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c7d03a00b5
Make struct pernet_operations::id unsigned.
There are 2 reasons to do so:
1)
This field is really an index into an zero based array and
thus is unsigned entity. Using negative value is out-of-bound
access by definition.
2)
On x86_64 unsigned 32-bit data which are mixed with pointers
via array indexing or offsets added or subtracted to pointers
are preffered to signed 32-bit data.
"int" being used as an array index needs to be sign-extended
to 64-bit before being used.
void f(long *p, int i)
{
g(p[i]);
}
roughly translates to
movsx rsi, esi
mov rdi, [rsi+...]
call g
MOVSX is 3 byte instruction which isn't necessary if the variable is
unsigned because x86_64 is zero extending by default.
Now, there is net_generic() function which, you guessed it right, uses
"int" as an array index:
static inline void *net_generic(const struct net *net, int id)
{
...
ptr = ng->ptr[id - 1];
...
}
And this function is used a lot, so those sign extensions add up.
Patch snipes ~1730 bytes on allyesconfig kernel (without all junk
messing with code generation):
add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730)
Unfortunately some functions actually grow bigger.
This is a semmingly random artefact of code generation with register
allocator being used differently. gcc decides that some variable
needs to live in new r8+ registers and every access now requires REX
prefix. Or it is shifted into r12, so [r12+0] addressing mode has to be
used which is longer than [r8]
However, overall balance is in negative direction:
add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730)
function old new delta
nfsd4_lock 3886 3959 +73
tipc_link_build_proto_msg 1096 1140 +44
mac80211_hwsim_new_radio 2776 2808 +32
tipc_mon_rcv 1032 1058 +26
svcauth_gss_legacy_init 1413 1429 +16
tipc_bcbase_select_primary 379 392 +13
nfsd4_exchange_id 1247 1260 +13
nfsd4_setclientid_confirm 782 793 +11
...
put_client_renew_locked 494 480 -14
ip_set_sockfn_get 730 716 -14
geneve_sock_add 829 813 -16
nfsd4_sequence_done 721 703 -18
nlmclnt_lookup_host 708 686 -22
nfsd4_lockt 1085 1063 -22
nfs_get_client 1077 1050 -27
tcf_bpf_init 1106 1076 -30
nfsd4_encode_fattr 5997 5930 -67
Total: Before=154856051, After=154854321, chg -0.00%
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
129 lines
3.7 KiB
C
129 lines
3.7 KiB
C
/*
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* per net namespace data structures for nfsd
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*
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* Copyright (C) 2012, Jeff Layton <jlayton@redhat.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc., 51
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* Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#ifndef __NFSD_NETNS_H__
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#define __NFSD_NETNS_H__
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#include <net/net_namespace.h>
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#include <net/netns/generic.h>
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/* Hash tables for nfs4_clientid state */
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#define CLIENT_HASH_BITS 4
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#define CLIENT_HASH_SIZE (1 << CLIENT_HASH_BITS)
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#define CLIENT_HASH_MASK (CLIENT_HASH_SIZE - 1)
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#define SESSION_HASH_SIZE 512
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struct cld_net;
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struct nfsd4_client_tracking_ops;
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/*
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* Represents a nfsd "container". With respect to nfsv4 state tracking, the
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* fields of interest are the *_id_hashtbls and the *_name_tree. These track
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* the nfs4_client objects by either short or long form clientid.
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*
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* Each nfsd_net runs a nfs4_laundromat workqueue job when necessary to clean
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* up expired clients and delegations within the container.
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*/
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struct nfsd_net {
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struct cld_net *cld_net;
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struct cache_detail *svc_expkey_cache;
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struct cache_detail *svc_export_cache;
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struct cache_detail *idtoname_cache;
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struct cache_detail *nametoid_cache;
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struct lock_manager nfsd4_manager;
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bool grace_ended;
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time_t boot_time;
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/*
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* reclaim_str_hashtbl[] holds known client info from previous reset/reboot
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* used in reboot/reset lease grace period processing
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*
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* conf_id_hashtbl[], and conf_name_tree hold confirmed
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* setclientid_confirmed info.
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*
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* unconf_str_hastbl[] and unconf_name_tree hold unconfirmed
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* setclientid info.
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*/
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struct list_head *reclaim_str_hashtbl;
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int reclaim_str_hashtbl_size;
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struct list_head *conf_id_hashtbl;
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struct rb_root conf_name_tree;
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struct list_head *unconf_id_hashtbl;
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struct rb_root unconf_name_tree;
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struct list_head *sessionid_hashtbl;
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/*
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* client_lru holds client queue ordered by nfs4_client.cl_time
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* for lease renewal.
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*
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* close_lru holds (open) stateowner queue ordered by nfs4_stateowner.so_time
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* for last close replay.
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*
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* All of the above fields are protected by the client_mutex.
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*/
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struct list_head client_lru;
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struct list_head close_lru;
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struct list_head del_recall_lru;
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/* protected by blocked_locks_lock */
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struct list_head blocked_locks_lru;
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struct delayed_work laundromat_work;
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/* client_lock protects the client lru list and session hash table */
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spinlock_t client_lock;
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/* protects blocked_locks_lru */
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spinlock_t blocked_locks_lock;
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struct file *rec_file;
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bool in_grace;
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const struct nfsd4_client_tracking_ops *client_tracking_ops;
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time_t nfsd4_lease;
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time_t nfsd4_grace;
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bool nfsd_net_up;
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bool lockd_up;
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/* Time of server startup */
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struct timeval nfssvc_boot;
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/*
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* Max number of connections this nfsd container will allow. Defaults
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* to '0' which is means that it bases this on the number of threads.
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*/
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unsigned int max_connections;
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u32 clientid_counter;
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u32 clverifier_counter;
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struct svc_serv *nfsd_serv;
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};
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/* Simple check to find out if a given net was properly initialized */
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#define nfsd_netns_ready(nn) ((nn)->sessionid_hashtbl)
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extern unsigned int nfsd_net_id;
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#endif /* __NFSD_NETNS_H__ */
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