| Message ID | 1614120294-1930-1-git-send-email-mikelley@microsoft.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [v2,1/1] scsi: storvsc: Enable scatterlist entry lengths > 4Kbytes | expand |
Michael Kelley <mikelley@microsoft.com> writes: > storvsc currently sets .dma_boundary to limit scatterlist entries > to 4 Kbytes, which is less efficient with huge pages that offer > large chunks of contiguous physical memory. Improve the algorithm > for creating the Hyper-V guest physical address PFN array so > that scatterlist entries with lengths > 4Kbytes are handled. > As a result, remove the .dma_boundary setting. > > The improved algorithm also adds support for scatterlist > entries with offsets >= 4Kbytes, which is supported by many > other SCSI low-level drivers. And it retains support for > architectures where possibly PAGE_SIZE != HV_HYP_PAGE_SIZE > (such as ARM64). > > Signed-off-by: Michael Kelley <mikelley@microsoft.com> > --- > > Changes in v2: > * Add HVPFN_DOWN() macro and use it instead of open coding > [Vitaly Kuznetsov] > * Change loop that fills pfn array and its initialization > [Vitaly Kuznetsov] > * Use offset_in_hvpage() instead of open coding > > > drivers/scsi/storvsc_drv.c | 66 ++++++++++++++++------------------------------ > include/linux/hyperv.h | 1 + > 2 files changed, 24 insertions(+), 43 deletions(-) > > diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c > index 2e4fa77..5ba3145 100644 > --- a/drivers/scsi/storvsc_drv.c > +++ b/drivers/scsi/storvsc_drv.c > @@ -1678,9 +1678,8 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd) > struct storvsc_cmd_request *cmd_request = scsi_cmd_priv(scmnd); > int i; > struct scatterlist *sgl; > - unsigned int sg_count = 0; > + unsigned int sg_count; > struct vmscsi_request *vm_srb; > - struct scatterlist *cur_sgl; > struct vmbus_packet_mpb_array *payload; > u32 payload_sz; > u32 length; > @@ -1759,8 +1758,8 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd) > payload_sz = sizeof(cmd_request->mpb); > > if (sg_count) { > - unsigned int hvpgoff = 0; > - unsigned long offset_in_hvpg = sgl->offset & ~HV_HYP_PAGE_MASK; > + unsigned int hvpgoff, hvpfns_to_add; > + unsigned long offset_in_hvpg = offset_in_hvpage(sgl->offset); > unsigned int hvpg_count = HVPFN_UP(offset_in_hvpg + length); > u64 hvpfn; > > @@ -1773,51 +1772,34 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd) > return SCSI_MLQUEUE_DEVICE_BUSY; > } > > - /* > - * sgl is a list of PAGEs, and payload->range.pfn_array > - * expects the page number in the unit of HV_HYP_PAGE_SIZE (the > - * page size that Hyper-V uses, so here we need to divide PAGEs > - * into HV_HYP_PAGE in case that PAGE_SIZE > HV_HYP_PAGE_SIZE. > - * Besides, payload->range.offset should be the offset in one > - * HV_HYP_PAGE. > - */ > payload->range.len = length; > payload->range.offset = offset_in_hvpg; > - hvpgoff = sgl->offset >> HV_HYP_PAGE_SHIFT; > > - cur_sgl = sgl; > - for (i = 0; i < hvpg_count; i++) { > + > + for (i = 0; sgl != NULL; sgl = sg_next(sgl)) { > /* > - * 'i' is the index of hv pages in the payload and > - * 'hvpgoff' is the offset (in hv pages) of the first > - * hv page in the the first page. The relationship > - * between the sum of 'i' and 'hvpgoff' and the offset > - * (in hv pages) in a payload page ('hvpgoff_in_page') > - * is as follow: > - * > - * |------------------ PAGE -------------------| > - * | NR_HV_HYP_PAGES_IN_PAGE hvpgs in total | > - * |hvpg|hvpg| ... |hvpg|... |hvpg| > - * ^ ^ ^ ^ > - * +-hvpgoff-+ +-hvpgoff_in_page-+ > - * ^ | > - * +--------------------- i ---------------------------+ > + * Init values for the current sgl entry. hvpgoff > + * and hvpfns_to_add are in units of Hyper-V size > + * pages. Handling