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Message-Id: <20230103233021.1457646-1-csander@purestorage.com>
Date: Tue, 3 Jan 2023 16:30:21 -0700
From: Caleb Sander <csander@...estorage.com>
To: Ariel Elior <aelior@...vell.com>,
Manish Chopra <manishc@...vell.com>,
Paolo Abeni <pabeni@...hat.com>,
Leon Romanovsky <leon@...nel.org>, netdev@...r.kernel.org
Cc: Joern Engel <joern@...estorage.com>,
Caleb Sander <csander@...estorage.com>,
Alok Prasad <palok@...vell.com>
Subject: [PATCH net v3] qed: allow sleep in qed_mcp_trace_dump()
By default, qed_mcp_cmd_and_union() delays 10us at a time in a loop
that can run 500K times, so calls to qed_mcp_nvm_rd_cmd()
may block the current thread for over 5s.
We observed thread scheduling delays over 700ms in production,
with stacktraces pointing to this code as the culprit.
qed_mcp_trace_dump() is called from ethtool, so sleeping is permitted.
It already can sleep in qed_mcp_halt(), which calls qed_mcp_cmd().
Add a "can sleep" parameter to qed_find_nvram_image() and
qed_nvram_read() so they can sleep during qed_mcp_trace_dump().
qed_mcp_trace_get_meta_info() and qed_mcp_trace_read_meta(),
called only by qed_mcp_trace_dump(), allow these functions to sleep.
I can't tell if the other caller (qed_grc_dump_mcp_hw_dump()) can sleep,
so keep b_can_sleep set to false when it calls these functions.
An example stacktrace from a custom warning we added to the kernel
showing a thread that has not scheduled despite long needing resched:
[ 2745.362925,17] ------------[ cut here ]------------
[ 2745.362941,17] WARNING: CPU: 23 PID: 5640 at arch/x86/kernel/irq.c:233 do_IRQ+0x15e/0x1a0()
[ 2745.362946,17] Thread not rescheduled for 744 ms after irq 99
[ 2745.362956,17] Modules linked in: ...
[ 2745.363339,17] CPU: 23 PID: 5640 Comm: lldpd Tainted: P O 4.4.182+ #202104120910+6d1da174272d.61x
[ 2745.363343,17] Hardware name: FOXCONN MercuryB/Quicksilver Controller, BIOS H11P1N09 07/08/2020
[ 2745.363346,17] 0000000000000000 ffff885ec07c3ed8 ffffffff8131eb2f ffff885ec07c3f20
[ 2745.363358,17] ffffffff81d14f64 ffff885ec07c3f10 ffffffff81072ac2 ffff88be98ed0000
[ 2745.363369,17] 0000000000000063 0000000000000174 0000000000000074 0000000000000000
[ 2745.363379,17] Call Trace:
[ 2745.363382,17] <IRQ> [<ffffffff8131eb2f>] dump_stack+0x8e/0xcf
[ 2745.363393,17] [<ffffffff81072ac2>] warn_slowpath_common+0x82/0xc0
[ 2745.363398,17] [<ffffffff81072b4c>] warn_slowpath_fmt+0x4c/0x50
[ 2745.363404,17] [<ffffffff810d5a8e>] ? rcu_irq_exit+0xae/0xc0
[ 2745.363408,17] [<ffffffff817c99fe>] do_IRQ+0x15e/0x1a0
[ 2745.363413,17] [<ffffffff817c7ac9>] common_interrupt+0x89/0x89
[ 2745.363416,17] <EOI> [<ffffffff8132aa74>] ? delay_tsc+0x24/0x50
[ 2745.363425,17] [<ffffffff8132aa04>] __udelay+0x34/0x40
[ 2745.363457,17] [<ffffffffa04d45ff>] qed_mcp_cmd_and_union+0x36f/0x7d0 [qed]
