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GFP_TEMPORARY was introduced by commit e12ba74d8ff3 ("Group short-lived
and reclaimable kernel allocations") along with __GFP_RECLAIMABLE. It's
primary motivation was to allow users to tell that an allocation is
short lived and so the allocator can try to place such allocations close
together and prevent long term fragmentation. As much as this sounds
like a reasonable semantic it becomes much less clear when to use the
highlevel GFP_TEMPORARY allocation flag. How long is temporary? Can the
context holding that memory sleep? Can it take locks? It seems there is
no good answer for those questions.
The current implementation of GFP_TEMPORARY is basically GFP_KERNEL |
__GFP_RECLAIMABLE which in itself is tricky because basically none of
the existing caller provide a way to reclaim the allocated memory. So
this is rather misleading and hard to evaluate for any benefits.
I have checked some random users and none of them has added the flag
with a specific justification. I suspect most of them just copied from
other existing users and others just thought it might be a good idea to
use without any measuring. This suggests that GFP_TEMPORARY just
motivates for cargo cult usage without any reasoning.
I believe that our gfp flags are quite complex already and especially
those with highlevel semantic should be clearly defined to prevent from
confusion and abuse. Therefore I propose dropping GFP_TEMPORARY and
replace all existing users to simply use GFP_KERNEL. Please note that
SLAB users with shrinkers will still get __GFP_RECLAIMABLE heuristic and
so they will be placed properly for memory fragmentation prevention.
I can see reasons we might want some gfp flag to reflect shorterm
allocations but I propose starting from a clear semantic definition and
only then add users with proper justification.
This was been brought up before LSF this year by Matthew [1] and it
turned out that GFP_TEMPORARY really doesn't have a clear semantic. It
seems to be a heuristic without any measured advantage for most (if not
all) its current users. The follow up discussion has revealed that
opinions on what might be temporary allocation differ a lot between
developers. So rather than trying to tweak existing users into a
semantic which they haven't expected I propose to simply remove the flag
and start from scratch if we really need a semantic for short term
allocations.
[1] http://lkml.kernel.org/r/20170118054945.GD18349@bombadil.infradead.org
[akpm@linux-foundation.org: fix typo]
[akpm@linux-foundation.org: coding-style fixes]
[sfr@canb.auug.org.au: drm/i915: fix up]
Link: http://lkml.kernel.org/r/20170816144703.378d4f4d@canb.auug.org.au
Link: http://lkml.kernel.org/r/20170728091904.14627-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Neil Brown <neilb@suse.de>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Pull block fixes from Jens Axboe:
"Small collection of fixes that would be nice to have in -rc1. This
contains:
- NVMe pull request form Christoph, mostly with fixes for nvme-pci,
host memory buffer in particular.
- Error handling fixup for cgwb_create(), in case allocation of 'wb'
fails. From Christophe Jaillet.
- Ensure that trace_block_getrq() gets the 'dev' in an appropriate
fashion, to avoid a potential NULL deref. From Greg Thelen.
- Regression fix for dm-mq with blk-mq, fixing a problem with
stacking IO schedulers. From me.
- string.h fixup, fixing an issue with memcpy_and_pad(). This
original change came in through an NVMe dependency, which is why
I'm including it here. From Martin Wilck.
- Fix potential int overflow in __blkdev_sectors_to_bio_pages(), from
Mikulas.
- MBR enable fix for sed-opal, from Scott"
* 'for-linus' of git://git.kernel.dk/linux-block:
block: directly insert blk-mq request from blk_insert_cloned_request()
mm/backing-dev.c: fix an error handling path in 'cgwb_create()'
string.h: un-fortify memcpy_and_pad
nvme-pci: implement the HMB entry number and size limitations
nvme-pci: propagate (some) errors from host memory buffer setup
nvme-pci: use appropriate initial chunk size for HMB allocation
nvme-pci: fix host memory buffer allocation fallback
nvme: fix lightnvm check
block: fix integer overflow in __blkdev_sectors_to_bio_pages()
block: sed-opal: Set MBRDone on S3 resume path if TPER is MBREnabled
block: tolerate tracing of NULL bio
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git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs
Pull f2fs updates from Jaegeuk Kim:
"In this round, we've mostly tuned f2fs to provide better user
experience for Android. Especially, we've worked on atomic write
feature again with SQLite community in order to support it officially.
And we added or modified several facilities to analyze and enhance IO
behaviors.
Major changes include:
- add app/fs io stat
- add inode checksum feature
- support project/journalled quota
- enhance atomic write with new ioctl() which exposes feature set
- enhance background gc/discard/fstrim flows with new gc_urgent mode
- add F2FS_IOC_FS{GET,SET}XATTR
- fix some quota flows"
* tag 'f2fs-for-4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (63 commits)
f2fs: hurry up to issue discard after io interruption
f2fs: fix to show correct discard_granularity in sysfs
f2fs: detect dirty inode in evict_inode
f2fs: clear radix tree dirty tag of pages whose dirty flag is cleared
f2fs: speed up gc_urgent mode with SSR
f2fs: better to wait for fstrim completion
f2fs: avoid race in between read xattr & write xattr
f2fs: make get_lock_data_page to handle encrypted inode
f2fs: use generic terms used for encrypted block management
f2fs: introduce f2fs_encrypted_file for clean-up
Revert "f2fs: add a new function get_ssr_cost"
f2fs: constify super_operations
f2fs: fix to wake up all sleeping flusher
f2fs: avoid race in between atomic_read & atomic_inc
f2fs: remove unneeded parameter of change_curseg
f2fs: update i_flags correctly
f2fs: don't check inode's checksum if it was dirtied or writebacked
f2fs: don't need to update inode checksum for recovery
f2fs: trigger fdatasync for non-atomic_write file
f2fs: fix to avoid race in between aio and gc
...
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__get_request() can call trace_block_getrq() with bio=NULL which causes
block_get_rq::TP_fast_assign() to deref a NULL pointer and panic.
Syzkaller fuzzer panics with
linux-next (1d53d908b79d7870d89063062584eead4cf83448):
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
Modules linked in:
CPU: 0 PID: 2983 Comm: syzkaller401111 Not tainted 4.13.0-rc7-next-20170901+ #13
task: ffff8801cf1da000 task.stack: ffff8801ce440000
RIP: 0010:perf_trace_block_get_rq+0x697/0x970 include/trace/events/block.h:384
RSP: 0018:ffff8801ce4473f0 EFLAGS: 00010246
RAX: ffff8801cf1da000 RBX: 1ffff10039c88e84 RCX: 1ffffd1ffff84d27
RDX: dffffc0000000001 RSI: 1ffff1003b643e7a RDI: ffffe8ffffc26938
RBP: ffff8801ce447530 R08: 1ffff1003b643e6c R09: ffffe8ffffc26964
R10: 0000000000000002 R11: fffff91ffff84d2d R12: ffffe8ffffc1f890
R13: ffffe8ffffc26930 R14: ffffffff85cad9e0 R15: 0000000000000000
FS: 0000000002641880(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000043e670 CR3: 00000001d1d7a000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
trace_block_getrq include/trace/events/block.h:423 [inline]
__get_request block/blk-core.c:1283 [inline]
get_request+0x1518/0x23b0 block/blk-core.c:1355
blk_old_get_request block/blk-core.c:1402 [inline]
blk_get_request+0x1d8/0x3c0 block/blk-core.c:1427
sg_scsi_ioctl+0x117/0x750 block/scsi_ioctl.c:451
sg_ioctl+0x192d/0x2ed0 drivers/scsi/sg.c:1070
vfs_ioctl fs/ioctl.c:45 [inline]
do_vfs_ioctl+0x1b1/0x1530 fs/ioctl.c:685
SYSC_ioctl fs/ioctl.c:700 [inline]
SyS_ioctl+0x8f/0xc0 fs/ioctl.c:691
entry_SYSCALL_64_fastpath+0x1f/0xbe
block_get_rq::TP_fast_assign() has multiple redundant ->dev assignments.
