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: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew 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.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the general page fault accounting by passing regs into
handle_mm_fault().  It naturally solve the issue of multiple page fault
accounting when page fault retry happened.

Remove the PERF_COUNT_SW_PAGE_FAULTS_[MAJ|MIN] perf events because it's
now also done in handle_mm_fault().

Move the PERF_COUNT_SW_PAGE_FAULTS event higher before taking mmap_sem for
the fault, then it'll match with the rest of the archs.
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NMax Filippov <jcmvbkbc@gmail.com>
Cc: Chris Zankel <chris@zankel.net>
Link: http://lkml.kernel.org/r/20200707225021.200906-24-peterx@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the general page fault accounting by passing regs into
handle_mm_fault().
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/r/20200707225021.200906-23-peterx@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the general page fault accounting by passing regs into
handle_mm_fault().  It naturally solve the issue of multiple page fault
accounting when page fault retry happened.
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Link: http://lkml.kernel.org/r/20200707225021.200906-22-peterx@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the general page fault accounting by passing regs into
handle_mm_fault().  It naturally solve the issue of multiple page fault
accounting when page fault retry happened.
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Link: http://lkml.kernel.org/r/20200707225021.200906-21-peterx@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the general page fault accounting by passing regs into
handle_mm_fault().  It naturally solve the issue of multiple page fault
accounting when page fault retry happened.
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Link: http://lkml.kernel.org/r/20200707225021.200906-20-peterx@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the general page fault accounting by passing regs into
handle_mm_fault().  It naturally solve the issue of multiple page fault
accounting when page fault retry happened.
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NGerald Schaefer <gerald.schaefer@de.ibm.com>
Acked-by: NGerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Link: http://lkml.kernel.org/r/20200707225021.200906-19-peterx@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the general page fault accounting by passing regs into
handle_mm_fault().  It naturally solve the issue of multiple page fault
accounting when page fault retry happened.
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NPekka Enberg <penberg@kernel.org>
Acked-by: NPalmer Dabbelt <palmerdabbelt@google.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Link: http://lkml.kernel.org/r/20200707225021.200906-18-peterx@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the general page fault accounting by passing regs into
handle_mm_fault().
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NMichael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Link: http://lkml.kernel.org/r/20200707225021.200906-17-peterx@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the general page fault accounting by passing regs into
handle_mm_fault().  It naturally solve the issue of multiple page fault
accounting when page fault retry happened.

Add the missing PERF_COUNT_SW_PAGE_FAULTS perf events too.  Note, the
other two perf events (PERF_COUNT_SW_PAGE_FAULTS_[MAJ|MIN]) were done in
handle_mm_fault().
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: James E.J. Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Link: http://lkml.kernel.org/r/20200707225021.200906-16-peterx@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the general page fault accounting by passing regs into
handle_mm_fault().  It naturally solve the issue of multiple page fault
accounting when page fault retry happened.

Add the missing PERF_COUNT_SW_PAGE_FAULTS perf events too.  Note, the
other two perf events (PERF_COUNT_SW_PAGE_FAULTS_[MAJ|MIN]) were done in
handle_mm_fault().
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NStafford Horne <shorne@gmail.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Link: http://lkml.kernel.org/r/20200707225021.200906-15-peterx@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the general page fault accounting by passing regs into
handle_mm_fault().  It naturally solve the issue of multiple page fault
accounting when page fault retry happened.

Add the missing PERF_COUNT_SW_PAGE_FAULTS perf events too.  Note, the
other two perf events (PERF_COUNT_SW_PAGE_FAULTS_[MAJ|MIN]) were done in
handle_mm_fault().
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Link: http://lkml.kernel.org/r/20200707225021.200906-14-peterx@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the general page fault accounting by passing regs into
handle_mm_fault().  It naturally solve the issue of multiple page fault
accounting when page fault retry happened.

Fix PERF_COUNT_SW_PAGE_FAULTS perf event manually for page fault retries,
by moving it before taking mmap_sem.
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NGreentime Hu <green.hu@gmail.com>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Link: http://lkml.kernel.org/r/20200707225021.200906-13-peterx@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the general page fault accounting by passing regs into
handle_mm_fault().  It naturally solve the issue of multiple page fault
accounting when page fault retry happened.

