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Date: Tue, 12 Mar 2013 18:04:16 +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 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 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; > rb->page_order = ilog2(nr_pages); > - rb->nr_pages = 1; > + rb->nr_pages = !!nr_pages; > > ring_buffer_init(rb, watermark, flags); > > > -- 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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