Only one of them is NULL tolerant. Favor the NULL tolerant one.
Fixes: 74d46992e0d9 ("block: replace bi_bdev with a gendisk pointer and partitions index")
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Thelen <gthelen@google.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs updates from David Sterba:
"The changes range through all types: cleanups, core chagnes, sanity
checks, fixes, other user visible changes, detailed list below:
- deprecated: user transaction ioctl
- mount option ssd does not change allocation alignments
- degraded read-write mount is allowed if all the raid profile
constraints are met, now based on more accurate check
- defrag: do not reset compression afterwards; the NOCOMPRESS flag
can be now overriden by defrag
- prep work for better extent reference tracking (related to the
qgroup slowness with balance)
- prep work for compression heuristics
- memory allocation reductions (may help latencies on a loaded
system)
- better accounting for io waiting states
- error handling improvements (removed BUGs)
- added more sanity checks for shared refs
- fix readdir vs pagefault deadlock under some circumstances
- fix for 'no-hole' mode, certain combination of compressed and
inline extents
- send: fix emission of invalid clone operations
- fixup file mode if setting acls fail
- more fixes from fuzzing
- oher cleanups"
* 'for-4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (104 commits)
btrfs: submit superblock io with REQ_META and REQ_PRIO
btrfs: remove unnecessary memory barrier in btrfs_direct_IO
btrfs: remove superfluous chunk_tree argument from btrfs_alloc_dev_extent
btrfs: Remove chunk_objectid parameter of btrfs_alloc_dev_extent
btrfs: pass fs_info to btrfs_del_root instead of tree_root
Btrfs: add one more sanity check for shared ref type
Btrfs: remove BUG_ON in __add_tree_block
Btrfs: remove BUG() in add_data_reference
Btrfs: remove BUG() in print_extent_item
Btrfs: remove BUG() in btrfs_extent_inline_ref_size
Btrfs: convert to use btrfs_get_extent_inline_ref_type
Btrfs: add a helper to retrive extent inline ref type
btrfs: scrub: simplify scrub worker initialization
btrfs: scrub: clean up division in scrub_find_csum
btrfs: scrub: clean up division in __scrub_mark_bitmap
btrfs: scrub: use bool for flush_all_writes
btrfs: preserve i_mode if __btrfs_set_acl() fails
btrfs: Remove extraneous chunk_objectid variable
btrfs: Remove chunk_objectid argument from btrfs_make_block_group
btrfs: Remove extra parentheses from condition in copy_items()
...
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Pull MMC updates from Ulf Hansson:
"MMC core:
- Continue to refactor the mmc block code to prepare for blkmq
- Move mmc block debugfs into block module
- Next step for eMMC CMDQ by adding a new mmc host interface for it
- Move Kconfig option MMC_DEBUG from core to host
- Some additional minor improvements
MMC host:
- Declare structs as const when applicable
- Explicitly request exclusive reset control when applicable
- Improve some error paths and other various cleanups
- sdhci: Preparations to support SDHCI OMAP
- sdhci: Improve some PM related code
- sdhci: Re-factoring and modernizations
- sdhci-xenon: Add runtime PM and system sleep support
- sdhci-xenon: Add support for eMMC HS400 Enhanced Strobe
- sdhci-cadence: Add system sleep support
- sdhci-of-at91: Improve system sleep support
- dw_mmc: Add support for Hisilicon hi3660
- sunxi: Add support for A83T eMMC
- sunxi: Add support for DDR52 mode
- meson-gx: Add support for UHS-I SD-cards
- meson-gx: Cleanups and improvements
- tmio: Fix CMD12 (STOP) handling
- tmio: Cleanups and improvements
- renesas_sdhi: Add r8a7743/5 support
- renesas-sdhi: Add support for R-Car Gen3 SDHI DMAC
- renesas_sdhi: Cleanups and improvements"
* tag 'mmc-v4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc: (145 commits)
mmc: renesas_sdhi: Add r8a7743/5 support
mmc: meson-gx: fix __ffsdi2 undefined on arm32
mmc: sdhci-xenon: add runtime pm support and reimplement standby
mmc: core: Move mmc_start_areq() declaration
mmc: mmci: stop building qcom dml as module
mmc: sunxi: Reset the device at probe time
clk: sunxi-ng: Provide a default reset hook
mmc: meson-gx: rework tuning function
mmc: meson-gx: change default tx phase
mmc: meson-gx: implement voltage switch callback
mmc: meson-gx: use CCF to handle the clock phases
mmc: meson-gx: implement card_busy callback
mmc: meson-gx: simplify interrupt handler
mmc: meson-gx: work around clk-stop issue
mmc: meson-gx: fix dual data rate mode frequencies
mmc: meson-gx: rework clock init function
mmc: meson-gx: rework clk_set function
mmc: meson-gx: rework set_ios function
mmc: meson-gx: cfg init overwrite values
mmc: meson-gx: initialize sane clk default before clock register
...
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Pull block layer updates from Jens Axboe:
"This is the first pull request for 4.14, containing most of the code
changes. It's a quiet series this round, which I think we needed after
the churn of the last few series. This contains:
- Fix for a registration race in loop, from Anton Volkov.
- Overflow complaint fix from Arnd for DAC960.
- Series of drbd changes from the usual suspects.
- Conversion of the stec/skd driver to blk-mq. From Bart.
- A few BFQ improvements/fixes from Paolo.
- CFQ improvement from Ritesh, allowing idling for group idle.
- A few fixes found by Dan's smatch, courtesy of Dan.
- A warning fixup for a race between changing the IO scheduler and
device remova. From David Jeffery.
- A few nbd fixes from Josef.
- Support for cgroup info in blktrace, from Shaohua.
- Also from Shaohua, new features in the null_blk driver to allow it
to actually hold data, among other things.
- Various corner cases and error handling fixes from Weiping Zhang.
- Improvements to the IO stats tracking for blk-mq from me. Can
drastically improve performance for fast devices and/or big
machines.
- Series from Christoph removing bi_bdev as being needed for IO
submission, in preparation for nvme multipathing code.
