| Message ID | 91286fcfc24795385fe4df0d69a48c34f8eac942.1637857372.git.huangy81@chinatelecom.cn (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | support dirty restraint on vCPU | expand |
huangy81@chinatelecom.cn writes: > From: Hyman Huang(黄勇) <huangy81@chinatelecom.cn> > > Implement dirtyrate calculation periodically basing on > dirty-ring and throttle vCPU until it reachs the quota > dirty page rate given by user. > > Introduce qmp commands set-dirty-limit/cancel-dirty-limit to > set/cancel dirty page limit on vCPU. > > Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn> > --- > cpus-common.c | 41 +++++++++++++++++++++++++++++++++++++++++ > include/hw/core/cpu.h | 9 +++++++++ > qapi/migration.json | 47 +++++++++++++++++++++++++++++++++++++++++++++++ > softmmu/vl.c | 1 + > 4 files changed, 98 insertions(+) > > diff --git a/cpus-common.c b/cpus-common.c > index 6e73d3e..3c156b3 100644 > --- a/cpus-common.c > +++ b/cpus-common.c > @@ -23,6 +23,11 @@ > #include "hw/core/cpu.h" > #include "sysemu/cpus.h" > #include "qemu/lockable.h" > +#include "sysemu/dirtylimit.h" > +#include "sysemu/cpu-throttle.h" > +#include "sysemu/kvm.h" > +#include "qapi/error.h" > +#include "qapi/qapi-commands-migration.h" > > static QemuMutex qemu_cpu_list_lock; > static QemuCond exclusive_cond; > @@ -352,3 +357,39 @@ void process_queued_cpu_work(CPUState *cpu) > qemu_mutex_unlock(&cpu->work_mutex); > qemu_cond_broadcast(&qemu_work_cond); > } > + > +void qmp_set_dirty_limit(int64_t idx, > + uint64_t dirtyrate, > + Error **errp) > +{ > + if (!kvm_enabled() || !kvm_dirty_ring_enabled()) { > + error_setg(errp, "setting a dirty page limit requires support from dirty ring"); Can we phrase the message in a way that gives the user a chance to guess what he needs to do to avoid it? Perhaps: "setting a dirty page limit requires KVM with accelerator property 'dirty-ring-size' set". > + return; > + } > + > + dirtylimit_calc(); > + dirtylimit_vcpu(idx, dirtyrate); > +} > + > +void qmp_cancel_dirty_limit(int64_t idx, > + Error **errp) > +{ Three cases: Case 1: enable is impossible, so nothing to do. Case 2: enable is possible and we actually enabled. Case 3: enable is possible, but we didn't. Nothing to do. > + if (!kvm_enabled() || !kvm_dirty_ring_enabled()) { > + error_setg(errp, "no need to cancel a dirty page limit as dirty ring not enabled"); > + return; This is case 1. We error out. > + } > + > + if (unlikely(!dirtylimit_cancel_vcpu(idx))) { I don't think unlikely() matters here. > + dirtylimit_calc_quit(); > + } In case 2, dirtylimit_calc_quit() returns zero if this was the last limit, else non-zero. If the former, we request the thread to stop. In case 3, dirtylimit_calc_quit() returns zero, and we do nothing. Why is case 1 and error, but case 3 isn't? Both could silently do nothing, like case 3 does now. Both could error out, like case 1 does now. A possible common error message: "there is no dirty page limit to cancel". I'd be okay with consistently doing nothing, and with consistently erroring out. > +} > + > +void dirtylimit_setup(int max_cpus) > +{ > + if (!kvm_enabled() || !kvm_dirty_ring_enabled()) { > + return; > + } > + > + dirtylimit_calc_state_init(max_cpus); > + dirtylimit_state_init(max_cpus); > +} > diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h > index e948e81..11df012 100644 > --- a/include/hw/core/cpu.h > +++ b/include/hw/core/cpu.h > @@ -881,6 +881,15 @@ void end_exclusive(void); > */ > void qemu_init_vcpu(CPUState *cpu); > > +/** > + * dirtylimit_setup: > + * > + * Initializes the global state of dirtylimit calculation and > + * dirtylimit