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Diffstat (limited to '')
| -rw-r--r-- | results/classifier/009/permissions/88281850 | 291 |
1 files changed, 291 insertions, 0 deletions
diff --git a/results/classifier/009/permissions/88281850 b/results/classifier/009/permissions/88281850 new file mode 100644 index 00000000..02513fac --- /dev/null +++ b/results/classifier/009/permissions/88281850 @@ -0,0 +1,291 @@ +permissions: 0.985 +other: 0.983 +debug: 0.979 +graphic: 0.974 +network: 0.973 +device: 0.970 +performance: 0.969 +semantic: 0.968 +boot: 0.967 +socket: 0.966 +files: 0.962 +PID: 0.959 +vnc: 0.945 +KVM: 0.881 + +[Bug] Take more 150s to boot qemu on ARM64 + +Hi all, +I encounter a issue with kernel 5.19-rc1 on a ARM64 board: it takes +about 150s between beginning to run qemu command and beginng to boot +Linux kernel ("EFI stub: Booting Linux Kernel..."). +But in kernel 5.18-rc4, it only takes about 5s. I git bisect the kernel +code and it finds c2445d387850 ("srcu: Add contention check to +call_srcu() srcu_data ->lock acquisition"). +The qemu (qemu version is 6.2.92) command i run is : + +./qemu-system-aarch64 -m 4G,slots=4,maxmem=8g \ +--trace "kvm*" \ +-cpu host \ +-machine virt,accel=kvm,gic-version=3 \ +-machine smp.cpus=2,smp.sockets=2 \ +-no-reboot \ +-nographic \ +-monitor unix:/home/cx/qmp-test,server,nowait \ +-bios /home/cx/boot/QEMU_EFI.fd \ +-kernel /home/cx/boot/Image \ +-device +pcie-root-port,port=0x8,chassis=1,id=net1,bus=pcie.0,multifunction=on,addr=0x1 +\ +-device vfio-pci,host=7d:01.3,id=net0 \ +-device virtio-blk-pci,drive=drive0,id=virtblk0,num-queues=4 \ +-drive file=/home/cx/boot/boot_ubuntu.img,if=none,id=drive0 \ +-append "rdinit=init console=ttyAMA0 root=/dev/vda rootfstype=ext4 rw " \ +-net none \ +-D /home/cx/qemu_log.txt +I am not familiar with rcu code, and don't know how it causes the issue. +Do you have any idea about this issue? +Best Regard, + +Xiang Chen + +On Mon, Jun 13, 2022 at 08:26:34PM +0800, chenxiang (M) wrote: +> +Hi all, +> +> +I encounter a issue with kernel 5.19-rc1 on a ARM64 board: it takes about +> +150s between beginning to run qemu command and beginng to boot Linux kernel +> +("EFI stub: Booting Linux Kernel..."). +> +> +But in kernel 5.18-rc4, it only takes about 5s. I git bisect the kernel code +> +and it finds c2445d387850 ("srcu: Add contention check to call_srcu() +> +srcu_data ->lock acquisition"). +> +> +The qemu (qemu version is 6.2.92) command i run is : +> +> +./qemu-system-aarch64 -m 4G,slots=4,maxmem=8g \ +> +--trace "kvm*" \ +> +-cpu host \ +> +-machine virt,accel=kvm,gic-version=3 \ +> +-machine smp.cpus=2,smp.sockets=2 \ +> +-no-reboot \ +> +-nographic \ +> +-monitor unix:/home/cx/qmp-test,server,nowait \ +> +-bios /home/cx/boot/QEMU_EFI.fd \ +> +-kernel /home/cx/boot/Image \ +> +-device +> +pcie-root-port,port=0x8,chassis=1,id=net1,bus=pcie.0,multifunction=on,addr=0x1 +> +\ +> +-device vfio-pci,host=7d:01.3,id=net0 \ +> +-device virtio-blk-pci,drive=drive0,id=virtblk0,num-queues=4 \ +> +-drive file=/home/cx/boot/boot_ubuntu.img,if=none,id=drive0 \ +> +-append "rdinit=init console=ttyAMA0 root=/dev/vda rootfstype=ext4 rw " \ +> +-net none \ +> +-D /home/cx/qemu_log.txt +> +> +I am not familiar with rcu code, and don't know how it causes the issue. Do +> +you have any idea