- Series from Bart, including various cleanups and fixes for switch
fall through case complaints"
* 'for-4.14/block' of git://git.kernel.dk/linux-block: (162 commits)
kernfs: checking for IS_ERR() instead of NULL
drbd: remove BIOSET_NEED_RESCUER flag from drbd_{md_,}io_bio_set
drbd: Fix allyesconfig build, fix recent commit
drbd: switch from kmalloc() to kmalloc_array()
drbd: abort drbd_start_resync if there is no connection
drbd: move global variables to drbd namespace and make some static
drbd: rename "usermode_helper" to "drbd_usermode_helper"
drbd: fix race between handshake and admin disconnect/down
drbd: fix potential deadlock when trying to detach during handshake
drbd: A single dot should be put into a sequence.
drbd: fix rmmod cleanup, remove _all_ debugfs entries
drbd: Use setup_timer() instead of init_timer() to simplify the code.
drbd: fix potential get_ldev/put_ldev refcount imbalance during attach
drbd: new disk-option disable-write-same
drbd: Fix resource role for newly created resources in events2
drbd: mark symbols static where possible
drbd: Send P_NEG_ACK upon write error in protocol != C
drbd: add explicit plugging when submitting batches
drbd: change list_for_each_safe to while(list_first_entry_or_null)
drbd: introduce drbd_recv_header_maybe_unplug
...
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git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen updates from Juergen Gross:
- the new pvcalls backend for routing socket calls from a guest to dom0
- some cleanups of Xen code
- a fix for wrong usage of {get,put}_cpu()
* tag 'for-linus-4.14b-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (27 commits)
xen/mmu: set MMU_NORMAL_PT_UPDATE in remap_area_mfn_pte_fn
xen: Don't try to call xen_alloc_p2m_entry() on autotranslating guests
xen/events: events_fifo: Don't use {get,put}_cpu() in xen_evtchn_fifo_init()
xen/pvcalls: use WARN_ON(1) instead of __WARN()
xen: remove not used trace functions
xen: remove unused function xen_set_domain_pte()
xen: remove tests for pvh mode in pure pv paths
xen-platform: constify pci_device_id.
xen: cleanup xen.h
xen: introduce a Kconfig option to enable the pvcalls backend
xen/pvcalls: implement write
xen/pvcalls: implement read
xen/pvcalls: implement the ioworker functions
xen/pvcalls: disconnect and module_exit
xen/pvcalls: implement release command
xen/pvcalls: implement poll command
xen/pvcalls: implement accept command
xen/pvcalls: implement listen command
xen/pvcalls: implement bind command
xen/pvcalls: implement connect command
...
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Merge updates from Andrew Morton:
- various misc bits
- DAX updates
- OCFS2
- most of MM
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (119 commits)
mm,fork: introduce MADV_WIPEONFORK
x86,mpx: make mpx depend on x86-64 to free up VMA flag
mm: add /proc/pid/smaps_rollup
mm: hugetlb: clear target sub-page last when clearing huge page
mm: oom: let oom_reap_task and exit_mmap run concurrently
swap: choose swap device according to numa node
mm: replace TIF_MEMDIE checks by tsk_is_oom_victim
mm, oom: do not rely on TIF_MEMDIE for memory reserves access
z3fold: use per-cpu unbuddied lists
mm, swap: don't use VMA based swap readahead if HDD is used as swap
mm, swap: add sysfs interface for VMA based swap readahead
mm, swap: VMA based swap readahead
mm, swap: fix swap readahead marking
mm, swap: add swap readahead hit statistics
mm/vmalloc.c: don't reinvent the wheel but use existing llist API
mm/vmstat.c: fix wrong comment
selftests/memfd: add memfd_create hugetlbfs selftest
mm/shmem: add hugetlbfs support to memfd_create()
mm, devm_memremap_pages: use multi-order radix for ZONE_DEVICE lookups
mm/vmalloc.c: halve the number of comparisons performed in pcpu_get_vm_areas()
...
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Introduce MADV_WIPEONFORK semantics, which result in a VMA being empty
in the child process after fork. This differs from MADV_DONTFORK in one
important way.
If a child process accesses memory that was MADV_WIPEONFORK, it will get
zeroes. The address ranges are still valid, they are just empty.
If a child process accesses memory that was MADV_DONTFORK, it will get a
segmentation fault, since those address ranges are no longer valid in
the child after fork.
Since MADV_DONTFORK also seems to be used to allow very large programs
to fork in systems with strict memory overcommit restrictions, changing
the semantics of MADV_DONTFORK might break existing programs.
MADV_WIPEONFORK only works on private, anonymous VMAs.
The use case is libraries that store or cache information, and want to
know that they need to regenerate it in the child process after fork.
Examples of this would be:
- systemd/pulseaudio API checks (fail after fork) (replacing a getpid
check, which is too slow without a PID cache)
- PKCS#11 API reinitialization check (mandated by specification)
- glibc's upcoming PRNG (reseed after fork)
- OpenSSL PRNG (reseed after fork)
The security benefits of a forking server having a re-inialized PRNG in
every child process are pretty obvious. However, due to libraries
having all kinds of internal state, and programs getting compiled with
many different versions of each library, it is unreasonable to expect
calling programs to re-initialize everything manually after fork.
A further complication is the proliferation of clone flags, programs
bypassing glibc's functions to call clone directly, and programs calling
unshare, causing the glibc pthread_atfork hook to not get called.
It would be better to have the kernel take care of this automatically.
The patch also adds MADV_KEEPONFORK, to undo the effects of a prior
MADV_WIPEONFORK.
This is similar to the OpenBSD minherit syscall with MAP_INHERIT_ZERO:
https://man.openbsd.org/minherit.2
[akpm@linux-foundation.org: numerically order arch/parisc/include/uapi/asm/mman.h #defines]
Link: http://lkml.kernel.org/r/20170811212829.29186-3-riel@redhat.com
Signed-off-by: Rik van Riel <riel@redhat.com>
Reported-by: Florian Weimer <fweimer@redhat.com>
Reported-by: Colm MacCártaigh <colm@allcosts.net>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Drewry <wad@chromium.org>
Cc: <linux-api@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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When servicing mmap() reads from file holes the current DAX code
allocates a page cache page of all zeroes and places the struct page
pointer in the mapping->page_tree radix tree.
This has three major drawbacks:
1) It consumes memory unnecessarily. For every 4k page that is read via
a DAX mmap() over a hole, we allocate a new page cache page. This
means that if you read 1GiB worth of pages, you end up using 1GiB of
zeroed memory. This is easily visible by looking at the overall
memory consumption of the system or by looking at /proc/[pid]/smaps:
7f62e72b3000-7f63272b3000 rw-s 00000000 103:00 12 /root/dax/data
Size: 1048576 kB
Rss: 1048576 kB
Pss: 1048576 kB
Shared_Clean: 0 kB
Shared_Dirty: 0 kB
Private_Clean: 1048576 kB
Private_Dirty: 0 kB
Referenced: 1048576 kB
Anonymous: 0 kB
LazyFree: 0 kB
AnonHugePages: 0 kB
ShmemPmdMapped: 0 kB
Shared_Hugetlb: 0 kB
Private_Hugetlb: 0 kB
Swap: 0 kB
SwapPss: 0 kB
KernelPageSize: 4 kB
MMUPageSize: 4 kB
Locked: 0 kB
2) It is slower than using a common zero page because each page fault
has more work to do. Instead of just inserting a common zero page we
have to allocate a page cache page, zero it, and then insert it. Here
are the average latencies of dax_load_hole() as measured by ftrace on
a random test box:
Old method, using zeroed page cache pages: 3.4 us
New method, using the common 4k zero page: 0.8 us
This was the average latency over 1 GiB of sequential reads done by
this simple fio script:
[global]
size=1G
filename=/root/dax/data
fallocate=none
[io]
rw=read
ioengine=mmap
3) The fact that we had to check for both DAX exceptional entries and
for page cache pages in the radix tree made the DAX code more
complex.