the PAGE_SIZE != HV_HYP_PAGE_SIZE > + * case also handles values of sgl->offset that are > + * larger than PAGE_SIZE. Such offsets are handled > + * even on other than the first sgl entry, provided > + * they are a multiple of PAGE_SIZE. > */ > - unsigned int hvpgoff_in_page = > - (i + hvpgoff) % NR_HV_HYP_PAGES_IN_PAGE; > + hvpgoff = HVPFN_DOWN(sgl->offset); > + hvpfn = page_to_hvpfn(sg_page(sgl)) + hvpgoff; > + hvpfns_to_add = HVPFN_UP(sgl->offset + sgl->length) - > + hvpgoff; > > /* > - * Two cases that we need to fetch a page: > - * 1) i == 0, the first step or > - * 2) hvpgoff_in_page == 0, when we reach the boundary > - * of a page. > + * Fill the next portion of the PFN array with > + * sequential Hyper-V PFNs for the continguous physical > + * memory described by the sgl entry. The end of the > + * last sgl should be reached at the same time that > + * the PFN array is filled. > */ > - if (hvpgoff_in_page == 0 || i == 0) { > - hvpfn = page_to_hvpfn(sg_page(cur_sgl)); > - cur_sgl = sg_next(cur_sgl); > - } > - > - payload->range.pfn_array[i] = hvpfn + hvpgoff_in_page; > + while (hvpfns_to_add--) > + payload->range.pfn_array[i++] = hvpfn++; > } > } > > @@ -1851,8 +1833,6 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd) > .slave_configure = storvsc_device_configure, > .cmd_per_lun = 2048, > .this_id = -1, > - /* Make sure we dont get a sg segment crosses a page boundary */ > - .dma_boundary = PAGE_SIZE-1, > /* Ensure there are no gaps in presented sgls */ > .virt_boundary_mask = PAGE_SIZE-1, > .no_write_same = 1, > diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h > index 5ddb479..a1eed76 100644 > --- a/include/linux/hyperv.h > +++ b/include/linux/hyperv.h > @@ -1717,6 +1717,7 @@ static inline unsigned long virt_to_hvpfn(void *addr) > #define NR_HV_HYP_PAGES_IN_PAGE (PAGE_SIZE / HV_HYP_PAGE_SIZE) > #define offset_in_hvpage(ptr) ((unsigned long)(ptr) & ~HV_HYP_PAGE_MASK) > #define HVPFN_UP(x) (((x) + HV_HYP_PAGE_SIZE-1) >> HV_HYP_PAGE_SHIFT) > +#define HVPFN_DOWN(x) ((x) >> HV_HYP_PAGE_SHIFT) > #define page_to_hvpfn(page) (page_to_pfn(page) * NR_HV_HYP_PAGES_IN_PAGE) > > #endif /* _HYPERV_H */ Thank you for implementing my suggestion in v2, Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
From: Vitaly Kuznetsov <vkuznets@redhat.com> Sent: Wednesday, March 3, 2021 1:09 AM > To: Michael Kelley <mikelley@microsoft.com> > Cc: KY Srinivasan <kys@microsoft.com>; martin.petersen@oracle.com; Long Li > <longli@microsoft.com>; wei.liu@kernel.org; jejb@linux.ibm.com; linux- > hyperv@vger.kernel.org; linux-kernel@vger.kernel.org; linux-scsi@vger.kernel.org > Subject: Re: [PATCH v2 1/1] scsi: storvsc: Enable scatterlist entry lengths > 4Kbytes > > Michael Kelley <mikelley@microsoft.com> writes: > > > storvsc currently sets .dma_boundary to limit scatterlist entries > > to 4 Kbytes, which is less efficient with huge pages that offer > > large chunks of contiguous physical memory. Improve the algorithm > > for creating the Hyper-V guest physical address PFN array so > > that scatterlist entries with lengths > 4Kbytes are handled. > > As a result, remove the .dma_boundary setting. > > > > The improved algorithm also adds support for scatterlist > > entries with offsets >= 4Kbytes, which is supported by many > > other SCSI low-level drivers. And it retains support for > > architectures where possibly PAGE_SIZE != HV_HYP_PAGE_SIZE > > (such as ARM64). > > > > Signed-off-by: Michael Kelley <mikelley@microsoft.com> > > --- > > > > Changes in v2: > > * Add HVPFN_DOWN() macro and use it instead of open coding > > [Vitaly Kuznetsov] > > * Change loop that fills pfn array and its initialization > > [Vitaly Kuznetsov] > > * Use offset_in_hvpage() instead of