From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Christie Date: Mon, 30 Oct 2017 03:44:35 +0000 Subject: [PATCH 15/19] tcmu: simplify dbi thresh handling Message-Id: <1509335079-5276-16-git-send-email-mchristi@redhat.com> List-Id: References: <1509335079-5276-1-git-send-email-mchristi@redhat.com> In-Reply-To: <1509335079-5276-1-git-send-email-mchristi@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: martin.petersen@oracle.com, jejb@linux.vnet.ibm.com, linux-scsi@vger.kernel.org, target-devel@vger.kernel.org, nab@linux-iscsi.org Cc: Mike Christie We do not really save a lot by trying to increase thresh a multiple of the existing value. This just simplifies the code by increasing it to whatever is needed for the command being executed. Signed-off-by: Mike Christie --- drivers/target/target_core_user.c | 22 +++------------------- 1 file changed, 3 insertions(+), 19 deletions(-) diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c index 68668a8..0630657 100644 --- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -79,7 +79,6 @@ #define DATA_BLOCK_SIZE PAGE_SIZE #define DATA_BLOCK_BITS (256 * 1024) #define DATA_SIZE (DATA_BLOCK_BITS * DATA_BLOCK_SIZE) -#define DATA_BLOCK_INIT_BITS 128 /* The total size of the ring is 8M + 256K * PAGE_SIZE */ #define TCMU_RING_SIZE (CMDR_SIZE + DATA_SIZE) @@ -699,7 +698,6 @@ static bool is_ring_space_avail(struct tcmu_dev *udev, struct tcmu_cmd *cmd, if ((space * DATA_BLOCK_SIZE) < data_needed) { unsigned long blocks_left = DATA_BLOCK_BITS - udev->dbi_thresh + space; - unsigned long grow; if (blocks_left < blocks_needed) { pr_debug("no data space: only %lu available, but ask for %zu\n", @@ -708,23 +706,9 @@ static bool is_ring_space_avail(struct tcmu_dev *udev, struct tcmu_cmd *cmd, return false; } - /* Try to expand the thresh */ - if (!udev->dbi_thresh) { - /* From idle state */ - uint32_t init_thresh = DATA_BLOCK_INIT_BITS; - - udev->dbi_thresh = max(blocks_needed, init_thresh); - } else { - /* - * Grow the data area by max(blocks needed, - * dbi_thresh / 2), but limited to the max - * DATA_BLOCK_BITS size. - */ - grow = max(blocks_needed, udev->dbi_thresh / 2); - udev->dbi_thresh += grow; - if (udev->dbi_thresh > DATA_BLOCK_BITS) - udev->dbi_thresh = DATA_BLOCK_BITS; - } + udev->dbi_thresh += blocks_needed; + if (udev->dbi_thresh > DATA_BLOCK_BITS) + udev->dbi_thresh = DATA_BLOCK_BITS; } return tcmu_get_empty_blocks(udev, cmd); -- 1.8.3.1