Solve these issues by following the lead of the DAX PMD code and using a
common 4k zero page instead. As with the PMD code we will now insert a
DAX exceptional entry into the radix tree instead of a struct page
pointer which allows us to remove all the special casing in the DAX
code.
Note that we do still pretty aggressively check for regular pages in the
DAX radix tree, especially where we take action based on the bits set in
the page. If we ever find a regular page in our radix tree now that
most likely means that someone besides DAX is inserting pages (which has
happened lots of times in the past), and we want to find that out early
and fail loudly.
This solution also removes the extra memory consumption. Here is that
same /proc/[pid]/smaps after 1GiB of reading from a hole with the new
code:
7f2054a74000-7f2094a74000 rw-s 00000000 103:00 12 /root/dax/data
Size: 1048576 kB
Rss: 0 kB
Pss: 0 kB
Shared_Clean: 0 kB
Shared_Dirty: 0 kB
Private_Clean: 0 kB
Private_Dirty: 0 kB
Referenced: 0 kB
Anonymous: 0 kB
LazyFree: 0 kB
AnonHugePages: 0 kB
ShmemPmdMapped: 0 kB
Shared_Hugetlb: 0 kB
Private_Hugetlb: 0 kB
Swap: 0 kB
SwapPss: 0 kB
KernelPageSize: 4 kB
MMUPageSize: 4 kB
Locked: 0 kB
Overall system memory consumption is similarly improved.
Another major change is that we remove dax_pfn_mkwrite() from our fault
flow, and instead rely on the page fault itself to make the PTE dirty
and writeable. The following description from the patch adding the
vm_insert_mixed_mkwrite() call explains this a little more:
"To be able to use the common 4k zero page in DAX we need to have our
PTE fault path look more like our PMD fault path where a PTE entry
can be marked as dirty and writeable as it is first inserted rather
than waiting for a follow-up dax_pfn_mkwrite() =>
finish_mkwrite_fault() call.
Right now we can rely on having a dax_pfn_mkwrite() call because we
can distinguish between these two cases in do_wp_page():
case 1: 4k zero page => writable DAX storage
case 2: read-only DAX storage => writeable DAX storage
This distinction is made by via vm_normal_page(). vm_normal_page()
returns false for the common 4k zero page, though, just as it does
for DAX ptes. Instead of special casing the DAX + 4k zero page case
we will simplify our DAX PTE page fault sequence so that it matches
our DAX PMD sequence, and get rid of the dax_pfn_mkwrite() helper.
We will instead use dax_iomap_fault() to handle write-protection
faults.
This means that insert_pfn() needs to follow the lead of
insert_pfn_pmd() and allow us to pass in a 'mkwrite' flag. If
'mkwrite' is set insert_pfn() will do the work that was previously
done by wp_page_reuse() as part of the dax_pfn_mkwrite() call path"
Link: http://lkml.kernel.org/r/20170724170616.25810-4-ross.zwisler@linux.intel.com
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Pull networking updates from David Miller:
1) Support ipv6 checksum offload in sunvnet driver, from Shannon
Nelson.
2) Move to RB-tree instead of custom AVL code in inetpeer, from Eric
Dumazet.
3) Allow generic XDP to work on virtual devices, from John Fastabend.
4) Add bpf device maps and XDP_REDIRECT, which can be used to build
arbitrary switching frameworks using XDP. From John Fastabend.
5) Remove UFO offloads from the tree, gave us little other than bugs.
6) Remove the IPSEC flow cache, from Florian Westphal.
7) Support ipv6 route offload in mlxsw driver.
8) Support VF representors in bnxt_en, from Sathya Perla.
9) Add support for forward error correction modes to ethtool, from
Vidya Sagar Ravipati.
10) Add time filter for packet scheduler action dumping, from Jamal Hadi
Salim.
11) Extend the zerocopy sendmsg() used by virtio and tap to regular
sockets via MSG_ZEROCOPY. From Willem de Bruijn.
12) Significantly rework value tracking in the BPF verifier, from Edward
Cree.
13) Add new jump instructions to eBPF, from Daniel Borkmann.
14) Rework rtnetlink plumbing so that operations can be run without
taking the RTNL semaphore. From Florian Westphal.
15) Support XDP in tap driver, from Jason Wang.
16) Add 32-bit eBPF JIT for ARM, from Shubham Bansal.
17) Add Huawei hinic ethernet driver.
18) Allow to report MD5 keys in TCP inet_diag dumps, from Ivan
Delalande.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1780 commits)
i40e: point wb_desc at the nvm_wb_desc during i40e_read_nvm_aq
i40e: avoid NVM acquire deadlock during NVM update
drivers: net: xgene: Remove return statement from void function
drivers: net: xgene: Configure tx/rx delay for ACPI
drivers: net: xgene: Read tx/rx delay for ACPI
rocker: fix kcalloc parameter order
rds: Fix non-atomic operation on shared flag variable
net: sched: don't use GFP_KERNEL under spin lock
vhost_net: correctly check tx avail during rx busy polling
net: mdio-mux: add mdio_mux parameter to mdio_mux_init()
rxrpc: Make service connection lookup always check for retry
net: stmmac: Delete dead code for MDIO registration
gianfar: Fix Tx flow control deactivation
cxgb4: Ignore MPS_TX_INT_CAUSE[Bubble] for T6
cxgb4: Fix pause frame count in t4_get_port_stats
cxgb4: fix memory leak
tun: rename generic_xdp to skb_xdp
tun: reserve extra headroom only when XDP is set
net: dsa: bcm_sf2: Configure IMP port TC2QOS mapping
net: dsa: bcm_sf2: Advertise number of egress queues
...
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This extends bridge fdb table tracepoints to also cover
learned fdb entries in the br_fdb_update path. Note that
unlike other tracepoints I have moved this to when the fdb
is modified because this is in the datapath and can generate
a lot of noise in the trace output. br_fdb_update is also called
from added_by_user context in the NTF_USE case which is already
traced ..hence the !added_by_user check.
Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Acked-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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There are some Xen specific trace functions defined in
include/trace/events/xen.h. Remove them.
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
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The function xen_set_domain_pte() is used nowhere in the kernel.
Remove it.
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
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Most of the information needed to issue requests to a CQE is already in
struct mmc_request and struct mmc_data. Add data block address, some flags,
and the task id (tag), and allow for cmd being NULL which it is for CQE
tasks.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
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A few useful tracepoints to trace bridge forwarding
database updates.
Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Creating as specific xdp_redirect_map variant of the xdp tracepoints
allow users to write simpler/faster BPF progs that get attached to
these tracepoints.
Goal is to still keep the tracepoints in xdp_redirect and xdp_redirect_map
similar enough, that a tool can read the top part of the TP_STRUCT and
produce similar monitor statistics.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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There is a need to separate the xdp_redirect tracepoint into two
tracepoints, for separating the error case from the normal forward
case.