open coding > > > > > > drivers/scsi/storvsc_drv.c | 66 ++++++++++++++++------------------------------ > > include/linux/hyperv.h | 1 + > > 2 files changed, 24 insertions(+), 43 deletions(-) > > > > diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c > > index 2e4fa77..5ba3145 100644 > > --- a/drivers/scsi/storvsc_drv.c > > +++ b/drivers/scsi/storvsc_drv.c > > @@ -1678,9 +1678,8 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct > scsi_cmnd *scmnd) > > struct storvsc_cmd_request *cmd_request = scsi_cmd_priv(scmnd); > > int i; > > struct scatterlist *sgl; > > - unsigned int sg_count = 0; > > + unsigned int sg_count; > > struct vmscsi_request *vm_srb; > > - struct scatterlist *cur_sgl; > > struct vmbus_packet_mpb_array *payload; > > u32 payload_sz; > > u32 length; > > @@ -1759,8 +1758,8 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct > scsi_cmnd *scmnd) > > payload_sz = sizeof(cmd_request->mpb); > > > > if (sg_count) { > > - unsigned int hvpgoff = 0; > > - unsigned long offset_in_hvpg = sgl->offset & ~HV_HYP_PAGE_MASK; > > + unsigned int hvpgoff, hvpfns_to_add; > > + unsigned long offset_in_hvpg = offset_in_hvpage(sgl->offset); > > unsigned int hvpg_count = HVPFN_UP(offset_in_hvpg + length); > > u64 hvpfn; > > > > @@ -1773,51 +1772,34 @@ static int storvsc_queuecommand(struct Scsi_Host *host, > struct scsi_cmnd *scmnd) > > return SCSI_MLQUEUE_DEVICE_BUSY; > > } > > > > - /* > > - * sgl is a list of PAGEs, and payload->range.pfn_array > > - * expects the page number in the unit of HV_HYP_PAGE_SIZE (the > > - * page size that Hyper-V uses, so here we need to divide PAGEs > > - * into HV_HYP_PAGE in case that PAGE_SIZE > HV_HYP_PAGE_SIZE. > > - * Besides, payload->range.offset should be the offset in one > > - * HV_HYP_PAGE. > > - */ > > payload->range.len = length; > > payload->range.offset = offset_in_hvpg; > > - hvpgoff = sgl->offset >> HV_HYP_PAGE_SHIFT; > > > > - cur_sgl = sgl; > > - for (i = 0; i < hvpg_count; i++) { > > + > > + for (i = 0; sgl != NULL; sgl = sg_next(sgl)) { > > /* > > - * 'i' is the index of hv pages in the payload and > > - * 'hvpgoff' is the offset (in hv pages) of the first > > - * hv page in the the first page. The relationship > > - * between the sum of 'i' and 'hvpgoff' and the offset > > - * (in hv pages) in a payload page ('hvpgoff_in_page') > > - * is as follow: > > - * > > - * |------------------ PAGE -------------------| > > - * | NR_HV_HYP_PAGES_IN_PAGE hvpgs in total | > > - * |hvpg|hvpg| ... |hvpg|... |hvpg| > > - * ^ ^ ^ ^ > > - * +-hvpgoff-+ +-hvpgoff_in_page-+ > > - * ^ | > > - * +--------------------- i ---------------------------+ > > + * Init values for the current sgl entry. hvpgoff > > + * and hvpfns_to_add are in units of Hyper-V size > > + * pages. Handling the PAGE_SIZE != HV_HYP_PAGE_SIZE > > + * case also handles values of sgl->offset that are > > + * larger than PAGE_SIZE. Such offsets are handled > > + * even on other than the first sgl entry, provided > > + * they are a multiple of PAGE_SIZE. > > */ > > - unsigned int hvpgoff_in_page = > > - (i + hvpgoff) % NR_HV_HYP_PAGES_IN_PAGE; > > + hvpgoff = HVPFN_DOWN(sgl->offset); > > + hvpfn = page_to_hvpfn(sg_page(sgl)) + hvpgoff; > > + hvpfns_to_add = HVPFN_UP(sgl->offset + sgl->length) - > > + hvpgoff; > > > > /* > > - * Two cases that we need to fetch a page: > > - * 1) i == 0, the first step or > > - * 2) hvpgoff_in_page == 0, when we reach the boundary > > - * of a page. > > + * Fill the next portion of the PFN array with > > + * sequential Hyper-V PFNs for the continguous physical > > + * memory described by the sgl entry. The end of the > > + * last sgl should be reached at the same time that > > + * the PFN array is filled. > > */ > > - if (hvpgoff_in_page == 0 || i == 0) { > > - hvpfn = page_to_hvpfn(sg_page(cur_sgl)); > > - cur_sgl = sg_next(cur_sgl); > > - } > > - > > - payload->range.pfn_array[i] = hvpfn + hvpgoff_in_page; > > + while (hvpfns_to_add--) > > + payload->range.pfn_array[i++] = hvpfn++; > > } > > } > > > > @@ -1851,8 +1833,6 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct > scsi_cmnd *scmnd) > > .slave_configure = storvsc_device_configure, > > .cmd_per_lun = 2048, > > .this_id = -1, > > - /* Make sure we dont get a sg segment crosses a page boundary */ > > - .dma_boundary = PAGE_SIZE-1, > > /* Ensure there are no gaps in presented sgls */ > > .virt_boundary_mask = PAGE_SIZE-1, > > .no_write_same = 1, > > diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h > > index 5ddb479..a1eed76 100644 > > --- a/include/linux/hyperv.h > > +++ b/include/linux/hyperv.h > > @@ -1717,6 +1717,7 @@ static inline unsigned long virt_to_hvpfn(void *addr) > > #define NR_HV_HYP_PAGES_IN_PAGE (PAGE_SIZE / HV_HYP_PAGE_SIZE) > > #define offset_in_hvpage(ptr) ((unsigned long)(ptr) & ~HV_HYP_PAGE_MASK) > > #define HVPFN_UP(x) (((x) + HV_HYP_PAGE_SIZE-1) >> HV_HYP_PAGE_SHIFT) > > +#define HVPFN_DOWN(x) ((x) >> HV_HYP_PAGE_SHIFT) > > #define page_to_hvpfn(page) (page_to_pfn(page) * > NR_HV_HYP_PAGES_IN_PAGE) > > > > #endif /* _HYPERV_H */ > > Thank you for implementing my suggestion in v2, > > Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> > > -- > Vitaly Martin -- Is anything else needed for you to pick up this patch? Michael
On Tue, 23 Feb 2021 14:44:54 -0800, Michael Kelley wrote: > storvsc currently sets .dma_boundary to limit scatterlist entries > to 4 Kbytes, which is less efficient with huge pages that offer > large chunks of contiguous physical memory. Improve the algorithm > for creating the Hyper-V guest physical address PFN array so > that scatterlist entries with lengths > 4Kbytes are handled. > As a result, remove the .dma_boundary setting. > > [...] Applied to 5.13/scsi-queue, thanks! [1/1] scsi: storvsc: Enable scatterlist entry lengths > 4Kbytes https://git.kernel.org/mkp/scsi/c/3d9c3dcc58e9
diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c index 2e4fa77..5ba3145 100644 --- a/drivers/scsi/storvsc_drv.c +++ b/drivers/scsi/storvsc_drv.c @@ -1678,9 +1678,8 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd) struct storvsc_cmd_request *cmd_request = scsi_cmd_priv(scmnd); int i; struct scatterlist *sgl; - unsigned int sg_count = 0; + unsigned int sg_count; struct vmscsi_request *vm_srb; - struct scatterlist *cur_sgl; struct vmbus_packet_mpb_array *payload; u32 payload_sz; u32 length; @@ -1759,8 +1758,8 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd) payload_sz = sizeof(cmd_request->mpb); if (sg_count) { - unsigned int hvpgoff = 0; - unsigned long offset_in_hvpg = sgl->offset & ~HV_HYP_PAGE_MASK; + unsigned int hvpgoff, hvpfns_to_add; + unsigned long offset_in_hvpg = offset_in_hvpage(sgl->offset); unsigned int hvpg_count = HVPFN_UP(offset_in_hvpg + length); u64 hvpfn; @@ -1773,51 +1772,34 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd) return SCSI_MLQUEUE_DEVICE_BUSY; } - /* - * sgl is a list of PAGEs, and payload->range.pfn_array - * expects the page number in the unit of HV_HYP_PAGE_SIZE (the - * page size that Hyper-V uses, so here we need to divide PAGEs - * into HV_HYP_PAGE in case that PAGE_SIZE > HV_HYP_PAGE_SIZE. - * Besides, payload->range.offset should be the offset in one - * HV_HYP_PAGE. - */ payload->range.len = length; payload->range.offset = offset_in_hvpg; - hvpgoff = sgl->offset >> HV_HYP_PAGE_SHIFT; - cur_sgl = sgl; - for (i = 0; i < hvpg_count; i++) { + + for (i = 0; sgl != NULL; sgl = sg_next(sgl)) { /* - * 'i' is the index of hv