From nobody Fri Dec 19 15:32:13 2025 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 72E4A170A1B; Sat, 31 Aug 2024 09:37:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.51 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725097078; cv=none; b=npsInTCWrKCUCAC3/CMLyrlH8S52423OTxtlF+4tpbHvDZ0IZ/YVXD8ZgYiYJb88Y5L9K0P1omXdjraquX6aisC0ahBN5+9QAhnlvZ/nFGFbQBlDVEMuuDdfrZlmU9eYyq2gX5SA8XwAZodJ1e2zLf9isF2i+HQ7IfyQYa4Q7RM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725097078; c=relaxed/simple; bh=Is8gMZiYzT6REmkxrkgk5qT74fiRXbxvg1E/pyuAfeQ=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=FwnG/fAVncclY+rOQI+oOi8/Nmjs0B+/3vFWci0n/x5DGFZZt3B/QRHfg2mv+qx0alvAC++8nmypQj2y/nrf8fEzY3ZZHtmBxJDQJfopccW1YfdN6vUgSTpIiVb5+9DHftrFrtlgOdLI6LMk83P3VC0rtNOIpWhfiNDJLNdG28M= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=none smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.93.142]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4WwqgW2BGXz4f3jYx; Sat, 31 Aug 2024 17:37:43 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.128]) by mail.maildlp.com (Postfix) with ESMTP id 666461A018D; Sat, 31 Aug 2024 17:37:53 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.124.27]) by APP4 (Coremail) with SMTP id gCh0CgBXzIJj5NJm0I_lDA--.58191S6; Sat, 31 Aug 2024 17:37:53 +0800 (CST) From: Hou Tao To: linux-fsdevel@vger.kernel.org Cc: Miklos Szeredi , Vivek Goyal , Stefan Hajnoczi , Bernd Schubert , "Michael S . Tsirkin" , Matthew Wilcox , Benjamin Coddington , Jingbo Xu , linux-kernel@vger.kernel.org, virtualization@lists.linux.dev, houtao1@huawei.com Subject: [PATCH v4 2/2] virtiofs: use GFP_NOFS when enqueuing request through kworker Date: Sat, 31 Aug 2024 17:37:50 +0800 Message-Id: <20240831093750.1593871-3-houtao@huaweicloud.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20240831093750.1593871-1-houtao@huaweicloud.com> References: <20240831093750.1593871-1-houtao@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: gCh0CgBXzIJj5NJm0I_lDA--.58191S6 X-Coremail-Antispam: 1UD129KBjvJXoWxGF4kXrWrXFy5Xry3GF15urg_yoWrAFykpr WDAa15CFWrJ3y2gFWkJF4UGr1akws3CFW7Ja4fXa4Skr4Yqr17CF18ZFy0qrZavrWkAF1x Wr4FqF4DuF47Zw7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUPFb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUXw A2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxS w2x7M28EF7xvwVC0I7IYx2IY67AKxVW5JVW7JwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxV W8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v2 6rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMc Ij6xIIjxv20xvE14v26r1Y6r17McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_ Jr0_Gr1lF7xvr2IYc2Ij64vIr41lFIxGxcIEc7CjxVA2Y2ka0xkIwI1lc7CjxVAaw2AFwI 0_Jw0_GFyl42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG 67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r1q6r43MI IYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E 14v26r4j6F4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJV W8JwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjxUrJPE DUUUU X-CM-SenderInfo: xkrx3t3r6k3tpzhluzxrxghudrp/ Content-Type: text/plain; charset="utf-8" From: Hou Tao When invoking virtio_fs_enqueue_req() through kworker, both the allocation of the sg array and the bounce buffer still use GFP_ATOMIC. Considering the size of the sg array may be greater than PAGE_SIZE, use GFP_NOFS instead of GFP_ATOMIC to lower the possibility of memory allocation failure and to avoid unnecessarily depleting the atomic reserves. GFP_NOFS is not passed to virtio_fs_enqueue_req() directly, GFP_KERNEL and memalloc_nofs_{save|restore} helpers are