commit c165f25d23ecb2f9f121ced20435415b931219e2 upstream

As a zpool_driver, zsmalloc can allocate movable memory because it support
migate pages.  But zbud and z3fold cannot allocate movable memory.

Add malloc_support_movable to zpool_driver.  If a zpool_driver support
allocate movable memory, set it to true.  And add
zpool_malloc_support_movable check malloc_support_movable to make sure if
a zpool support allocate movable memory.

Link: http://lkml.kernel.org/r/20190605100630.13293-1-teawaterz@linux.alibaba.comSigned-off-by: NHui Zhu <teawaterz@linux.alibaba.com>
Reviewed-by: NShakeel Butt <shakeelb@google.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitalywool@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: NYang Shi <yang.shi@linux.alibaba.com>
Acked-by: NCaspar Zhang <caspar@linux.alibaba.com>

The functions zs_page_isolate, zs_page_migrate, zs_page_putback,
lock_zspage, trylock_zspage and structure zsmalloc_aops are local to
source and do not need to be in global scope, so make them static.

Cleans up sparse warnings:
  symbol 'zs_page_isolate' was not declared. Should it be static?
  symbol 'zs_page_migrate' was not declared. Should it be static?
  symbol 'zs_page_putback' was not declared. Should it be static?
  symbol 'zsmalloc_aops' was not declared. Should it be static?
  symbol 'lock_zspage' was not declared. Should it be static?
  symbol 'trylock_zspage' was not declared. Should it be static?

[arnd@arndb.de: hide unused lock_zspage]
  Link: http://lkml.kernel.org/r/20180706130924.3891230-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/20180624213322.13776-1-colin.king@canonical.comSigned-off-by: NColin Ian King <colin.king@canonical.com>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/*.c files use symbolic and octal styles for permissions.

Using octal and not symbolic permissions is preferred by many as more
readable.

https://lkml.org/lkml/2016/8/2/1945

Prefer the direct use of octal for permissions.

Done using
$ scripts/checkpatch.pl -f --types=SYMBOLIC_PERMS --fix-inplace mm/*.c
and some typing.

Before:	 $ git grep -P -w "0[0-7]{3,3}" mm | wc -l
44
After:	 $ git grep -P -w "0[0-7]{3,3}" mm | wc -l
86

Miscellanea:

o Whitespace neatening around these conversions.

Link: http://lkml.kernel.org/r/2e032ef111eebcd4c5952bae86763b541d373469.1522102887.git.joe@perches.comSigned-off-by: NJoe Perches <joe@perches.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Link: http://lkml.kernel.org/r/1519585191-10180-4-git-send-email-rppt@linux.vnet.ibm.comSigned-off-by: NMike Rapoport <rppt@linux.vnet.ibm.com>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Patch series "zsmalloc/zram: drop zram's max_zpage_size", v3.

ZRAM's max_zpage_size is a bad thing.  It forces zsmalloc to store
normal objects as huge ones, which results in bigger zsmalloc memory
usage.  Drop it and use actual zsmalloc huge-class value when decide if
the object is huge or not.

This patch (of 2):

Not every object can be share its zspage with other objects, e.g.  when
the object is as big as zspage or nearly as big a zspage.  For such
objects zsmalloc has a so called huge class - every object which belongs
to huge class consumes the entire zspage (which consists of a physical
page).  On x86_64, PAGE_SHIFT 12 box, the first non-huge class size is
3264, so starting down from size 3264, objects can share page(-s) and
thus minimize memory wastage.

ZRAM, however, has its own statically defined watermark for huge
objects, namely "3 * PAGE_SIZE / 4 = 3072", and forcibly stores every
object larger than this watermark (3072) as a PAGE_SIZE object, in other
words, to a huge class, while zsmalloc can keep some of those objects in
non-huge classes.  This results in increased memory consumption.

zsmalloc knows better if the object is huge or not.  Introduce
zs_huge_class_size() function which tells if the given object can be
stored in one of non-huge classes or not.  This will let us to drop
ZRAM's huge object watermark and fully rely on zsmalloc when we decide
if the object is huge.