Due to the extreme speeds XDP is operating at, loading a tracepoint
have a measurable impact. Single core XDP REDIRECT (ethtool tuned
rx-usecs 25) can do 13.7 Mpps forwarding, but loading a simple
bpf_prog at the tracepoint (with a return 0) reduce perf to 10.2 Mpps
(CPU E5-1650 v4 @ 3.60GHz, driver: ixgbe)
The overhead of loading a bpf-based tracepoint can be calculated to
cost 25 nanosec ((1/13782002-1/10267937)*10^9 = -24.83 ns).
Using perf record on the tracepoint event, with a non-matching --filter
expression, the overhead is much larger. Performance drops to 8.3 Mpps,
cost 48 nanosec ((1/13782002-1/8312497)*10^9 = -47.74))
Having a separate tracepoint for err cases, which should be less
frequent, allow running a continuous monitor for errors while not
affecting the redirect forward performance (this have also been
verified by measurements).
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Given previous patch expose the map_id, it seems natural to also
report the bpf prog id.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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To make sense of the map index, the tracepoint user also need to know
that map we are talking about. Supply the map pointer but only expose
the map->id.
The 'to_index' is renamed 'to_ifindex'. In the xdp_redirect_map case,
this is the result of the devmap lookup. The map lookup key is exposed
as map_index, which is needed to troubleshoot in case the lookup failed.
The 'to_ifindex' is placed after 'err' to keep TP_STRUCT as common as
possible.
This also keeps the TP_STRUCT similar enough, that userspace can write
a monitor program, that doesn't need to care about whether
bpf_redirect or bpf_redirect_map were used.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Supplying the action argument XDP_REDIRECT to the tracepoint xdp_redirect
is redundant as it is only called in-case this action was specified.
Remove the argument, but keep "act" member of the tracepoint struct and
populate it with XDP_REDIRECT. This makes it easier to write a common bpf_prog
processing events.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Remove the net_device string name from the xdp_exception tracepoint,
like the xdp_redirect tracepoint.
Align the TP_STRUCT to have common entries between these two
tracepoint.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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There is too much overhead in the current trace_xdp_redirect
tracepoint as it does strcpy and strlen on the net_device names.
Besides, exposing the ifindex/index is actually the information that
is needed in the tracepoint to diagnose issues. When a lookup fails
(either ifindex or devmap index) then there is a need for saying which
to_index that have issues.
V2: Adjust args to be aligned with trace_xdp_exception.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This way we don't need a block_device structure to submit I/O. The
block_device has different life time rules from the gendisk and
request_queue and is usually only available when the block device node
is open. Other callers need to explicitly create one (e.g. the lightnvm
passthrough code, or the new nvme multipathing code).
For the actual I/O path all that we need is the gendisk, which exists
once per block device. But given that the block layer also does
partition remapping we additionally need a partition index, which is
used for said remapping in generic_make_request.
Note that all the block drivers generally want request_queue or
sometimes the gendisk, so this removes a layer of indirection all
over the stack.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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This patch adds tracepoint for f2fs_gc.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu
Pull RCU updates from Paul E. McKenney:
- Removal of spin_unlock_wait()
- SRCU updates
- Torture-test updates
- Documentation updates
- Miscellaneous fixes
- CPU-hotplug fixes
- Miscellaneous non-RCU fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The return error code need to be included in the tracepoint
xdp:xdp_redirect, else its not possible to distinguish successful or
failed XDP_REDIRECT transmits.
XDP have no queuing mechanism. Thus, it is fairly easily to overrun a
NIC transmit queue. The eBPF program invoking helpers (bpf_redirect
or bpf_redirect_map) to redirect a packet doesn't get any feedback
whether the packet was actually transmitted.
Info on failed transmits in the tracepoint xdp:xdp_redirect, is
interesting as this opens for providing a feedback-loop to the
receiving XDP program.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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We have define for FSID size so use it.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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The main purpose of this tracepoint is to monitor bulk dequeue
in the network qdisc layer, as it cannot be deducted from the
existing qdisc stats.
The txq_state can be used for determining the reason for zero packet
dequeues, see enum netdev_queue_state_t.
Notice all packets doesn't necessary activate this tracepoint. As
qdiscs with flag TCQ_F_CAN_BYPASS, can directly invoke
sch_direct_xmit() when qdisc_qlen is zero.
Remember that perf record supports filters like:
perf record -e qdisc:qdisc_dequeue \
--filter 'ifindex == 4 && (packets > 1 || txq_state > 0)'
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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All callers of flush_space pass the same number for orig/num_bytes
arguments. Let's remove one of the numbers and also modify the trace
point to show only a single number - bytes requested.
Seems that last point where the two parameters were treated differently
is before the ticketed enospc rework.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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This patch adds a tracepoint event for prelim_ref insertion and
merging. For each, the ref being inserted or merged and the count
of tree nodes is issued.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Tracepoint arguments are all read-only. If we mark the arguments
as const, we're able to keep or convert those arguments to const
where appropriate.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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While comparing signed and unsigned variables, compiler will converts the
signed value to unsigned one, due to this reason, {in,de}crease_sleep_time
may return overflowed result.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/mellanox/linux
Saeed Mahameed says:
====================
mlx5-shared-2017-08-07
This series includes some mlx5 updates for both net-next and rdma trees.
From Saeed,
Core driver updates to allow selectively building the driver with
or without some large driver components, such as
- E-Switch (Ethernet SRIOV support).
- Multi-Physical Function Switch (MPFs) support.
For that we split E-Switch and MPFs functionalities into separate files.
From Erez,
Delay mlx5_core events when mlx5 interfaces, namely mlx5_ib, registration
is taking place and until it completes.
From Rabie,
Increase the maximum supported flow counters.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
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Two variables in ext4_inode_info, i_reserved_meta_blocks and
i_allocated_meta_blocks, are unused. Removing them saves a little
memory per in-memory inode and cleans up clutter in several tracepoints.
Adjust tracepoint output from ext4_alloc_da_blocks() for consistency
and fix a typo and whitespace near these changes.
Signed-off-by: Eric Whitney <enwlinux@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
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inode number and generation can identify a kernfs node. We are going to
export the identification by exportfs operations, so put ino and
generation into a separate structure. It's convenient when later patches
use the identification.
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
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Strings used in event tracing need to be specially handled, for example,
being copied to the trace buffer instead of being pointed to by the trace
buffer. Although the TPS() macro can be used to "launder" pointed-to
strings, this might not be all that effective within a loadable module.
This commit therefore copies rcutorture's strings to the trace buffer.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
|
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|
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This adds a trace event for xdp redirect which may help when debugging
XDP programs that use redirect bpf commands.
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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semantic
__GFP_REPEAT was designed to allow retry-but-eventually-fail semantic to
the page allocator. This has been true but only for allocations
requests larger than PAGE_ALLOC_COSTLY_ORDER. It has been always
ignored for smaller sizes. This is a bit unfortunate because there is
no way to express the same semantic for those requests and they are
considered too important to fail so they might end up looping in the
page allocator for ever, similarly to GFP_NOFAIL requests.
