Serge, Did i talk to you regarding these tests in our OLS 2008 meeting ? I do not remember exactly, but, when i saw this posting, i thought may be there was some conversation.
Regards-- Subrata On Mon, 2009-03-16 at 17:56 +0530, Subrata Modak wrote: > Hi Oren, > > On Tue, Jan 27, 2009 at 10:37 PM, Oren Laadan <[email protected]> > wrote: > Checkpoint-restart (c/r): a couple of fixes in preparation for > 64bit > architectures, and a couple of fixes for bugss (comments from > Serge > Hallyn, Sudakvev Bhattiprolu and Nathan Lynch). Updated and > tested > against v2.6.28. > > Can you kindly share those test cases/code with us ? > > Regards-- > Subrata > > > > > Aiming for -mm. > > The git tree tracking v13, branch 'ckpt-v13' (and older > versions): > git://git.ncl.cs.columbia.edu/pub/git/linux-cr.git > > Restarting multiple processes requires 'mktree' userspace > tool: > git://git.ncl.cs.columbia.edu/pub/git/user-cr.git > > Oren. > > > -- > Why do we want it? It allows containers to be moved between > physical > machines' kernels in the same way that VMWare can move VMs > between > physical machines' hypervisors. There are currently at least > two > out-of-tree implementations of this in the commercial world > (IBM's > Metacluster and Parallels' OpenVZ/Virtuozzo) and several in > the academic > world like Zap. > > Why do we need it in mainline now? Because we already have > plenty of > out-of-tree ones, and want to know what an in-tree one will > be like. :) > What *I* want right now is the extra review and scrutiny that > comes with > a mainline submission to make sure we're not going in a > direction > contrary to the community. > > This only supports pretty simple apps. But, I trust Ingo when > he says: > >> > > Generally, if something works for simple apps already > (in a robust, > >> > > compatible and supportable way) and users find it "very > cool", then > >> > > support for more complex apps is not far in the > future. but if you > >> > > want to support more complex apps straight away, it > takes forever and > >> > > gets ugly. > > We're *certainly* going to be changing the ABI (which is the > format of > the checkpoint). I'd like to follow the model that we used > for > ext4-dev, which is to make it very clear that this is a > development-only > feature for now. Perhaps we do that by making the interface > only > available through debugfs or something similar for now. Or, > reserving > the syscall numbers but require some runtime switch to be > thrown before > they can be used. I'm open to suggestions here. > -- > > -- > Todo: > - Add support for x86-64 and improve ABI > - Refine or change syscall interface > - Handle multiple namespaces in a container (e.g. save the > filesystem > namespaces state with the file descriptors) > - Security (without CAPS_SYS_ADMIN files restore may fail) > > Changelog: > > [2008-Dec-17] v12: > - Fix re-alloc/reset of pgarr chain to correctly reuse > buffers > (empty pgarr are saves in a separate pool chain) > - Add a couple of missed calls to cr_hbuf_put() > - cr_kwrite/cr_kread() again use vfs_read(), vfs_write() > (safer) > - Split cr_write/cr_read() to two parts: _cr_write/read() > helper > - Befriend with sparse: explicit conversion to 'void __user > *' > - Redrefine 'pr_fmt' ind replace cr_debug() with pr_debug() > > [2008-Dec-05] v11: > - Use contents of 'init->fs->root' instead of pointing to it > - Ignore symlinks (there is no such thing as an open symlink) > - cr_scan_fds() retries from scratch if it hits size limits > - Add missing test for VM_MAYSHARE when dumping memory > - Improve documentation about: behavior when tasks aren't > fronen, > life span of the object hash, references to objects in the > hash > > [2008-Nov-26] v10: > - Grab vfs root of container init, rather than current > process > - Acquire dcache_lock around call to __d_path() in > cr_fill_name() > - Force end-of-string in cr_read_string() (fix possible DoS) > - Introduce cr_write_buffer(), cr_read_buffer() and > cr_read_buf_type() > > [2008-Nov-10] v9: > - Support multiple processes c/r > - Extend checkpoint header with archtiecture dependent header > - Misc bug fixes (see individual changelogs) > - Rebase to v2.6.28-rc3. > > [2008-Oct-29] v8: > - Support "external" checkpoint > - Include Dave Hansen's 'deny-checkpoint' patch > - Split docs