[sergey.senozhatsky.work@gmail.com: add pool param to zs_huge_class_size()]
  Link: http://lkml.kernel.org/r/20180314081833.1096-2-sergey.senozhatsky@gmail.com
Link: http://lkml.kernel.org/r/20180306070639.7389-2-sergey.senozhatsky@gmail.comSigned-off-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

...instead of open coding file operations followed by custom ->open()
callbacks per each attribute.

[andriy.shevchenko@linux.intel.com: add tags, fix compilation issue]
  Link: http://lkml.kernel.org/r/20180217144253.58604-1-andriy.shevchenko@linux.intel.com
Link: http://lkml.kernel.org/r/20180214154644.54505-1-andriy.shevchenko@linux.intel.comSigned-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: NMatthew Wilcox <mawilcox@microsoft.com>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: NChristoph Lameter <cl@linux.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Dennis Zhou <dennisszhou@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With boot-time switching between paging mode we will have variable
MAX_PHYSMEM_BITS.

Let's use the maximum variable possible for CONFIG_X86_5LEVEL=y
configuration to define zsmalloc data structures.

The patch introduces MAX_POSSIBLE_PHYSMEM_BITS to cover such case.
It also suits well to handle PAE special case.
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: NNitin Gupta <ngupta@vflare.org>
Acked-by: NMinchan Kim <minchan@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180214111656.88514-3-kirill.shutemov@linux.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Fix warning about shifting unsigned literals being undefined behavior.

Link: http://lkml.kernel.org/r/1515642078-4259-1-git-send-email-nick.desaulniers@gmail.comSigned-off-by: NNick Desaulniers <nick.desaulniers@gmail.com>
Suggested-by: NMinchan Kim <minchan@kernel.org>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Nick Desaulniers <nick.desaulniers@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We waste sizeof(swp_entry_t) for zswap header when using zsmalloc as
zpool driver because zsmalloc doesn't support eviction.

Add zpool_evictable() to detect if zpool is potentially evictable, and
use it in zswap to avoid waste memory for zswap header.

[yuzhao@google.com: The zpool->" prefix is a result of copy & paste]
  Link: http://lkml.kernel.org/r/20180110225626.110330-1-yuzhao@google.com
Link: http://lkml.kernel.org/r/20180110224741.83751-1-yuzhao@google.comSigned-off-by: NYu Zhao <yuzhao@google.com>
Acked-by: NDan Streetman <ddstreet@ieee.org>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Structure zs_pool has special flag to indicate success of shrinker
initialization.  unregister_shrinker() has improved and can detect by
itself whether actual deinitialization should be performed or not, so
extra flag becomes redundant.

[akpm@linux-foundation.org: update comment (Aliaksei), remove unneeded cast]
Link: http://lkml.kernel.org/r/1513680552-9798-1-git-send-email-akaraliou.dev@gmail.comSigned-off-by: NAliaksei Karaliou <akaraliou.dev@gmail.com>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

`struct file_system_type' and alloc_anon_inode() function are defined in
fs.h, include it directly.

Link: http://lkml.kernel.org/r/20171219104219.3017-1-sergey.senozhatsky@gmail.comSigned-off-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use BUG_ON(in_interrupt()) in zs_map_object().  This is not a new
BUG_ON(), it's always been there, but was recently changed to
VM_BUG_ON().  There are several problems there.  First, we use use
per-CPU mappings both in zsmalloc and in zram, and interrupt may easily
corrupt those buffers.  Second, and more importantly, we believe it's
possible to start leaking sensitive information.  Consider the following
case:

-> process P
	swap out
	 zram
	  per-cpu mapping CPU1
	   compress page A
-> IRQ

	swap out
	 zram
	  per-cpu mapping CPU1
	   compress page B
	    write page from per-cpu mapping CPU1 to zsmalloc pool
	iret

-> process P
	    write page from per-cpu mapping CPU1 to zsmalloc pool  [*]
	return

* so we store overwritten data that actually belongs to another
  page (task) and potentially contains sensitive data. And when
  process P will page fault it's going to read (swap in) that
  other task's data.