[ 2745.363473,17] [<ffffffffa04d5ced>] qed_mcp_nvm_rd_cmd+0x4d/0x90 [qed]
[ 2745.363490,17] [<ffffffffa04e1dc7>] qed_mcp_trace_dump+0x4a7/0x630 [qed]
[ 2745.363504,17] [<ffffffffa04e2556>] ? qed_fw_asserts_dump+0x1d6/0x1f0 [qed]
[ 2745.363520,17] [<ffffffffa04e4ea7>] qed_dbg_mcp_trace_get_dump_buf_size+0x37/0x80 [qed]
[ 2745.363536,17] [<ffffffffa04ea881>] qed_dbg_feature_size+0x61/0xa0 [qed]
[ 2745.363551,17] [<ffffffffa04eb427>] qed_dbg_all_data_size+0x247/0x260 [qed]
[ 2745.363560,17] [<ffffffffa0482c10>] qede_get_regs_len+0x30/0x40 [qede]
[ 2745.363566,17] [<ffffffff816c9783>] ethtool_get_drvinfo+0xe3/0x190
[ 2745.363570,17] [<ffffffff816cc152>] dev_ethtool+0x1362/0x2140
[ 2745.363575,17] [<ffffffff8109bcc6>] ? finish_task_switch+0x76/0x260
[ 2745.363580,17] [<ffffffff817c2116>] ? __schedule+0x3c6/0x9d0
[ 2745.363585,17] [<ffffffff810dbd50>] ? hrtimer_start_range_ns+0x1d0/0x370
[ 2745.363589,17] [<ffffffff816c1e5b>] ? dev_get_by_name_rcu+0x6b/0x90
[ 2745.363594,17] [<ffffffff816de6a8>] dev_ioctl+0xe8/0x710
[ 2745.363599,17] [<ffffffff816a58a8>] sock_do_ioctl+0x48/0x60
[ 2745.363603,17] [<ffffffff816a5d87>] sock_ioctl+0x1c7/0x280
[ 2745.363608,17] [<ffffffff8111f393>] ? seccomp_phase1+0x83/0x220
[ 2745.363612,17] [<ffffffff811e3503>] do_vfs_ioctl+0x2b3/0x4e0
[ 2745.363616,17] [<ffffffff811e3771>] SyS_ioctl+0x41/0x70
[ 2745.363619,17] [<ffffffff817c6ffe>] entry_SYSCALL_64_fastpath+0x1e/0x79
[ 2745.363622,17] ---[ end trace f6954aa440266421 ]---
Fixes: c965db4446291 ("qed: Add support for debug data collection")
Signed-off-by: Caleb Sander <csander@...estorage.com>
Acked-by: Alok Prasad <palok@...vell.com>
---
drivers/net/ethernet/qlogic/qed/qed_debug.c | 28 +++++++++++++++------
1 file changed, 20 insertions(+), 8 deletions(-)
---
v3: add stacktrace to commit message and put Fixes tag first
v2: add Acked-by and Fixes tags to commit message
diff --git a/drivers/net/ethernet/qlogic/qed/qed_debug.c b/drivers/net/ethernet/qlogic/qed/qed_debug.c
index 86ecb080b153..cdcead614e9f 100644
--- a/drivers/net/ethernet/qlogic/qed/qed_debug.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_debug.c
@@ -1830,11 +1830,12 @@ static void qed_grc_clear_all_prty(struct qed_hwfn *p_hwfn,
/* Finds the meta data image in NVRAM */
static enum dbg_status qed_find_nvram_image(struct qed_hwfn *p_hwfn,
struct qed_ptt *p_ptt,
u32 image_type,
u32 *nvram_offset_bytes,
- u32 *nvram_size_bytes)
+ u32 *nvram_size_bytes,
+ bool b_can_sleep)
{
u32 ret_mcp_resp, ret_mcp_param, ret_txn_size;
struct mcp_file_att file_att;
int nvm_result;
@@ -1844,11 +1845,12 @@ static enum dbg_status qed_find_nvram_image(struct qed_hwfn *p_hwfn,
DRV_MSG_CODE_NVM_GET_FILE_ATT,
image_type,
&ret_mcp_resp,
&ret_mcp_param,
&ret_txn_size,
- (u32 *)&file_att, false);
+ (u32 *)&file_att,
+ b_can_sleep);
