Messages in this thread |  | | Date | Thu, 15 Feb 2007 17:51:51 +0100 | From | Ingo Molnar <> | Subject | [patch 00/14] Syslets, generic asynchronous system call support, v2 |
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this is the v2 release of the syslet subsystem. This is an interim release, not all known and pending items are fixed/changed yet - the tree is still work in progress:
http://redhat.com/~mingo/syslet-patches/
The biggest conceptual change in v2 is the ability of cachemiss threads to be turned into user threads. This fixes signal handling, makes them ptrace-eable, etc. (I've updated the sample userspace code at the URL above to also do user-space cachemiss processing - just Ctrl-Z the async-test.c run to trigger it action.)
Things not yet done in v2 and planned for v3:
- multiple completion rings support
- share the 'spare thread' between multiple rings, to further reduce startup costs.
- remove mlock() reliance
Changes since v1:
- FPU support fixed: detach FPU state from kernel thread state (implemented by Arjan van de Ven)
- remove superfluous CLONE_VM from create_async_thread() (noticed by Jens Axboe)
- sys_umem_add() does not ignore -EFAULT of __put_user() (noticed by Andrew Morton)
- use VERIFY_READ instead of VERIFY_WRITE in copy_uatom() (noticed by Andrew Morton)
- move schedule() to tail of loop in cachemiss_loop() (noticed by Andrew Morton)
- added move_user_context() arch op
- added async_syscall() and recursion protection against re-entry of sys_async_exec(), sys_fork()/sys_clone(), etc.
- added sys_async_thread() call - a user-space thread can thus call back into the syslet subsystem and continue cachemiss work.
- further cleanups in the include files
- race fixes to sys_async_wait()
- optimized out the kmalloc()/kfree() of the async_head
- async_thread structure not on the kernel stack anymore, to allow async contexts to run user-space.
- added support for head_stack and head_eip to enable the initial thread/task to run a cachemiss user context too, if it gets turned into a cachemiss thread.
As always, comments, suggestions, reports are welcome.
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