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    SubjectRe: [PATCH v5 2/7] mm, kasan: SLAB support
    From
    2016-03-11 16:05 GMT+03:00 Alexander Potapenko <glider@google.com>:
    > On Fri, Mar 11, 2016 at 12:47 PM, Andrey Ryabinin
    > <ryabinin.a.a@gmail.com> wrote:
    >> 2016-03-09 14:05 GMT+03:00 Alexander Potapenko <glider@google.com>:
    >>
    >>> +struct kasan_track {
    >>> + u64 cpu : 6; /* for NR_CPUS = 64 */
    >>
    >> What about NR_CPUS > 64 ?
    > After a discussion with Dmitry we've decided to drop |cpu| and |when|
    > at all, as they do not actually help debugging.
    > This way we'll make kasan_track only 8 bytes (4 bytes for PID, 4 bytes
    > for stack handle).
    > Then the meta structures will be smaller and have nice alignment:
    >

    Sounds good.

    > struct kasan_track {
    > u32 pid;
    > depot_stack_handle_t stack;
    > };
    >
    > struct kasan_alloc_meta {
    > struct kasan_track track;
    > u32 state : 2; /* enum kasan_state */
    > u32 alloc_size : 30;
    > u32 reserved; /* we can use it to store an additional stack
    > handle, e.g. for debugging RCU */
    > };
    >
    > struct kasan_free_meta {
    > /* This field is used while the object is in the quarantine.
    > * Otherwise it might be used for the allocator freelist.
    > */
    > void **quarantine_link;
    > struct kasan_track track;
    > };
    >
    >
    >>> + u64 pid : 16; /* 65536 processes */
    >>> + u64 when : 42; /* ~140 years */
    >>> +};
    >>> +
    >
    >
    >
    > --
    > Alexander Potapenko
    > Software Engineer
    >
    > Google Germany GmbH
    > Erika-Mann-Straße, 33
    > 80636 München
    >
    > Geschäftsführer: Matthew Scott Sucherman, Paul Terence Manicle
    > Registergericht und -nummer: Hamburg, HRB 86891
    > Sitz der Gesellschaft: Hamburg

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