| Message ID | 20210720025105.103680-2-wangkefeng.wang@huawei.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | arm64: support page mapping percpu first chunk allocator | expand |
On Tue, Jul 20, 2021 at 10:51:03AM +0800, Kefeng Wang wrote: > There are some fixed locations in the vmalloc area be reserved > in ARM(see iotable_init()) and ARM64(see map_kernel()), but for > pcpu_page_first_chunk(), it calls vm_area_register_early() and > choose VMALLOC_START as the start address of vmap area which > could be conflicted with above address, then could trigger a > BUG_ON in vm_area_add_early(). > > Let's choose the end of existing address range in vmlist as the > start address instead of VMALLOC_START to avoid the BUG_ON. > > Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> > --- > mm/vmalloc.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index d5cd52805149..a98cf97f032f 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -2238,12 +2238,14 @@ void __init vm_area_add_early(struct vm_struct *vm) > */ > void __init vm_area_register_early(struct vm_struct *vm, size_t align) > { > - static size_t vm_init_off __initdata; > + unsigned long vm_start = VMALLOC_START; > + struct vm_struct *tmp; > unsigned long addr; > > - addr = ALIGN(VMALLOC_START + vm_init_off, align); > - vm_init_off = PFN_ALIGN(addr + vm->size) - VMALLOC_START; > + for (tmp = vmlist; tmp; tmp = tmp->next) > + vm_start = (unsigned long)tmp->addr + tmp->size; > > + addr = ALIGN(vm_start, align); > vm->addr = (void *)addr; > > vm_area_add_early(vm); Is there a risk of breaking other architectures? It doesn't look like to me but I thought I'd ask. Also, instead of always picking the end, could we search for a range that fits?
On 2021/8/1 23:23, Catalin Marinas wrote: > On Tue, Jul 20, 2021 at 10:51:03AM +0800, Kefeng Wang wrote: >> There are some fixed locations in the vmalloc area be reserved >> in ARM(see iotable_init()) and ARM64(see map_kernel()), but for >> pcpu_page_first_chunk(), it calls vm_area_register_early() and >> choose VMALLOC_START as the start address of vmap area which >> could be conflicted with above address, then could trigger a >> BUG_ON in vm_area_add_early(). >> >> Let's choose the end of existing address range in vmlist as the >> start address instead of VMALLOC_START to avoid the BUG_ON. >> >> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> >> --- >> mm/vmalloc.c | 8 +++++--- >> 1 file changed, 5 insertions(+), 3 deletions(-) >> >> diff --git a/mm/vmalloc.c b/mm/vmalloc.c >> index d5cd52805149..a98cf97f032f 100644 >> --- a/mm/vmalloc.c >> +++ b/mm/vmalloc.c >> @@ -2238,12 +2238,14 @@ void __init vm_area_add_early(struct vm_struct *vm) >> */ >> void __init vm_area_register_early(struct vm_struct *vm, size_t align) >> { >> - static size_t vm_init_off __initdata; >> + unsigned long vm_start = VMALLOC_START; >> + struct vm_struct *tmp; >> unsigned long addr; >> >> - addr = ALIGN(VMALLOC_START + vm_init_off, align); >> - vm_init_off = PFN_ALIGN(addr + vm->size) - VMALLOC_START; >> + for (tmp = vmlist; tmp; tmp = tmp->next) >> + vm_start = (unsigned long)tmp->addr + tmp->size; >> >> + addr = ALIGN(vm_start, align); >> vm->addr = (void *)addr; >> >> vm_area_add_early(vm); > Is there a risk of breaking other architectures? It doesn't look like to > me but I thought I'd ask. Before this patch, vm_init_off is to record the offset from VMALLOC_START, but it use VMALLOC_START as start address on the function vm_area_register_early() called firstly, this will cause the BUG_ON. With this patch, the most important change is that we choose the start address via dynamic calculate the 'start' address by traversing the list. [wkf@localhost linux-next]$ git grep vm_area_register_early arch/alpha/mm/init.c: vm_area_register_early(&console_remap_vm, PAGE_SIZE); arch/x86/xen/p2m.c: