On 3/2/20 8:36 PM, Minchan Kim wrote:
> Bail out to prevent unnecessary CPU overhead if target process has
> pending fatal signal during (MADV_COLD|MADV_PAGEOUT) operation.
>
> Reviewed-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
> Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx>
Nit below:
> ---
> mm/madvise.c | 29 +++++++++++++++++++++--------
> 1 file changed, 21 insertions(+), 8 deletions(-)
>
> diff --git a/mm/madvise.c b/mm/madvise.c
> index 349473fc6683..6543f2bfc3d8 100644
> --- a/mm/madvise.c
> +++ b/mm/madvise.c
> @@ -36,6 +36,7 @@
> struct madvise_walk_private {
> struct mmu_gather *tlb;
> bool pageout;
> + struct task_struct *target_task;
> };
>
> /*
> @@ -316,6 +317,10 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd,
> if (fatal_signal_pending(current))
> return -EINTR;
>
> + if (private->target_task &&
> + fatal_signal_pending(private->target_task))
> + return -EINTR;
With madvise(2) private->target_task will be current, thus current will be
tested twice. Not wrong, but maybe add a "private->target_task != current"
condition?
