This patchset is against Minchan's vrange work here: https://lkml.org/lkml/2013/3/12/105 Extending it to support volatile ranges on files. In effect providing the same functionality of my earlier file based volatile range patches on-top of Minchan's anonymous volatile range work. Volatile ranges on files are different then on anonymous memory, because the volatility state can be shared between multiple applications. This makes storing the volatile ranges exclusively in the mm_struct (or in vmas as in Minchan's earlier work) inappropriate. The patchset starts with some minor cleanup. Then we introduce the idea of a vrange_root, which provides a interval-tree root and a lock to protect the tree. This structure can then be stored in the mm_struct or in an addres_space. Then the same infrastructure can be used to manage volatile ranges on both anonymous and file backed memory. Next we introduce a parallel fvrange() syscall for creating volatile ranges directly against files. And finally, we change the range pruging logic to be able to handle both anonymous and file volatile ranges. Now there are some quirks still to be resolved with the approach used here. The biggest one being the vrange() call can't be used to create volatile ranges against mmapped files. Instead only the fvrange() can be used to create file backed volatile ranges. This could be overcome by iterating across all the process VMAs to determine if they're anonymous or file based, and if file-based, create a VMA sized volatile range on the mapping pointed to by the VMA. But this would have downsides, as Minchan has been clear that he wants to optmize the vrange() calls so that it is very cheap to create and destroy volatile ranges. Having simple per-process ranges be created means we don't have to iterate across the vmas in the range to determine if they're anonymous or file backed. Instead the current vrange() code just creates per process ranges (which may or may not cover mmapped file data), but will only purge anonymous pages in that range. This keeps the vrange() call cheap. Additionally, just creating or destroying a single range is very simple to do, and requires a fixed amount of memory known up front. Thus we can allocate needed data prior to making any modifications. But If we were to create a range that crosses anonymous and file backed pages, it must create or destroy multiple per-process or per-file ranges. This could require an unknown number of allocations, opening the possibility of getting an ENOMEM half-way through the operation, leaving the volatile range partially created or destroyed. So to keep this simple for this first pass, for now we have two syscalls for two types of volatile ranges. Let me know if you have any thoughts or comments. I'm sure there's plenty of room for improvement here. In the meantime I'll be playing with some different approaches to try to handle single volatile ranges that cross file and anonymous vmas. The entire queue, both Minchan's changes and mine can be found here: git://git.linaro.org/people/jstultz/android-dev.git dev/vrange-minchan thanks -john Cc: linux-mm@xxxxxxxxx Cc: Michael Kerrisk <mtk.manpages@xxxxxxxxx> Cc: Arun Sharma <asharma@xxxxxx> Cc: Mel Gorman <mel@xxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Dave Hansen <dave@xxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxx> Cc: Neil Brown <neilb@xxxxxxx> Cc: Mike Hommey <mh@xxxxxxxxxxxx> Cc: Taras Glek <tglek@xxxxxxxxxxx> Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Cc: Jason Evans <je@xxxxxx> Cc: sanjay@xxxxxxxxxx Cc: Paul Turner <pjt@xxxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Michel Lespinasse <walken@xxxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Minchan Kim <minchan@xxxxxxxxxx> John Stultz (4): vrange: Make various vrange.c local functions static vrange: Introduce vrange_root to make vrange structures more flexible vrange: Support fvrange() syscall for file based volatile ranges vrange: Enable purging of file backed volatile ranges arch/x86/syscalls/syscall_64.tbl | 1 + fs/file_table.c | 5 + fs/inode.c | 2 + fs/proc/task_mmu.c | 10 +- include/linux/fs.h | 2 + include/linux/mm_types.h | 4 +- include/linux/vrange.h | 60 ++++--- include/linux/vrange_types.h | 22 +++ kernel/fork.c | 2 +- mm/vrange.c | 334 ++++++++++++++++++++++++++------------ 10 files changed, 308 insertions(+), 134 deletions(-) create mode 100644 include/linux/vrange_types.h -- 1.7.10.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>