip the perf
event accountings).  With that, we can safely remove all the outliers now.

There's another functional change in that now we account the page faults
to the caller of gup, rather than the task_struct that passed into the gup
code.  More information of this can be found at [1].

After this patch, below things should never be touched again outside
handle_mm_fault():

  - task_struct.[maj|min]_flt
  - PERF_COUNT_SW_PAGE_FAULTS_[MAJ|MIN]

[1] https://lore.kernel.org/lkml/CAHk-=wj_V2Tps2QrMn20_W0OJF9xqNh52XSGA42s-ZJ8Y+GyKw@mail.gmail.com/

Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: James E.J. Bottomley <James.Bottomley@HansenPartnership.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200707225021.200906-25-peterx@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:58:04 -07:00
..
skas mmap locking API: convert mmap_sem comments 2020-06-09 09:39:14 -07:00
asm-offsets.c um: get rid of pointless include "..." where include <...> will do 2012-10-09 22:28:45 +02:00
config.c.in um: Add SPDX headers to files in arch/um/kernel/ 2019-09-15 21:37:17 +02:00
dyn.lds.S Revert "um: Enable CONFIG_CONSTRUCTORS" 2020-01-19 22:42:06 +01:00
early_printk.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
exec.c um: Add SPDX headers to files in arch/um/kernel/ 2019-09-15 21:37:17 +02:00
exitcode.c proc: convert everything to "struct proc_ops" 2020-02-04 03:05:26 +00:00
gmon_syms.c um: Add SPDX headers to files in arch/um/kernel/ 2019-09-15 21:37:17 +02:00
gprof_syms.c um: Add SPDX headers to files in arch/um/kernel/ 2019-09-15 21:37:17 +02:00
initrd.c um: Add SPDX headers to files in arch/um/kernel/ 2019-09-15 21:37:17 +02:00
irq.c um: irq: Fix LAST_IRQ usage in init_IRQ() 2019-09-16 08:38:58 +02:00
kmsg_dump.c um: Don't use console_drivers directly 2020-03-29 23:17:10 +02:00
ksyms.c um: Add SPDX headers to files in arch/um/kernel/ 2019-09-15 21:37:17 +02:00
maccess.c maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault 2020-06-17 10:57:41 -07:00
Makefile um: Add SPDX headers to files in arch/um/kernel/ 2019-09-15 21:37:17 +02:00
mem.c asm-generic: pgalloc: provide generic pgd_free() 2020-08-07 11:33:26 -07:00
physmem.c um: Add SPDX headers to files in arch/um/kernel/ 2019-09-15 21:37:17 +02:00
process.c arch: rename copy_thread_tls() back to copy_thread() 2020-07-04 23:41:37 +02:00
ptrace.c um: Add SPDX headers to files in arch/um/kernel/ 2019-09-15 21:37:17 +02:00
reboot.c um: Add SPDX headers to files in arch/um/kernel/ 2019-09-15 21:37:17 +02:00
sigio.c um: Add SPDX headers to files in arch/um/kernel/ 2019-09-15 21:37:17 +02:00
signal.c um: Add SPDX headers to files in arch/um/kernel/ 2019-09-15 21:37:17 +02:00
stacktrace.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
syscall.c um: Add SPDX headers to files in arch/um/kernel/ 2019-09-15 21:37:17 +02:00
sysrq.c kernel: rename show_stack_loglvl() => show_stack() 2020-06-09 09:39:13 -07:00
time.c um: Implement ndelay/udelay in time-travel mode 2020-03-29 23:29:52 +02:00
tlb.c mmap locking API: convert mmap_sem comments 2020-06-09 09:39:14 -07:00
trap.c mm: clean up the last pieces of page fault accountings 2020-08-12 10:58:04 -07:00
um_arch.c mm: don't include asm/pgtable.h if linux/mm.h is already included 2020-06-09 09:39:13 -07:00
umid.c um: Add SPDX headers to files in arch/um/kernel/ 2019-09-15 21:37:17 +02:00
uml.lds.S um: Fix overlapping ELF segments when statically linked 2020-03-29 23:21:29 +02:00
vmlinux.lds.S