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x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: C8C32100002 X-Stat-Signature: 7j46jinn81tth75t518uqy6mkg6ossqp X-HE-Tag: 1684664916-369792 X-HE-Meta: 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 5fO794y5 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Hi David, On Sat, 20 May 2023 01:00:45 +0100 David Howells wrote: > For the splice from the trace seq buffer, just use copy_splice_read(). So this is because you will remove generic_file_splice_read() (since it's buggy), right? > > In the future, something better can probably be done by gifting pages from > seq->buf into the pipe, but that would require changing seq->buf into a > vmap over an array of pages. So what we need is to introduce a vmap? We introduced splice support for avoiding copy ringbuffer pages, but this drops it. Thus this will drop performance of splice on ring buffer (trace file). If it is correct, can you also add a note about that? Thank you, > > Signed-off-by: David Howells > cc: Christoph Hellwig > cc: Al Viro > cc: Jens Axboe > cc: Steven Rostedt > cc: Masami Hiramatsu > cc: linux-kernel@vger.kernel.org > cc: linux-trace-kernel@vger.kernel.org > cc: linux-fsdevel@vger.kernel.org > cc: linux-block@vger.kernel.org > cc: linux-mm@kvack.org > --- > kernel/trace/trace.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index ebc59781456a..c210d02fac97 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c > @@ -5171,7 +5171,7 @@ static const struct file_operations tracing_fops = { > .open = tracing_open, > .read = seq_read, > .read_iter = seq_read_iter, > - .splice_read = generic_file_splice_read, > + .splice_read = copy_splice_read, > .write = tracing_write_stub, > .llseek = tracing_lseek, > .release = tracing_release, > -- Masami Hiramatsu (Google)