[Qemu-devel] [PATCH V8 0/6] coroutine: mmap stack memory and stack size

[Peter Lieven <pl@kamp.de>]

I decided to split this from the rest of the Qemu RSS usage series as
it contains the more or less non contentious patches.

I omitted the MAP_GROWSDOWN flag in mmap as we are not 100% sure which
side effects it has.

I kept the guard page which is now nicely makes the stacks visible in
smaps. The old version of the relevent patch lacked the MAP_FIXED flag
in the second call to mmap.

v7->v8:
 The series failed on platforms with 64kB page size. Thus the following changes
 where made:
 - Patch 1: add the guard page to the stack memory and do not deduct it [Kevin, Stephan]
 - Patch 1: Submit the requested page size as a pointer so that qemu_alloc_stack can
            adjust the size according to system requirements and that the full size is usable
            to the caller.
 - Patch 6: reduced stack size to 60kB so that on systems with 4kB page size we still get
            64kB allocations.

v6->v7:
 - Patch 1: avoid multiple calls to sysconf and getpagesize [Richard]

v5->v6:
 - Patch 1: added info that the guard page is deducted from stack memory to
            commit msg and headers [Stefan]
 - rebased to master

v4->v5:
 - Patch 1: check if _SC_THREAD_STACK_MIN is defined
 - Patch 1: guard against sysconf(_SC_THREAD_STACK_MIN) returning -1 [Eric]

v3->v4:
 - Patch 1: add a static function to adjust the stack size [Richard]
 - Patch 1: round up the stack size to multiple of the pagesize.

v2->v3:
 - Patch 1,6: adjusted commit message to mention the guard page [Markus]

v1->v2:
 - Patch 1: added an architecture dependend guard page [Richard]
 - Patch 1: avoid stacks smaller than _SC_THREAD_STACK_MIN [Richard]
 - Patch 1: use mmap+mprotect instead of mmap+mmap [Richard]
 - Patch 5: u_int32_t -> uint32_t [Richard]
 - Patch 5: only available if stack grows down

Peter Lieven (6):
  oslib-posix: add helpers for stack alloc and free
  coroutine: add a macro for the coroutine stack size
  coroutine-ucontext: use helper for allocating stack memory
  coroutine-sigaltstack: use helper for allocating stack memory
  oslib-posix: add a configure switch to debug stack usage
  coroutine: reduce stack size to 60kB

 configure                    | 19 +++++++++++
 include/qemu/coroutine_int.h |  2 ++
 include/sysemu/os-posix.h    | 27 +++++++++++++++
 util/coroutine-sigaltstack.c |  9 ++---
 util/coroutine-ucontext.c    | 11 +++---
 util/coroutine-win32.c       |  2 +-
 util/oslib-posix.c           | 81 ++++++++++++++++++++++++++++++++++++++++++++
 7 files changed, 141 insertions(+), 10 deletions(-)

-- 
1.9.1