Now that the whole tree has been cleaned up and accidental or misled
usage of __GFP_REPEAT flag has been removed for !costly requests we can
give the original flag a better name and more importantly a more useful
semantic. Let's rename it to __GFP_RETRY_MAYFAIL which tells the user
that the allocator would try really hard but there is no promise of a
success. This will work independent of the order and overrides the
default allocator behavior. Page allocator users have several levels of
guarantee vs. cost options (take GFP_KERNEL as an example)
- GFP_KERNEL & ~__GFP_RECLAIM - optimistic allocation without _any_
attempt to free memory at all. The most light weight mode which even
doesn't kick the background reclaim. Should be used carefully because
it might deplete the memory and the next user might hit the more
aggressive reclaim
- GFP_KERNEL & ~__GFP_DIRECT_RECLAIM (or GFP_NOWAIT)- optimistic
allocation without any attempt to free memory from the current
context but can wake kswapd to reclaim memory if the zone is below
the low watermark. Can be used from either atomic contexts or when
the request is a performance optimization and there is another
fallback for a slow path.
- (GFP_KERNEL|__GFP_HIGH) & ~__GFP_DIRECT_RECLAIM (aka GFP_ATOMIC) -
non sleeping allocation with an expensive fallback so it can access
some portion of memory reserves. Usually used from interrupt/bh
context with an expensive slow path fallback.
- GFP_KERNEL - both background and direct reclaim are allowed and the
_default_ page allocator behavior is used. That means that !costly
allocation requests are basically nofail but there is no guarantee of
that behavior so failures have to be checked properly by callers
(e.g. OOM killer victim is allowed to fail currently).
- GFP_KERNEL | __GFP_NORETRY - overrides the default allocator behavior
and all allocation requests fail early rather than cause disruptive
reclaim (one round of reclaim in this implementation). The OOM killer
is not invoked.
- GFP_KERNEL | __GFP_RETRY_MAYFAIL - overrides the default allocator
behavior and all allocation requests try really hard. The request
will fail if the reclaim cannot make any progress. The OOM killer
won't be triggered.
- GFP_KERNEL | __GFP_NOFAIL - overrides the default allocator behavior
and all allocation requests will loop endlessly until they succeed.
This might be really dangerous especially for larger orders.
Existing users of __GFP_REPEAT are changed to __GFP_RETRY_MAYFAIL
because they already had their semantic. No new users are added.
__alloc_pages_slowpath is changed to bail out for __GFP_RETRY_MAYFAIL if
there is no progress and we have already passed the OOM point.
This means that all the reclaim opportunities have been exhausted except
the most disruptive one (the OOM killer) and a user defined fallback
behavior is more sensible than keep retrying in the page allocator.
[akpm@linux-foundation.org: fix arch/sparc/kernel/mdesc.c]
[mhocko@suse.com: semantic fix]
Link: http://lkml.kernel.org/r/20170626123847.GM11534@dhcp22.suse.cz
[mhocko@kernel.org: address other thing spotted by Vlastimil]
Link: http://lkml.kernel.org/r/20170626124233.GN11534@dhcp22.suse.cz
Link: http://lkml.kernel.org/r/20170623085345.11304-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Alex Belits <alex.belits@cavium.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: David Daney <david.daney@cavium.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: NeilBrown <neilb@suse.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux
Pull i2c updates from Wolfram Sang:
"This pull request contains:
- i2c core reorganization. One source file became too monolithic. It
is now split up, yet we still have the same named object as the
final output. This should ease maintenance.
- new drivers: ZTE ZX2967 family, ASPEED 24XX/25XX
- designware driver gained slave mode support
- xgene-slimpro driver gained ACPI support
- bigger overhaul for pca-platform driver
- the algo-bit module now supports messages with enforced STOP
- slightly bigger than usual set of driver updates and improvements
and with much appreciated quality assurance from Andy Shevchenko"
* 'i2c/for-4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (51 commits)
i2c: Provide a stub for i2c_detect_slave_mode()
i2c: designware: Let slave adapter support be optional
i2c: designware: Make HW init functions static
i2c: designware: fix spelling mistakes
i2c: pca-platform: propagate error from i2c_pca_add_numbered_bus
i2c: pca-platform: correctly set algo_data.reset_chip
i2c: acpi: Do not create i2c-clients for LNXVIDEO ACPI devices
i2c: designware: enable SLAVE in platform module
i2c: designware: add SLAVE mode functions
i2c: zx2967: drop COMPILE_TEST dependency
i2c: zx2967: always use the same device when printing errors
i2c: pca-platform: use dev_warn/dev_info instead of printk
i2c: pca-platform: use device managed allocations
i2c: pca-platform: add devicetree awareness
i2c: pca-platform: switch to struct gpio_desc
dt-bindings: add bindings for i2c-pca-platform
i2c: cadance: fix ctrl/addr reg write order
i2c: zx2967: add i2c controller driver for ZTE's zx2967 family
dt: bindings: add documentation for zx2967 family i2c controller
i2c: algo-bit: add support for I2C_M_STOP
...
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Merge more updates from Andrew Morton:
- most of the rest of MM
- KASAN updates
- lib/ updates
- checkpatch updates
- some binfmt_elf changes
- various misc bits
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (115 commits)
kernel/exit.c: avoid undefined behaviour when calling wait4()
kernel/signal.c: avoid undefined behaviour in kill_something_info
binfmt_elf: safely increment argv pointers
s390: reduce ELF_ET_DYN_BASE
powerpc: move ELF_ET_DYN_BASE to 4GB / 4MB
arm64: move ELF_ET_DYN_BASE to 4GB / 4MB
arm: move ELF_ET_DYN_BASE to 4MB
binfmt_elf: use ELF_ET_DYN_BASE only for PIE
fs, epoll: short circuit fetching events if thread has been killed
checkpatch: improve multi-line alignment test
checkpatch: improve macro reuse test
checkpatch: change format of --color argument to --color[=WHEN]
checkpatch: silence perl 5.26.0 unescaped left brace warnings
checkpatch: improve tests for multiple line function definitions
checkpatch: remove false warning for commit reference
checkpatch: fix stepping through statements with $stat and ctx_statement_block
checkpatch: [HLP]LIST_HEAD is also declaration
checkpatch: warn when a MAINTAINERS entry isn't [A-Z]:\t
checkpatch: improve the unnecessary OOM message test
lib/bsearch.c: micro-optimize pivot position calculation
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During the debugging of the problem described in
https://lkml.org/lkml/2017/5/17/542 and fixed by Tetsuo Handa in
https://lkml.org/lkml/2017/5/19/383 , I've found that the existing debug
output is not really useful to understand issues related to the oom
reaper.
So, I assume, that adding some tracepoints might help with debugging of
similar issues.
Trace the following events:
1) a process is marked as an oom victim,
2) a process is added to the oom reaper list,
3) the oom reaper starts reaping process's mm,
4) the oom reaper finished reaping,
5) the oom reaper skips reaping.