pages in the payload and - * 'hvpgoff' is the offset (in hv pages) of the first - * hv page in the the first page. The relationship - * between the sum of 'i' and 'hvpgoff' and the offset - * (in hv pages) in a payload page ('hvpgoff_in_page') - * is as follow: - * - * |------------------ PAGE -------------------| - * | NR_HV_HYP_PAGES_IN_PAGE hvpgs in total | - * |hvpg|hvpg| ... |hvpg|... |hvpg| - * ^ ^ ^ ^ - * +-hvpgoff-+ +-hvpgoff_in_page-+ - * ^ | - * +--------------------- i ---------------------------+ + * Init values for the current sgl entry. hvpgoff + * and hvpfns_to_add are in units of Hyper-V size + * pages. Handling the PAGE_SIZE != HV_HYP_PAGE_SIZE + * case also handles values of sgl->offset that are + * larger than PAGE_SIZE. Such offsets are handled + * even on other than the first sgl entry, provided + * they are a multiple of PAGE_SIZE. */ - unsigned int hvpgoff_in_page = - (i + hvpgoff) % NR_HV_HYP_PAGES_IN_PAGE; + hvpgoff = HVPFN_DOWN(sgl->offset); + hvpfn = page_to_hvpfn(sg_page(sgl)) + hvpgoff; + hvpfns_to_add = HVPFN_UP(sgl->offset + sgl->length) - + hvpgoff; /* - * Two cases that we need to fetch a page: - * 1) i == 0, the first step or - * 2) hvpgoff_in_page == 0, when we reach the boundary - * of a page. + * Fill the next portion of the PFN array with + * sequential Hyper-V PFNs for the continguous physical + * memory described by the sgl entry. The end of the + * last sgl should be reached at the same time that + * the PFN array is filled. */ - if (hvpgoff_in_page == 0 || i == 0) { - hvpfn = page_to_hvpfn(sg_page(cur_sgl)); - cur_sgl = sg_next(cur_sgl); - } - - payload->range.pfn_array[i] = hvpfn + hvpgoff_in_page; + while (hvpfns_to_add--) + payload->range.pfn_array[i++] = hvpfn++; } } @@ -1851,8 +1833,6 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd) .slave_configure = storvsc_device_configure, .cmd_per_lun = 2048, .this_id = -1, - /* Make sure we dont get a sg segment crosses a page boundary */ - .dma_boundary = PAGE_SIZE-1, /* Ensure there are no gaps in presented sgls */ .virt_boundary_mask = PAGE_SIZE-1, .no_write_same = 1, diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h index 5ddb479..a1eed76 100644 --- a/include/linux/hyperv.h +++ b/include/linux/hyperv.h @@ -1717,6 +1717,7 @@ static inline unsigned long virt_to_hvpfn(void *addr) #define NR_HV_HYP_PAGES_IN_PAGE (PAGE_SIZE / HV_HYP_PAGE_SIZE) #define offset_in_hvpage(ptr) ((unsigned long)(ptr) & ~HV_HYP_PAGE_MASK) #define HVPFN_UP(x) (((x) + HV_HYP_PAGE_SIZE-1) >> HV_HYP_PAGE_SHIFT) +#define HVPFN_DOWN(x) ((x) >> HV_HYP_PAGE_SHIFT) #define page_to_hvpfn(page) (page_to_pfn(page) * NR_HV_HYP_PAGES_IN_PAGE) #endif /* _HYPERV_H */
storvsc currently sets .dma_boundary to limit scatterlist entries to 4 Kbytes, which is less efficient with huge pages that offer large chunks of contiguous physical memory. Improve the algorithm for creating the Hyper-V guest physical address PFN array so that scatterlist entries with lengths > 4Kbytes are handled. As a result, remove the .dma_boundary setting. The improved algorithm also adds support for scatterlist entries with offsets >= 4Kbytes, which is supported by many other SCSI low-level drivers. And it retains support for architectures where possibly PAGE_SIZE != HV_HYP_PAGE_SIZE (such as ARM64). Signed-off-by: Michael Kelley <mikelley@microsoft.com> --- Changes in v2: * Add HVPFN_DOWN() macro and use it instead of open coding [Vitaly Kuznetsov] * Change loop that fills pfn array and its initialization [Vitaly Kuznetsov] * Use offset_in_hvpage() instead of open coding drivers/scsi/storvsc_drv.c | 66 ++++++++++++++++------------------------------ include/linux/hyperv.h | 1 + 2 files changed, 24 insertions(+), 43 deletions(-)