used instead. It may seem OK to pass GFP_NOFS to virtio_fs_enqueue_req() as well when queuing the request for the first time, but this is not the case. The reason is that fuse_request_queue_background() may call ->queue_request_and_unlock() while holding fc->bg_lock, which is a spin-lock. Therefore, still use GFP_ATOMIC for it. Signed-off-by: Hou Tao Reviewed-by: Jingbo Xu --- fs/fuse/virtio_fs.c | 24 +++++++++++++++--------- 1 file changed, 15 insertions(+), 9 deletions(-) diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c index 43d66ab5e891..9bc48b3ca384 100644 --- a/fs/fuse/virtio_fs.c +++ b/fs/fuse/virtio_fs.c @@ -95,7 +95,8 @@ struct virtio_fs_req_work { }; =20 static int virtio_fs_enqueue_req(struct virtio_fs_vq *fsvq, - struct fuse_req *req, bool in_flight); + struct fuse_req *req, bool in_flight, + gfp_t gfp); =20 static const struct constant_table dax_param_enums[] =3D { {"always", FUSE_DAX_ALWAYS }, @@ -439,6 +440,8 @@ static void virtio_fs_request_dispatch_work(struct work= _struct *work) =20 /* Dispatch pending requests */ while (1) { + unsigned int flags; + spin_lock(&fsvq->lock); req =3D list_first_entry_or_null(&fsvq->queued_reqs, struct fuse_req, list); @@ -449,7 +452,9 @@ static void virtio_fs_request_dispatch_work(struct work= _struct *work) list_del_init(&req->list); spin_unlock(&fsvq->lock); =20 - ret =3D virtio_fs_enqueue_req(fsvq, req, true); + flags =3D memalloc_nofs_save(); + ret =3D virtio_fs_enqueue_req(fsvq, req, true, GFP_KERNEL); + memalloc_nofs_restore(flags); if (ret < 0) { if (ret =3D=3D -ENOSPC) { spin_lock(&fsvq->lock); @@ -550,7 +555,7 @@ static void virtio_fs_hiprio_dispatch_work(struct work_= struct *work) } =20 /* Allocate and copy args into req->argbuf */ -static int copy_args_to_argbuf(struct fuse_req *req) +static int copy_args_to_argbuf(struct fuse_req *req, gfp_t gfp) { struct fuse_args *args =3D req->args; unsigned int offset =3D 0; @@ -564,7 +569,7 @@ static int copy_args_to_argbuf(struct fuse_req *req) len =3D fuse_len_args(num_in, (struct fuse_arg *) args->in_args) + fuse_len_args(num_out, args->out_args); =20 - req->argbuf =3D kmalloc(len, GFP_ATOMIC); + req->argbuf =3D kmalloc(len, gfp); if (!req->argbuf) return -ENOMEM; =20 @@ -1239,7 +1244,8 @@ static unsigned int sg_init_fuse_args(struct scatterl= ist *sg, =20 /* Add a request to a virtqueue and kick the device */ static int virtio_fs_enqueue_req(struct virtio_fs_vq *fsvq, - struct fuse_req *req, bool in_flight) + struct fuse_req *req, bool in_flight, + gfp_t gfp) { /* requests need at least 4 elements */ struct scatterlist *stack_sgs[6]; @@ -1260,8 +1266,8 @@ static int virtio_fs_enqueue_req(struct virtio_fs_vq = *fsvq, /* Does the sglist fit on the stack? */ total_sgs =3D sg_count_fuse_req(req); if (total_sgs > ARRAY_SIZE(stack_sgs)) { - sgs =3D kmalloc_array(total_sgs, sizeof(sgs[0]), GFP_ATOMIC); - sg =3D kmalloc_array(total_sgs, sizeof(sg[0]), GFP_ATOMIC); + sgs =3D kmalloc_array(total_sgs, sizeof(sgs[0]), gfp); + sg =3D kmalloc_array(total_sgs, sizeof(sg[0]), gfp); if (!sgs || !sg) { ret =3D -ENOMEM; goto out; @@ -1269,7 +1275,7 @@ static int virtio_fs_enqueue_req(struct virtio_fs_vq = *fsvq, } =20 /* Use a bounce buffer since stack args cannot be mapped */ - ret =3D copy_args_to_argbuf(req); + ret =3D copy_args_to_argbuf(req, gfp); if (ret < 0) goto out; =20 @@ -1367,7 +1373,7 @@ __releases(fiq->lock) queue_id); =20 fsvq =3D &fs->vqs[queue_id]; - ret =3D virtio_fs_enqueue_req(fsvq, req, false); + ret =3D virtio_fs_enqueue_req(fsvq, req, false, GFP_ATOMIC); if (ret < 0) { if (ret =3D=3D -ENOSPC) { /* --=20 2.29.2