Messages in this thread | | | Subject | Re: [PATCH] perf_events: improve DS/BTS/PEBS buffer allocation | From | Peter Zijlstra <> | Date | Mon, 13 Sep 2010 17:41:16 +0200 |
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On Mon, 2010-09-13 at 17:31 +0200, Stephane Eranian wrote: > On Mon, Sep 13, 2010 at 5:24 PM, Peter Zijlstra <peterz@infradead.org> wrote: > > On Mon, 2010-09-13 at 17:20 +0200, Stephane Eranian wrote: > > > >> That is the case we the sizes you have chosen today. For DS, we > >> could round up to one page for now. > > > > Markus chose the BTS size, for PEBS a single page was plenty since we do > > single event things (although we could do multiple for attr.precise_ip < > > 2). > > > > For DS there's: > > kmalloc_node(sizeof(struct ds), GFP_KERNEL | __GFP_ZERO, cpu_node(cpu)); > > > Ok, let try again with alloc_pages_node() + kmalloc_node(). > I think we can stick with kmalloc() for DS because we are far from > consuming a page.
Thing is, if you're really seeing allocation failures, alloc_pages_node() isn't going to help. And the problem is, these allocations aren't movable, so memory compaction and all the other fancy stuff aren't really going to help much :/
There was some talk about a function that should sync all of vmalloc space, but iirc it was broken for some configs.
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