Fix PERF_COUNT_SW_PAGE_FAULTS perf event manually for page fault retries,
by moving it before taking mmap_sem.
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NThomas Bogendoerfer <tsbogend@alpha.franken.de>
Link: http://lkml.kernel.org/r/20200707225021.200906-12-peterx@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the general page fault accounting by passing regs into
handle_mm_fault().  It naturally solve the issue of multiple page fault
accounting when page fault retry happened.

Add the missing PERF_COUNT_SW_PAGE_FAULTS perf events too.  Note, the
other two perf events (PERF_COUNT_SW_PAGE_FAULTS_[MAJ|MIN]) were done in
handle_mm_fault().
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Michal Simek <monstr@monstr.eu>
Link: http://lkml.kernel.org/r/20200707225021.200906-11-peterx@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the general page fault accounting by passing regs into
handle_mm_fault().  It naturally solve the issue of multiple page fault
accounting when page fault retry happened.

Add the missing PERF_COUNT_SW_PAGE_FAULTS perf events too.  Note, the
other two perf events (PERF_COUNT_SW_PAGE_FAULTS_[MAJ|MIN]) were done in
handle_mm_fault().
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Link: http://lkml.kernel.org/r/20200707225021.200906-10-peterx@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the general page fault accounting by passing regs into
handle_mm_fault().  It naturally solve the issue of multiple page fault
accounting when page fault retry happened.

Add the missing PERF_COUNT_SW_PAGE_FAULTS perf events too.  Note, the
other two perf events (PERF_COUNT_SW_PAGE_FAULTS_[MAJ|MIN]) were done in
handle_mm_fault().
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/20200707225021.200906-9-peterx@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the general page fault accounting by passing regs into
handle_mm_fault().  It naturally solve the issue of multiple page fault
accounting when page fault retry happened.

Add the missing PERF_COUNT_SW_PAGE_FAULTS perf events too.  Note, the
other two perf events (PERF_COUNT_SW_PAGE_FAULTS_[MAJ|MIN]) were done in
handle_mm_fault().
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NBrian Cain <bcain@codeaurora.org>
Link: http://lkml.kernel.org/r/20200707225021.200906-8-peterx@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the general page fault accounting by passing regs into
handle_mm_fault().  It naturally solve the issue of multiple page fault
accounting when page fault retry happened.
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NGuo Ren <guoren@kernel.org>
Link: http://lkml.kernel.org/r/20200707225021.200906-7-peterx@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the general page fault accounting by passing regs into
handle_mm_fault().  It naturally solve the issue of multiple page fault
accounting when page fault retry happened.  To do this, we pass pt_regs
pointer into __do_page_fault().
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NWill Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Link: http://lkml.kernel.org/r/20200707225021.200906-6-peterx@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the general page fault accounting by passing regs into
handle_mm_fault().  It naturally solve the issue of multiple page fault
accounting when page fault retry happened.  To do this, we need to pass
the pt_regs pointer into __do_page_fault().

Fix PERF_COUNT_SW_PAGE_FAULTS perf event manually for page fault retries,
by moving it before taking mmap_sem.
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/20200707225021.200906-5-peterx@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the general page fault accounting by passing regs into
handle_mm_fault().  It naturally solve the issue of multiple page fault
accounting when page fault retry happened.

Fix PERF_COUNT_SW_PAGE_FAULTS perf event manually for page fault retries,
by moving it before taking mmap_sem.
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Vineet Gupta <vgupta@synopsys.com>
Link: http://lkml.kernel.org/r/20200707225021.200906-4-peterx@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the general page fault accounting by passing regs into
handle_mm_fault().

Add the missing PERF_COUNT_SW_PAGE_FAULTS perf events too.  Note, the
other two perf events (PERF_COUNT_SW_PAGE_FAULTS_[MAJ|MIN]) were done in
handle_mm_fault().
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Link: http://lkml.kernel.org/r/20200707225021.200906-3-peterx@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Patch series "mm: Page fault accounting cleanups", v5.