Link: http://lkml.kernel.org/r/20170929045140.4055-1-sergey.senozhatsky@gmail.comSigned-off-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

zs_stat_inc/dec/get() uses enum zs_stat_type for the stat type, however
some callers pass an enum fullness_group value.  Change the type to int to
reflect the actual use of the functions and get rid of 'enum-conversion'
warnings

Link: http://lkml.kernel.org/r/20170731175000.56538-1-mka@chromium.orgSigned-off-by: NMatthias Kaehlcke <mka@chromium.org>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Cc: Doug Anderson <dianders@chromium.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Introduce a new migration mode that allow to offload the copy to a device
DMA engine.  This changes the workflow of migration and not all
address_space migratepage callback can support this.

This is intended to be use by migrate_vma() which itself is use for thing
like HMM (see include/linux/hmm.h).

No additional per-filesystem migratepage testing is needed.  I disables
MIGRATE_SYNC_NO_COPY in all problematic migratepage() callback and i
added comment in those to explain why (part of this patch).  The commit
message is unclear it should say that any callback that wish to support
this new mode need to be aware of the difference in the migration flow
from other mode.

Some of these callbacks do extra locking while copying (aio, zsmalloc,
balloon, ...) and for DMA to be effective you want to copy multiple
pages in one DMA operations.  But in the problematic case you can not
easily hold the extra lock accross multiple call to this callback.

Usual flow is:

For each page {
 1 - lock page
 2 - call migratepage() callback
 3 - (extra locking in some migratepage() callback)
 4 - migrate page state (freeze refcount, update page cache, buffer
     head, ...)
 5 - copy page
 6 - (unlock any extra lock of migratepage() callback)
 7 - return from migratepage() callback
 8 - unlock page
}

The new mode MIGRATE_SYNC_NO_COPY:
 1 - lock multiple pages
For each page {
 2 - call migratepage() callback
 3 - abort in all problematic migratepage() callback
 4 - migrate page state (freeze refcount, update page cache, buffer
     head, ...)
} // finished all calls to migratepage() callback
 5 - DMA copy multiple pages
 6 - unlock all the pages

To support MIGRATE_SYNC_NO_COPY in the problematic case we would need a
new callback migratepages() (for instance) that deals with multiple
pages in one transaction.

Because the problematic cases are not important for current usage I did
not wanted to complexify this patchset even more for no good reason.

Link: http://lkml.kernel.org/r/20170817000548.32038-14-jglisse@redhat.comSigned-off-by: NJérôme Glisse <jglisse@redhat.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Evgeny Baskakov <ebaskakov@nvidia.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mark Hairgrove <mhairgrove@nvidia.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Sherry Cheung <SCheung@nvidia.com>
Cc: Subhash Gutti <sgutti@nvidia.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Bob Liu <liubo95@huawei.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Getting -EBUSY from zs_page_migrate will make migration slow (retry) or
fail (zs_page_putback will schedule_work free_work, but it cannot ensure
the success).

I noticed this issue because my Kernel patched
(https://lkml.org/lkml/2014/5/28/113) that will remove retry in
__alloc_contig_migrate_range.

This retry will handle the -EBUSY because it will re-isolate the page
and re-call migrate_pages.  Without it will make cma_alloc fail at once
with -EBUSY.

According to the review from Minchan Kim in
https://lkml.org/lkml/2014/5/28/113, I update the patch to skip
unnecessary loops but not return -EBUSY if zspage is not inuse.

Following is what I got with highalloc-performance in a vbox with 2 cpu
1G memory 512 zram as swap.  And the swappiness is set to 100.

