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Date: Wed, 13 Mar 2013 12:15:57 +0100 From: Jiri Olsa <jolsa@...hat.com> To: Peter Zijlstra <a.p.zijlstra@...llo.nl> Cc: linux-kernel@...r.kernel.org, Corey Ashford <cjashfor@...ux.vnet.ibm.com>, Frederic Weisbecker <fweisbec@...il.com>, Ingo Molnar <mingo@...e.hu>, Namhyung Kim <namhyung@...nel.org>, Paul Mackerras <paulus@...ba.org>, Arnaldo Carvalho de Melo <acme@...hat.com> Subject: Re: [PATCHv3] perf: Fix vmalloc ring buffer free function On Tue, Mar 12, 2013 at 06:04:16PM +0100, Jiri Olsa wrote: > On Tue, Mar 12, 2013 at 05:24:50PM +0100, Peter Zijlstra wrote: > > Right you are.. > > > > How about something like the below; using that 0 << -1 is still 0. > > hum.. we are obviously not on the same page wrt 'confusing' ;-) > > looks ok, I'll test it hi, it work's fine.. Tested-by: Jiri Olsa <jolsa@...hat.com> > > jirka > > > > > --- > > kernel/events/ring_buffer.c | 8 ++++---- > > 1 file changed, 4 insertions(+), 4 deletions(-) > > > > diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c > > index 23cb34f..e72ca70 100644 > > --- a/kernel/events/ring_buffer.c > > +++ b/kernel/events/ring_buffer.c > > @@ -316,7 +316,7 @@ void rb_free(struct ring_buffer *rb) > > struct page * > > perf_mmap_to_page(struct ring_buffer *rb, unsigned long pgoff) > > { > > - if (pgoff > (1UL << page_order(rb))) > > + if (pgoff > (rb->nr_pages << page_order(rb))) > > return NULL; > > > > return vmalloc_to_page((void *)rb->user_page + pgoff * PAGE_SIZE); > > @@ -336,10 +336,10 @@ static void rb_free_work(struct work_struct *work) > > int i, nr; > > > > rb = container_of(work, struct ring_buffer, work); > > - nr = 1 << page_order(rb); > > + nr = rb->nr_pages << page_order(rb); > > > > base = rb->user_page; > > - for (i = 0; i < nr + 1; i++) > > + for (i = 0; i <= nr; i++) > > perf_mmap_unmark_page(base + (i * PAGE_SIZE)); > > > > vfree(base); > > @@ -373,7 +373,7 @@ struct ring_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags) > > rb->user_page = all_buf; > > rb->data_pages[0] = all_buf + PAGE_SIZE; just a nit pick.. in case of having just user page, data_pages[0] holds wrong pointer, but it 'should' be never touch in this case -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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