Commit bd46543d authored by Wen Yang's avatar Wen Yang Committed by Christian Brauner
Browse files

eventfd: move 'eventfd-count' printing out of spinlock 



When printing eventfd->count, interrupts will be disabled and a spinlock
will be obtained, competing with eventfd_write(). By moving the
"eventfd-count" print out of the spinlock and merging multiple
seq_printf() into one, it could improve a bit, just like timerfd_show().

Signed-off-by: default avatarWen Yang <wenyang.linux@foxmail.com>
Link: https://lore.kernel.org/r/tencent_B0B3D2BD9861FD009E03AB18A81783322709@qq.com


Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dylan Yudaken <dylany@fb.com>
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Eric Biggers <ebiggers@google.com>
Cc: <linux-fsdevel@vger.kernel.org>
Cc: <linux-kernel@vger.kernel.org>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 3948abaa

fs/eventfd.c

+9 −4
Original line number Diff line number Diff line
@@ -283,13 +283,18 @@ static ssize_t eventfd_write(struct file *file, const char __user *buf, size_t c 
static void eventfd_show_fdinfo(struct seq_file *m, struct file *f)

{

	struct eventfd_ctx *ctx = f->private_data;

	__u64 cnt;



	spin_lock_irq(&ctx->wqh.lock);

	seq_printf(m, "eventfd-count: %16llx\n",

		   (unsigned long long)ctx->count);

	cnt = ctx->count;

	spin_unlock_irq(&ctx->wqh.lock);

	seq_printf(m, "eventfd-id: %d\n", ctx->id);

	seq_printf(m, "eventfd-semaphore: %d\n",



	seq_printf(m,

		   "eventfd-count: %16llx\n"

		   "eventfd-id: %d\n"

		   "eventfd-semaphore: %d\n",

		   cnt,

		   ctx->id,

		   !!(ctx->flags & EFD_SEMAPHORE));

}

#endif