                                   ori          ne
                                  orig         new
Minor Faults                  50805113    50830235
Major Faults                     43918       56530
Swap Ins                         42087       55680
Swap Outs                        89718      104700
Allocation stalls                    0           0
DMA allocs                       57787       52364
DMA32 allocs                  47964599    48043563
Normal allocs                        0           0
Movable allocs                       0           0
Direct pages scanned             45493       23167
Kswapd pages scanned           1565222     1725078
Kswapd pages reclaimed         1342222     1503037
Direct pages reclaimed           45615       25186
Kswapd efficiency                  85%         87%
Kswapd velocity               1897.101    1949.042
Direct efficiency                 100%        108%
Direct velocity                 55.139      26.175
Percentage direct scans             2%          1%
Zone normal velocity          1952.240    1975.217
Zone dma32 velocity              0.000       0.000
Zone dma velocity                0.000       0.000
Page writes by reclaim       89764.000  105233.000
Page writes file                    46         533
Page writes anon                 89718      104700
Page reclaim immediate           21457        3699
Sector Reads                   3259688     3441368
Sector Writes                  3667252     3754836
Page rescued immediate               0           0
Slabs scanned                  1042872     1160855
Direct inode steals               8042       10089
Kswapd inode steals              54295       29170
Kswapd skipped wait                  0           0
THP fault alloc                    175         154
THP collapse alloc                 226         289
THP splits                           0           0
THP fault fallback                  11          14
THP collapse fail                    3           2
Compaction stalls                  536         646
Compaction success                 322         358
Compaction failures                214         288
Page migrate success            119608      111063
Page migrate failure              2723        2593
Compaction pages isolated       250179      232652
Compaction migrate scanned     9131832     9942306
Compaction free scanned        2093272     2613998
Compaction cost                    192         189
NUMA alloc hit                47124555    47193990
NUMA alloc miss                      0           0
NUMA interleave hit                  0           0
NUMA alloc local              47124555    47193990
NUMA base PTE updates                0           0
NUMA huge PMD updates                0           0
NUMA page range updates              0           0
NUMA hint faults                     0           0
NUMA hint local faults               0           0
NUMA hint local percent            100         100
NUMA pages migrated                  0           0
AutoNUMA cost                       0%          0%

[akpm@linux-foundation.org: remove newline, per Minchan]
Link: http://lkml.kernel.org/r/1500889535-19648-1-git-send-email-zhuhui@xiaomi.comSigned-off-by: NHui Zhu <zhuhui@xiaomi.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Mike reported kernel goes oops with ltp:zram03 testcase.

  zram: Added device: zram0
  zram0: detected capacity change from 0 to 107374182400
  BUG: unable to handle kernel paging request at 0000306d61727a77
  IP: zs_map_object+0xb9/0x260
  PGD 0
  P4D 0
  Oops: 0000 [#1] SMP
  Dumping ftrace buffer:
     (ftrace buffer empty)
  Modules linked in: zram(E) xfs(E) libcrc32c(E) btrfs(E) xor(E) raid6_pq(E) loop(E) ebtable_filter(E) ebtables(E) ip6table_filter(E) ip6_tables(E) iptable_filter(E) ip_tables(E) x_tables(E) af_packet(E) br_netfilter(E) bridge(E) stp(E) llc(E) iscsi_ibft(E) iscsi_boot_sysfs(E) nls_iso8859_1(E) nls_cp437(E) vfat(E) fat(E) intel_powerclamp(E) coretemp(E) cdc_ether(E) kvm_intel(E) usbnet(E) mii(E) kvm(E) irqbypass(E) crct10dif_pclmul(E) crc32_pclmul(E) crc32c_intel(E) iTCO_wdt(E) ghash_clmulni_intel(E) bnx2(E) iTCO_vendor_support(E) pcbc(E) ioatdma(E) ipmi_ssif(E) aesni_intel(E) i5500_temp(E) i2c_i801(E) aes_x86_64(E) lpc_ich(E) shpchp(E) mfd_core(E) crypto_simd(E) i7core_edac(E) dca(E) glue_helper(E) cryptd(E) ipmi_si(E) button(E) acpi_cpufreq(E) ipmi_devintf(E) pcspkr(E) ipmi_msghandler(E)
   nfsd(E) auth_rpcgss(E) nfs_acl(E) lockd(E) grace(E) sunrpc(E) ext4(E) crc16(E) mbcache(E) jbd2(E) sd_mod(E) ata_generic(E) i2c_algo_bit(E) ata_piix(E) drm_kms_helper(E) ahci(E) syscopyarea(E) sysfillrect(E) libahci(E) sysimgblt(E) fb_sys_fops(E) uhci_hcd(E) ehci_pci(E) ttm(E) ehci_hcd(E) libata(E) drm(E) megaraid_sas(E) usbcore(E) sg(E) dm_multipath(E) dm_mod(E) scsi_dh_rdac(E) scsi_dh_emc(E) scsi_dh_alua(E) scsi_mod(E) efivarfs(E) autofs4(E) [last unloaded: zram]
  CPU: 6 PID: 12356 Comm: swapon Tainted: G            E   4.13.0.g87b2c3fc-default #194
  Hardware name: IBM System x3550 M3 -[7944K3G]-/69Y5698     , BIOS -[D6E150AUS-1.10]- 12/15/2010
  task: ffff880158d2c4c0 task.stack: ffffc90001680000
  RIP: 0010:zs_map_object+0xb9/0x260
  Call Trace:
   zram_bvec_rw.isra.26+0xe8/0x780 [zram]
   zram_rw_page+0x6e/0xa0 [zram]
   bdev_read_page+0x81/0xb0
   do_mpage_readpage+0x51a/0x710
   mpage_readpages+0x122/0x1a0
   blkdev_readpages+0x1d/0x20
   __do_page_cache_readahead+0x1b2/0x270
   ondemand_readahead+0x180/0x2c0
   page_cache_sync_readahead+0x31/0x50
   generic_file_read_iter+0x7e7/0xaf0
   blkdev_read_iter+0x37/0x40
   __vfs_read+0xce/0x140
   vfs_read+0x9e/0x150
   SyS_read+0x46/0xa0
   entry_SYSCALL_64_fastpath+0x1a/0xa5
  Code: 81 e6 00 c0 3f 00 81 fe 00 00 16 00 0f 85 9f 01 00 00 0f b7 13 65 ff 05 5e 07 dc 7e 66 c1 ea 02 81 e2 ff 01 00 00 49 8b 54 d4 08 <8b> 4a 48 41 0f af ce 81 e1 ff 0f 00 00 41 89 c9 48 c7 c3 a0 70
  RIP: zs_map_object+0xb9/0x260 RSP: ffffc90001683988
  CR2: 0000306d61727a77

