[osv-dev] [PATCH 8/8] lazy stack: new tracepoint for stack pre-faults

This last patch of the series adds new tracepoint - mmu_vm_stack_fault - which when enabled allows one to see how particular app triggers the stack page faults. The tracepoint captures the stack fault address, the thread id and number of the page (0 being the 1st page). Please note this does not c

[osv-dev] [PATCH 7/8] lazy stack: activate lazy stack in pthreads

This patch adds new mmap flag - mmap_stack - that is used when mmaping a stack when creating new pthread. This new flag is only used when the build parameter CONF_lazy_stack is enabled. Signed-off-by: Waldemar Kozaczuk --- include/osv/mmu-defs.hh | 1 + libc/mman.cc| 7 +-- libc/

[osv-dev] [PATCH 5/8] lazy stack: ensure next stack page conditionally if interrupts and preemption enabled

This patch modifies the last set of call sites where we do not know statically if any of interrupts or preemption are enabled. In those cases we dynamically check if both preemtion and interrupts are enabled and only then pre-fault the stack. Most of these places are in the tracepoint and sampler

[osv-dev] [PATCH 6/8] lazy stack: prevent deadlock when taking vma_list_mutex for write

This patch makes all functions in core/mmu.cc that take vma_list_mutex for write to pre-fault the stack two pages deep before using the mutex. This is necessary to prevent any follow up stack faults down the call stack after the vma_list_mutex is take for write as this would lead to a deadlock exp

[osv-dev] [PATCH 4/8] lazy stack: ensure next stack page dynamically if preemption enabled

This patch modifies number of critical places mostly in the scheduler code to dynamically pre-fault the stack if preemption is enabled. In all these places we can be statically sure that interrupts are enabled but not so sure about preemption (maybe in future we can prove it is enabled at least in

[osv-dev] [PATCH 3/8] lazy stack: ensure next stack page statically

This patch modifies all relevant places, where we statically know that both interrupts and preemption should be enabled, to unconditionally pre-fault the stack. These include places in code before: - WITH_LOCK(preemption_lock) block - WITH_LOCK(rcu_read_lock) block - sched::preempt_disable() call

[osv-dev] [PATCH 2/8] lazy stack: do nothing in kernel threads and on populated stack

This patch annotates the relevant call sites with the invariant assert expressions to validate assumptions that let us do "nothing" in all these cases. We also reorganize some code in the scheduler to help differentiate between cases when given function/method is called with interrupts or preemptio

[osv-dev] [PATCH 1/8] lazy stack: inline assembly to pre-fault stack

This is the 1st of the total of eight patches that implement optional support of so called "lazy stack" feature. The lazy stack is well explained by the issue #143 and allows to save substantial amount of memory if application spawns many pthreads with large stacks by letting stack grow dynamically

Re: [osv-dev] [COMMIT osv master] trace: do not use malloc/free when interrupts are disabled

On Tue, Aug 30, 2022 at 6:59 PM Commit Bot wrote: > From: Waldemar Kozaczuk > Committer: Waldemar Kozaczuk > Branch: master > > trace: do not use malloc/free when interrupts are disabled > > This patch fixes a subtle bug found when working on lazy stack changes > and trying to establish some in

Re: [osv-dev] [COMMIT osv master] aarch64 trace: make compiler pick a register instead of x0

What a difference one character makes :-) -- Nadav Har'El n...@scylladb.com On Tue, Aug 30, 2022 at 6:59 PM Commit Bot wrote: > From: Waldemar Kozaczuk > Committer: Waldemar Kozaczuk > Branch: master > > aarch64 trace: make compiler pick a register instead of x0 > > This subtle 1-character p

[osv-dev] [COMMIT osv master] aarch64: download boost program-options library needed by some tests

From: Waldemar Kozaczuk Committer: Waldemar Kozaczuk Branch: master aarch64: download boost program-options library needed by some tests Signed-off-by: Waldemar Kozaczuk --- diff --git a/scripts/download_aarch64_packages.py b/scripts/download_aarch64_packages.py --- a/scripts/download_aarch6

[osv-dev] [COMMIT osv master] trace: do not use malloc/free when interrupts are disabled

From: Waldemar Kozaczuk Committer: Waldemar Kozaczuk Branch: master trace: do not use malloc/free when interrupts are disabled This patch fixes a subtle bug found when working on lazy stack changes and trying to establish some invariants in relevant places in the kernel code. One of the finding

[osv-dev] [COMMIT osv master] aarch64 trace: make compiler pick a register instead of x0

From: Waldemar Kozaczuk Committer: Waldemar Kozaczuk Branch: master aarch64 trace: make compiler pick a register instead of x0 This subtle 1-character patch fixes a nasty bug that causes interrupts to be enabled instead of correctly restored to the state it was when saving the state. This bug w