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c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1771856459; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Gd3OmvsplKIPl813mRZWly59V7xqaiRqqJWFXFoYp/Y=; b=gwpKr5WSiypHKV7rViQMdVkiZauhUkInMnkI03i1UDIznm9QYJkDOybWECr2HZOdWLfTyc nfo0o057EYHc4SGDzu4j9VbrC2HG6ZLC9Hj2WgEmhla7R11+4m4GIAD1MhEFF5ed3L9Fry yFmOKDoJZtiF8l2iYCQMiTd8isjN7dE= X-MC-Unique: jNruTWd1NHqBBVWbzeKzXg-1 X-Mimecast-MFC-AGG-ID: jNruTWd1NHqBBVWbzeKzXg_1771856453 From: Stefan Hajnoczi To: qemu-devel@nongnu.org Cc: Paolo Bonzini , Fam Zheng , qemu-block@nongnu.org, Stefan Hajnoczi , Peter Maydell , Jens Axboe Subject: [PULL 2/2] fdmon-io_uring: check CQ ring directly in gsource_check Date: Mon, 23 Feb 2026 09:20:31 -0500 Message-ID: <20260223142031.1397832-3-stefanha@redhat.com> In-Reply-To: <20260223142031.1397832-1-stefanha@redhat.com> References: <20260223142031.1397832-1-stefanha@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; 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charset="utf-8" From: Jens Axboe gsource_check() only looks at the ppoll revents for the io_uring fd, but CQEs can be posted during gsource_prepare()'s io_uring_submit() call via kernel task_work processing on syscall exit. These completions are already sitting in the CQ ring but the ring fd may not be signaled yet, causing gsource_check() to return false. Add a fallback io_uring_cq_ready() check so completions that arrive during submission are dispatched immediately rather than waiting for the next ppoll() cycle. Signed-off-by: Jens Axboe Message-ID: <20260213143225.161043-3-axboe@kernel.dk> Signed-off-by: Stefan Hajnoczi --- util/fdmon-io_uring.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/util/fdmon-io_uring.c b/util/fdmon-io_uring.c index d0b56127c6..b81e412402 100644 --- a/util/fdmon-io_uring.c +++ b/util/fdmon-io_uring.c @@ -344,7 +344,19 @@ static void fdmon_io_uring_gsource_prepare(AioContext = *ctx) static bool fdmon_io_uring_gsource_check(AioContext *ctx) { gpointer tag =3D ctx->io_uring_fd_tag; - return g_source_query_unix_fd(&ctx->source, tag) & G_IO_IN; + + /* Check ppoll revents (normal path) */ + if (g_source_query_unix_fd(&ctx->source, tag) & G_IO_IN) { + return true; + } + + /* + * Also check for CQEs that may have been posted during prepare's + * io_uring_submit() via task_work on syscall exit. Without this, + * the main loop can miss completions and sleep in ppoll() until the + * next timer fires. + */ + return io_uring_cq_ready(&ctx->fdmon_io_uring); } =20 /* Dispatch CQE handlers that are ready */ --=20 2.53.0