How it works in practice? Below is an example which show how the problem
mentioned above can be found: one process is added twice to the
oom_reaper list:
$ cd /sys/kernel/debug/tracing
$ echo "oom:mark_victim" > set_event
$ echo "oom:wake_reaper" >> set_event
$ echo "oom:skip_task_reaping" >> set_event
$ echo "oom:start_task_reaping" >> set_event
$ echo "oom:finish_task_reaping" >> set_event
$ cat trace_pipe
allocate-502 [001] .... 91.836405: mark_victim: pid=502
allocate-502 [001] .N.. 91.837356: wake_reaper: pid=502
allocate-502 [000] .N.. 91.871149: wake_reaper: pid=502
oom_reaper-23 [000] .... 91.871177: start_task_reaping: pid=502
oom_reaper-23 [000] .N.. 91.879511: finish_task_reaping: pid=502
oom_reaper-23 [000] .... 91.879580: skip_task_reaping: pid=502
Link: http://lkml.kernel.org/r/20170530185231.GA13412@castle
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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After enabling CONFIG_TRACE_ENUM_MAP_FILE (which will soon be renamed to
CONFIG_TRACE_EVAL_MAP_FILE), I am able to examine the enums that have
been evaluated:
# cat /sys/kernel/debug/tracing/enum_map
(which will soon be renamed to eval_map)
And it showed some interesting results:
[..]
ZONE_MOVABLE 3 (oom)
ZONE_NORMAL 2 (oom)
ZONE_DMA32 1 (oom)
ZONE_DMA 0 (oom)
3 3 (oom)
2 2 (oom)
1 1 (oom)
COMPACT_PRIO_ASYNC 2 (oom)
COMPACT_PRIO_SYNC_LIGHT 1 (oom)
COMPACT_PRIO_SYNC_FULL 0 (oom)
[..]
ZONE_DMA 0 (vmscan)
3 3 (vmscan)
2 2 (vmscan)
1 1 (vmscan)
COMPACT_PRIO_ASYNC 2 (vmscan)
[..]
ZONE_DMA 0 (kmem)
3 3 (kmem)
2 2 (kmem)
1 1 (kmem)
COMPACT_PRIO_ASYNC 2 (kmem)
[..]
ZONE_DMA 0 (compaction)
3 3 (compaction)
2 2 (compaction)
1 1 (compaction)
COMPACT_PRIO_ASYNC 2 (compaction)
[..]
The name within the parenthesis are the trace systems that the enum/eval
maps are associated with. When there's a number evaluated to another
number, that tells me that the TRACE_DEFINE_ENUM() was used on a #define
and not an enum. As #defines get converted normally, they are not needed
to be evaluated.
Each of the above trace systems with the number to number evaluation
included the file include/trace/events/mmflags.h which has:
/* High-level compaction status feedback */
#define COMPACTION_FAILED 1
#define COMPACTION_WITHDRAWN 2
#define COMPACTION_PROGRESS 3
[..]
#define COMPACTION_FEEDBACK \
EM(COMPACTION_FAILED, "failed") \
EM(COMPACTION_WITHDRAWN, "withdrawn") \
EMe(COMPACTION_PROGRESS, "progress")
Which is still needed for the __print_symbolic() usage in the
trace_event. But it is not needed to be evaluated.
Removing the evaluation part removes the unnecessary evaluations of
numbers to numbers.
Link: http://lkml.kernel.org/r/20170615074944.7be9a647@gandalf.local.home
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs
Pull f2fs updates from Jaegeuk Kim:
"In this round, we've added new features such as disk quota and statx,
and modified internal bio management flow to merge more IOs depending
on block types. We've also made internal threads freezeable for
Android battery life. In addition to them, there are some patches to
avoid lock contention as well as a couple of deadlock conditions.
Enhancements:
- support usrquota, grpquota, and statx
- manage DATA/NODE typed bios separately to serialize more IOs
- modify f2fs_lock_op/wio_mutex to avoid lock contention
- prevent lock contention in migratepage
Bug fixes:
- fix missing load of written inode flag
- fix worst case victim selection in GC
- freezeable GC and discard threads for Android battery life
- sanitize f2fs metadata to deal with security hole
- clean up sysfs-related code and docs"
* tag 'for-f2fs-4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (59 commits)
f2fs: support plain user/group quota
f2fs: avoid deadlock caused by lock order of page and lock_op
f2fs: use spin_{,un}lock_irq{save,restore}
f2fs: relax migratepage for atomic written page
f2fs: don't count inode block in in-memory inode.i_blocks
Revert "f2fs: fix to clean previous mount option when remount_fs"
f2fs: do not set LOST_PINO for renamed dir
f2fs: do not set LOST_PINO for newly created dir
f2fs: skip ->writepages for {mete,node}_inode during recovery
f2fs: introduce __check_sit_bitmap
f2fs: stop gc/discard thread in prior during umount
f2fs: introduce reserved_blocks in sysfs
f2fs: avoid redundant f2fs_flush after remount
f2fs: report # of free inodes more precisely
f2fs: add ioctl to do gc with target block address
f2fs: don't need to check encrypted inode for partial truncation
f2fs: measure inode.i_blocks as generic filesystem
f2fs: set CP_TRIMMED_FLAG correctly
f2fs: require key for truncate(2) of encrypted file
f2fs: move sysfs code from super.c to fs/f2fs/sysfs.c
...
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git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux
Pull Writeback error handling updates from Jeff Layton:
"This pile represents the bulk of the writeback error handling fixes
that I have for this cycle. Some of the earlier patches in this pile
may look trivial but they are prerequisites for later patches in the
series.
The aim of this set is to improve how we track and report writeback
errors to userland. Most applications that care about data integrity
will periodically call fsync/fdatasync/msync to ensure that their
writes have made it to the backing store.
For a very long time, we have tracked writeback errors using two flags
in the address_space: AS_EIO and AS_ENOSPC. Those flags are set when a
writeback error occurs (via mapping_set_error) and are cleared as a
side-effect of filemap_check_errors (as you noted yesterday). This
model really sucks for userland.
Only the first task to call fsync (or msync or fdatasync) will see the
error. Any subsequent task calling fsync on a file will get back 0
(unless another writeback error occurs in the interim). If I have
several tasks writing to a file and calling fsync to ensure that their
writes got stored, then I need to have them coordinate with one
another. That's difficult enough, but in a world of containerized
setups that coordination may even not be possible.
But wait...it gets worse!
The calls to filemap_check_errors can be buried pretty far down in the
call stack, and there are internal callers of filemap_write_and_wait
and the like that also end up clearing those errors. Many of those
callers ignore the error return from that function or return it to
userland at nonsensical times (e.g. truncate() or stat()). If I get
back -EIO on a truncate, there is no reason to think that it was
because some previous writeback failed, and a subsequent fsync() will
(incorrectly) return 0.
This pile aims to do three things:
1) ensure that when a writeback error occurs that that error will be
reported to userland on a subsequent fsync/fdatasync/msync call,
regardless of what internal callers are doing
2) report writeback errors on all file descriptions that were open at
the time that the error occurred. This is a user-visible change,
but I think most applications are written to assume this behavior
anyway. Those that aren't are unlikely to be hurt by it.
3) document what filesystems should do when there is a writeback
error. Today, there is very little consistency between them, and a
lot of cargo-cult copying. We need to make it very clear what
filesystems should do in this situation.