This is v5 of the pf accounting cleanup series.  It originates from Gerald
Schaefer's report on an issue a week ago regarding to incorrect page fault
accountings for retried page fault after commit 4064b982 ("mm: allow
VM_FAULT_RETRY for multiple times"):

  https://lore.kernel.org/lkml/20200610174811.44b94525@thinkpad/

What this series did:

  - Correct page fault accounting: we do accounting for a page fault
    (no matter whether it's from #PF handling, or gup, or anything else)
    only with the one that completed the fault.  For example, page fault
    retries should not be counted in page fault counters.  Same to the
    perf events.

  - Unify definition of PERF_COUNT_SW_PAGE_FAULTS: currently this perf
    event is used in an adhoc way across different archs.

    Case (1): for many archs it's done at the entry of a page fault
    handler, so that it will also cover e.g.  errornous faults.

    Case (2): for some other archs, it is only accounted when the page
    fault is resolved successfully.

    Case (3): there're still quite some archs that have not enabled
    this perf event.

    Since this series will touch merely all the archs, we unify this
    perf event to always follow case (1), which is the one that makes most
    sense.  And since we moved the accounting into handle_mm_fault, the
    other two MAJ/MIN perf events are well taken care of naturally.

  - Unify definition of "major faults": the definition of "major
    fault" is slightly changed when used in accounting (not
    VM_FAULT_MAJOR).  More information in patch 1.

  - Always account the page fault onto the one that triggered the page
    fault.  This does not matter much for #PF handlings, but mostly for
    gup.  More information on this in patch 25.

Patchset layout:

Patch 1:     Introduced the accounting in handle_mm_fault(), not enabled.
Patch 2-23:  Enable the new accounting for arch #PF handlers one by one.
Patch 24:    Enable the new accounting for the rest outliers (gup, iommu, etc.)
Patch 25:    Cleanup GUP task_struct pointer since it's not needed any more

This patch (of 25):

This is a preparation patch to move page fault accountings into the
general code in handle_mm_fault().  This includes both the per task
flt_maj/flt_min counters, and the major/minor page fault perf events.  To
do this, the pt_regs pointer is passed into handle_mm_fault().

PERF_COUNT_SW_PAGE_FAULTS should still be kept in per-arch page fault
handlers.

So far, all the pt_regs pointer that passed into handle_mm_fault() is
NULL, which means this patch should have no intented functional change.
Suggested-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew 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/20200707225021.200906-1-peterx@redhat.com
Link: http://lkml.kernel.org/r/20200707225021.200906-2-peterx@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There is a well-defined migration target allocation callback. Use it.
Signed-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Roman Gushchin <guro@fb.com>
Link: http://lkml.kernel.org/r/1596180906-8442-3-git-send-email-iamjoonsoo.kim@lge.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

new_non_cma_page() in gup.c requires to allocate the new page that is not
on the CMA area.  new_non_cma_page() implements it by using allocation
scope APIs.

However, there is a work-around for hugetlb.  Normal hugetlb page
allocation API for migration is alloc_huge_page_nodemask().  It consists
of two steps.  First is dequeing from the pool.  Second is, if there is no
available page on the queue, allocating by using the page allocator.

new_non_cma_page() can't use this API since first step (deque) isn't aware
of scope API to exclude CMA area.  So, new_non_cma_page() exports hugetlb
internal function for the second step, alloc_migrate_huge_page(), to
global scope and uses it directly.  This is suboptimal since hugetlb pages
on the queue cannot be utilized.

This patch tries to fix this situation by making the deque function on
hugetlb CMA aware.  In the deque function, CMA memory is skipped if
PF_MEMALLOC_NOCMA flag is found.
Signed-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NMike Kravetz <mike.kravetz@oracle.com>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Roman Gushchin <guro@fb.com>
Link: http://lkml.kernel.org/r/1596180906-8442-2-git-send-email-iamjoonsoo.kim@lge.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We have well defined scope API to exclude CMA region.  Use it rather than
manipulating gfp_mask manually.  With this change, we can now restore
__GFP_MOVABLE for gfp_mask like as usual migration target allocation.  It
would result in that the ZONE_MOVABLE is also searched by page allocator.
For hugetlb, gfp_mask is redefined since it has a regular allocation mask
filter for migration target.  __GPF_NOWARN is added to hugetlb gfp_mask
filter since a new user for gfp_mask filter, gup, want to be silent when
allocation fails.

