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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] add trim command to blkback interface
On 12/06/2010 03:28 AM, Owen Smith wrote: > > [PATCH] add trim command to blkback interface > > > > This patch adds the trim operation to the blkback ring protocol. > > The ring protocol is extended by unioning the current read/write/write > barrier specific fields with fields specific for trim, and allowing > further expansion with additional union members, providing the > structure size and alignment do not change. > > > > Blkback will respond to trim operations with a BLKIF_RSP_EOPNOTSUPP, > to avoid using the default response of writing an error log entry and > returning BLKIF_RSP_ERROR. > > > > Trim commands are passed with sector_number as the sector index to > begin trim operations at, and nr_sectors as the number of sectors to > be trimmed. These sectors should be trimmed if the underlying block > device supports trimming. More information about trim commands: > > http://t13.org/Documents/UploadedDocuments/docs2008/e07154r6-Data_Set_Management_Proposal_for_ATA-ACS2.doc > Aside from the comments in my reply to Jan's mail, I can't actually get an applyable patch out of this; its all mashed up with quoted-printable. Could you repost as a plain-text attachment if you can't convince your mailer to send a plain-text email? Thanks, J > > > This patch is intended to fix an interface, not supply the > implementation of trim in the backend drivers. > > > > Signed-off-by: Owen Smith <owen.smith@xxxxxxxxxx> > > > > > > diff --git a/drivers/xen/blkback/blkback.c b/drivers/xen/blkback/blkback.c > > index 0bef445..bd09512 100644 > > --- a/drivers/xen/blkback/blkback.c > > +++ b/drivers/xen/blkback/blkback.c > > @@ -367,6 +367,11 @@ static int do_block_io_op(blkif_t *blkif) > > blkif->st_wr_req++; > > > dispatch_rw_block_io(blkif, &req, pending_req); > > break; > > + case BLKIF_OP_TRIM: > > + make_response(blkif, > req.id, req.operation, > > + > BLKIF_RSP_EOPNOTSUPP); > > + free_req(pending_req); > > + break; > > default: > > /* A good sign > something is wrong: sleep for a while to > > * avoid excessive CPU > consumption by a bad guest. */ > > @@ -424,7 +429,7 @@ static void dispatch_rw_block_io(blkif_t *blkif, > > } > > preq.dev = req->handle; > > - preq.sector_number = req->sector_number; > > + preq.sector_number = req->rw.sector_number; > > preq.nr_sects = 0; > > pending_req->blkif = blkif; > > @@ -436,11 +441,11 @@ static void dispatch_rw_block_io(blkif_t *blkif, > > for (i = 0; i < nseg; i++) { > > uint32_t flags; > > - seg[i].nsec = req->seg[i].last_sect - > > - req->seg[i].first_sect + 1; > > + seg[i].nsec = req->rw.seg[i].last_sect - > > + > req->rw.seg[i].first_sect + 1; > > - if ((req->seg[i].last_sect >= > (PAGE_SIZE >> 9)) || > > - (req->seg[i].last_sect < > req->seg[i].first_sect)) > > + if ((req->rw.seg[i].last_sect >= > (PAGE_SIZE >> 9)) || > > + (req->rw.seg[i].last_sect < > req->rw.seg[i].first_sect)) > > goto fail_response; > > preq.nr_sects += seg[i].nsec; > > @@ -448,7 +453,7 @@ static void dispatch_rw_block_io(blkif_t *blkif, > > if (operation != READ) > > flags |= GNTMAP_readonly; > > gnttab_set_map_op(&map[i], > vaddr(pending_req, i), flags, > > - > req->seg[i].gref, blkif->domid); > > + > req->rw.seg[i].gref, blkif->domid); > > } > > ret = > HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map, nseg); > > @@ -466,11 +471,11 @@ static void dispatch_rw_block_io(blkif_t *blkif, > > > page_to_pfn(pending_page(pending_req, i)), > > > FOREIGN_FRAME(map[i].dev_bus_addr >> PAGE_SHIFT)); > > seg[i].buf = map[i].dev_bus_addr | > > - (req->seg[i].first_sect > << 9); > > + > (req->rw.seg[i].first_sect << 9); > > > blkback_pagemap_set(vaddr_pagenr(pending_req, i), > > > pending_page(pending_req, i), > > > blkif->domid, req->handle, > > - > req->seg[i].gref); > > + > req->rw.seg[i].gref); > > pending_handle(pending_req, i) = > map[i].handle; > > } > > diff --git a/include/xen/blkif.h b/include/xen/blkif.h > > index 7172081..e727e5d 100644 > > --- a/include/xen/blkif.h > > +++ b/include/xen/blkif.h > > @@ -44,8 +44,18 @@ struct blkif_x86_32_request { > > uint8_t nr_segments; /* number of > segments */ > > blkif_vdev_t handle; /* only