This is the third version of: http://marc.info/?l=linux-scsi&m=120038907123706&w=2 The changes from the second version are: - Fixed the memory leak bug that Boaz pointed out. shots->backup_sense_buffer has gone. One sense buffer is allocated per host and it's always attached to the scsi_cmnd linked with freelist (backup command). - Calling scsi_setup_command_sense_buffer in scsi_host_alloc instead of scsi_add_host. The first version tries to allocates as many buffers as shost->can_queue so scsi_setup_command_sense_buffer is called in scsi_add_host. But, it's not the case any more, so this calls scsi_setup_command_sense_buffer in scsi_host_alloc like scsi_setup_command_freelist. I did the same tests against this patch (though I knew there were not the performnace differences): dynamic sense buf (slub) | 483.5 MB/s IOPS 123772.7/s For convenience, here are the previous results: scsi-misc (slub) | 486.9 MB/s IOPS 124652.9/s dynamic sense buf (slub) | 483.2 MB/s IOPS 123704.1/s I put the results and the kernel configuration: http://www.kernel.org/pub/linux/kernel/people/tomo/sense/ = From: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx> Subject: [PATCH] use dynamically allocated sense buffer This removes static array sense_buffer in scsi_cmnd and uses dynamically allocated sense_buffer (with GFP_DMA). The reason for doing this is that some architectures need cacheline aligned buffer for DMA: http://lkml.org/lkml/2007/11/19/2 The problems are that scsi_eh_prep_cmnd puts scsi_cmnd::sense_buffer to sglist and some LLDs directly DMA to scsi_cmnd::sense_buffer. It's necessary to DMA to scsi_cmnd::sense_buffer safely. This patch solves these issues. __scsi_get_command allocates sense_buffer via kmem_cache_alloc and attaches it to a scsi_cmnd so everything just work as before. Signed-off-by: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx> --- drivers/scsi/hosts.c | 9 ++++++- drivers/scsi/scsi.c | 61 ++++++++++++++++++++++++++++++++++++++++++++- drivers/scsi/scsi_priv.h | 2 + include/scsi/scsi_cmnd.h | 2 +- 4 files changed, 70 insertions(+), 4 deletions(-) diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c index 9a10b43..f5d3fbb 100644 --- a/drivers/scsi/hosts.c +++ b/drivers/scsi/hosts.c @@ -268,6 +268,7 @@ static void scsi_host_dev_release(struct device *dev) } scsi_destroy_command_freelist(shost); + scsi_destroy_command_sense_buffer(shost); if (shost->bqt) blk_free_tags(shost->bqt); @@ -372,10 +373,14 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize) else shost->dma_boundary = 0xffffffff; - rval = scsi_setup_command_freelist(shost); + rval = scsi_setup_command_sense_buffer(shost); if (rval) goto fail_kfree; + rval = scsi_setup_command_freelist(shost); + if (rval) + goto fail_destroy_sense; + device_initialize(&shost->shost_gendev); snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d", shost->host_no); @@ -399,6 +404,8 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize) fail_destroy_freelist: scsi_destroy_command_freelist(shost); + fail_destroy_sense: + scsi_destroy_command_sense_buffer(shost); fail_kfree: kfree(shost); return NULL; diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c index 54ff611..0a4a5b8 100644 --- a/drivers/scsi/scsi.c +++ b/drivers/scsi/scsi.c @@ -161,6 +161,9 @@ static struct scsi_host_cmd_pool scsi_cmd_dma_pool = { static DEFINE_MUTEX(host_cmd_pool_mutex); +static struct kmem_cache *sense_buffer_slab; +static int sense_buffer_slab_users; + /** * __scsi_get_command - Allocate a struct scsi_cmnd * @shost: host to transmit command @@ -172,6 +175,7 @@ static DEFINE_MUTEX(host_cmd_pool_mutex); struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask) { struct scsi_cmnd *cmd; + unsigned char *buf; cmd = kmem_cache_alloc(shost->cmd_pool->slab, gfp_mask | shost->cmd_pool->gfp_mask); @@ -186,6 +190,21 @@ struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask) list_del_init(&cmd->list); } spin_unlock_irqrestore(&shost->free_list_lock, flags); + + if (cmd) { + buf = cmd->sense_buffer; + memset(cmd, 0, sizeof(*cmd)); + cmd->sense_buffer = buf; + } + } else { + buf = kmem_cache_alloc(sense_buffer_slab, __GFP_DMA|gfp_mask); + if (likely(buf)) { + memset(cmd, 0, sizeof(*cmd)); + cmd->sense_buffer = buf; + } else { + kmem_cache_free(shost->cmd_pool->slab, cmd); + cmd = NULL; + } } return cmd; @@ -212,7 +231,6 @@ struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask) if (likely(cmd != NULL)) { unsigned long flags; - memset(cmd, 0, sizeof(*cmd)); cmd->device = dev; init_timer(&cmd->eh_timeout); INIT_LIST_HEAD(&cmd->list); @@ -246,8 +264,10 @@ void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd, } spin_unlock_irqrestore(&shost->free_list_lock, flags); - if (likely(cmd != NULL)) + if (likely(cmd != NULL)) { + kmem_cache_free(sense_buffer_slab, cmd->sense_buffer); kmem_cache_free(shost->cmd_pool->slab, cmd); + } put_device(dev); } @@ -290,6 +310,7 @@ int scsi_setup_command_freelist(struct Scsi_Host *shost) { struct scsi_host_cmd_pool *pool; struct scsi_cmnd *cmd; + unsigned char *sense_buffer; spin_lock_init(&shost->free_list_lock); INIT_LIST_HEAD(&shost->free_list); @@ -319,9 +340,18 @@ int scsi_setup_command_freelist(struct Scsi_Host *shost) GFP_KERNEL | shost->cmd_pool->gfp_mask); if (!cmd) goto fail2; + + sense_buffer = kmem_cache_alloc(sense_buffer_slab, + GFP_KERNEL | __GFP_DMA); + if (!sense_buffer) + goto destroy_backup; + + cmd->sense_buffer = sense_buffer; list_add(&cmd->list, &shost->free_list); return 0; +destroy_backup: + kmem_cache_free(shost->cmd_pool->slab, cmd); fail2: mutex_lock(&host_cmd_pool_mutex); if (!--pool->users) @@ -342,6 +372,7 @@ void scsi_destroy_command_freelist(struct Scsi_Host *shost) cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list); list_del_init(&cmd->list); + kmem_cache_free(sense_buffer_slab, cmd->sense_buffer); kmem_cache_free(shost->cmd_pool->slab, cmd); } @@ -351,6 +382,32 @@ void scsi_destroy_command_freelist(struct Scsi_Host *shost) mutex_unlock(&host_cmd_pool_mutex); } +int scsi_setup_command_sense_buffer(struct Scsi_Host *shost) +{ + mutex_lock(&host_cmd_pool_mutex); + if (!sense_buffer_slab_users) { + sense_buffer_slab = kmem_cache_create("scsi_sense_buffer", + SCSI_SENSE_BUFFERSIZE, + 0, SLAB_CACHE_DMA, NULL); + if (!sense_buffer_slab) { + mutex_unlock(&host_cmd_pool_mutex); + return -ENOMEM; + } + } + sense_buffer_slab_users++; + mutex_unlock(&host_cmd_pool_mutex); + + return 0; +} + +void scsi_destroy_command_sense_buffer(struct Scsi_Host *shost) +{ + mutex_lock(&host_cmd_pool_mutex); + if (!--sense_buffer_slab_users) + kmem_cache_destroy(sense_buffer_slab); + mutex_unlock(&host_cmd_pool_mutex); +} + #ifdef CONFIG_SCSI_LOGGING void scsi_log_send(struct scsi_cmnd *cmd) { diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h index 3f34e93..55c6f71 100644 --- a/drivers/scsi/scsi_priv.h +++ b/drivers/scsi/scsi_priv.h @@ -27,6 +27,8 @@ extern void scsi_exit_hosts(void); extern int scsi_dispatch_cmd(struct scsi_cmnd *cmd); extern int scsi_setup_command_freelist(struct Scsi_Host *shost); extern void scsi_destroy_command_freelist(struct Scsi_Host *shost); +extern int scsi_setup_command_sense_buffer(struct Scsi_Host *shost); +extern void scsi_destroy_command_sense_buffer(struct Scsi_Host *shost); extern void __scsi_done(struct scsi_cmnd *cmd); #ifdef CONFIG_SCSI_LOGGING void scsi_log_send(struct scsi_cmnd *cmd); diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h index 3f47e52..abd7479 100644 --- a/include/scsi/scsi_cmnd.h +++ b/include/scsi/scsi_cmnd.h @@ -88,7 +88,7 @@ struct scsi_cmnd { working on */ #define SCSI_SENSE_BUFFERSIZE 96 - unsigned char sense_buffer[SCSI_SENSE_BUFFERSIZE]; + unsigned char *sense_buffer; /* obtained by REQUEST SENSE when * CHECK CONDITION is received on original * command (auto-sense) */ -- 1.5.3.4 - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