Note that this can be considered as a fix for the commit 9a4e9f3b
("mm: update get_user_pages_longterm to migrate pages allocated from CMA
region").  However, "Fixes" tag isn't added here since it is just
suboptimal but it doesn't cause any problem.
Suggested-by: NMichal Hocko <mhocko@suse.com>
Signed-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Link: http://lkml.kernel.org/r/1596180906-8442-1-git-send-email-iamjoonsoo.kim@lge.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There is a well-defined standard migration target callback.  Use it
directly.
Signed-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NMichal Hocko <mhocko@suse.com>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Roman Gushchin <guro@fb.com>
Link: http://lkml.kernel.org/r/1594622517-20681-8-git-send-email-iamjoonsoo.kim@lge.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There is a well-defined migration target allocation callback.  Use it.
Signed-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NMichal Hocko <mhocko@suse.com>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Roman Gushchin <guro@fb.com>
Link: http://lkml.kernel.org/r/1594622517-20681-7-git-send-email-iamjoonsoo.kim@lge.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There are some similar functions for migration target allocation.  Since
there is no fundamental difference, it's better to keep just one rather
than keeping all variants.  This patch implements base migration target
allocation function.  In the following patches, variants will be converted
to use this function.

Changes should be mechanical, but, unfortunately, there are some
differences.  First, some callers' nodemask is assgined to NULL since NULL
nodemask will be considered as all available nodes, that is,
&node_states[N_MEMORY].  Second, for hugetlb page allocation, gfp_mask is
redefined as regular hugetlb allocation gfp_mask plus __GFP_THISNODE if
user provided gfp_mask has it.  This is because future caller of this
function requires to set this node constaint.  Lastly, if provided nodeid
is NUMA_NO_NODE, nodeid is set up to the node where migration source
lives.  It helps to remove simple wrappers for setting up the nodeid.

Note that PageHighmem() call in previous function is changed to open-code
"is_highmem_idx()" since it provides more readability.

[akpm@linux-foundation.org: tweak patch title, per Vlastimil]
[akpm@linux-foundation.org: fix typo in comment]
Signed-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Roman Gushchin <guro@fb.com>
Link: http://lkml.kernel.org/r/1594622517-20681-6-git-send-email-iamjoonsoo.kim@lge.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/migrate: clear __GFP_RECLAIM to make the migration callback consistent with regular THP allocations

new_page_nodemask is a migration callback and it tries to use a common gfp
flags for the target page allocation whether it is a base page or a THP.
The later only adds GFP_TRANSHUGE to the given mask.  This results in the
allocation being slightly more aggressive than necessary because the
resulting gfp mask will contain also __GFP_RECLAIM_KSWAPD.  THP
allocations usually exclude this flag to reduce over eager background
reclaim during a high THP allocation load which has been seen during large
mmaps initialization.  There is no indication that this is a problem for
migration as well but theoretically the same might happen when migrating
large mappings to a different node.  Make the migration callback
consistent with regular THP allocations.

[akpm@linux-foundation.org: fix comment typo, per Vlastimil]
Signed-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NMichal Hocko <mhocko@suse.com>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Roman Gushchin <guro@fb.com>
Link: http://lkml.kernel.org/r/1594622517-20681-5-git-send-email-iamjoonsoo.kim@lge.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There is no difference between two migration callback functions,
alloc_huge_page_node() and alloc_huge_page_nodemask(), except
__GFP_THISNODE handling.  It's redundant to have two almost similar
functions in order to handle this flag.  So, this patch tries to remove
one by introducing a new argument, gfp_mask, to
alloc_huge_page_nodemask().

After introducing gfp_mask argument, it's caller's job to provide correct
gfp_mask.  So, every callsites for alloc_huge_page_nodemask() are changed
to provide gfp_mask.