He bisected the problem is [1].

After commit cf8e0fed ("mm/zsmalloc: simplify zs_max_alloc_size
handling"), zram doesn't use double pointer for pool->size_class any
more in zs_create_pool so counter function zs_destroy_pool don't need to
free it, either.

Otherwise, it does kfree wrong address and then, kernel goes Oops.

Link: http://lkml.kernel.org/r/20170725062650.GA12134@bbox
Fixes: cf8e0fed ("mm/zsmalloc: simplify zs_max_alloc_size handling")
Signed-off-by: NMinchan Kim <minchan@kernel.org>
Reported-by: NMike Galbraith <efault@gmx.de>
Tested-by: NMike Galbraith <efault@gmx.de>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 40f9fb8c ("mm/zsmalloc: support allocating obj with size of
ZS_MAX_ALLOC_SIZE") fixes a size calculation error that prevented
zsmalloc to allocate an object of the maximal size (ZS_MAX_ALLOC_SIZE).
I think however the fix is unneededly complicated.

This patch replaces the dynamic calculation of zs_size_classes at init
time by a compile time calculation that uses the DIV_ROUND_UP() macro
already used in get_size_class_index().

[akpm@linux-foundation.org: use min_t]
Link: http://lkml.kernel.org/r/20170630114859.1979-1-jmarchan@redhat.comSigned-off-by: NJerome Marchand <jmarchan@redhat.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Mahendran Ganesh <opensource.ganesh@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

is_first_page() is only called from the macro VM_BUG_ON_PAGE() which is
only compiled in as a runtime check when CONFIG_DEBUG_VM is set,
otherwise is checked at compile time and not actually compiled in.

Fixes the following warning, found with Clang:

  mm/zsmalloc.c:472:12: warning: function 'is_first_page' is not needed and will not be emitted [-Wunneeded-internal-declaration]
  static int is_first_page(struct page *page)
           ^

Link: http://lkml.kernel.org/r/20170524053859.29059-1-nick.desaulniers@gmail.comSigned-off-by: NNick Desaulniers <nick.desaulniers@gmail.com>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Now 64K page system, zsamlloc has 257 classes so 8 class bit is not
enough.  With that, it corrupts the system when zsmalloc stores
65536byte data(ie, index number 256) so that this patch increases class
bit for simple fix for stable backport.  We should clean up this mess
soon.

  index	size
  0	32
  1	288
  ..
  ..
  204	52256
  256	65536

Fixes: 3783689a ("zsmalloc: introduce zspage structure")
Link: http://lkml.kernel.org/r/1492042622-12074-3-git-send-email-minchan@kernel.orgSigned-off-by: NMinchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Update files that depend on the magic.h inclusion.
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

The class index and fullness group are not encoded in
(first)page->mapping any more, after commit 3783689a ("zsmalloc:
introduce zspage structure").  Instead, they are store in struct zspage.