To achieve this, the set adds a new data type (errseq_t) and then
builds new writeback error tracking infrastructure around that. Once
all of that is in place, we change the filesystems to use the new
infrastructure for reporting wb errors to userland.
Note that this is just the initial foray into cleaning up this mess.
There is a lot of work remaining here:
1) convert the rest of the filesystems in a similar fashion. Once the
initial set is in, then I think most other fs' will be fairly
simple to convert. Hopefully most of those can in via individual
filesystem trees.
2) convert internal waiters on writeback to use errseq_t for
detecting errors instead of relying on the AS_* flags. I have some
draft patches for this for ext4, but they are not quite ready for
prime time yet.
This was a discussion topic this year at LSF/MM too. If you're
interested in the gory details, LWN has some good articles about this:
https://lwn.net/Articles/718734/
https://lwn.net/Articles/724307/"
* tag 'for-linus-v4.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux:
btrfs: minimal conversion to errseq_t writeback error reporting on fsync
xfs: minimal conversion to errseq_t writeback error reporting
ext4: use errseq_t based error handling for reporting data writeback errors
fs: convert __generic_file_fsync to use errseq_t based reporting
block: convert to errseq_t based writeback error tracking
dax: set errors in mapping when writeback fails
Documentation: flesh out the section in vfs.txt on storing and reporting writeback errors
mm: set both AS_EIO/AS_ENOSPC and errseq_t in mapping_set_error
fs: new infrastructure for writeback error handling and reporting
lib: add errseq_t type and infrastructure for handling it
mm: don't TestClearPageError in __filemap_fdatawait_range
mm: clear AS_EIO/AS_ENOSPC when writeback initiation fails
jbd2: don't clear and reset errors after waiting on writeback
buffer: set errors in mapping at the time that the error occurs
fs: check for writeback errors after syncing out buffers in generic_file_fsync
buffer: use mapping_set_error instead of setting the flag
mm: fix mapping_set_error call in me_pagecache_dirty
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git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"The new features of this release:
- Added TRACE_DEFINE_SIZEOF() which allows trace events that use
sizeof() it the TP_printk() to be converted to the actual size such
that trace-cmd and perf can parse them correctly.
- Some rework of the TRACE_DEFINE_ENUM() such that the above
TRACE_DEFINE_SIZEOF() could reuse the same code.
- Recording of tgid (Thread Group ID). This is similar to how task
COMMs are recorded (cached at sched_switch), where it is in a table
and used on output of the trace and trace_pipe files.
- Have ":mod:<module>" be cached when written into set_ftrace_filter.
Then the functions of the module will be traced at module load.
- Some random clean ups and small fixes"
* tag 'trace-v4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (26 commits)
ftrace: Test for NULL iter->tr in regex for stack_trace_filter changes
ftrace: Decrement count for dyn_ftrace_total_info for init functions
ftrace: Unlock hash mutex on failed allocation in process_mod_list()
tracing: Add support for display of tgid in trace output
tracing: Add support for recording tgid of tasks
ftrace: Decrement count for dyn_ftrace_total_info file
ftrace: Remove unused function ftrace_arch_read_dyn_info()
sh/ftrace: Remove only user of ftrace_arch_read_dyn_info()
ftrace: Have cached module filters be an active filter
ftrace: Implement cached modules tracing on module load
ftrace: Have the cached module list show in set_ftrace_filter
ftrace: Add :mod: caching infrastructure to trace_array
tracing: Show address when function names are not found
ftrace: Add missing comment for FTRACE_OPS_FL_RCU
tracing: Rename update the enum_map file
tracing: Add TRACE_DEFINE_SIZEOF() macros
tracing: define TRACE_DEFINE_SIZEOF() macro to map sizeof's to their values
tracing: Rename enum_replace to eval_replace
trace: rename enum_map functions
trace: rename trace.c enum functions
...
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git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
Pull percpu updates from Tejun Heo:
"These are the percpu changes for the v4.13-rc1 merge window. There are
a couple visibility related changes - tracepoints and allocator stats
through debugfs, along with __ro_after_init markings and a cosmetic
rename in percpu_counter.
Please note that the simple O(#elements_in_the_chunk) area allocator
used by percpu allocator is again showing scalability issues,
primarily with bpf allocating and freeing large number of counters.
Dennis is working on the replacement allocator and the percpu
allocator will be seeing increased churns in the coming cycles"
* 'for-4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
percpu: fix static checker warnings in pcpu_destroy_chunk
percpu: fix early calls for spinlock in pcpu_stats
percpu: resolve err may not be initialized in pcpu_alloc
percpu_counter: Rename __percpu_counter_add to percpu_counter_add_batch
percpu: add tracepoint support for percpu memory
percpu: expose statistics about percpu memory via debugfs
percpu: migrate percpu data structures to internal header
percpu: add missing lockdep_assert_held to func pcpu_free_area
mark most percpu globals as __ro_after_init
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Most filesystems currently use mapping_set_error and
filemap_check_errors for setting and reporting/clearing writeback errors
at the mapping level. filemap_check_errors is indirectly called from
most of the filemap_fdatawait_* functions and from
filemap_write_and_wait*. These functions are called from all sorts of
contexts to wait on writeback to finish -- e.g. mostly in fsync, but
also in truncate calls, getattr, etc.
The non-fsync callers are problematic. We should be reporting writeback
errors during fsync, but many places spread over the tree clear out
errors before they can be properly reported, or report errors at
nonsensical times.
If I get -EIO on a stat() call, there is no reason for me to assume that
it is because some previous writeback failed. The fact that it also
clears out the error such that a subsequent fsync returns 0 is a bug,
and a nasty one since that's potentially silent data corruption.
This patch adds a small bit of new infrastructure for setting and
reporting errors during address_space writeback. While the above was my
original impetus for adding this, I think it's also the case that
current fsync semantics are just problematic for userland. Most
applications that call fsync do so to ensure that the data they wrote
has hit the backing store.
In the case where there are multiple writers to the file at the same
time, this is really hard to determine. The first one to call fsync will
see any stored error, and the rest get back 0. The processes with open
fds may not be associated with one another in any way. They could even
be in different containers, so ensuring coordination between all fsync
callers is not really an option.
One way to remedy this would be to track what file descriptor was used
to dirty the file, but that's rather cumbersome and would likely be
slow. However, there is a simpler way to improve the semantics here
without incurring too much overhead.
This set adds an errseq_t to struct address_space, and a corresponding
one is added to struct file. Writeback errors are recorded in the
mapping's errseq_t, and the one in struct file is used as the "since"
value.
This changes the semantics of the Linux fsync implementation such that
applications can now use it to determine whether there were any
writeback errors since fsync(fd) was last called (or since the file was
opened in the case of fsync having never been called).
Note that those writeback errors may have occurred when writing data
that was dirtied via an entirely different fd, but that's the case now
with the current mapping_set_error/filemap_check_error infrastructure.
This will at least prevent you from getting a false report of success.
The new behavior is still consistent with the POSIX spec, and is more
reliable for application developers. This patch just adds some basic
infrastructure for doing this, and ensures that the f_wb_err "cursor"
is properly set when a file is opened. Later patches will change the
existing code to use this new infrastructure for reporting errors at
fsync time.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
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