about this issue? +Please see the discussion here: +https://lore.kernel.org/all/20615615-0013-5adc-584f-2b1d5c03ebfc@linaro.org/ +Though that report requires ACPI to be forced on to get the +delay, which results in more than 9,000 back-to-back calls to +synchronize_srcu_expedited(). I cannot reproduce this on my setup, even +with an artificial tight loop invoking synchronize_srcu_expedited(), +but then again I don't have ARM hardware. + +My current guess is that the following patch, but with larger values for +SRCU_MAX_NODELAY_PHASE. Here "larger" might well be up in the hundreds, +or perhaps even larger. + +If you get a chance to experiment with this, could you please reply +to the discussion at the above URL? (Or let me know, and I can CC +you on the next message in that thread.) + + Thanx, Paul + +------------------------------------------------------------------------ + +diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c +index 50ba70f019dea..0db7873f4e95b 100644 +--- a/kernel/rcu/srcutree.c ++++ b/kernel/rcu/srcutree.c +@@ -513,7 +513,7 @@ static bool srcu_readers_active(struct srcu_struct *ssp) + + #define SRCU_INTERVAL 1 // Base delay if no expedited GPs +pending. + #define SRCU_MAX_INTERVAL 10 // Maximum incremental delay from slow +readers. +-#define SRCU_MAX_NODELAY_PHASE 1 // Maximum per-GP-phase consecutive +no-delay instances. ++#define SRCU_MAX_NODELAY_PHASE 3 // Maximum per-GP-phase consecutive +no-delay instances. + #define SRCU_MAX_NODELAY 100 // Maximum consecutive no-delay +instances. + + /* +@@ -522,16 +522,22 @@ static bool srcu_readers_active(struct srcu_struct *ssp) + */ + static unsigned long srcu_get_delay(struct srcu_struct *ssp) + { ++ unsigned long gpstart; ++ unsigned long j; + unsigned long jbase = SRCU_INTERVAL; + + if (ULONG_CMP_LT(READ_ONCE(ssp->srcu_gp_seq), +READ_ONCE(ssp->srcu_gp_seq_needed_exp))) + jbase = 0; +- if (rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq))) +- jbase += jiffies - READ_ONCE(ssp->srcu_gp_start); +- if (!jbase) { +- WRITE_ONCE(ssp->srcu_n_exp_nodelay, +READ_ONCE(ssp->srcu_n_exp_nodelay) + 1); +- if (READ_ONCE(ssp->srcu_n_exp_nodelay) > SRCU_MAX_NODELAY_PHASE) +- jbase = 1; ++ if (rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq))) { ++ j = jiffies - 1; ++ gpstart = READ_ONCE(ssp->srcu_gp_start); ++ if (time_after(j, gpstart)) ++ jbase += j - gpstart; ++ if (!jbase) { ++ WRITE_ONCE(ssp->srcu_n_exp_nodelay, +READ_ONCE(ssp->srcu_n_exp_nodelay) + 1); ++ if (READ_ONCE(ssp->srcu_n_exp_nodelay) > +SRCU_MAX_NODELAY_PHASE) ++ jbase = 1; ++ } + } + return jbase > SRCU_MAX_INTERVAL ? SRCU_MAX_INTERVAL : jbase; + } + +å¨ 2022/6/13 21:22, Paul E. McKenney åé: +On Mon, Jun 13, 2022 at 08:26:34PM +0800, chenxiang (M) wrote: +Hi all, + +I encounter a issue with kernel 5.19-rc1 on a ARM64 board: it takes about +150s between beginning to run qemu command and beginng to boot Linux kernel +("EFI stub: Booting Linux Kernel..."). + +But in kernel 5.18-rc4, it only takes about 5s. I git bisect the kernel code +and it finds c2445d387850 ("srcu: Add contention check to call_srcu() +srcu_data ->lock acquisition"). + +The qemu (qemu version is 6.2.92) command i run is : + +./qemu-system-aarch64 -m 4G,slots=4,maxmem=8g \ +--trace "kvm*" \ +-cpu host \ +-machine virt,accel=kvm,gic-version=3 \ +-machine smp.cpus=2,smp.sockets=2 \ +-no-reboot \ +-nographic \ +-monitor unix:/home/cx/qmp-test,server,nowait \ +-bios /home/cx/boot/QEMU_EFI.fd \ +-kernel /home/cx/boot/Image \ +-device +pcie-root-port,port=0x8,chassis=1,id=net1,bus=pcie.0,multifunction=on,addr=0x1 +\ +-device vfio-pci,host=7d:01.3,id=net0 \ +-device virtio-blk-pci,drive=drive0,id=virtblk0,num-queues=4 \ +-drive file=/home/cx/boot/boot_ubuntu.img,if=none,id=drive0 \ +-append "rdinit=init console=ttyAMA0 root=/dev/vda rootfstype=ext4 rw " \ +-net none \ +-D /home/cx/qemu_log.txt + +I am not familiar with rcu code, and don't know how it causes the issue. Do +you have any idea about this issue? +Please see the discussion here: +https://lore.kernel.org/all/20615615-0013-5adc-584f-2b1d5c03ebfc@linaro.org/ +Though that report requires ACPI to be forced on to get the +delay, which results in more than 9,000 back-to-back calls to +synchronize_srcu_expedited(). I cannot reproduce this on my setup, even +with an artificial tight loop invoking synchronize_srcu_expedited(), +but then again I don't have ARM hardware. + +My current guess is that the following patch, but with larger values for +SRCU_MAX_NODELAY_PHASE. Here "larger" might well be up in the hundreds, +or perhaps even larger. + +If you get a chance to experiment with this, could you please reply +to the discussion at the above URL? (Or let me know, and I can CC +you on the next message in that thread.) +Ok, thanks, i will reply it on above URL. +Thanx, Paul + +------------------------------------------------------------------------ + +diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c +index 50ba70f019dea..0db7873f4e95b 100644 +--- a/kernel/rcu/srcutree.c ++++ b/kernel/rcu/srcutree.c +@@ -513,7 +513,7 @@ static bool srcu_readers_active(struct srcu_struct *ssp) +#define SRCU_INTERVAL 1 // Base delay if no expedited GPs pending. +#define SRCU_MAX_INTERVAL 10 // Maximum incremental delay from slow +readers. +-#define SRCU_MAX_NODELAY_PHASE 1 // Maximum per-GP-phase consecutive +no-delay instances. ++#define SRCU_MAX_NODELAY_PHASE 3 // Maximum per-GP-phase consecutive +no-delay instances. + #define SRCU_MAX_NODELAY 100 // Maximum consecutive no-delay +instances. +/* +@@ -522,16 +522,22 @@ static bool srcu_readers_active(struct srcu_struct *ssp) + */ + static unsigned long srcu_get_delay(struct srcu_struct *ssp) + { ++ unsigned long gpstart; ++ unsigned long j; + unsigned long jbase = SRCU_INTERVAL; +if (ULONG_CMP_LT(READ_ONCE(ssp->srcu_gp_seq), READ_ONCE(ssp->srcu_gp_seq_needed_exp))) +jbase = 0; +- if (rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq))) +- jbase += jiffies - READ_ONCE(ssp->srcu_gp_start); +- if (!jbase) { +- WRITE_ONCE(ssp->srcu_n_exp_nodelay, +READ_ONCE(ssp->srcu_n_exp_nodelay) + 1); +- if (READ_ONCE(ssp->srcu_n_exp_nodelay) > SRCU_MAX_NODELAY_PHASE) +- jbase = 1; ++ if (rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq))) { ++ j = jiffies - 1; ++ gpstart = READ_ONCE(ssp->srcu_gp_start); ++ if (time_after(j, gpstart)) ++ jbase += j - gpstart; ++ if (!jbase) { ++ WRITE_ONCE(ssp->srcu_n_exp_nodelay, +READ_ONCE(ssp->srcu_n_exp_nodelay) + 1); ++ if (READ_ONCE(ssp->srcu_n_exp_nodelay) > +SRCU_MAX_NODELAY_PHASE) ++ jbase = 1; ++ } + } + return jbase > SRCU_MAX_INTERVAL ? SRCU_MAX_INTERVAL : jbase; + } +. + |