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  1. 14 10月, 2020 4 次提交
  3. 06 9月, 2020 2 次提交
    • M
      mm/hugetlb: fix a race between hugetlb sysctl handlers · 17743798
      由 Muchun Song 提交于 
      There is a race between the assignment of `table->data` and write value
to the pointer of `table->data` in the __do_proc_doulongvec_minmax() on
the other thread.

  CPU0:                                 CPU1:
                                        proc_sys_write
  hugetlb_sysctl_handler                  proc_sys_call_handler
  hugetlb_sysctl_handler_common             hugetlb_sysctl_handler
    table->data = &tmp;                       hugetlb_sysctl_handler_common
                                                table->data = &tmp;
      proc_doulongvec_minmax
        do_proc_doulongvec_minmax           sysctl_head_finish
          __do_proc_doulongvec_minmax         unuse_table
            i = table->data;
            *i = val;  // corrupt CPU1's stack

Fix this by duplicating the `table`, and only update the duplicate of
it.  And introduce a helper of proc_hugetlb_doulongvec_minmax() to
simplify the code.

The following oops was seen:

    BUG: kernel NULL pointer dereference, address: 0000000000000000
    #PF: supervisor instruction fetch in kernel mode
    #PF: error_code(0x0010) - not-present page
    Code: Bad RIP value.
    ...
    Call Trace:
     ? set_max_huge_pages+0x3da/0x4f0
     ? alloc_pool_huge_page+0x150/0x150
     ? proc_doulongvec_minmax+0x46/0x60
     ? hugetlb_sysctl_handler_common+0x1c7/0x200
     ? nr_hugepages_store+0x20/0x20
     ? copy_fd_bitmaps+0x170/0x170
     ? hugetlb_sysctl_handler+0x1e/0x20
     ? proc_sys_call_handler+0x2f1/0x300
     ? unregister_sysctl_table+0xb0/0xb0
     ? __fd_install+0x78/0x100
     ? proc_sys_write+0x14/0x20
     ? __vfs_write+0x4d/0x90
     ? vfs_write+0xef/0x240
     ? ksys_write+0xc0/0x160
     ? __ia32_sys_read+0x50/0x50
     ? __close_fd+0x129/0x150
     ? __x64_sys_write+0x43/0x50
     ? do_syscall_64+0x6c/0x200
     ? entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: e5ff2159 ("hugetlb: multiple hstates for multiple page sizes")
Signed-off-by: NMuchun Song <songmuchun@bytedance.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NMike Kravetz <mike.kravetz@oracle.com>
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/20200828031146.43035-1-songmuchun@bytedance.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      17743798
    • L
      mm/hugetlb: try preferred node first when alloc gigantic page from cma · 953f064a
      由 Li Xinhai 提交于 
      Since commit cf11e85f ("mm: hugetlb: optionally allocate gigantic
hugepages using cma"), the gigantic page would be allocated from node
which is not the preferred node, although there are pages available from
that node.  The reason is that the nid parameter has been ignored in
alloc_gigantic_page().

Besides, the __GFP_THISNODE also need be checked if user required to
alloc only from the preferred node.

After this patch, the preferred node is tried first before other allowed
nodes, and don't try to allocate from other nodes if __GFP_THISNODE is
specified.  If user don't specify the preferred node, the current node
will be used as preferred node, which makes sure consistent behavior of
allocating gigantic and non-gigantic hugetlb page.

Fixes: cf11e85f ("mm: hugetlb: optionally allocate gigantic hugepages using cma")
Signed-off-by: NLi Xinhai <lixinhai.lxh@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NMike Kravetz <mike.kravetz@oracle.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Link: https://lkml.kernel.org/r/20200902025016.697260-1-lixinhai.lxh@gmail.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      953f064a
  5. 13 8月, 2020 6 次提交
  7. 08 8月, 2020 2 次提交
    • P
      mm/hugetlb: fix calculation of adjust_range_if_pmd_sharing_possible · 75802ca6
      由 Peter Xu 提交于 
      This is found by code observation only.