Just delete this unneeded comment.

Link: http://lkml.kernel.org/r/1486620822-36826-1-git-send-email-xieyisheng1@huawei.comSigned-off-by: NYisheng Xie <xieyisheng1@huawei.com>
Suggested-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We had used page->lru to link the component pages (except the first
page) of a zspage, and used INIT_LIST_HEAD(&page->lru) to init it.
Therefore, to get the last page's next page, which is NULL, we had to
use page flag PG_Private_2 to identify it.

But now, we use page->freelist to link all of the pages in zspage and
init the page->freelist as NULL for last page, so no need to use
PG_Private_2 anymore.

This remove redundant SetPagePrivate2 in create_page_chain and
ClearPagePrivate2 in reset_page().  Save a few cycles for migration of
zsmalloc page :)

Link: http://lkml.kernel.org/r/1487076509-49270-1-git-send-email-xieyisheng1@huawei.comSigned-off-by: NYisheng Xie <xieyisheng1@huawei.com>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Delete extra semicolon, and fix some typos.

Link: http://lkml.kernel.org/r/586F1823.4050107@huawei.comSigned-off-by: NXishi Qiu <qiuxishi@huawei.com>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs.
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: linux-mm@kvack.org
Cc: Minchan Kim <minchan@kernel.org>
Cc: rt@linutronix.de
Cc: Nitin Gupta <ngupta@vflare.org>
Link: http://lkml.kernel.org/r/20161126231350.10321-11-bigeasy@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

iput() tests whether its argument is NULL and then returns immediately.
Thus the test around the call is not needed.

This issue was detected by using the Coccinelle software.

Link: http://lkml.kernel.org/r/559cf499-4a01-25f9-c87f-24d906626a57@users.sourceforge.netSigned-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use ClearPagePrivate/ClearPagePrivate2 helpers to clear
PG_private/PG_private_2 in page->flags

Link: http://lkml.kernel.org/r/1467882338-4300-7-git-send-email-opensource.ganesh@gmail.comSigned-off-by: NGanesh Mahendran <opensource.ganesh@gmail.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add __init,__exit attribute for function that only called in module
init/exit to save memory.

Link: http://lkml.kernel.org/r/1467882338-4300-6-git-send-email-opensource.ganesh@gmail.comSigned-off-by: NGanesh Mahendran <opensource.ganesh@gmail.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Some minor commebnt changes:

 1). update zs_malloc(),zs_create_pool() function header
 2). update "Usage of struct page fields"

Link: http://lkml.kernel.org/r/1467882338-4300-5-git-send-email-opensource.ganesh@gmail.comSigned-off-by: NGanesh Mahendran <opensource.ganesh@gmail.com>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently, if a class can not be merged, the max objects of zspage in
that class may be calculated twice.

This patch calculate max objects of zspage at the begin, and pass the
value to can_merge() to decide whether the class can be merged.

Also this patch remove function get_maxobj_per_zspage(), as there is no
other place to call this function.

Link: http://lkml.kernel.org/r/1467882338-4300-4-git-send-email-opensource.ganesh@gmail.comSigned-off-by: NGanesh Mahendran <opensource.ganesh@gmail.com>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

num of max objects in zspage is stored in each size_class now.  So there
is no need to re-calculate it.

Link: http://lkml.kernel.org/r/1467882338-4300-3-git-send-email-opensource.ganesh@gmail.comSigned-off-by: NGanesh Mahendran <opensource.ganesh@gmail.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

the obj index value should be updated after return from
find_alloced_obj() to avoid CPU burning caused by unnecessary object
scanning.

