Re: [PATCH] perf/core: fast breakpoint modification via _IOC_MODIFY_BREAKPOINT

From: Jiri Olsa
Date: Mon Nov 06 2017 - 04:23:18 EST


On Sun, Nov 05, 2017 at 02:35:34PM -0800, Milind Chabbi wrote:

SNIP

> +static int _perf_event_modify_breakpoint(struct perf_event *bp,
> + struct perf_event_attr *attr)
> +{
> + u64 old_addr = bp->attr.bp_addr;
> + u64 old_len = bp->attr.bp_len;
> + int old_type = bp->attr.bp_type;
> + int err = 0;
> +
> + _perf_event_disable(bp);
> +
> + bp->attr.bp_addr = attr->bp_addr;
> + bp->attr.bp_type = attr->bp_type;
> + bp->attr.bp_len = attr->bp_len;
> +
> + if (attr->disabled)
> + goto end;
> +
> + err = validate_hw_breakpoint(bp);

thre patch is mangled.. seems like you've lost all your tabs somehow

anyway, should you also do the release_bp_slot/reserve_bp_slot
magic to keep the slot accounting corrent?

jirka