Firstly, the worst case scenario should assume the whole range was covered
by pmd sharing.  The old algorithm might not work as expected for ranges
like (1g-2m, 1g+2m), where the adjusted range should be (0, 1g+2m) but the
expected range should be (0, 2g).

Since at it, remove the loop since it should not be required.  With that,
the new code should be faster too when the invalidating range is huge.

Mike said:

: With range (1g-2m, 1g+2m) within a vma (0, 2g) the existing code will only
: adjust to (0, 1g+2m) which is incorrect.
:
: We should cc stable.  The original reason for adjusting the range was to
: prevent data corruption (getting wrong page).  Since the range is not
: always adjusted correctly, the potential for corruption still exists.
:
: However, I am fairly confident that adjust_range_if_pmd_sharing_possible
: is only gong to be called in two cases:
:
: 1) for a single page
: 2) for range == entire vma
:
: In those cases, the current code should produce the correct results.
:
: To be safe, let's just cc stable.

Fixes: 017b1660 ("mm: migration: fix migration of huge PMD shared pages")
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NMike Kravetz <mike.kravetz@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200730201636.74778-1-peterx@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      75802ca6
    • M
      mm: remove unneeded includes of <asm/pgalloc.h> · ca15ca40
      由 Mike Rapoport 提交于 
      Patch series "mm: cleanup usage of <asm/pgalloc.h>"

Most architectures have very similar versions of pXd_alloc_one() and
pXd_free_one() for intermediate levels of page table.  These patches add
generic versions of these functions in <asm-generic/pgalloc.h> and enable
use of the generic functions where appropriate.

In addition, functions declared and defined in <asm/pgalloc.h> headers are
used mostly by core mm and early mm initialization in arch and there is no
actual reason to have the <asm/pgalloc.h> included all over the place.
The first patch in this series removes unneeded includes of
<asm/pgalloc.h>

In the end it didn't work out as neatly as I hoped and moving
pXd_alloc_track() definitions to <asm-generic/pgalloc.h> would require
unnecessary changes to arches that have custom page table allocations, so
I've decided to move lib/ioremap.c to mm/ and make pgalloc-track.h local
to mm/.

This patch (of 8):

In most cases <asm/pgalloc.h> header is required only for allocations of
page table memory.  Most of the .c files that include that header do not
use symbols declared in <asm/pgalloc.h> and do not require that header.

As for the other header files that used to include <asm/pgalloc.h>, it is
possible to move that include into the .c file that actually uses symbols
from <asm/pgalloc.h> and drop the include from the header file.

The process was somewhat automated using

	sed -i -E '/[<"]asm\/pgalloc\.h/d' \
                $(grep -L -w -f /tmp/xx \
                        $(git grep -E -l '[<"]asm/pgalloc\.h'))

where /tmp/xx contains all the symbols defined in
arch/*/include/asm/pgalloc.h.

[rppt@linux.ibm.com: fix powerpc warning]
Signed-off-by: NMike Rapoport <rppt@linux.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NPekka Enberg <penberg@kernel.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>	[m68k]
Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Matthew Wilcox <willy@infradead.org>
Link: http://lkml.kernel.org/r/20200627143453.31835-1-rppt@kernel.org
Link: http://lkml.kernel.org/r/20200627143453.31835-2-rppt@kernel.orgSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      ca15ca40
  9. 25 7月, 2020 1 次提交
  11. 04 7月, 2020 1 次提交
  13. 10 6月, 2020 2 次提交
    • M
      mmap locking API: convert mmap_sem comments · c1e8d7c6
      由 Michel Lespinasse 提交于 
      Convert comments that reference mmap_sem to reference mmap_lock instead.

