From f6f740a5114396fb60542b49c0fb8137a7e6137b Mon Sep 17 00:00:00 2001 From: Gregory Nutt Date: Sun, 8 Oct 2017 09:06:35 -0600 Subject: [PATCH] Update TODO list --- TODO | 32 +++++++++++++++++++++++++++----- 1 file changed, 27 insertions(+), 5 deletions(-) diff --git a/TODO b/TODO index 64cc683d12..44b180e688 100644 --- a/TODO +++ b/TODO @@ -1,4 +1,4 @@ -NuttX TODO List (Last updated August 22, 2017) +NuttX TODO List (Last updated October 9, 2017) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This file summarizes known NuttX bugs, limitations, inconsistencies with @@ -222,14 +222,35 @@ o Task/Scheduler (sched/) wrapper around nx_sem_wait() that adds the cancellation point and that sets the errno value on failures. + On particularly difficult issue is the use of common memory + manager C, and NX libraries in the build. For the FLAT + build, that is not such a issue because the OS internal + versions of the interfaces can be used. But is a difficult + problem for PROTECTED and KERNEL builds where the OS links + with a different version of the libraries than does the + application: The OS version would use the OS internal + interfaces and the application would use the standard + interfaces. + + But that raises yet another issue: If the application + version of the libraries use the standard interfaces + internally, then they may generate unexpected cancellation + points. For example, the memory management would take a + semaphore using sem_wait() to get exclusive access to the + heap. That means that every call to malloc() and free() + would be a cancellation point, a clear POSIX violation. + Changes like that could clean up some of this internal craziness. UPDATE: - 2017-1003: This change has been completed for the case of - semaphores used int he OS. Still need to checkout signals + 2017-10-03: This change has been completed for the case of + semaphores used in the OS. Still need to checkout signals and messages queues that are also used in the OS. Also backed out commit b4747286b19d3b15193b2a5e8a0fe48fa0a8638c. + 2017-10-86: This change has been completed for the case of + signals used in the OS. Still need to checkout messages + queues that are also used in the OS. Status: Open Priority: Low. Things are working OK the way they are. But the design @@ -522,8 +543,9 @@ o pthreads (sched/pthreads) big loss from the experience I gained." Title: ISSUES WITH CANCELLATION POINTS - Description: According to POIX cancellation points must occur when a thread is executing - the following functions. There are some execptions as noted: + Description: According to POSIX cancellation points must occur when a + thread is executing the following functions. There are some + exceptions as noted: accept() mq_timedsend() NA putpmsg() sigtimedwait() 04 aio_suspend() NA msgrcv() pwrite() NA sigwait()