wierd new config options - Kernel

This is a discussion on wierd new config options - Kernel ; Why is UNEVICTABLE_LRU and option? Is there any rason to turn it off or is this just to confuse users? CORE_DUMP_DEFAULT_ELF_HEADERS is similarly odd, it turns something on that break old userspace, this really really should be a sysctl to ...

+ Reply to Thread
Results 1 to 6 of 6

Thread: wierd new config options

  1. wierd new config options

    Why is UNEVICTABLE_LRU and option? Is there any rason to turn it off or
    is this just to confuse users?

    CORE_DUMP_DEFAULT_ELF_HEADERS is similarly odd, it turns something on
    that break old userspace, this really really should be a sysctl to turn
    on instead of a config option.
    --
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

  2. Re: wierd new config options

    On Thu, 2008-10-23 at 20:18 +0200, Christoph Hellwig wrote:
    > Why is UNEVICTABLE_LRU and option? Is there any rason to turn it off or
    > is this just to confuse users?



    We discussed this back when we first submitted the patches. I
    considered the NONRECLAIMABLE/UNEVICTABLE LRU mechanism to be a wee bit
    experimental at the time. I wasn't sure that all platform that do want
    memory management would necessarily also want the unevictable lru. It's
    easier for me to build it with the option and remove it later than vice
    versa. If the consensus of the community is that it should always be
    enabled, then I'm fine with removing the option.

    Lee

    >
    > CORE_DUMP_DEFAULT_ELF_HEADERS is similarly odd, it turns something on
    > that break old userspace, this really really should be a sysctl to turn
    > on instead of a config option.


    --
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

  3. Re: wierd new config options

    On Thu, Oct 23, 2008 at 03:16:44PM -0400, Lee Schermerhorn wrote:
    > On Thu, 2008-10-23 at 20:18 +0200, Christoph Hellwig wrote:
    > > Why is UNEVICTABLE_LRU and option? Is there any rason to turn it off or
    > > is this just to confuse users?

    >
    >
    > We discussed this back when we first submitted the patches. I
    > considered the NONRECLAIMABLE/UNEVICTABLE LRU mechanism to be a wee bit
    > experimental at the time. I wasn't sure that all platform that do want
    > memory management would necessarily also want the unevictable lru. It's
    > easier for me to build it with the option and remove it later than vice
    > versa. If the consensus of the community is that it should always be
    > enabled, then I'm fine with removing the option.


    The problem is that average admin can't make useful judgement on
    this: active pageout lists -- what the hell is it?, kswapd -- ok, I
    remember this process from ps(1) output, "will not waste" -- ok, good
    thing, "will use one page flag" -- how many more I have?, what will
    happen if they emptied?

    And distro kernel maintainer should also make a decision -- not a module, after all.
    --
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

  4. Re: wierd new config options

    Christoph Hellwig wrote:
    > Why is UNEVICTABLE_LRU and option? Is there any rason to turn it off or
    > is this just to confuse users?


    Since the swapout code itself is already configurable with
    CONFIG_SWAP, I do believe we want to be able to config out
    the unevictable LRU code.

    I guess it could be argued that maybe CONFIG_UNEVICTABLE_LRU
    should just be folded into CONFIG_SWAP...

    --
    All Rights Reversed
    --
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

  5. Re: wierd new config options

    On Thu, Oct 23, 2008 at 03:59:42PM -0400, Rik van Riel wrote:
    > Christoph Hellwig wrote:
    > >Why is UNEVICTABLE_LRU and option? Is there any rason to turn it off or
    > >is this just to confuse users?

    >
    > Since the swapout code itself is already configurable with
    > CONFIG_SWAP, I do believe we want to be able to config out
    > the unevictable LRU code.
    >
    > I guess it could be argued that maybe CONFIG_UNEVICTABLE_LRU
    > should just be folded into CONFIG_SWAP...


    Sounds like a good plan.

    --
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

  6. Re: wierd new config options

    > CORE_DUMP_DEFAULT_ELF_HEADERS is similarly odd, it turns something on
    > that break old userspace, this really really should be a sysctl to turn
    > on instead of a config option.


    Both the kconfig help text and the commit's log mention that this is
    controlled per-process via /proc/PID/coredump_filter. The new config
    option only changes the boot-time default value to be inherited.


    Thanks,
    Roland
    --
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

+ Reply to Thread