vm_area_register_early(&vm, PMD_SIZE * PMDS_PER_MID_PAGE); mm/percpu.c: vm_area_register_early(&vm, PAGE_SIZE); [wkf@localhost linux-next]$ git grep vm_area_add_early arch/arm/mm/ioremap.c: vm_area_add_early(vm); arch/arm64/mm/mmu.c: vm_area_add_early(vma); x86/alpha won't call vm_area_add_early(), only arm64 could call both vm_area_add_early() and vm_area_register_early() when this patchset is merged. so it won't break other architectures. > > Also, instead of always picking the end, could we search for a range > that fits? We only need a space in vmalloc range, using end or a range in the middle is not different. >
On Mon, Aug 02, 2021 at 10:39:04AM +0800, Kefeng Wang wrote: > On 2021/8/1 23:23, Catalin Marinas wrote: > > On Tue, Jul 20, 2021 at 10:51:03AM +0800, Kefeng Wang wrote: > > > There are some fixed locations in the vmalloc area be reserved > > > in ARM(see iotable_init()) and ARM64(see map_kernel()), but for > > > pcpu_page_first_chunk(), it calls vm_area_register_early() and > > > choose VMALLOC_START as the start address of vmap area which > > > could be conflicted with above address, then could trigger a > > > BUG_ON in vm_area_add_early(). > > > > > > Let's choose the end of existing address range in vmlist as the > > > start address instead of VMALLOC_START to avoid the BUG_ON. > > > > > > Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> > > > --- > > > mm/vmalloc.c | 8 +++++--- > > > 1 file changed, 5 insertions(+), 3 deletions(-) > > > > > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > > > index d5cd52805149..a98cf97f032f 100644 > > > --- a/mm/vmalloc.c > > > +++ b/mm/vmalloc.c > > > @@ -2238,12 +2238,14 @@ void __init vm_area_add_early(struct vm_struct *vm) > > > */ > > > void __init vm_area_register_early(struct vm_struct *vm, size_t align) > > > { > > > - static size_t vm_init_off __initdata; > > > + unsigned long vm_start = VMALLOC_START; > > > + struct vm_struct *tmp; > > > unsigned long addr; > > > - addr = ALIGN(VMALLOC_START + vm_init_off, align); > > > - vm_init_off = PFN_ALIGN(addr + vm->size) - VMALLOC_START; > > > + for (tmp = vmlist; tmp; tmp = tmp->next) > > > + vm_start = (unsigned long)tmp->addr + tmp->size; > > > + addr = ALIGN(vm_start, align); > > > vm->addr = (void *)addr; > > > vm_area_add_early(vm); > > Is there a risk of breaking other architectures? It doesn't look like to > > me but I thought I'd ask. > > Before this patch, vm_init_off is to record the offset from VMALLOC_START, > > but it use VMALLOC_START as start address on the function > vm_area_register_early() > > called firstly, this will cause the BUG_ON. > > With this patch, the most important change is that we choose the start > address via > > dynamic calculate the 'start' address by traversing the list. > > [wkf@localhost linux-next]$ git grep vm_area_register_early > arch/alpha/mm/init.c: vm_area_register_early(&console_remap_vm, PAGE_SIZE); > arch/x86/xen/p2m.c: vm_area_register_early(&vm, PMD_SIZE * > PMDS_PER_MID_PAGE); > mm/percpu.c: vm_area_register_early(&vm, PAGE_SIZE); > [wkf@localhost linux-next]$ git grep vm_area_add_early > arch/arm/mm/ioremap.c: vm_area_add_early(vm); > arch/arm64/mm/mmu.c: vm_area_add_early(vma); > > x86/alpha won't call vm_area_add_early(), only arm64 could call both vm_area_add_early() > and vm_area_register_early() when this patchset is merged. so it won't break other architectures. Thanks for checking. > > Also, instead of always picking the end, could we search for a range > > that fits? > > We only need a space in vmalloc range, using end or a range in the middle > is not different. I was thinking of making it more future-proof in case one registers a vm area towards the end of the range. It's fairly easy to pick a range in the middle now that you are adding a list traversal.