/* Check response */
if (nvm_result || (ret_mcp_resp & FW_MSG_CODE_MASK) !=
FW_MSG_CODE_NVM_OK)
return DBG_STATUS_NVRAM_GET_IMAGE_FAILED;
@@ -1871,11 +1873,13 @@ static enum dbg_status qed_find_nvram_image(struct qed_hwfn *p_hwfn,
/* Reads data from NVRAM */
static enum dbg_status qed_nvram_read(struct qed_hwfn *p_hwfn,
struct qed_ptt *p_ptt,
u32 nvram_offset_bytes,
- u32 nvram_size_bytes, u32 *ret_buf)
+ u32 nvram_size_bytes,
+ u32 *ret_buf,
+ bool b_can_sleep)
{
u32 ret_mcp_resp, ret_mcp_param, ret_read_size, bytes_to_copy;
s32 bytes_left = nvram_size_bytes;
u32 read_offset = 0, param = 0;
@@ -1897,11 +1901,11 @@ static enum dbg_status qed_nvram_read(struct qed_hwfn *p_hwfn,
if (qed_mcp_nvm_rd_cmd(p_hwfn, p_ptt,
DRV_MSG_CODE_NVM_READ_NVRAM, param,
&ret_mcp_resp,
&ret_mcp_param, &ret_read_size,
(u32 *)((u8 *)ret_buf + read_offset),
- false))
+ b_can_sleep))
return DBG_STATUS_NVRAM_READ_FAILED;
/* Check response */
if ((ret_mcp_resp & FW_MSG_CODE_MASK) != FW_MSG_CODE_NVM_OK)
return DBG_STATUS_NVRAM_READ_FAILED;
@@ -3378,11 +3382,12 @@ static u32 qed_grc_dump_mcp_hw_dump(struct qed_hwfn *p_hwfn,
/* Read HW dump image from NVRAM */
status = qed_find_nvram_image(p_hwfn,
p_ptt,
NVM_TYPE_HW_DUMP_OUT,
&hw_dump_offset_bytes,
- &hw_dump_size_bytes);
+ &hw_dump_size_bytes,
+ false);
if (status != DBG_STATUS_OK)
return 0;
hw_dump_size_dwords = BYTES_TO_DWORDS(hw_dump_size_bytes);
@@ -3395,11 +3400,13 @@ static u32 qed_grc_dump_mcp_hw_dump(struct qed_hwfn *p_hwfn,
/* Read MCP HW dump image into dump buffer */
if (dump && hw_dump_size_dwords) {
status = qed_nvram_read(p_hwfn,
p_ptt,
hw_dump_offset_bytes,
- hw_dump_size_bytes, dump_buf + offset);
+ hw_dump_size_bytes,
+ dump_buf + offset,
+ false);
if (status != DBG_STATUS_OK) {
DP_NOTICE(p_hwfn,
"Failed to read MCP HW Dump image from NVRAM\n");
return 0;
}
@@ -4121,11 +4128,13 @@ static enum dbg_status qed_mcp_trace_get_meta_info(struct qed_hwfn *p_hwfn,
(*running_bundle_id ==
DIR_ID_1) ? NVM_TYPE_MFW_TRACE1 : NVM_TYPE_MFW_TRACE2;
return qed_find_nvram_image(p_hwfn,
p_ptt,
nvram_image_type,
- trace_meta_offset, trace_meta_size);
+ trace_meta_offset,
+ trace_meta_size,
+ true);
}
/* Reads the MCP Trace meta data from NVRAM into the specified buffer */
static enum dbg_status qed_mcp_trace_read_meta(struct qed_hwfn *p_hwfn,
struct qed_ptt *p_ptt,
@@ -4137,11 +4146,14 @@ static enum dbg_status qed_mcp_trace_read_meta(struct qed_hwfn *p_hwfn,
u32 signature;
/* Read meta data from NVRAM */
status = qed_nvram_read(p_hwfn,
p_ptt,
- nvram_offset_in_bytes, size_in_bytes, buf);
+ nvram_offset_in_bytes,
+ size_in_bytes,
+ buf,
+ true);
if (status != DBG_STATUS_OK)
return status;
/* Extract and check first signature */
signature = qed_read_unaligned_dword(byte_buf);
--
2.25.1
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