linux/net
Michal Hocko dcda9b0471 mm, tree wide: replace __GFP_REPEAT by __GFP_RETRY_MAYFAIL with more useful 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>
2017-07-12 16:26:03 -07:00
..
6lowpan 6lowpan: Don't set IFF_NO_QUEUE 2017-04-12 22:02:40 +02:00
9p sched/wait: Rename wait_queue_t => wait_queue_entry_t 2017-06-20 12:18:27 +02:00
802 net: introduce __skb_put_[zero, data, u8] 2017-06-20 13:30:14 -04:00
8021q net: add netlink_ext_ack argument to rtnl_link_ops.validate 2017-06-26 23:13:22 -04:00
appletalk networking: make skb_push & __skb_push return void pointers 2017-06-16 11:48:40 -04:00
atm net, atm: convert eg_cache_entry.use from atomic_t to refcount_t 2017-07-04 22:35:16 +01:00
ax25 net, ax25: convert ax25_cb.refcount from atomic_t to refcount_t 2017-07-04 22:35:19 +01:00
batman-adv networking: make skb_put & friends return void pointers 2017-06-16 11:48:39 -04:00
bluetooth Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2017-07-05 12:31:59 -07:00
bpf bpf: Align packet data properly in program testing framework. 2017-05-02 11:46:28 -04:00
bridge Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf 2017-07-06 14:02:22 +01:00
caif net: convert sock.sk_wmem_alloc from atomic_t to refcount_t 2017-07-01 07:39:08 -07:00
can networking: introduce and use skb_put_data() 2017-06-16 11:48:37 -04:00
ceph libceph: osd_state is 32 bits wide in luminous 2017-07-07 17:25:19 +02:00
core mm, tree wide: replace __GFP_REPEAT by __GFP_RETRY_MAYFAIL with more useful semantic 2017-07-12 16:26:03 -07:00
dcb dcb: enforce minimum length on IEEE_APPS attribute 2017-05-21 13:42:33 -04:00
dccp net: convert sk_buff.users from atomic_t to refcount_t 2017-07-01 07:39:07 -07:00
decnet net, decnet: convert dn_fib_info.fib_clntref from atomic_t to refcount_t 2017-07-04 22:35:15 +01:00
dns_resolver Merge branch 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-03-03 10:16:38 -08:00
dsa net: manual clean code which call skb_put_[data:zero] 2017-06-20 13:30:15 -04:00
ethernet networking: make skb_push & __skb_push return void pointers 2017-06-16 11:48:40 -04:00
hsr net: add netlink_ext_ack argument to rtnl_link_ops.newlink 2017-06-26 23:13:21 -04:00
ieee802154 net: add netlink_ext_ack argument to rtnl_link_ops.validate 2017-06-26 23:13:22 -04:00
ife net: Introduce ife encapsulation module 2017-02-03 15:16:45 -05:00
ipv4 tcp: md5: tcp_md5_do_lookup_exact() can be static 2017-07-06 10:54:15 +01:00
ipv6 net: ipv6: Compare lwstate in detecting duplicate nexthops 2017-07-06 10:48:01 +01:00
ipx net, ipx: convert ipx_route.refcnt from atomic_t to refcount_t 2017-07-04 22:35:17 +01:00
irda Merge branch 'work.memdup_user' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-07-05 16:05:24 -07:00
iucv iucv: Convert sk_wmem_alloc accesses to refcount_t. 2017-07-03 02:31:22 -07:00
kcm net: convert sock.sk_wmem_alloc from atomic_t to refcount_t 2017-07-01 07:39:08 -07:00
key net, xfrm: convert xfrm_policy.refcnt from atomic_t to refcount_t 2017-07-04 22:35:18 +01:00
l2tp net, l2tp: convert l2tp_session.ref_count from atomic_t to refcount_t 2017-07-04 22:35:15 +01:00
l3mdev
lapb net, lapb: convert lapb_cb.refcnt from atomic_t to refcount_t 2017-07-04 22:35:16 +01:00
llc net, llc: convert llc_sap.refcnt from atomic_t to refcount_t 2017-07-04 22:35:15 +01:00