[akpm@linux-foundation.org: fix up linux-next leftovers]
[akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil]
[akpm@linux-foundation.org: more linux-next fixups, per Michel]
Signed-off-by: NMichel Lespinasse <walken@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NVlastimil Babka <vbabka@suse.cz>
Reviewed-by: NDaniel Jordan <daniel.m.jordan@oracle.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: Liam Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ying Han <yinghan@google.com>
Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      c1e8d7c6
    • M
      mm: don't include asm/pgtable.h if linux/mm.h is already included · e31cf2f4
      由 Mike Rapoport 提交于 
      Patch series "mm: consolidate definitions of page table accessors", v2.

The low level page table accessors (pXY_index(), pXY_offset()) are
duplicated across all architectures and sometimes more than once.  For
instance, we have 31 definition of pgd_offset() for 25 supported
architectures.

Most of these definitions are actually identical and typically it boils
down to, e.g.

static inline unsigned long pmd_index(unsigned long address)
{
        return (address >> PMD_SHIFT) & (PTRS_PER_PMD - 1);
}

static inline pmd_t *pmd_offset(pud_t *pud, unsigned long address)
{
        return (pmd_t *)pud_page_vaddr(*pud) + pmd_index(address);
}

These definitions can be shared among 90% of the arches provided
XYZ_SHIFT, PTRS_PER_XYZ and xyz_page_vaddr() are defined.

For architectures that really need a custom version there is always
possibility to override the generic version with the usual ifdefs magic.

These patches introduce include/linux/pgtable.h that replaces
include/asm-generic/pgtable.h and add the definitions of the page table
accessors to the new header.

This patch (of 12):

The linux/mm.h header includes <asm/pgtable.h> to allow inlining of the
functions involving page table manipulations, e.g.  pte_alloc() and
pmd_alloc().  So, there is no point to explicitly include <asm/pgtable.h>
in the files that include <linux/mm.h>.

The include statements in such cases are remove with a simple loop:

	for f in $(git grep -l "include <linux/mm.h>") ; do
		sed -i -e '/include <asm\/pgtable.h>/ d' $f
	done
Signed-off-by: NMike Rapoport <rppt@linux.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
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: Mike Rapoport <rppt@kernel.org>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.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/20200514170327.31389-1-rppt@kernel.org
Link: http://lkml.kernel.org/r/20200514170327.31389-2-rppt@kernel.orgSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      e31cf2f4
  15. 05 6月, 2020 1 次提交
  17. 04 6月, 2020 6 次提交
    • L
      mm/hugetlb: avoid unnecessary check on pud and pmd entry in huge_pte_offset · 8ac0b81a
      由 Li Xinhai 提交于 
      When huge_pte_offset() is called, the parameter sz can only be PUD_SIZE or
PMD_SIZE.  If sz is PUD_SIZE and code can reach pud, then *pud must be
none, or normal hugetlb entry, or non-present (migration or hwpoisoned)
hugetlb entry, and we can directly return pud.  When sz is PMD_SIZE, pud
must be none or present, and if code can reach pmd, we can directly return
pmd.

So after this patch the code is simplified by first check on the parameter
sz, and avoid unnecessary checks in current code.  Same semantics of
existing code is maintained.

More details about relevant commits:
commit 9b19df29 ("mm/hugetlb.c: make huge_pte_offset() consistent
and document behaviour") changed the code path for pud and pmd handling,
see comments about why this patch intends to change it.
...
	pud = pud_offset(p4d, addr);
	if (sz != PUD_SIZE && pud_none(*pud)) // [1]
		return NULL;
	/* hugepage or swap? */
	if (pud_huge(*pud) || !pud_present(*pud)) // [2]
		return (pte_t *)pud;

	pmd = pmd_offset(pud, addr);
	if (sz != PMD_SIZE && pmd_none(*pmd)) // [3]
		return NULL;
	/* hugepage or swap? */
	if (pmd_huge(*pmd) || !pmd_present(*pmd)) // [4]
		return (pte_t *)pmd;

	return NULL; // [5]
...
[1]: this is necessary, return NULL for sz == PMD_SIZE;
[2]: if sz == PUD_SIZE, all valid values of pud entry will cause return;
[3]: dead code, sz != PMD_SIZE never true;
[4]: all valid values of pmd entry will cause return;
[5]: dead code, because of check in [4].

