Hey Folks,
Can I get review further since I resolved most of concerns(especially,
description stuff) I got from previous iteration?
On Mon, Jan 27, 2020 at 04:16:36PM -0800, Minchan Kim wrote:
> Now, we have MADV_PAGEOUT and MADV_COLD as madvise hinting API. With that,
> application could give hints to kernel what memory range are preferred to be
> reclaimed. However, in some platform(e.g., Android), the information
> required to make the hinting decision is not known to the app.
> Instead, it is known to a centralized userspace daemon(e.g., ActivityManagerService),
> and that daemon must be able to initiate reclaim on its own without any app
> involvement.
>
> To solve the concern, this patch introduces new syscall - process_madvise(2).
> Bascially, it's same with madvise(2) syscall but it has some differences.
>
> 1. It needs pidfd of target process to provide the hint
> 2. It supports only MADV_{COLD|PAGEOUT|MERGEABLE|UNMEREABLE} at this moment.
> Other hints in madvise will be opened when there are explicit requests from
> community to prevent unexpected bugs we couldn't support.
> 3. Only privileged processes can do something for other process's address
> space.
>
> For more detail of the new API, please see "mm: introduce external memory hinting API"
> description in this patchset.
>
> Minchan Kim (3):
> mm: factor out madvise's core functionality
> mm: introduce external memory hinting API
> mm: support both pid and pidfd for process_madvise
>
> Oleksandr Natalenko (2):
> mm/madvise: employ mmget_still_valid for write lock
> mm/madvise: allow KSM hints for remote API
>
> * from v2 - https://lore.kernel.org/linux-mm/20200116235953.163318-1-minchan@xxxxxxxxxx/
> * check signal callee and caller to bail out - Kirill Tkhai
> * put more clarification for justification of new API
>
> * from v1 - https://lore.kernel.org/linux-mm/20200110213433.94739-1-minchan@xxxxxxxxxx/
> * fix syscall number - SeongJae
> * use get_pid_task - Kirill Tkhai
> * extend API to support pid as well as pidfd - Kirill Tkhai
>
> arch/alpha/kernel/syscalls/syscall.tbl | 1 +
> arch/arm/tools/syscall.tbl | 1 +
> arch/arm64/include/asm/unistd.h | 2 +-
> arch/arm64/include/asm/unistd32.h | 2 +
> arch/ia64/kernel/syscalls/syscall.tbl | 1 +
> arch/m68k/kernel/syscalls/syscall.tbl | 1 +
> arch/microblaze/kernel/syscalls/syscall.tbl | 1 +
> arch/mips/kernel/syscalls/syscall_n32.tbl | 1 +
> arch/mips/kernel/syscalls/syscall_n64.tbl | 1 +
> arch/parisc/kernel/syscalls/syscall.tbl | 1 +
> arch/powerpc/kernel/syscalls/syscall.tbl | 1 +
> arch/s390/kernel/syscalls/syscall.tbl | 1 +
> arch/sh/kernel/syscalls/syscall.tbl | 1 +
> arch/sparc/kernel/syscalls/syscall.tbl | 1 +
> arch/x86/entry/syscalls/syscall_32.tbl | 1 +
> arch/x86/entry/syscalls/syscall_64.tbl | 1 +
> arch/xtensa/kernel/syscalls/syscall.tbl | 1 +
> include/linux/pid.h | 1 +
> include/linux/syscalls.h | 3 +
> include/uapi/asm-generic/unistd.h | 5 +-
> kernel/exit.c | 17 --
> kernel/pid.c | 17 ++
> kernel/sys_ni.c | 1 +
> mm/madvise.c | 277 ++++++++++++++------
> 24 files changed, 238 insertions(+), 102 deletions(-)
>
> --
> 2.25.0.341.g760bfbb309-goog
>