in Documentation/checkpoint/..., and improve > contents > > [2008-Oct-17] v7: > - Fix save/restore state of FPU > - Fix argument given to kunmap_atomic() in memory > dump/restore > > [2008-Oct-07] v6: > - Balance all calls to cr_hbuf_get() with matching > cr_hbuf_put() > (even though it's not really needed) > - Add assumptions and what's-missing to documentation > - Misc fixes and cleanups > > [2008-Sep-11] v5: > - Config is now 'def_bool n' by default > - Improve memory dump/restore code (following Dave Hansen's > comments) > - Change dump format (and code) to allow chunks of <vaddrs, > pages> > instead of one long list of each > - Fix use of follow_page() to avoid faulting in non-present > pages > - Memory restore now maps user pages explicitly to copy data > into them, > instead of reading directly to user space; got rid of > mprotect_fixup() > - Remove preempt_disable() when restoring debug registers > - Rename headers files s/ckpt/checkpoint/ > - Fix misc bugs in files dump/restore > - Fixes and cleanups on some error paths > - Fix misc coding style > > [2008-Sep-09] v4: > - Various fixes and clean-ups > - Fix calculation of hash table size > - Fix header structure alignment > - Use stand list_... for cr_pgarr > > [2008-Aug-29] v3: > - Various fixes and clean-ups > - Use standard hlist_... for hash table > - Better use of standard kmalloc/kfree > > [2008-Aug-20] v2: > - Added Dump and restore of open files (regular and > directories) > - Added basic handling of shared objects, and improve > handling of > 'parent tag' concept > - Added documentation > - Improved ABI, 64bit padding for image data > - Improved locking when saving/restoring memory > - Added UTS information to header (release, version, machine) > - Cleanup extraction of filename from a file pointer > - Refactor to allow easier reviewing > - Remove requirement for CAPS_SYS_ADMIN until we come up with > a > security policy (this means that file restore may fail) > - Other cleanup and response to comments for v1 > > [2008-Jul-29] v1: > - Initial version: support a single task with address space > of only > private anonymous or file-mapped VMAs; syscalls ignore > pid/crid > argument and act on current process. > > -- > At the containers mini-conference before OLS, the consensus > among > all the stakeholders was that doing checkpoint/restart in the > kernel > as much as possible was the best approach. With this > approach, the > kernel will export a relatively opaque 'blob' of data to > userspace > which can then be handed to the new kernel at restore time. > > This is different than what had been proposed before, which > was > that a userspace application would be responsible for > collecting > all of this data. We were also planning on adding lots of > new, > little kernel interfaces for all of the things that needed > checkpointing. This unites those into a single, grand > interface. > > The 'blob' will contain copies of select portions of kernel > structures such as vmas and mm_structs. It will also contain > copies of the actual memory that the process uses. Any > changes > in this blob's format between kernel revisions can be handled > by > an in-userspace conversion program. > > This is a similar approach to virtually all of the commercial > checkpoint/restart products out there, as well as the research > project Zap. > > These patches basically serialize internel kernel state and > write > it out to a file descriptor. The checkpoint and restore are > done > with two new system calls: sys_checkpoint and sys_restart. > > In this incarnation, they can only work checkpoint and restore > a > single task. The task's address space may consist of only > private, > simple vma's - anonymous or file-mapped. The open files may > consist > of only simple files and directories. > -- > > -- > To unsubscribe from this list: send the line "unsubscribe > linux-kernel" in > the body of a message to [email protected] > More majordomo info at > http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > > > > -- > Regards & Thanks-- > Subrata > ------------------------------------------------------------------------------ > Apps built with the Adobe(R) Flex(R) framework and Flex Builder(TM) are > powering Web 2.0 with engaging, cross-platform capabilities. 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