itself. This is prepared for vCPU dirtylimit which > + * could be triggered during vm lifecycle. > + */ > +void dirtylimit_setup(int max_cpus); > + > #define SSTEP_ENABLE 0x1 /* Enable simulated HW single stepping */ > #define SSTEP_NOIRQ 0x2 /* Do not use IRQ while single stepping */ > #define SSTEP_NOTIMER 0x4 /* Do not Timers while single stepping */ > diff --git a/qapi/migration.json b/qapi/migration.json > index bbfd48c..2b0fe19 100644 > --- a/qapi/migration.json > +++ b/qapi/migration.json > @@ -1850,6 +1850,53 @@ > { 'command': 'query-dirty-rate', 'returns': 'DirtyRateInfo' } > > ## > +# @set-dirty-limit: > +# > +# Set the upper limit of dirty page rate for a vCPU. > +# > +# This command could be used to cap the vCPU memory load, which is also "Could be used" suggests there are other uses. I don't think there are. > +# refered as "dirty page rate". Users can use set-dirty-limit unconditionally, > +# but if one want to know which vCPU is in high memory load and which vCPU "one wants" > +# should be limited, using calc-dirty-rate command with dirty-ring mode maybe "may be" > +# an availiable method. Note that this command requires support from dirty "available". Consider using a spell checker. > +# ring, which means property "dirty-ring-size" of accelerator object "kvm" > +# must be set. Please limit doc comment line length to approximately 70 characters for legibility. Here's my try: ## # @set-dirty-limit: # # Set the upper limit of dirty page rate for a virtual CPU. # # Requires KVM with accelerator property "dirty-ring-size" set. # A virtual CPU's dirty page rate is a measure of its memory load. # To observe dirty page rates, use @calc-dirty-rate. > +# > +# @cpu-index: vCPU index to set dirty page limit. I'd go with # @cpu-index: index of the virtual CPU. > +# > +# @dirty-rate: upper limit for the specified vCPU's dirty page rate (MB/s) > +# > +# Since: 7.0 > +# > +# Example: > +# {"execute": "set-dirty-limit"} > +# "arguments": { "cpu-index": 0, > +# "dirty-rate": 200 } } > +# > +## > +{ 'command': 'set-dirty-limit', > + 'data': { 'cpu-index': 'int', 'dirty-rate': 'uint64' } } > + > +## > +# @cancel-dirty-limit: > +# > +# Cancel the dirty page limit for the vCPU which has been set with > +# set-dirty-limit command. Note that this command requires support from > +# dirty ring, same as the "set-dirty-limit" command. > +# > +# @cpu-index: vCPU index to cancel the dirty page limit > +# > +# Since: 7.0 > +# > +# Example: > +# {"execute": "cancel-dirty-limit"} > +# "arguments": { "cpu-index": 0 } } > +# > +## > +{ 'command': 'cancel-dirty-limit', > + 'data': { 'cpu-index': 'int' } } > + > +## > # @snapshot-save: > # > # Save a VM snapshot > diff --git a/softmmu/vl.c b/softmmu/vl.c > index 620a1f1..0f83ce3 100644 > --- a/softmmu/vl.c > +++ b/softmmu/vl.c > @@ -3777,5 +3777,6 @@ void qemu_init(int argc, char **argv, char **envp) > qemu_init_displays(); > accel_setup_post(current_machine); > os_setup_post(); > + dirtylimit_setup(current_machine->smp.max_cpus); > resume_mux_open(); > }
在 2021/11/26 15:03, Markus Armbruster 写道: > huangy81@chinatelecom.cn writes: > >> From: Hyman Huang(黄勇) <huangy81@chinatelecom.cn> >> >> Implement dirtyrate calculation periodically basing on >> dirty-ring and throttle vCPU until it reachs the quota >> dirty page rate given by user. >> >> Introduce qmp commands set-dirty-limit/cancel-dirty-limit to >> set/cancel dirty page limit on vCPU. >> >> Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn> >> --- >> cpus-common.c | 41 +++++++++++++++++++++++++++++++++++++++++ >> include/hw/core/cpu.h | 9 +++++++++ >> qapi/migration.json | 47 +++++++++++++++++++++++++++++++++++++++++++++++ >> softmmu/vl.c | 1 + >> 4 files changed, 98 insertions(+) >> >> diff --git a/cpus-common.c b/cpus-common.c >> index 6e73d3e..3c156b3 100644 >> --- a/cpus-common.c >> +++ b/cpus-common.c >> @@ -23,6 +23,11 @@ >> #include "hw/core/cpu.h" >> #include "sysemu/cpus.h" >> #include "qemu/lockable.h" >> +#include "sysemu/dirtylimit.h" >> +#include "sysemu/cpu-throttle.h" >> +#include "sysemu/kvm.h" >> +#include "qapi/error.h" >> +#include "qapi/qapi-commands-migration.h" >> >> static QemuMutex qemu_cpu_list_lock; >> static QemuCond exclusive_cond; >> @@ -352,3 +357,39 @@ void process_queued_cpu_work(CPUState *cpu) >> qemu_mutex_unlock(&cpu->work_mutex); >> qemu_cond_broadcast(&qemu_work_cond); >> } >> + >> +void qmp_set_dirty_limit(int64_t idx, >> + uint64_t dirtyrate, >> + Error **errp) >> +{ >> + if (!kvm_enabled() || !kvm_dirty_ring_enabled()) { >> + error_setg(errp, "setting a dirty page limit requires support from dirty ring"); > > Can we phrase the message in a way that gives the user a chance to guess > what he needs to do to avoid it? > > Perhaps: "setting a dirty page limit requires KVM with accelerator > property 'dirty-ring-size' set". Sound good, this make things more clear. > >> + return; >> + } >> + >> + dirtylimit_calc(); >> + dirtylimit_vcpu(idx, dirtyrate); >> +} >> + >> +void qmp_cancel_dirty_limit(int64_t idx, >> + Error **errp) >> +{ > > Three cases: > > Case 1: enable is impossible, so nothing to do. > > Case 2: enable is possible and we actually enabled. > > Case 3: enable is possible, but we didn't. Nothing to do. > >> + if (!kvm_enabled() || !kvm_dirty_ring_enabled()) { >> + error_setg(errp, "no need to cancel a dirty page limit as dirty ring not enabled"); >> + return; > > This is case 1. We error out. > >> + } >> + >> + if (unlikely(!dirtylimit_cancel_vcpu(idx))) { > > I don't think unlikely() matters here. > >> + dirtylimit_calc_quit(); >> + } > > In case 2, dirtylimit_calc_quit() returns zero if this was the last > limit, else non-zero. If the former, we request the thread to stop.I am wildly guessing you misunderstood the function dirtylimit_cancel_vcpu, see below. > > In case 3, dirtylimit_calc_quit() returns zero, and we do nothing. In this case, we cancel the "dirtylimit thread" in function dirtylimit_cancel_vcpu actually, if it was the last limit thread of the whole vm, dirtylimit_cancel_vcpu return zero and we request the dirtyrate calculation thread to stop, so we call the function dirtylimit_calc_quit , which stop the "dirtyrate calculation thread" internally. > > Why is case 1 and error, but case 3 isn't? > > Both could silently do nothing, like case 3 does now. > > Both could error out, like case 1 does now. A possible common error > message: "there is no dirty page limit to cancel". > > I'd be okay with consistently doing nothing, and with consistently > erroring out. > >> +} >> + >> +void dirtylimit_setup(int max_cpus) >> +{ >> + if (!kvm_enabled() || !kvm_dirty_ring_enabled()) { >> + return; >> + } >> + >> + dirtylimit_calc_state_init(max_cpus); >> + dirtylimit_state_init(max_cpus); >> +} >> diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h >> index e948e81..11df012 100644 >> --- a/include/hw/core/cpu.h >> +++ b/include/hw/core/cpu.h >> @@ -881,6 +881,15 @@ void end_exclusive(void); >> */ >> void qemu_init_vcpu(CPUState *cpu); >> >> +/** >> + * dirtylimit_setup: >> + * >> + * Initializes the global state of dirtylimit calculation and >> + * dirtylimit itself. This is prepared for vCPU dirtylimit which >> + * could be triggered during vm lifecycle. >> + */ >> +void dirtylimit_setup(int max_cpus); >> + >> #define SSTEP_ENABLE 0x1 /* Enable simulated HW single stepping */ >> #define SSTEP_NOIRQ 0x2 /* Do not use IRQ while single stepping */ >> #define SSTEP_NOTIMER 0x4 /* Do not Timers while single stepping */ >> diff --git a/qapi/migration.json b/qapi/migration.json >> index bbfd48c..2b0fe19 100644 >> --- a/qapi/migration.json >> +++ b/qapi/migration.json >> @@ -1850,6 +1850,53 @@ >> { 'command': 'query-dirty-rate', 'returns': 'DirtyRateInfo' } >> >> ## >> +# @set-dirty-limit: >> +# >> +# Set the upper limit of dirty page rate for a vCPU. >> +# >> +# This command could be used to cap the vCPU memory load, which is also > > "Could be used" suggests there are other uses. I don't think there are. > >> +# refered as "dirty page rate". Users can use set-dirty-limit unconditionally, >> +# but if one want to know which vCPU is in high memory load and which vCPU > > "one wants" > >> +# should be limited, using calc-dirty-rate command with dirty-ring mode maybe > > "may be" > >> +# an availiable method. Note that this command requires support from dirty > > "available". Consider using a spell checker. > >> +# ring, which means property "dirty-ring-size" of accelerator object "kvm" >> +# must be set. > > Please limit doc comment line length to approximately 70 characters for > legibility. > > Here's my try: > > ## > # @set-dirty-limit: > # > # Set the upper limit of dirty page rate for a virtual CPU. > # > # Requires KVM with accelerator property "dirty-ring-size" set. > # A virtual CPU's dirty page rate is a measure of its memory load. > # To observe dirty page rates, use @calc-dirty-rate. > >> +# >> +# @cpu-index: vCPU index to set dirty page limit. > > I'd go with > > # @cpu-index: index of the virtual CPU. > Indeed, this make the document more legible. Thank Markus very much for the careful code review, i'll pick up all this next version. >> +# >> +# @dirty-rate: upper limit for the specified vCPU's dirty page rate (MB/s) >> +# >> +# Since: 7.0 >> +# >> +# Example: >> +# {"execute": "set-dirty-limit"} >> +# "arguments": { "cpu-index": 0, >> +# "dirty-rate": 200 } } >> +# >> +## >> +{ 'command': 'set-dirty-limit', >> + 'data': { 'cpu-index': 'int', 'dirty-rate': 'uint64' } } >> + >> +## >> +# @cancel-dirty-limit: >> +# >> +# Cancel the dirty page limit for the vCPU which has been set with >> +# set-dirty-limit command. Note that this command requires support from >> +# dirty ring, same as the "set-dirty-limit" command. >> +# >> +# @cpu-index: vCPU index to cancel the dirty page limit >> +# >> +# Since: 7.0 >> +# >> +# Example: >> +# {"execute": "cancel-dirty-limit"} >> +# "arguments": { "cpu-index": 0 } } >> +# >> +## >> +{ 'command': 'cancel-dirty-limit', >> + 'data': { 'cpu-index': 'int' } } >> + >> +## >> # @snapshot-save: >> # >> # Save a VM snapshot >> diff --git a/softmmu/vl.c b/softmmu/vl.c >> index 620a1f1..0f83ce3 100644 >> --- a/softmmu/vl.c >> +++ b/softmmu/vl.c >> @@ -3777,5 +3777,6 @@ void qemu_init(int argc, char **argv, char **envp) >> qemu_init_displays(); >> accel_setup_post(current_machine); >> os_setup_post(); >> + dirtylimit_setup(current_machine->smp.max_cpus); >> resume_mux_open(); >> } >
