Re: "Cannot allocate memory" on ring creation (not RLIMIT_MEMLOCK)

From: Josef <josef.grieb@gmail.com>
To: Pavel Begunkov <asml.silence@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>,
	Norman Maurer <norman.maurer@googlemail.com>,
	Dmitry Kadashev <dkadashev@gmail.com>,
	io-uring <io-uring@vger.kernel.org>
Subject: Re: "Cannot allocate memory" on ring creation (not RLIMIT_MEMLOCK)
Date: Mon, 21 Dec 2020 09:22:44 +0100	[thread overview]
Message-ID: <CAAss7+pyB8m1b8=oqG4c7MwxCCc+Kirgbxy1U8Xs4VidZxSZkw@mail.gmail.com> (raw)
In-Reply-To: <31cf2c96-82a5-3c21-e413-3eccc772495c@gmail.com>

Pavel I'm sorry...my kernel build process was wrong...the same kernel
patch(the first one) was used...I run different load tests on all 3
patches several times

your first patch works great and unfortunately second and third patch
doesn't work

Here the patch summary:

first patch works:

[1] git://git.kernel.dk/linux-block
branch io_uring-5.11, commit dd20166236953c8cd14f4c668bf972af32f0c6be

diff --git a/fs/io_uring.c b/fs/io_uring.c
index f3690dfdd564..3a98e6dd71c0 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -8919,8 +8919,6 @@ void __io_uring_files_cancel(struct files_struct *files)
                struct io_ring_ctx *ctx = file->private_data;

                io_uring_cancel_task_requests(ctx, files);
-               if (files)
-                       io_uring_del_task_file(file);
        }

        atomic_dec(&tctx->in_idle);
@@ -8960,6 +8958,8 @@ static s64 tctx_inflight(struct io_uring_task *tctx)
 void __io_uring_task_cancel(void)
 {
        struct io_uring_task *tctx = current->io_uring;
+       struct file *file;
+       unsigned long index;
        DEFINE_WAIT(wait);
        s64 inflight;

@@ -8986,6 +8986,9 @@ void __io_uring_task_cancel(void)

        finish_wait(&tctx->wait, &wait);
        atomic_dec(&tctx->in_idle);
+
+       xa_for_each(&tctx->xa, index, file)
+               io_uring_del_task_file(file);
 }

 static int io_uring_flush(struct file *file, void *data)
diff --git a/include/linux/io_uring.h b/include/linux/io_uring.h
index 35b2d845704d..54925c74aa88 100644
--- a/include/linux/io_uring.h
+++ b/include/linux/io_uring.h
@@ -48,7 +48,7 @@ static inline void io_uring_task_cancel(void)
 static inline void io_uring_files_cancel(struct files_struct *files)
 {
        if (current->io_uring && !xa_empty(&current->io_uring->xa))
-               __io_uring_files_cancel(files);
+               __io_uring_task_cancel();
 }
 static inline void io_uring_free(struct task_struct *tsk)
 {

second patch:

diff --git a/fs/io_uring.c b/fs/io_uring.c
index f3690dfdd564..4e1fb4054516 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -8620,6 +8620,10 @@ static int io_remove_personalities(int id, void
*p, void *data)
        return 0;
 }

+static void io_cancel_defer_files(struct io_ring_ctx *ctx,
+                                 struct task_struct *task,
+                                 struct files_struct *files);
+
 static void io_ring_exit_work(struct work_struct *work)
 {
        struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx,
@@ -8633,6 +8637,8 @@ static void io_ring_exit_work(struct work_struct *work)
         */
        do {
                io_iopoll_try_reap_events(ctx);
+               io_poll_remove_all(ctx, NULL, NULL);
+               io_kill_timeouts(ctx, NULL, NULL);
        } while (!wait_for_completion_timeout(&ctx->ref_comp, HZ/20));
        io_ring_ctx_free(ctx);
 }
@@ -8647,6 +8653,7 @@ static void io_ring_ctx_wait_and_kill(struct
io_ring_ctx *ctx)

                io_cqring_overflow_flush(ctx, true, NULL, NULL);
        mutex_unlock(&ctx->uring_lock);

+       io_cancel_defer_files(ctx, NULL, NULL);
        io_kill_timeouts(ctx, NULL, NULL);
        io_poll_remove_all(ctx, NULL, NULL);

third patch you already sent which is similar to the second one:
https://lore.kernel.org/io-uring/a195a207-db03-6e23-b642-0d04bf7777ec@gmail.com/T/#t

-- 
Josef