Link: http://lkml.kernel.org/r/1467882338-4300-2-git-send-email-opensource.ganesh@gmail.comSigned-off-by: NGanesh Mahendran <opensource.ganesh@gmail.com>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is a cleanup patch.  Change "index" to "obj_index" to keep
consistent with others in zsmalloc.

Link: http://lkml.kernel.org/r/1467882338-4300-1-git-send-email-opensource.ganesh@gmail.comSigned-off-by: NGanesh Mahendran <opensource.ganesh@gmail.com>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Randy reported below build error.

> In file included from ../include/linux/balloon_compaction.h:48:0,
>                  from ../mm/balloon_compaction.c:11:
> ../include/linux/compaction.h:237:51: warning: 'struct node' declared inside parameter list [enabled by default]
>  static inline int compaction_register_node(struct node *node)
> ../include/linux/compaction.h:237:51: warning: its scope is only this definition or declaration, which is probably not what you want [enabled by default]
> ../include/linux/compaction.h:242:54: warning: 'struct node' declared inside parameter list [enabled by default]
>  static inline void compaction_unregister_node(struct node *node)
>

It was caused by non-lru page migration which needs compaction.h but
compaction.h doesn't include any header to be standalone.

I think proper header for non-lru page migration is migrate.h rather
than compaction.h because migrate.h has already headers needed to work
non-lru page migration indirectly like isolate_mode_t, migrate_mode
MIGRATEPAGE_SUCCESS.

[akpm@linux-foundation.org: revert mm-balloon-use-general-non-lru-movable-page-feature-fix.patch temp fix]
Link: http://lkml.kernel.org/r/20160610003304.GE29779@bboxSigned-off-by: NMinchan Kim <minchan@kernel.org>
Reported-by: NRandy Dunlap <rdunlap@infradead.org>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Gioh Kim <gi-oh.kim@profitbricks.com>
Cc: Rafael Aquini <aquini@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

zram is very popular for some of the embedded world (e.g., TV, mobile
phones).  On those system, zsmalloc's consumed memory size is never
trivial (one of example from real product system, total memory: 800M,
zsmalloc consumed: 150M), so we have used this out of tree patch to
monitor system memory behavior via /proc/vmstat.

With zsmalloc in vmstat, it helps in tracking down system behavior due
to memory usage.

[minchan@kernel.org: zsmalloc: follow up zsmalloc vmstat]
  Link: http://lkml.kernel.org/r/20160607091737.GC23435@bbox
[akpm@linux-foundation.org: fix build with CONFIG_ZSMALLOC=m]
Link: http://lkml.kernel.org/r/1464919731-13255-1-git-send-email-minchan@kernel.orgSigned-off-by: NMinchan Kim <minchan@kernel.org>
Cc: Sangseok Lee <sangseok.lee@lge.com>
Cc: Chanho Min <chanho.min@lge.com>
Cc: Chan Gyun Jeong <chan.jeong@lge.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Static check warns using tag as bit shifter.  It doesn't break current
working but not good for redability.  Let's use OBJ_TAG_BIT as bit
shifter instead of OBJ_ALLOCATED_TAG.

Link: http://lkml.kernel.org/r/20160607045146.GF26230@bboxSigned-off-by: NMinchan Kim <minchan@kernel.org>
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch introduces run-time migration feature for zspage.

For migration, VM uses page.lru field so it would be better to not use
page.next field which is unified with page.lru for own purpose.  For
that, firstly, we can get first object offset of the page via runtime
calculation instead of using page.index so we can use page.index as link
for page chaining instead of page.next.

In case of huge object, it stores handle to page.index instead of next
link of page chaining because huge object doesn't need to next link for
page chaining.  So get_next_page need to identify huge object to return
NULL.  For it, this patch uses PG_owner_priv_1 flag of the page flag.

For migration, it supports three functions

* zs_page_isolate

It isolates a zspage which includes a subpage VM want to migrate from
class so anyone cannot allocate new object from the zspage.

We could try to isolate a zspage by the number of subpage so subsequent
isolation trial of other subpage of the zpsage shouldn't fail.  For
that, we introduce zspage.isolated count.  With that, zs_page_isolate
can know whether zspage is already isolated or not for migration so if
it is isolated for migration, subsequent isolation trial can be
successful without trying further isolation.

