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![Nicholas Piggin](/assets/img/avatar_default.png)
This counter tracks the number of watches a user has, to compare against the 'max_user_watches' limit. This causes a scalability bottleneck on SPECjbb2015 on large systems as there is only one user. Changing to a per-cpu counter increases throughput of the benchmark by about 30% on a 16-socket, > 1000 thread system. [rdunlap@infradead.org: fix build errors in kernel/user.c when CONFIG_EPOLL=n] [npiggin@gmail.com: move ifdefs into wrapper functions, slightly improve panic message] Link: https://lkml.kernel.org/r/1628051945.fens3r99ox.astroid@bobo.none [akpm@linux-foundation.org: tweak user_epoll_alloc(), per Guenter] Link: https://lkml.kernel.org/r/20210804191421.GA1900577@roeck-us.net Link: https://lkml.kernel.org/r/20210802032013.2751916-1-npiggin@gmail.com Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reported-by: Anton Blanchard <anton@ozlabs.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
55 lines
1.5 KiB
C
55 lines
1.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_SCHED_USER_H
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#define _LINUX_SCHED_USER_H
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#include <linux/uidgid.h>
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#include <linux/atomic.h>
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#include <linux/percpu_counter.h>
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#include <linux/refcount.h>
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#include <linux/ratelimit.h>
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/*
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* Some day this will be a full-fledged user tracking system..
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*/
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struct user_struct {
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refcount_t __count; /* reference count */
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#ifdef CONFIG_EPOLL
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struct percpu_counter epoll_watches; /* The number of file descriptors currently watched */
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#endif
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unsigned long unix_inflight; /* How many files in flight in unix sockets */
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atomic_long_t pipe_bufs; /* how many pages are allocated in pipe buffers */
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/* Hash table maintenance information */
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struct hlist_node uidhash_node;
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kuid_t uid;
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#if defined(CONFIG_PERF_EVENTS) || defined(CONFIG_BPF_SYSCALL) || \
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defined(CONFIG_NET) || defined(CONFIG_IO_URING)
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atomic_long_t locked_vm;
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#endif
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#ifdef CONFIG_WATCH_QUEUE
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atomic_t nr_watches; /* The number of watches this user currently has */
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#endif
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/* Miscellaneous per-user rate limit */
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struct ratelimit_state ratelimit;
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};
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extern int uids_sysfs_init(void);
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extern struct user_struct *find_user(kuid_t);
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extern struct user_struct root_user;
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#define INIT_USER (&root_user)
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/* per-UID process charging. */
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extern struct user_struct * alloc_uid(kuid_t);
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static inline struct user_struct *get_uid(struct user_struct *u)
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{
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refcount_inc(&u->__count);
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return u;
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}
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extern void free_uid(struct user_struct *);
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#endif /* _LINUX_SCHED_USER_H */
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