diff --git a/cpus-common.c b/cpus-common.c index 6e73d3e..3c156b3 100644 --- a/cpus-common.c +++ b/cpus-common.c @@ -23,6 +23,11 @@ #include "hw/core/cpu.h" #include "sysemu/cpus.h" #include "qemu/lockable.h" +#include "sysemu/dirtylimit.h" +#include "sysemu/cpu-throttle.h" +#include "sysemu/kvm.h" +#include "qapi/error.h" +#include "qapi/qapi-commands-migration.h" static QemuMutex qemu_cpu_list_lock; static QemuCond exclusive_cond; @@ -352,3 +357,39 @@ void process_queued_cpu_work(CPUState *cpu) qemu_mutex_unlock(&cpu->work_mutex); qemu_cond_broadcast(&qemu_work_cond); } + +void qmp_set_dirty_limit(int64_t idx, + uint64_t dirtyrate, + Error **errp) +{ + if (!kvm_enabled() || !kvm_dirty_ring_enabled()) { + error_setg(errp, "setting a dirty page limit requires support from dirty ring"); + return; + } + + dirtylimit_calc(); + dirtylimit_vcpu(idx, dirtyrate); +} + +void qmp_cancel_dirty_limit(int64_t idx, + Error **errp) +{ + if (!kvm_enabled() || !kvm_dirty_ring_enabled()) { + error_setg(errp, "no need to cancel a dirty page limit as dirty ring not enabled"); + return; + } + + if (unlikely(!dirtylimit_cancel_vcpu(idx))) { + dirtylimit_calc_quit(); + } +} + +void dirtylimit_setup(int max_cpus) +{ + if (!kvm_enabled() || !kvm_dirty_ring_enabled()) { + return; + } + + dirtylimit_calc_state_init(max_cpus); + dirtylimit_state_init(max_cpus); +} diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h index e948e81..11df012 100644 --- a/include/hw/core/cpu.h +++ b/include/hw/core/cpu.h @@ -881,6 +881,15 @@ void end_exclusive(void); */ void qemu_init_vcpu(CPUState *cpu); +/** + * dirtylimit_setup: + * + * Initializes the global state of dirtylimit calculation and + * dirtylimit itself. This is prepared for vCPU dirtylimit which + * could be triggered during vm lifecycle. + */ +void dirtylimit_setup(int max_cpus); + #define SSTEP_ENABLE 0x1 /* Enable simulated HW single stepping */ #define SSTEP_NOIRQ 0x2 /* Do not use IRQ while single stepping */ #define SSTEP_NOTIMER 0x4 /* Do not Timers while single stepping */ diff --git a/qapi/migration.json b/qapi/migration.json index bbfd48c..2b0fe19 100644 --- a/qapi/migration.json +++ b/qapi/migration.json @@ -1850,6 +1850,53 @@ { 'command': 'query-dirty-rate', 'returns': 'DirtyRateInfo' } ## +# @set-dirty-limit: +# +# Set the upper limit of dirty page rate for a vCPU. +# +# This command could be used to cap the vCPU memory load, which is also +# refered as "dirty page rate". Users can use set-dirty-limit unconditionally, +# but if one want to know which vCPU is in high memory load and which vCPU +# should be limited, using calc-dirty-rate command with dirty-ring mode maybe +# an availiable method. Note that this command requires support from dirty +# ring, which means property "dirty-ring-size" of accelerator object "kvm" +# must be set. +# +# @cpu-index: vCPU index to set dirty page limit. +# +# @dirty-rate: upper limit for the specified vCPU's dirty page rate (MB/s) +# +# Since: 7.0 +# +# Example: +# {"execute": "set-dirty-limit"} +# "arguments": { "cpu-index": 0, +# "dirty-rate": 200 } } +# +## +{ 'command': 'set-dirty-limit', + 'data': { 'cpu-index': 'int', 'dirty-rate': 'uint64' } } + +## +# @cancel-dirty-limit: +# +# Cancel the dirty page limit for the vCPU which has been set with +# set-dirty-limit command. Note that this command requires support from +# dirty ring, same as the "set-dirty-limit" command. +# +# @cpu-index: vCPU index to cancel the dirty page limit +# +# Since: 7.0 +# +# Example: +# {"execute": "cancel-dirty-limit"} +# "arguments": { "cpu-index": 0 } } +# +## +{ 'command': 'cancel-dirty-limit', + 'data': { 'cpu-index': 'int' } } + +## # @snapshot-save: # # Save a VM snapshot diff --git a/softmmu/vl.c b/softmmu/vl.c index 620a1f1..0f83ce3 100644 --- a/softmmu/vl.c +++ b/softmmu/vl.c @@ -3777,5 +3777,6 @@ void qemu_init(int argc, char **argv, char **envp) qemu_init_displays(); accel_setup_post(current_machine); os_setup_post(); + dirtylimit_setup(current_machine->smp.max_cpus); resume_mux_open(); }