Re: [PATCH] Expose SHM_HUGETLB in shmctl(id, IPC_STAT, ...)

Arun Sharma <[email protected]> wrote:
>
>  Andrew Morton wrote:
> 
>  >>>How important is this feature?
>  >>
>  >>Without this feature, an application has no way to figure out if a given 
>  >>segment is hugetlb or not. Applications need to know this to be able to 
>  >>handle alignment issues properly.
>  >>
>  >>Also, if the flag is exported via ipcs, the system administrator would 
>  >>have a better idea about how the hugetlb pages she configured on the 
>  >>system are getting used.
>  >>
>  > 
>  > 
>  > I'd suggest that any API which allows us to query the hugeness of a piece
>  > of memory should also work for mmap(hugetld_fd...).  IOW: this capability
>  > shouldn't be restricted to sysv shm areas.
> 
>  The capability I was talking about was the ability to figure out where 
>  the configured hugetlb pages are going (vs is this a hugetlb page?).

Well, please figure out a way which has less risk of breaking userspace.

Bear in mind that the sort of apps we're talking about here are
dubiously-written monsters with long and costly upgrade cycles and we tend
to not get any reports until many many months after we made a kernel
change.  It's very costly all round and we need to be cautious.
-
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/

---

• Follow-Ups:
  • Re: [PATCH] Expose SHM_HUGETLB in shmctl(id, IPC_STAT, ...)
    • From: "Michael Kerrisk" <[email protected]>

• References:
  • [PATCH] Expose SHM_HUGETLB in shmctl(id, IPC_STAT, ...)
    • From: Arun Sharma <[email protected]>
  • Re: [PATCH] Expose SHM_HUGETLB in shmctl(id, IPC_STAT, ...)
    • From: Andrew Morton <[email protected]>
  • Re: [PATCH] Expose SHM_HUGETLB in shmctl(id, IPC_STAT, ...)
    • From: Arun Sharma <[email protected]>
  • Re: [PATCH] Expose SHM_HUGETLB in shmctl(id, IPC_STAT, ...)
    • From: Andrew Morton <[email protected]>
  • Re: [PATCH] Expose SHM_HUGETLB in shmctl(id, IPC_STAT, ...)
    • From: Arun Sharma <[email protected]>
  • Re: [PATCH] Expose SHM_HUGETLB in shmctl(id, IPC_STAT, ...)
    • From: Andrew Morton <[email protected]>
  • Re: [PATCH] Expose SHM_HUGETLB in shmctl(id, IPC_STAT, ...)
    • From: Arun Sharma <[email protected]>

• Prev by Date: Re: [PATCH] plugsched - update Kconfig
• Next by Date: [PATCH] plugsched - update Kconfig-1
• Previous by thread: Re: [PATCH] Expose SHM_HUGETLB in shmctl(id, IPC_STAT, ...)
• Next by thread: Re: [PATCH] Expose SHM_HUGETLB in shmctl(id, IPC_STAT, ...)
• Index(es):
  • Date
  • Thread

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]