Note that it's safe to remove a node id check in alloc_huge_page_node()
since there is no caller passing NUMA_NO_NODE as a node id.
Signed-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NMike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: NVlastimil Babka <vbabka@suse.cz>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Roman Gushchin <guro@fb.com>
Link: http://lkml.kernel.org/r/1594622517-20681-4-git-send-email-iamjoonsoo.kim@lge.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It's not performance sensitive function.  Move it to .c.  This is a
preparation step for future change.
Signed-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NVlastimil Babka <vbabka@suse.cz>
Acked-by: NMike Kravetz <mike.kravetz@oracle.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Roman Gushchin <guro@fb.com>
Link: http://lkml.kernel.org/r/1594622517-20681-3-git-send-email-iamjoonsoo.kim@lge.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Patch series "clean-up the migration target allocation functions", v5.

This patch (of 9):

For locality, it's better to migrate the page to the same node rather than
the node of the current caller's cpu.
Signed-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NVlastimil Babka <vbabka@suse.cz>
Acked-by: NRoman Gushchin <guro@fb.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Link: http://lkml.kernel.org/r/1594622517-20681-1-git-send-email-iamjoonsoo.kim@lge.com
Link: http://lkml.kernel.org/r/1594622517-20681-2-git-send-email-iamjoonsoo.kim@lge.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Remove the superfuous break, as there is a 'return' before it.
Signed-off-by: NLiao Pingfang <liao.pingfang@zte.com.cn>
Signed-off-by: NYi Wang <wang.yi59@zte.com.cn>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1594724361-11525-1-git-send-email-wang.yi59@zte.com.cnSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Two functions are only called via function pointers, don't bother
inlining them.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Link: http://lkml.kernel.org/r/20200710200312.GA960353@localhost.localdomainSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fixes the observed warnings:
scripts/gdb/linux/rbtree.py:20: SyntaxWarning: "is" with a literal. Did
you mean "=="?
  if node is 0:
scripts/gdb/linux/rbtree.py:36: SyntaxWarning: "is" with a literal. Did
you mean "=="?
  if node is 0:

It looks like this is a new warning added in Python 3.8. I've only seen
this once after adding the add-auto-load-safe-path rule to my ~/.gdbinit
for a new tree.

Fixes: commit 449ca0c9 ("scripts/gdb: add rb tree iterating utilities")
Signed-off-by: NNick Desaulniers <ndesaulniers@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NStephen Boyd <swboyd@chromium.org>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Kieran Bingham <kbingham@kernel.org>
Cc: Aymeric Agon-Rambosson <aymeric.agon@yandex.com>
Link: http://lkml.kernel.org/r/20200805225015.2847624-1-ndesaulniers@google.com
Link: https://adamj.eu/tech/2020/01/21/why-does-python-3-8-syntaxwarning-for-is-literal/Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix sparse build warnings:

kernel/kcov.c:99:1: warning:
 symbol '__pcpu_scope_kcov_percpu_data' was not declared. Should it be static?
kernel/kcov.c:778:6: warning:
 symbol 'kcov_remote_softirq_start' was not declared. Should it be static?
kernel/kcov.c:795:6: warning:
 symbol 'kcov_remote_softirq_stop' was not declared. Should it be static?
Reported-by: NHulk Robot <hulkci@huawei.com>
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NAndrey Konovalov <andreyknvl@google.com>
Link: http://lkml.kernel.org/r/20200702115501.73077-1-weiyongjun1@huawei.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Unconditionally add -fno-stack-protector to KCOV's compiler options, as
all supported compilers support the option.  This saves a compiler
invocation to determine if the option is supported.

Because Clang does not support -fno-conserve-stack, and
-fno-stack-protector was wrapped in the same cc-option, we were missing
-fno-stack-protector with Clang. Unconditionally adding this option
fixes this for Clang.
Suggested-by: NNick Desaulniers <ndesaulniers@google.com>
Signed-off-by: NMarco Elver <elver@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NNick Desaulniers <ndesaulniers@google.com>
Reviewed-by: NAndrey Konovalov <andreyknvl@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Link: http://lkml.kernel.org/r/20200615184302.7591-1-elver@google.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Since print_oops_end_marker() is not used externally, also remove it in
kernel.h at the same time.
Signed-off-by: NYue Hu <huyue2@yulong.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Kees Cook <keescook@chromium.org>
Link: http://lkml.kernel.org/r/20200724011516.12756-1-zbestahu@gmail.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>