Messages in this thread Patch in this message | | | From | Nigel Cunningham <> | Subject | [Suspend2][ 04/20] [Suspend2] Calculate pagedir1 growth allowance. | Date | Tue, 27 Jun 2006 08:35:00 +1000 |
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While writing the LRU, and (more importantly) as a result of suspending the drivers, the amount of memory needed for the atomic copy may increase significantly. This amount is always predictable - LRU I/O will only ever get a few more slab pages allocated, and drivers suspend and resume will allocate a fixed number. The problem is that most drivers use virtually nothing, so that the default allowance of 100 pages is ample. NVidia drivers especially, however, allocate thousands of pages in some configurations, so we need a way for the user to be able to tune or autotune this value.
This routine provides a method for autotuning. If the allowance is set to zero, this routine will be invoked, determining how much extra memory will be allocated by the drivers when the real call is made later. We can then take that, plus our normal 100 page allowance, as the value to use.
Signed-off-by: Nigel Cunningham <nigel@suspend2.net>
kernel/power/prepare_image.c | 26 ++++++++++++++++++++++++++ 1 files changed, 26 insertions(+), 0 deletions(-)
diff --git a/kernel/power/prepare_image.c b/kernel/power/prepare_image.c index cb1a3da..271f904 100644 --- a/kernel/power/prepare_image.c +++ b/kernel/power/prepare_image.c @@ -81,3 +81,29 @@ long real_nr_free_pages(void) return nr_free_pages() + num_pcp_pages(); } +/* + * Discover how much extra memory will be required by the drivers + * when they're asked to suspend. We can then ensure that amount + * of memory is available when we really want it. + */ +static void get_extra_pd1_allowance(void) +{ + int orig_num_free = real_nr_free_pages(), final; + + suspend_prepare_status(CLEAR_BAR, "Finding allowance for drivers."); + device_suspend(PMSG_FREEZE); + local_irq_disable(); /* irqs might have been re-enabled on us */ + device_power_down(PMSG_FREEZE); + + final = real_nr_free_pages(); + + device_power_up(); + local_irq_enable(); + + device_resume(); + + extra_pd1_pages_allowance = max( + orig_num_free - final + MIN_EXTRA_PAGES_ALLOWANCE, + MIN_EXTRA_PAGES_ALLOWANCE); +} + -- Nigel Cunningham nigel at suspend2 dot net - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.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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