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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: Wen 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: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Wen Yang 2024-01-15 23:27:00 +08:00 committed by Christian Brauner
parent 3948abaa4e
commit bd46543d7f
1 changed files with 9 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
fs/eventfd.c
View File

@ -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