On Fri, 15 Feb 2008, Paul Jackson wrote:
> --- 2.6.24-mm1.orig/include/linux/mempolicy.h 2008-02-15 00:11:10.000000000
> -0800
> +++ 2.6.24-mm1/include/linux/mempolicy.h 2008-02-15 15:16:16.031031424
> -0800
> @@ -8,6 +8,14 @@
> * Copyright 2003,2004 Andi Kleen SuSE Labs
> */
>
> +/*
> + * The 'policy' field of 'struct mempolicy' has both a mode and
> + * some flags packed into it. The flags (MPOL_F_* below) occupy
> + * the high bit positions (MPOL_MODE_FLAGS), and the mempolicy
> + * modes (the "Policies" below) are encoded in the remaining low
> + * bit positions.
> + */
> +
> /* Policies */
> enum {
> MPOL_DEFAULT,
> @@ -18,16 +26,12 @@ enum {
> };
>
> /*
> - * The lower MPOL_FLAG_SHIFT bits of the policy mode represent the MPOL_*
> - * constants defined in the above enum. The upper bits represent optional
> - * set_mempolicy() or mbind() MPOL_F_* mode flags.
> + * Optional flags that modify nodemask numbering.
> */
> -#define MPOL_FLAG_SHIFT (8)
> -#define MPOL_MODE_MASK ((1 << MPOL_FLAG_SHIFT) - 1)
> -
> -/* Flags for set_mempolicy */
> -#define MPOL_F_STATIC_NODES (1 << MPOL_FLAG_SHIFT)
> -#define MPOL_MODE_FLAGS (MPOL_F_STATIC_NODES) /* legal
> set_mempolicy() MPOL_F_* flags */
> +#define MPOL_F_RELATIVE_NODES (1<<14) /* remapped relative to
> cpuset */
> +#define MPOL_F_STATIC_NODES (1<<15) /* unremapped physical masks */
> +#define MPOL_MODE_FLAGS (MPOL_F_RELATIVE_NODES|MPOL_F_STATIC_NODES)
> + /* combined MPOL_F_* mask flags
> */
>
> /* Flags for get_mempolicy */
> #define MPOL_F_NODE (1<<0) /* return next IL mode instead of node mask */
> @@ -128,14 +132,14 @@ static inline int mpol_equal(struct memp
>
> #define mpol_set_vma_default(vma) ((vma)->vm_policy = NULL)
>
> -static inline unsigned char mpol_mode(unsigned short mode)
> +static inline unsigned short mpol_mode(unsigned short mode)
> {
> - return mode & MPOL_MODE_MASK;
> + return mode & ~MPOL_MODE_FLAGS;
> }
>
> static inline unsigned short mpol_flags(unsigned short mode)
> {
> - return mode & ~MPOL_MODE_MASK;
> + return mode & MPOL_MODE_FLAGS;
> }
>
> /*
> @@ -201,7 +205,7 @@ static inline int mpol_equal(struct memp
>
> #define mpol_set_vma_default(vma) do {} while(0)
>
> -static inline unsigned char mpol_mode(unsigned short mode)
> +static inline unsigned short mpol_mode(unsigned short mode)
> {
> return 0;
> }
> --- 2.6.24-mm1.orig/mm/mempolicy.c 2008-02-15 00:18:35.000000000 -0800
> +++ 2.6.24-mm1/mm/mempolicy.c 2008-02-15 08:16:52.034431591 -0800
> @@ -884,8 +884,6 @@ asmlinkage long sys_mbind(unsigned long
>
> if (mpol_mode(mode) >= MPOL_MAX)
> return -EINVAL;
> - if (mpol_flags(mode) & ~MPOL_MODE_FLAGS)
> - return -EINVAL;
> err = get_nodes(&nodes, nmask, maxnode);
> if (err)
> return err;
> @@ -898,13 +896,9 @@ asmlinkage long sys_set_mempolicy(int mo
> {
> int err;
> nodemask_t nodes;
> - unsigned short flags;
>
> if (mpol_mode(mode) >= MPOL_MAX)
> return -EINVAL;
> - if (mpol_flags(mode) & ~MPOL_MODE_FLAGS)
> - return -EINVAL;
> - flags = mpol_flags(mode) & MPOL_MODE_FLAGS;
> err = get_nodes(&nodes, nmask, maxnode);
> if (err)
> return err;
>
There's been significant changes in this area since my last posting, but I
agree that doing a slight variation of this is better.
On that topic, I am ready to post the updated patchset but I'd like to do
it with your bitmap_onto() patch so that I can fully implement and test
MPOL_F_RELATIVE_NODES. Do you know when the patch that adds
bitmap_onto(), which is a name I think I noticed you liking, will be
available?
David
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