* zs_page_migrate

First of all, it holds write-side zspage->lock to prevent migrate other
subpage in zspage.  Then, lock all objects in the page VM want to
migrate.  The reason we should lock all objects in the page is due to
race between zs_map_object and zs_page_migrate.

  zs_map_object				zs_page_migrate

  pin_tag(handle)
  obj = handle_to_obj(handle)
  obj_to_location(obj, &page, &obj_idx);

					write_lock(&zspage->lock)
					if (!trypin_tag(handle))
						goto unpin_object

  zspage = get_zspage(page);
  read_lock(&zspage->lock);

If zs_page_migrate doesn't do trypin_tag, zs_map_object's page can be
stale by migration so it goes crash.

If it locks all of objects successfully, it copies content from old page
to new one, finally, create new zspage chain with new page.  And if it's
last isolated subpage in the zspage, put the zspage back to class.

* zs_page_putback

It returns isolated zspage to right fullness_group list if it fails to
migrate a page.  If it find a zspage is ZS_EMPTY, it queues zspage
freeing to workqueue.  See below about async zspage freeing.

This patch introduces asynchronous zspage free.  The reason to need it
is we need page_lock to clear PG_movable but unfortunately, zs_free path
should be atomic so the apporach is try to grab page_lock.  If it got
page_lock of all of pages successfully, it can free zspage immediately.
Otherwise, it queues free request and free zspage via workqueue in
process context.

If zs_free finds the zspage is isolated when it try to free zspage, it
delays the freeing until zs_page_putback finds it so it will free free
the zspage finally.

In this patch, we expand fullness_list from ZS_EMPTY to ZS_FULL.  First
of all, it will use ZS_EMPTY list for delay freeing.  And with adding
ZS_FULL list, it makes to identify whether zspage is isolated or not via
list_empty(&zspage->list) test.

[minchan@kernel.org: zsmalloc: keep first object offset in struct page]
  Link: http://lkml.kernel.org/r/1465788015-23195-1-git-send-email-minchan@kernel.org
[minchan@kernel.org: zsmalloc: zspage sanity check]
  Link: http://lkml.kernel.org/r/20160603010129.GC3304@bbox
Link: http://lkml.kernel.org/r/1464736881-24886-12-git-send-email-minchan@kernel.orgSigned-off-by: NMinchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Zsmalloc stores first free object's <PFN, obj_idx> position into freeobj
in each zspage.  If we change it with index from first_page instead of
position, it makes page migration simple because we don't need to
correct other entries for linked list if a page is migrated out.

Link: http://lkml.kernel.org/r/1464736881-24886-11-git-send-email-minchan@kernel.orgSigned-off-by: NMinchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently, putback_zspage does free zspage under class->lock if fullness
become ZS_EMPTY but it makes trouble to implement locking scheme for new
zspage migration.  So, this patch is to separate free_zspage from
putback_zspage and free zspage out of class->lock which is preparation
for zspage migration.

Link: http://lkml.kernel.org/r/1464736881-24886-10-git-send-email-minchan@kernel.orgSigned-off-by: NMinchan Kim <minchan@kernel.org>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We have squeezed meta data of zspage into first page's descriptor.  So,
to get meta data from subpage, we should get first page first of all.
But it makes trouble to implment page migration feature of zsmalloc
because any place where to get first page from subpage can be raced with
first page migration.  IOW, first page it got could be stale.  For
preventing it, I have tried several approahces but it made code
complicated so finally, I concluded to separate metadata from first
page.  Of course, it consumes more memory.  IOW, 16bytes per zspage on
32bit at the moment.  It means we lost 1% at *worst case*(40B/4096B)
which is not bad I think at the cost of maintenance.

Link: http://lkml.kernel.org/r/1464736881-24886-9-git-send-email-minchan@kernel.orgSigned-off-by: NMinchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

For page migration, we need to create page chain of zspage dynamically
so this patch factors it out from alloc_zspage.

Link: http://lkml.kernel.org/r/1464736881-24886-8-git-send-email-minchan@kernel.orgSigned-off-by: NMinchan Kim <minchan@kernel.org>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>