| Message ID | 20180323001538.31876-1-longli@linuxonhyperv.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
> -----Original Message----- > From: Long Li <longli@linuxonhyperv.com> > Sent: Thursday, March 22, 2018 8:16 PM > To: KY Srinivasan <kys@microsoft.com>; Haiyang Zhang > <haiyangz@microsoft.com>; Stephen Hemminger <sthemmin@microsoft.com>; > James E . J . Bottomley <JBottomley@odin.com>; Martin K . Petersen > <martin.petersen@oracle.com>; devel@linuxdriverproject.org; linux- > scsi@vger.kernel.org; linux-kernel@vger.kernel.org > Cc: Long Li <longli@microsoft.com> > Subject: [PATCH 1/3] Vmbus: Add function to report available ring buffer to > write in total ring size percentage > > From: Long Li <longli@microsoft.com> > > Netvsc has a similar function to calculate how much ring buffer in percentage > is available to write. This function is useful for storvsc and other vmbus devices. > > Define a similar function in vmbus to be used by storvsc. > > Signed-off-by: Long Li <longli@microsoft.com> > --- Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c index 8699bb969e7e..3c836c099a8f 100644 --- a/drivers/hv/ring_buffer.c +++ b/drivers/hv/ring_buffer.c @@ -227,6 +227,8 @@ int hv_ringbuffer_init(struct hv_ring_buffer_info *ring_info, ring_info->ring_buffer->feature_bits.value = 1; ring_info->ring_size = page_cnt << PAGE_SHIFT; + ring_info->ring_size_div10_reciprocal = + reciprocal_value(ring_info->ring_size / 10); ring_info->ring_datasize = ring_info->ring_size - sizeof(struct hv_ring_buffer); diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h index 2048f3c3b68a..eb7204851089 100644 --- a/include/linux/hyperv.h +++ b/include/linux/hyperv.h @@ -36,6 +36,7 @@ #include <linux/device.h> #include <linux/mod_devicetable.h> #include <linux/interrupt.h> +#include <linux/reciprocal_div.h> #define MAX_PAGE_BUFFER_COUNT 32 #define MAX_MULTIPAGE_BUFFER_COUNT 32 /* 128K */ @@ -121,6 +122,7 @@ struct hv_ring_buffer { struct hv_ring_buffer_info { struct hv_ring_buffer *ring_buffer; u32 ring_size; /* Include the shared header */ + struct reciprocal_value ring_size_div10_reciprocal; spinlock_t ring_lock; u32 ring_datasize; /* < ring_size */ @@ -155,6 +157,16 @@ static inline u32 hv_get_bytes_to_write(const struct hv_ring_buffer_info *rbi) return write; } +static inline u32 hv_get_avail_to_write_percent( + const struct hv_ring_buffer_info *rbi) +{ + u32 avail_write = hv_get_bytes_to_write(rbi); + + return reciprocal_divide( + (avail_write << 3) + (avail_write << 1), + rbi->ring_size_div10_reciprocal); +} + /* * VMBUS version is 32 bit entity broken up into * two 16 bit quantities: major_number. minor_number.