| Message ID | 20191111023930.638129-9-damien.lemoal@wdc.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | Zoned block device enhancements and zone report rework | expand |
On 11/11/19 3:39 AM, Damien Le Moal wrote: > There is no need to arbitrarily limit the size of a report zone to the > number of zones defined by SD_ZBC_REPORT_MAX_ZONES. Rather, simply > calculate the report buffer size needed for the requested number of > zones without exceeding the device total number of zones. This buffer > size limitation to the hardware maximum transfer size and page mapping > capabilities is kept unchanged. Starting with this initial buffer size, > the allocation is optimized by iterating over decreasing buffer size > until the allocation succeeds (each iteration is allowed to fail fast > using the __GFP_NORETRY flag). This ensures forward progress for zone > reports and avoids failures of zones revalidation under memory pressure. > > While at it, also replace the hard coded 512 B sector size with the > SECTOR_SIZE macro. > > Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> > --- > drivers/scsi/sd_zbc.c | 24 +++++++++++++----------- > 1 file changed, 13 insertions(+), 11 deletions(-) > Reviewed-by: Hannes Reinecke <hare@suse.de> Cheers, Hannes
On Mon, Nov 11, 2019 at 11:39:29AM +0900, Damien Le Moal wrote: > There is no need to arbitrarily limit the size of a report zone to the > number of zones defined by SD_ZBC_REPORT_MAX_ZONES. Rather, simply > calculate the report buffer size needed for the requested number of > zones without exceeding the device total number of zones. This buffer > size limitation to the hardware maximum transfer size and page mapping > capabilities is kept unchanged. Starting with this initial buffer size, > the allocation is optimized by iterating over decreasing buffer size > until the allocation succeeds (each iteration is allowed to fail fast > using the __GFP_NORETRY flag). This ensures forward progress for zone > reports and avoids failures of zones revalidation under memory pressure. > > While at it, also replace the hard coded 512 B sector size with the > SECTOR_SIZE macro. > > Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Looks fine even with the __vmalloc usage: Reviewed-by: Christoph Hellwig <hch@lst.de>
Damien, > There is no need to arbitrarily limit the size of a report zone to the > number of zones defined by SD_ZBC_REPORT_MAX_ZONES. Rather, simply > calculate the report buffer size needed for the requested number of > zones without exceeding the device total number of zones. This buffer > size limitation to the hardware maximum transfer size and page mapping > capabilities is kept unchanged. Starting with this initial buffer size, > the allocation is optimized by iterating over decreasing buffer size > until the allocation succeeds (each iteration is allowed to fail fast > using the __GFP_NORETRY flag). This ensures forward progress for zone > reports and avoids failures of zones revalidation under memory pressure. Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
diff --git a/drivers/scsi/sd_zbc.c b/drivers/scsi/sd_zbc.c index 7c4690f26698..663608d1003b 100644 --- a/drivers/scsi/sd_zbc.c +++ b/drivers/scsi/sd_zbc.c @@ -104,11 +104,6 @@ static int sd_zbc_do_report_zones(struct scsi_disk *sdkp, unsigned char *buf, return 0; } -/* - * Maximum number of zones to get with one report zones command. - */ -#define SD_ZBC_REPORT_MAX_ZONES 8192U - /** * Allocate a buffer for report zones reply. * @sdkp: The target disk @@ -138,17 +133,24 @@ static void *sd_zbc_alloc_report_buffer(struct scsi_disk *sdkp, * sure that the allocated buffer can always be mapped by limiting the * number of pages allocated to the HBA max segments limit. */ - nr_zones = min(nr_zones, SD_ZBC_REPORT_MAX_ZONES); - bufsize = roundup((nr_zones + 1) * 64, 512); + nr_zones = min(nr_zones, sdkp->nr_zones); + bufsize = roundup((nr_zones + 1) * 64, SECTOR_SIZE); bufsize = min_t(size_t, bufsize, queue_max_hw_sectors(q) << SECTOR_SHIFT); bufsize = min_t(size_t, bufsize, queue_max_segments(q) << PAGE_SHIFT); - buf = vzalloc(bufsize); - if (buf) - *buflen = bufsize; + while (bufsize >= SECTOR_SIZE) { + buf = __vmalloc(bufsize, + GFP_KERNEL | __GFP_ZERO | __GFP_NORETRY, + PAGE_KERNEL); + if (buf) { + *buflen = bufsize; + return buf; + } + bufsize >>= 1; + } - return buf; + return NULL; } /**
There is no need to arbitrarily limit the size of a report zone to the number of zones defined by SD_ZBC_REPORT_MAX_ZONES. Rather, simply calculate the report buffer size needed for the requested number of zones without exceeding the device total number of zones. This buffer size limitation to the hardware maximum transfer size and page mapping capabilities is kept unchanged. Starting with this initial buffer size, the allocation is optimized by iterating over decreasing buffer size until the allocation succeeds (each iteration is allowed to fail fast using the __GFP_NORETRY flag). This ensures forward progress for zone reports and avoids failures of zones revalidation under memory pressure. While at it, also replace the hard coded 512 B sector size with the SECTOR_SIZE macro. Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> --- drivers/scsi/sd_zbc.c | 24 +++++++++++++----------- 1 file changed, 13 insertions(+), 11 deletions(-)