Now, this patch combines [1] and [2] for pud, and combines [3], [4] and
[5] for pmd, so avoid unnecessary checks.

I don't try to catch any invalid values in page table entry, as that will
be checked by caller and avoid extra branch in this function.  Also no
assert on sz must equal PUD_SIZE or PMD_SIZE, since this function only
call for hugetlb mapping.

For commit 3c1d7e6c ("mm/hugetlb: fix a addressing exception caused by
huge_pte_offset"), since we don't read the entry more than once now,
variable pud_entry and pmd_entry are not needed.
Signed-off-by: NLi Xinhai <lixinhai.lxh@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Punit Agrawal <punit.agrawal@arm.com>
Cc: Longpeng <longpeng2@huawei.com>
Link: http://lkml.kernel.org/r/1587794313-16849-1-git-send-email-lixinhai.lxh@gmail.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      8ac0b81a
    • M
      hugetlbfs: fix changes to command line processing · c2833a5b
      由 Mike Kravetz 提交于 
      Previously, a check for hugepages_supported was added before processing
hugetlb command line parameters.  On some architectures such as powerpc,
hugepages_supported() is not set to true until after command line
processing.  Therefore, no hugetlb command line parameters would be
accepted.

Remove the additional checks for hugepages_supported.  In hugetlb_init,
print a warning if !hugepages_supported and command line parameters were
specified.
Reported-by: NSandipan Das <sandipan.osd@gmail.com>
Signed-off-by: NMike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Link: http://lkml.kernel.org/r/b1f04f9f-fa46-c2a0-7693-4a0679d2a1ee@oracle.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      c2833a5b
    • M
      hugetlbfs: clean up command line processing · 282f4214
      由 Mike Kravetz 提交于 
      With all hugetlb page processing done in a single file clean up code.

- Make code match desired semantics
  - Update documentation with semantics
- Make all warnings and errors messages start with 'HugeTLB:'.
- Consistently name command line parsing routines.
- Warn if !hugepages_supported() and command line parameters have
  been specified.
- Add comments to code
  - Describe some of the subtle interactions
  - Describe semantics of command line arguments

This patch also fixes issues with implicitly setting the number of
gigantic huge pages to preallocate.  Previously on X86 command line,

        hugepages=2 default_hugepagesz=1G

would result in zero 1G pages being preallocated and,

        # grep HugePages_Total /proc/meminfo
        HugePages_Total:       0
        # sysctl -a | grep nr_hugepages
        vm.nr_hugepages = 2
        vm.nr_hugepages_mempolicy = 2
        # cat /proc/sys/vm/nr_hugepages
        2

After this patch 2 gigantic pages will be preallocated and all the proc,
sysfs, sysctl and meminfo files will accurately reflect this.

To address the issue with gigantic pages, a small change in behavior was
made to command line processing.  Previously the command line,

        hugepages=128 default_hugepagesz=2M hugepagesz=2M hugepages=256

would result in the allocation of 256 2M huge pages.  The value 128 would
be ignored without any warning.  After this patch, 128 2M pages will be
allocated and a warning message will be displayed indicating the value of
256 is ignored.  This change in behavior is required because allocation of
implicitly specified gigantic pages must be done when the
default_hugepagesz= is encountered for gigantic pages.  Previously the
code waited until later in the boot process (hugetlb_init), to allocate
pages of default size.  However the bootmem allocator required for
gigantic allocations is not available at this time.
Signed-off-by: NMike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Tested-by: NSandipan Das <sandipan@linux.ibm.com>
Acked-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>	[s390]
Acked-by: NWill Deacon <will@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Longpeng <longpeng2@huawei.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Nitesh Narayan Lal <nitesh@redhat.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Anders Roxell <anders.roxell@linaro.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Link: http://lkml.kernel.org/r/20200417185049.275845-5-mike.kravetz@oracle.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      282f4214
    • M
      hugetlbfs: remove hugetlb_add_hstate() warning for existing hstate · 38237830
      由 Mike Kravetz 提交于 
      hugetlb_add_hstate() prints a warning if the hstate already exists.  This
was originally done as part of kernel command line parsing.  If
'hugepagesz=' was specified more than once, the warning

