| Message ID | c5bd5a82d1250471822cbf5891ea1866166cd9e6.1550740533.git.bblock@linux.ibm.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [v2,1/2] scsi: replace GFP_ATOMIC with GFP_KERNEL for allocations in scsi_scan.c | expand |
On Thu, 2019-02-21 at 10:18 +0100, Benjamin Block wrote: > Looking at the code of scsi_alloc_sdev(), and all the calling contexts, > there seems to be no reason to use GFP_ATMOIC here. All the different > call-contexts use a mutex at some point, and nothing in between that > requires no sleeping, as far as I could see. Additionally, the code that > later allocates the block queue for the device (scsi_mq_alloc_queue()) > already uses GFP_KERNEL. > > > [ ... ] > > So replace all these, and give them a bit of a better chance to succeed, > with more chances of reclaim. Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Benjamin, > We had a test-report where, under memory pressure, adding LUNs to the > systems would fail (the tests add LUNs strictly in sequence): Applied to 5.1/scsi-queue, thanks!
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c index dd0d516f65e2..53380e07b40e 100644 --- a/drivers/scsi/scsi_scan.c +++ b/drivers/scsi/scsi_scan.c @@ -220,7 +220,7 @@ static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget, struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); sdev = kzalloc(sizeof(*sdev) + shost->transportt->device_size, - GFP_ATOMIC); + GFP_KERNEL); if (!sdev) goto out; @@ -788,7 +788,7 @@ static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result, */ sdev->inquiry = kmemdup(inq_result, max_t(size_t, sdev->inquiry_len, 36), - GFP_ATOMIC); + GFP_KERNEL); if (sdev->inquiry == NULL) return SCSI_SCAN_NO_RESPONSE; @@ -1079,7 +1079,7 @@ static int scsi_probe_and_add_lun(struct scsi_target *starget, if (!sdev) goto out; - result = kmalloc(result_len, GFP_ATOMIC | + result = kmalloc(result_len, GFP_KERNEL | ((shost->unchecked_isa_dma) ? __GFP_DMA : 0)); if (!result) goto out_free_sdev;
We had a test-report where, under memory pressure, adding LUNs to the systems would fail (the tests add LUNs strictly in sequence): [ 5525.853432] scsi 0:0:1:1088045124: Direct-Access IBM 2107900 .148 PQ: 0 ANSI: 5 [ 5525.853826] scsi 0:0:1:1088045124: alua: supports implicit TPGS [ 5525.853830] scsi 0:0:1:1088045124: alua: device naa.6005076303ffd32700000000000044da port group 0 rel port 43 [ 5525.853931] sd 0:0:1:1088045124: Attached scsi generic sg10 type 0 [ 5525.854075] sd 0:0:1:1088045124: [sdk] Disabling DIF Type 1 protection [ 5525.855495] sd 0:0:1:1088045124: [sdk] 2097152 512-byte logical blocks: (1.07 GB/1.00 GiB) [ 5525.855606] sd 0:0:1:1088045124: [sdk] Write Protect is off [ 5525.855609] sd 0:0:1:1088045124: [sdk] Mode Sense: ed 00 00 08 [ 5525.855795] sd 0:0:1:1088045124: [sdk] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA [ 5525.857838] sdk: sdk1 [ 5525.859468] sd 0:0:1:1088045124: [sdk] Attached SCSI disk [ 5525.865073] sd 0:0:1:1088045124: alua: transition timeout set to 60 seconds [ 5525.865078] sd 0:0:1:1088045124: alua: port group 00 state A preferred supports tolusnA [ 5526.015070] sd 0:0:1:1088045124: alua: port group 00 state A preferred supports tolusnA [ 5526.015213] sd 0:0:1:1088045124: alua: port group 00 state A preferred supports tolusnA [ 5526.587439] scsi_alloc_sdev: Allocation failure during SCSI scanning, some SCSI devices might not be configured [ 5526.588562] scsi_alloc_sdev: Allocation failure during SCSI scanning, some SCSI devices might not be configured Looking at the code of scsi_alloc_sdev(), and all the calling contexts, there seems to be no reason to use GFP_ATMOIC here. All the different call-contexts use a mutex at some point, and nothing in between that requires no sleeping, as far as I could see. Additionally, the code that later allocates the block queue for the device (scsi_mq_alloc_queue()) already uses GFP_KERNEL. There are similar allocations in two other functions: scsi_probe_and_add_lun(), and scsi_add_lun(),; that can also be done with GFP_KERNEL. Here is the contexts for the three functions so far: scsi_alloc_sdev() scsi_probe_and_add_lun() scsi_sequential_lun_scan() __scsi_scan_target() scsi_scan_target() mutex_lock() scsi_scan_channel() scsi_scan_host_selected() mutex_lock() scsi_report_lun_scan() __scsi_scan_target() ... __scsi_add_device() mutex_lock() __scsi_scan_target() ... scsi_report_lun_scan() ... scsi_get_host_dev() mutex_lock() scsi_probe_and_add_lun() ... scsi_add_lun() scsi_probe_and_add_lun() ... So replace all these, and give them a bit of a better chance to succeed, with more chances of reclaim. Signed-off-by: Benjamin Block <bblock@linux.ibm.com> --- drivers/scsi/scsi_scan.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)