Messages in this thread | | | From | Joel Fernandes <> | Date | Wed, 4 Apr 2018 09:03:47 -0700 | Subject | Re: [PATCH] ring-buffer: Add set/clear_current_oom_origin() during allocations |
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On Wed, Apr 4, 2018 at 9:00 AM, Steven Rostedt <rostedt@goodmis.org> wrote: > On Wed, 4 Apr 2018 11:53:10 -0400 > Steven Rostedt <rostedt@goodmis.org> wrote: > >> @@ -1162,35 +1163,60 @@ static int rb_check_pages(struct ring_buffer_per_cpu *cpu_buffer) >> static int __rb_allocate_pages(long nr_pages, struct list_head *pages, int cpu) >> { >> struct buffer_page *bpage, *tmp; >> + bool user_thread = current->mm != NULL; >> + gfp_t mflags; >> long i; >> >> - /* Check if the available memory is there first */ >> + /* >> + * Check if the available memory is there first. >> + * Note, si_mem_available() only gives us a rough estimate of available >> + * memory. It may not be accurate. But we don't care, we just want >> + * to prevent doing any allocation when it is obvious that it is >> + * not going to succeed. >> + */ > > In case you are wondering how I tested this, I simply added: > > #if 0 >> i = si_mem_available(); >> if (i < nr_pages) >> return -ENOMEM; > #endif > > for the tests. Note, without this, I tried to allocate all memory > (bisecting it with allocations that failed and allocations that > succeeded), and couldn't trigger an OOM :-/
I guess you need to have something *else* other than the write to buffer_size_kb doing the GFP_KERNEL allocations but unfortunately gets OOM killed?
Also, I agree with the new patch and its nice idea to do that.
thanks,
- Joel
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