	pr_warn("hugepagesz= specified twice, ignoring\n");

would be printed.

Some architectures want to enable all huge page sizes.  They would call
hugetlb_add_hstate for all supported sizes.  However, this was done after
command line processing and as a result hstates could have already been
created for some sizes.  To make sure no warning were printed, there would
often be code like:

	if (!size_to_hstate(size)
		hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT)

The only time we want to print the warning is as the result of command
line processing.  So, remove the warning from hugetlb_add_hstate and add
it to the single arch independent routine processing "hugepagesz=".  After
this, calls to size_to_hstate() in arch specific code can be removed and
hugetlb_add_hstate can be called without worrying about warning messages.

[mike.kravetz@oracle.com: fix hugetlb initialization]
  Link: http://lkml.kernel.org/r/4c36c6ce-3774-78fa-abc4-b7346bf24348@oracle.com
  Link: http://lkml.kernel.org/r/20200428205614.246260-5-mike.kravetz@oracle.comSigned-off-by: NMike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Tested-by: NAnders Roxell <anders.roxell@linaro.org>
Acked-by: NMina Almasry <almasrymina@google.com>
Acked-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>	[s390]
Acked-by: NWill Deacon <will@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Longpeng <longpeng2@huawei.com>
Cc: Nitesh Narayan Lal <nitesh@redhat.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Link: http://lkml.kernel.org/r/20200417185049.275845-4-mike.kravetz@oracle.com
Link: http://lkml.kernel.org/r/20200428205614.246260-4-mike.kravetz@oracle.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      38237830
    • M
      hugetlbfs: move hugepagesz= parsing to arch independent code · 359f2544
      由 Mike Kravetz 提交于 
      Now that architectures provide arch_hugetlb_valid_size(), parsing of
"hugepagesz=" can be done in architecture independent code.  Create a
single routine to handle hugepagesz= parsing and remove all arch specific
routines.  We can also remove the interface hugetlb_bad_size() as this is
no longer used outside arch independent code.

This also provides consistent behavior of hugetlbfs command line options.
The hugepagesz= option should only be specified once for a specific size,
but some architectures allow multiple instances.  This appears to be more
of an oversight when code was added by some architectures to set up ALL
huge pages sizes.
Signed-off-by: NMike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Tested-by: NSandipan Das <sandipan@linux.ibm.com>
Reviewed-by: NPeter Xu <peterx@redhat.com>
Acked-by: NMina Almasry <almasrymina@google.com>
Acked-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>	[s390]
Acked-by: NWill Deacon <will@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Longpeng <longpeng2@huawei.com>
Cc: Nitesh Narayan Lal <nitesh@redhat.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Anders Roxell <anders.roxell@linaro.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Link: http://lkml.kernel.org/r/20200417185049.275845-3-mike.kravetz@oracle.com
Link: http://lkml.kernel.org/r/20200428205614.246260-3-mike.kravetz@oracle.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      359f2544
    • M
      hugetlbfs: add arch_hugetlb_valid_size · ae94da89
      由 Mike Kravetz 提交于 
      Patch series "Clean up hugetlb boot command line processing", v4.

