From patchwork Tue Mar 11 08:48:52 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Junxian Huang X-Patchwork-Id: 14011305 Received: from szxga04-in.huawei.com (szxga04-in.huawei.com [45.249.212.190]) (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 401D822ACDC for ; Tue, 11 Mar 2025 08:56:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.190 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741683398; cv=none; b=evZ7SvyYrzIFbMWHj3O4eiYfDd4fYPiaVCkqCwSa0aYKLnhA7XXlkWJ0fmTZRMdoh1Pa1892yL+j4tn5nz1Ho9/o6yJA9cbBXIOhZNpjN6lOsBZSSKTrcDwOc8iSVm54X4SGZzcKwGGs/xXkrc40h66zjEIEtQu4ZonKCJKeZXk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741683398; c=relaxed/simple; bh=TO1Q8vT8+yhGMcwMDgOP7WVVe6y6Gzr9tzJOfl24xeg=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=EX81X9JHhVr59RIbjyk3+fQwmD4BiRE7qeoqKIXWRbPl+PAU24fUvXWNEmNoL96+M6ICds8VxpenpNj9Ya9Sf6/x3Jmnk0mYhmifjtavvzMKektKL/DHTK3rOxhNQLqojZImgqFSLIDbNY11TZQLb6dHjSZHAfZOt6nyxnGmqvw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=hisilicon.com; spf=pass smtp.mailfrom=hisilicon.com; arc=none smtp.client-ip=45.249.212.190 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=hisilicon.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=hisilicon.com Received: from mail.maildlp.com (unknown [172.19.162.112]) by szxga04-in.huawei.com (SkyGuard) with ESMTP id 4ZBnbk28Wyz2CcGj; Tue, 11 Mar 2025 16:53:22 +0800 (CST) Received: from kwepemf100018.china.huawei.com (unknown [7.202.181.17]) by mail.maildlp.com (Postfix) with ESMTPS id 9E96D140109; Tue, 11 Mar 2025 16:56:32 +0800 (CST) Received: from localhost.localdomain (10.90.30.45) by kwepemf100018.china.huawei.com (7.202.181.17) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Tue, 11 Mar 2025 16:56:32 +0800 From: Junxian Huang To: , CC: , , , Subject: [PATCH for-rc 2/7] RDMA/hns: Fix soft lockup during bt pages loop Date: Tue, 11 Mar 2025 16:48:52 +0800 Message-ID: <20250311084857.3803665-3-huangjunxian6@hisilicon.com> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20250311084857.3803665-1-huangjunxian6@hisilicon.com> References: <20250311084857.3803665-1-huangjunxian6@hisilicon.com> Precedence: bulk X-Mailing-List: linux-rdma@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To kwepemf100018.china.huawei.com (7.202.181.17) Driver runs a for-loop when allocating bt pages and mapping them with buffer pages. When a large buffer (e.g. MR over 100GB) is being allocated, it may require a considerable loop count. This will lead to soft lockup: watchdog: BUG: soft lockup - CPU#27 stuck for 22s! ... Call trace: hem_list_alloc_mid_bt+0x124/0x394 [hns_roce_hw_v2] hns_roce_hem_list_request+0xf8/0x160 [hns_roce_hw_v2] hns_roce_mtr_create+0x2e4/0x360 [hns_roce_hw_v2] alloc_mr_pbl+0xd4/0x17c [hns_roce_hw_v2] hns_roce_reg_user_mr+0xf8/0x190 [hns_roce_hw_v2] ib_uverbs_reg_mr+0x118/0x290 watchdog: BUG: soft lockup - CPU#35 stuck for 23s! ... Call trace: hns_roce_hem_list_find_mtt+0x7c/0xb0 [hns_roce_hw_v2] mtr_map_bufs+0xc4/0x204 [hns_roce_hw_v2] hns_roce_mtr_create+0x31c/0x3c4 [hns_roce_hw_v2] alloc_mr_pbl+0xb0/0x160 [hns_roce_hw_v2] hns_roce_reg_user_mr+0x108/0x1c0 [hns_roce_hw_v2] ib_uverbs_reg_mr+0x120/0x2bc Add a cond_resched() to fix soft lockup during these loops. In order not to affect the allocation performance of normal-size buffer, set the loop count of a 100GB MR as the threshold to call cond_resched(). Fixes: 38389eaa4db1 ("RDMA/hns: Add mtr support for mixed multihop addressing") Signed-off-by: Junxian Huang --- drivers/infiniband/hw/hns/hns_roce_hem.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/drivers/infiniband/hw/hns/hns_roce_hem.c b/drivers/infiniband/hw/hns/hns_roce_hem.c index 605562122ecc..ca0798224e56 100644 --- a/drivers/infiniband/hw/hns/hns_roce_hem.c +++ b/drivers/infiniband/hw/hns/hns_roce_hem.c @@ -1361,6 +1361,11 @@ static int hem_list_alloc_root_bt(struct hns_roce_dev *hr_dev, return ret; } +/* This is the bottom bt pages number of a 100G MR on 4K OS, assuming + * the bt page size is not expanded by cal_best_bt_pg_sz() + */ +#define RESCHED_LOOP_CNT_THRESHOLD_ON_4K 12800 + /* construct the base address table and link them by address hop config */ int hns_roce_hem_list_request(struct hns_roce_dev *hr_dev, struct hns_roce_hem_list *hem_list, @@ -1369,6 +1374,7 @@ int hns_roce_hem_list_request(struct hns_roce_dev *hr_dev, { const struct hns_roce_buf_region *r; int ofs, end; + int loop; int unit; int ret; int i; @@ -1386,7 +1392,10 @@ int hns_roce_hem_list_request(struct hns_roce_dev *hr_dev, continue; end = r->offset + r->count; - for (ofs = r->offset; ofs < end; ofs += unit) { + for (ofs = r->offset, loop = 1; ofs < end; ofs += unit, loop++) { + if (!(loop % RESCHED_LOOP_CNT_THRESHOLD_ON_4K)) + cond_resched(); + ret = hem_list_alloc_mid_bt(hr_dev, r, unit, ofs, hem_list->mid_bt[i], &hem_list->btm_bt); @@ -1443,9 +1452,14 @@ void *hns_roce_hem_list_find_mtt(struct hns_roce_dev *hr_dev, struct list_head *head = &hem_list->btm_bt; struct hns_roce_hem_item *hem, *temp_hem; void *cpu_base = NULL; + int loop = 1; int nr = 0; list_for_each_entry_safe(hem, temp_hem, head, sibling) { + if (!(loop % RESCHED_LOOP_CNT_THRESHOLD_ON_4K)) + cond_resched(); + loop++; + if (hem_list_page_is_in_range(hem, offset)) { nr = offset - hem->start; cpu_base = hem->addr + nr * BA_BYTE_LEN;