mac80211 net: manual clean code which call skb_put_[data:zero] 2017-06-20 13:30:15 -04:00
mac802154 net: Fix inconsistent teardown and release of private netdev state. 2017-06-07 15:53:24 -04:00
mpls mpls: fix uninitialized in_label var warning in mpls_getroute 2017-07-08 11:26:41 +01:00
ncsi networking: make skb_push & __skb_push return void pointers 2017-06-16 11:48:40 -04:00
netfilter net/netfilter/x_tables.c: use kvmalloc() in xt_alloc_table_info() 2017-07-12 16:26:02 -07:00
netlabel netlink: pass extended ACK struct to parsing functions 2017-04-13 13:58:22 -04:00
netlink net: convert sock.sk_refcnt from atomic_t to refcount_t 2017-07-01 07:39:08 -07:00
netrom net, netrom: convert nr_node.refcount from atomic_t to refcount_t 2017-07-04 22:35:17 +01:00
nfc NFC: Add sockaddr length checks before accessing sa_family in bind handlers 2017-06-23 00:38:31 +02:00
openvswitch openvswitch: fix mis-ordered comment lines for ovs_skb_cb 2017-07-03 05:54:00 -07:00
packet net: convert packet_fanout.sk_ref from atomic_t to refcount_t 2017-07-01 07:39:09 -07:00
phonet net: convert sock.sk_refcnt from atomic_t to refcount_t 2017-07-01 07:39:08 -07:00
psample networking: make skb_put & friends return void pointers 2017-06-16 11:48:39 -04:00
qrtr networking: make skb_put & friends return void pointers 2017-06-16 11:48:39 -04:00
rds rds: tcp: use sock_create_lite() to create the accept socket 2017-07-08 11:16:16 +01:00
rfkill net: rfkill: gpio: Switch to devm_acpi_dev_add_driver_gpios() 2017-06-13 11:07:51 +02:00
rose net: Work around lockdep limitation in sockets that use sockets 2017-03-09 18:23:27 -08:00
rxrpc net: convert sock.sk_refcnt from atomic_t to refcount_t 2017-07-01 07:39:08 -07:00
sched mm, tree wide: replace __GFP_REPEAT by __GFP_RETRY_MAYFAIL with more useful semantic 2017-07-12 16:26:03 -07:00
sctp sctp: set the value of flowi6_oif to sk_bound_dev_if to make sctp_v6_get_dst to find the correct route entry. 2017-07-06 11:39:54 +01:00
smc net/smc: Add warning about remote memory exposure 2017-05-16 14:49:43 -04:00
strparser strparser: destroy workqueue on module exit 2017-03-03 20:43:26 -08:00
sunrpc net, sunrpc: convert gss_upcall_msg.count from atomic_t to refcount_t 2017-07-04 22:35:17 +01:00
switchdev net: switchdev: Change notifier chain to be atomic 2017-06-08 14:16:24 -04:00
tipc net: convert sock.sk_refcnt from atomic_t to refcount_t 2017-07-01 07:39:08 -07:00
tls TLS: Fix length check in do_tls_getsockopt_tx() 2017-07-06 10:58:19 +01:00
unix Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2017-07-05 12:31:59 -07:00
vmw_vsock net: manual clean code which call skb_put_[data:zero] 2017-06-20 13:30:15 -04:00
wimax
wireless netlink validation fixes for nl80211 2017-07-07 11:35:55 +01:00
x25 net, x25: convert x25_neigh.refcnt from atomic_t to refcount_t 2017-07-04 22:35:18 +01:00
xfrm net, xfrm: convert sec_path.refcnt from atomic_t to refcount_t 2017-07-04 22:35:18 +01:00
compat.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2017-02-22 10:15:09 -08:00
Kconfig tls: kernel TLS support 2017-06-15 12:12:40 -04:00
Makefile tls: kernel TLS support 2017-06-15 12:12:40 -04:00
socket.c Merge branch 'work.misc-set_fs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-07-05 13:13:32 -07:00
sysctl_net.c sysctl: Remove dead register_sysctl_root 2017-04-16 23:42:49 -05:00