Longpeng(Mike) reported a weird message from hugetlb command line
processing and proposed a solution [1].  While the proposed patch does
address the specific issue, there are other related issues in command line
processing.  As hugetlbfs evolved, updates to command line processing have
been made to meet immediate needs and not necessarily in a coordinated
manner.  The result is that some processing is done in arch specific code,
some is done in arch independent code and coordination is problematic.
Semantics can vary between architectures.

The patch series does the following:
- Define arch specific arch_hugetlb_valid_size routine used to validate
  passed huge page sizes.
- Move hugepagesz= command line parsing out of arch specific code and into
  an arch independent routine.
- Clean up command line processing to follow desired semantics and
  document those semantics.

[1] https://lore.kernel.org/linux-mm/20200305033014.1152-1-longpeng2@huawei.com

This patch (of 3):

The architecture independent routine hugetlb_default_setup sets up the
default huge pages size.  It has no way to verify if the passed value is
valid, so it accepts it and attempts to validate at a later time.  This
requires undocumented cooperation between the arch specific and arch
independent code.

For architectures that support more than one huge page size, provide a
routine arch_hugetlb_valid_size to validate a huge page size.
hugetlb_default_setup can use this to validate passed values.

arch_hugetlb_valid_size will also be used in a subsequent patch to move
processing of the "hugepagesz=" in arch specific code to a common routine
in arch independent code.
Signed-off-by: NMike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>	[s390]
Acked-by: NWill Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Longpeng <longpeng2@huawei.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Nitesh Narayan Lal <nitesh@redhat.com>
Cc: Anders Roxell <anders.roxell@linaro.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Link: http://lkml.kernel.org/r/20200428205614.246260-1-mike.kravetz@oracle.com
Link: http://lkml.kernel.org/r/20200428205614.246260-2-mike.kravetz@oracle.com
Link: http://lkml.kernel.org/r/20200417185049.275845-1-mike.kravetz@oracle.com
Link: http://lkml.kernel.org/r/20200417185049.275845-2-mike.kravetz@oracle.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      ae94da89
  19. 27 4月, 2020 1 次提交
  21. 22 4月, 2020 1 次提交
    • L
      mm/hugetlb: fix a addressing exception caused by huge_pte_offset · 3c1d7e6c
      由 Longpeng 提交于 
      Our machine encountered a panic(addressing exception) after run for a
long time and the calltrace is:

    RIP: hugetlb_fault+0x307/0xbe0
    RSP: 0018:ffff9567fc27f808  EFLAGS: 00010286
    RAX: e800c03ff1258d48 RBX: ffffd3bb003b69c0 RCX: e800c03ff1258d48
    RDX: 17ff3fc00eda72b7 RSI: 00003ffffffff000 RDI: e800c03ff1258d48
    RBP: ffff9567fc27f8c8 R08: e800c03ff1258d48 R09: 0000000000000080
    R10: ffffaba0704c22a8 R11: 0000000000000001 R12: ffff95c87b4b60d8
    R13: 00005fff00000000 R14: 0000000000000000 R15: ffff9567face8074
    FS:  00007fe2d9ffb700(0000) GS:ffff956900e40000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: ffffd3bb003b69c0 CR3: 000000be67374000 CR4: 00000000003627e0
    DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
    DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
    Call Trace:
      follow_hugetlb_page+0x175/0x540
      __get_user_pages+0x2a0/0x7e0
      __get_user_pages_unlocked+0x15d/0x210
      __gfn_to_pfn_memslot+0x3c5/0x460 [kvm]
      try_async_pf+0x6e/0x2a0 [kvm]
      tdp_page_fault+0x151/0x2d0 [kvm]
     ...
      kvm_arch_vcpu_ioctl_run+0x330/0x490 [kvm]
      kvm_vcpu_ioctl+0x309/0x6d0 [kvm]
      do_vfs_ioctl+0x3f0/0x540
      SyS_ioctl+0xa1/0xc0
      system_call_fastpath+0x22/0x27

For 1G hugepages, huge_pte_offset() wants to return NULL or pudp, but it
may return a wrong 'pmdp' if there is a race.  Please look at the
following code snippet:

    ...
    pud = pud_offset(p4d, addr);
    if (sz != PUD_SIZE && pud_none(*pud))
        return NULL;
    /* hugepage or swap? */
    if (pud_huge(*pud) || !pud_present(*pud))
        return (pte_t *)pud;

    pmd = pmd_offset(pud, addr);
    if (sz != PMD_SIZE && pmd_none(*pmd))
        return NULL;
    /* hugepage or swap? */
    if (pmd_huge(*pmd) || !pmd_present(*pmd))
        return (pte_t *)pmd;
    ...

The following sequence would trigger this bug:

 - CPU0: sz = PUD_SIZE and *pud = 0 , continue
 - CPU0: "pud_huge(*pud)" is false
 - CPU1: calling hugetlb_no_page and set *pud to xxxx8e7(PRESENT)
 - CPU0: "!pud_present(*pud)" is false, continue
 - CPU0: pmd = pmd_offset(pud, addr) and maybe return a wrong pmdp

However, we want CPU0 to return NULL or pudp in this case.

We must make sure there is exactly one dereference of pud and pmd.
Signed-off-by: NLongpeng <longpeng2@huawei.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NMike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: NJason Gunthorpe <jgg@mellanox.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200413010342.771-1-longpeng2@huawei.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      3c1d7e6c
  23. 11 4月, 2020 1 次提交
    • R
      mm: hugetlb: optionally allocate gigantic hugepages using cma · cf11e85f
      由 Roman Gushchin 提交于 
      Commit 944d9fec ("hugetlb: add support for gigantic page allocation
at runtime") has added the run-time allocation of gigantic pages.

However it actually works only at early stages of the system loading,
when the majority of memory is free.  After some time the memory gets
fragmented by non-movable pages, so the chances to find a contiguous 1GB
block are getting close to zero.  Even dropping caches manually doesn't
help a lot.

At large scale rebooting servers in order to allocate gigantic hugepages
is quite expensive and complex.  At the same time keeping some constant
percentage of memory in reserved hugepages even if the workload isn't
using it is a big waste: not all workloads can benefit from using 1 GB
pages.

The following solution can solve the problem:
1) On boot time a dedicated cma area* is reserved. The size is passed
   as a kernel argument.
2) Run-time allocations of gigantic hugepages are performed using the
   cma allocator and the dedicated cma area

In this case gigantic hugepages can be allocated successfully with a
high probability, however the memory isn't completely wasted if nobody
is using 1GB hugepages: it can be used for pagecache, anon memory, THPs,
etc.

* On a multi-node machine a per-node cma area is allocated on each node.
  Following gigantic hugetlb allocation are using the first available
  numa node if the mask isn't specified by a user.

Usage:
1) configure the kernel to allocate a cma area for hugetlb allocations:
   pass hugetlb_cma=10G as a kernel argument

2) allocate hugetlb pages as usual, e.g.
   echo 10 > /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages

If the option isn't enabled or the allocation of the cma area failed,
the current behavior of the system is preserved.

x86 and arm-64 are covered by this patch, other architectures can be
trivially added later.

The patch contains clean-ups and fixes proposed and implemented by Aslan
Bakirov and Randy Dunlap.  It also contains ideas and suggestions
proposed by Rik van Riel, Michal Hocko and Mike Kravetz.  Thanks!
Signed-off-by: NRoman Gushchin <guro@fb.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Tested-by: NAndreas Schaufler <andreas.schaufler@gmx.de>
Acked-by: NMike Kravetz <mike.kravetz@oracle.com>
Acked-by: NMichal Hocko <mhocko@kernel.org>
Cc: Aslan Bakirov <aslan@fb.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Link: http://lkml.kernel.org/r/20200407163840.92263-3-guro@fb.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      cf11e85f
  25. 08 4月, 2020 1 次提交
  27. 03 4月, 2020 11 次提交