On Mon, 8 Oct 2012, Dave Jones wrote:
> unanswered question: why are the buffer sizes here different ? which is correct?
>
Given the current set of mempolicy modes and flags, it's 34, but this can
change if new modes or flags are added with longer names. I see no reason
why shmem shouldn't round up to the nearest power-of-2 of 64 like it
already does, but 50 is certainly safe as well in task_mmu.c.
> diff -durpN '--exclude-from=/home/davej/.exclude' src/git-trees/kernel/linux/fs/proc/task_mmu.c linux-dj/fs/proc/task_mmu.c
> --- src/git-trees/kernel/linux/fs/proc/task_mmu.c 2012-05-31 22:32:46.778150675 -0400
> +++ linux-dj/fs/proc/task_mmu.c 2012-10-04 19:31:41.269988984 -0400
> @@ -1162,6 +1162,7 @@ static int show_numa_map(struct seq_file
> struct mm_walk walk = {};
> struct mempolicy *pol;
> int n;
> + int ret;
> char buffer[50];
>
> if (!mm)
> @@ -1178,7 +1179,11 @@ static int show_numa_map(struct seq_file
> walk.mm = mm;
>
> pol = get_vma_policy(proc_priv->task, vma, vma->vm_start);
> - mpol_to_str(buffer, sizeof(buffer), pol, 0);
> + memset(buffer, 0, sizeof(buffer));
> + ret = mpol_to_str(buffer, sizeof(buffer), pol, 0);
> + if (ret < 0)
> + return 0;
We should need the mpol_cond_put(pol) here before returning.
> +
> mpol_cond_put(pol);
>
> seq_printf(m, "%08lx %s", vma->vm_start, buffer);
> diff -durpN '--exclude-from=/home/davej/.exclude' src/git-trees/kernel/linux/mm/shmem.c linux-dj/mm/shmem.c
> --- src/git-trees/kernel/linux/mm/shmem.c 2012-10-02 15:49:51.977277944 -0400
> +++ linux-dj/mm/shmem.c 2012-10-04 19:32:28.862949907 -0400
> @@ -885,13 +885,15 @@ redirty:
> static void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol)
> {
> char buffer[64];
> + int ret;
>
> if (!mpol || mpol->mode == MPOL_DEFAULT)
> return; /* show nothing */
>
> - mpol_to_str(buffer, sizeof(buffer), mpol, 1);
> -
> - seq_printf(seq, ",mpol=%s", buffer);
> + memset(buffer, 0, sizeof(buffer));
> + ret = mpol_to_str(buffer, sizeof(buffer), mpol, 1);
> + if (ret > 0)
> + seq_printf(seq, ",mpol=%s", buffer);
> }
>
> static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo)
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