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| author |   Nicholas Piggin <npiggin@gmail.com> | 2021-09-07 20:00:00 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2021-09-08 11:50:27 -0700 |
| commit | 1e1c15839df084f4011825fee922aa976c9159dc (patch) | |
| tree | eba0d3e4771362a9032bb3637607cd41f52b2ae6 /include | |
| parent | checkpatch: improve GIT_COMMIT_ID test (diff) | |
| download | linux-dev-1e1c15839df084f4011825fee922aa976c9159dc.tar.xz linux-dev-1e1c15839df084f4011825fee922aa976c9159dc.zip | |
fs/epoll: use a per-cpu counter for user's watches count
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>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/sched/user.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/sched/user.h b/include/linux/sched/user.h index 2462f7d07695..00ed419dd464 100644 --- a/include/linux/sched/user.h +++ b/include/linux/sched/user.h @@ -4,6 +4,7 @@ #include <linux/uidgid.h> #include <linux/atomic.h> +#include <linux/percpu_counter.h> #include <linux/refcount.h> #include <linux/ratelimit.h> @@ -13,7 +14,7 @@ struct user_struct { refcount_t __count; /* reference count */ #ifdef CONFIG_EPOLL - atomic_long_t epoll_watches; /* The number of file descriptors currently watched */ + struct percpu_counter epoll_watches; /* The number of file descriptors currently watched */ #endif unsigned long unix_inflight; /* How many files in flight in unix sockets */ atomic_long_t pipe_bufs; /* how many pages are allocated in pipe buffers */ |