On 2021/8/4 19:14, Catalin Marinas wrote: > On Mon, Aug 02, 2021 at 10:39:04AM +0800, Kefeng Wang wrote: >> On 2021/8/1 23:23, Catalin Marinas wrote: >>> On Tue, Jul 20, 2021 at 10:51:03AM +0800, Kefeng Wang wrote: >>>> There are some fixed locations in the vmalloc area be reserved >>>> in ARM(see iotable_init()) and ARM64(see map_kernel()), but for >>>> pcpu_page_first_chunk(), it calls vm_area_register_early() and >>>> choose VMALLOC_START as the start address of vmap area which >>>> could be conflicted with above address, then could trigger a >>>> BUG_ON in vm_area_add_early(). >>>> >>>> Let's choose the end of existing address range in vmlist as the >>>> start address instead of VMALLOC_START to avoid the BUG_ON. >>>> >>>> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> >>>> --- >>>> mm/vmalloc.c | 8 +++++--- >>>> 1 file changed, 5 insertions(+), 3 deletions(-) >>>> >>>> diff --git a/mm/vmalloc.c b/mm/vmalloc.c >>>> index d5cd52805149..a98cf97f032f 100644 >>>> --- a/mm/vmalloc.c >>>> +++ b/mm/vmalloc.c >>>> @@ -2238,12 +2238,14 @@ void __init vm_area_add_early(struct vm_struct *vm) >>>> */ >>>> void __init vm_area_register_early(struct vm_struct *vm, size_t align) >>>> { >>>> - static size_t vm_init_off __initdata; >>>> + unsigned long vm_start = VMALLOC_START; >>>> + struct vm_struct *tmp; >>>> unsigned long addr; >>>> - addr = ALIGN(VMALLOC_START + vm_init_off, align); >>>> - vm_init_off = PFN_ALIGN(addr + vm->size) - VMALLOC_START; >>>> + for (tmp = vmlist; tmp; tmp = tmp->next) >>>> + vm_start = (unsigned long)tmp->addr + tmp->size; >>>> + addr = ALIGN(vm_start, align); >>>> vm->addr = (void *)addr; >>>> vm_area_add_early(vm); >>> Is there a risk of breaking other architectures? It doesn't look like to >>> me but I thought I'd ask. >> Before this patch, vm_init_off is to record the offset from VMALLOC_START, >> >> but it use VMALLOC_START as start address on the function >> vm_area_register_early() >> >> called firstly, this will cause the BUG_ON. >> >> With this patch, the most important change is that we choose the start >> address via >> >> dynamic calculate the 'start' address by traversing the list. >> >> [wkf@localhost linux-next]$ git grep vm_area_register_early >> arch/alpha/mm/init.c: vm_area_register_early(&console_remap_vm, PAGE_SIZE); >> arch/x86/xen/p2m.c: vm_area_register_early(&vm, PMD_SIZE * >> PMDS_PER_MID_PAGE); >> mm/percpu.c: vm_area_register_early(&vm, PAGE_SIZE); >> [wkf@localhost linux-next]$ git grep vm_area_add_early >> arch/arm/mm/ioremap.c: vm_area_add_early(vm); >> arch/arm64/mm/mmu.c: vm_area_add_early(vma); >> >> x86/alpha won't call vm_area_add_early(), only arm64 could call both vm_area_add_early() >> and vm_area_register_early() when this patchset is merged. so it won't break other architectures. > Thanks for checking. > >>> Also, instead of always picking the end, could we search for a range >>> that fits? >> We only need a space in vmalloc range, using end or a range in the middle >> is not different. > I was thinking of making it more future-proof in case one registers a > vm area towards the end of the range. It's fairly easy to pick a range > in the middle now that you are adding a list traversal. ok, will chose a suitable hole in the vmalloc range. >
diff --git a/mm/vmalloc.c b/mm/vmalloc.c index d5cd52805149..a98cf97f032f 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -2238,12 +2238,14 @@ void __init vm_area_add_early(struct vm_struct *vm) */ void __init vm_area_register_early(struct vm_struct *vm, size_t align) { - static size_t vm_init_off __initdata; + unsigned long vm_start = VMALLOC_START; + struct vm_struct *tmp; unsigned long addr; - addr = ALIGN(VMALLOC_START + vm_init_off, align); - vm_init_off = PFN_ALIGN(addr + vm->size) - VMALLOC_START; + for (tmp = vmlist; tmp; tmp = tmp->next) + vm_start = (unsigned long)tmp->addr + tmp->size; + addr = ALIGN(vm_start, align); vm->addr = (void *)addr; vm_area_add_early(vm);
There are some fixed locations in the vmalloc area be reserved in ARM(see iotable_init()) and ARM64(see map_kernel()), but for pcpu_page_first_chunk(), it calls vm_area_register_early() and choose VMALLOC_START as the start address of vmap area which could be conflicted with above address, then could trigger a BUG_ON in vm_area_add_early(). Let's choose the end of existing address range in vmlist as the start address instead of VMALLOC_START to avoid the BUG_ON. Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> --- mm/vmalloc.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)