Apologies... I misspelled the family name of one of the Erlangen University authors of the first two patches in this patchset, so any reply-alls to any of the patch posts will see a bounce. If you reply-all to any of these patches, kindly change one of the recipients to: andor.daam@xxxxxxxxxxxxxx (was misspelled andor.damm) I regret the inconvenience... :-( > -----Original Message----- > From: Dan Magenheimer [mailto:dan.magenheimer@xxxxxxxxxx] > Sent: Wednesday, October 31, 2012 9:08 AM > To: devel@xxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; gregkh@xxxxxxxxxxxxxxxxxxx; linux- > mm@xxxxxxxxx; ngupta@xxxxxxxxxx; konrad.wilk@xxxxxxxxxx; sjenning@xxxxxxxxxxxxxxxxxx; > minchan@xxxxxxxxxx; dan.magenheimer@xxxxxxxxxx; fschmaus@xxxxxxxxx; andor.damm@xxxxxxxxxxxxxx; > ilendir@xxxxxxxxxxxxxx; akpm@xxxxxxxxxxxxxxxxxxxx; mgorman@xxxxxxx > Subject: [PATCH 0/5] enable all tmem backends to be built and loaded as modules > > Since various parts of transcendent memory ("tmem") [1] were first posted in > 2009, reviewers have suggested that various tmem features should be built > as a module and enabled by loading the module, rather than the current clunky > method of compiling as a built-in and enabling via boot parameter. Due > to certain tmem initialization steps, that was not feasible at the time. > > [1] http://lwn.net/Articles/454795/ > > This patchset allows each of the three merged transcendent memory > backends (zcache, ramster, Xen tmem) to be used as modules by first > enabling transcendent memory frontends (cleancache, frontswap) to deal > with "lazy initialization" and, second, by adding the necessary code for > the backends to be built and loaded as modules. > > The original mechanism to enable tmem backends -- namely to hardwire > them into the kernel and select/enable one with a kernel boot > parameter -- is retained but should be considered deprecated. When > backends are loaded as modules, certain knobs will now be > properly selected via module_params rather than via undocumented > kernel boot parameters. Note that module UNloading is not yet > supported as it is lower priority and will require significant > additional work. > > The lazy initialization support is necessary because filesystems > and swap devices are normally mounted early in boot and these > activites normally trigger tmem calls to setup certain data structures; > if the respective cleancache/frontswap ops are not yet registered > by a back end, the tmem setup would fail for these devices and > cleancache/frontswap would never be enabled for them which limits > much of the value of tmem in many system configurations. Lazy > initialization records the necessary information in cleancache/frontswap > data structures and "replays" it after the ops are registered > to ensure that all filesystems and swap devices can benefit from > the loaded tmem backend. > > Patches 1 and 2 are the original [2] patches to cleancache and frontswap > proposed by Erlangen University, but rebased to 3.7-rcN plus a couple > of bug fixes I found necessary to run properly. I have not attempted > any code cleanup. I have also added defines to ensure at runtime > that backends are not loaded as modules if the frontend patches are not > yet merged; this is useful to avoid any build dependency (since the > frontends may be merged into linux-next through different trees and > at different times than some backends) and once the entire patchset > is safely merged, these defines/ifdefs can be removed. > > [2] http://www.spinics.net/lists/linux-mm/msg31490.html > > Patch 3 enables module support for zcache2. Zsmalloc support > has not yet been merged into zcache2 but, once merged, could now > easily be selected via a module_param. > > Patch 4 enables module support for ramster. Ramster will now be > enabled with a module_param to zcache2. > > Patch 5 enables module support for the Xen tmem shim. Xen > self-ballooning and frontswap-selfshrinking are also "lazily" > initialized when the Xen tmem shim is loaded as a module, unless > explicitly disabled by module_params. > > Signed-off-by: Dan Magenheimer <dan.magenheimer@xxxxxxxxxx> > > --- > Diffstat: > > drivers/staging/ramster/Kconfig | 6 +- > drivers/staging/ramster/Makefile | 11 +- > drivers/staging/ramster/ramster.h | 6 +- > drivers/staging/ramster/ramster/nodemanager.c | 9 +- > drivers/staging/ramster/ramster/ramster.c | 29 +++- > drivers/staging/ramster/ramster/ramster.h | 2 +- > .../staging/ramster/ramster/ramster_nodemanager.h | 2 + > drivers/staging/ramster/tmem.c | 6 +- > drivers/staging/ramster/tmem.h | 8 +- > drivers/staging/ramster/zcache-main.c | 61 +++++++- > drivers/staging/ramster/zcache.h | 2 +- > drivers/xen/Kconfig | 4 +- > drivers/xen/tmem.c | 56 ++++++-- > drivers/xen/xen-selfballoon.c | 13 +- > include/linux/cleancache.h | 1 + > include/linux/frontswap.h | 1 + > include/xen/tmem.h | 8 + > mm/cleancache.c | 157 +++++++++++++++++-- > mm/frontswap.c | 70 ++++++++- > 19 files changed, 379 insertions(+), 73 deletions(-) _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