for read/write > requests */ > > uint64_t id; /* private guest value, > echoed in resp */ > > - blkif_sector_t sector_number;/* start sector idx on > disk (r/w only) */ > > - struct blkif_request_segment > seg[BLKIF_MAX_SEGMENTS_PER_REQUEST]; > > + > > + union { > > + struct blkif_x86_32_request_rw { > > + blkif_sector_t > sector_number;/* start sector idx on disk (r/w only) */ > > + struct > blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST]; > > + } rw; > > + > > + struct blkif_x86_32_request_trim { > > + blkif_sector_t > sector_number; > > + uint64_t nr_sectors; > > + } trim; > > + }; > > }; > > struct blkif_x86_32_response { > > uint64_t id; /* copied from request */ > > @@ -62,8 +72,18 @@ struct blkif_x86_64_request { > > uint8_t nr_segments; /* number of > segments */ > > blkif_vdev_t handle; /* only for read/write > requests */ > > uint64_t __attribute__((__aligned__(8))) id; > > - blkif_sector_t sector_number;/* start sector idx on > disk (r/w only) */ > > - struct blkif_request_segment > seg[BLKIF_MAX_SEGMENTS_PER_REQUEST]; > > + > > + union { > > + struct blkif_x86_64_request_rw { > > + blkif_sector_t > sector_number;/* start sector idx on disk (r/w only) */ > > + struct > blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST]; > > + } rw; > > + > > + struct blkif_x86_64_request_trim { > > + blkif_sector_t > sector_number; > > + uint64_t nr_sectors; > > + } trim; > > + }; > > }; > > struct blkif_x86_64_response { > > uint64_t __attribute__((__aligned__(8))) id; > > @@ -97,12 +117,24 @@ static void inline blkif_get_x86_32_req(struct > blkif_request *dst, struct blkif_ > > dst->nr_segments = src->nr_segments; > > dst->handle = src->handle; > > dst->id = src->id; > > - dst->sector_number = src->sector_number; > > - barrier(); > > - if (n > dst->nr_segments) > > - n = dst->nr_segments; > > - for (i = 0; i < n; i++) > > - dst->seg[i] = src->seg[i]; > > + switch (src->operation) { > > + case BLKIF_OP_READ: > > + case BLKIF_OP_WRITE: > > + case BLKIF_OP_WRITE_BARRIER: > > + dst->rw.sector_number = > src->rw.sector_number; > > + barrier(); > > + if (n > dst->nr_segments) > > + n = dst->nr_segments; > > + for (i = 0; i < n; i++) > > + dst->rw.seg[i] = > src->rw.seg[i]; > > + break; > > + case BLKIF_OP_TRIM: > > + dst->trim.sector_number = > src->trim.sector_number; > > + dst->trim.nr_sectors = src->trim.nr_sectors; > > + break; > > + default: > > + break; > > + } > > } > > static void inline blkif_get_x86_64_req(struct blkif_request *dst, > struct blkif_x86_64_request *src) > > @@ -112,12 +144,24 @@ static void inline blkif_get_x86_64_req(struct > blkif_request *dst, struct blkif_ > > dst->nr_segments = src->nr_segments; > > dst->handle = src->handle; > > dst->id = src->id; > > - dst->sector_number = src->sector_number; > > - barrier(); > > - if (n > dst->nr_segments) > > - n = dst->nr_segments; > > - for (i = 0; i < n; i++) > > - dst->seg[i] = src->seg[i]; > > + switch (src->operation) { > > + case BLKIF_OP_READ: > > + case BLKIF_OP_WRITE: > > + case BLKIF_OP_WRITE_BARRIER: > > + dst->rw.sector_number = > src->rw.sector_number; > > + barrier(); > > + if (n > dst->nr_segments) > > + n = dst->nr_segments; > > + for (i = 0; i < n; i++) > > + dst->rw.seg[i] = > src->rw.seg[i]; > > + break; > > + case BLKIF_OP_TRIM: > > + dst->trim.sector_number = > src->trim.sector_number; > > + dst->trim.nr_sectors = src->trim.nr_sectors; > > + break; > > + default: > > + break; > > + } > > } > > #endif /* __XEN_BLKIF_H__ */ > > diff --git a/include/xen/interface/io/blkif.h > b/include/xen/interface/io/blkif.h > > index 68dd2b4..54bb598 100644 > > --- a/include/xen/interface/io/blkif.h > > +++ b/include/xen/interface/io/blkif.h > > @@ -43,6 +43,17 @@ typedef uint64_t blkif_sector_t; > > * create the "feature-barrier" node! > > */ > > #define BLKIF_OP_WRITE_BARRIER 2 > > +/* > > + * Recognised only if "feature-trim" is present in backend xenbus info. > > + * The "feature_trim" node contains a boolean indicating whether trim > > + * requests are likely to succeed or fail. Either way, a trim request > > + * may fail at any time with BLKIF_RSP_EOPNOTSUPP if it is unsupported by > > + * the underlying block-device hardware. The boolean simply indicates > whether > > + * or not it is worthwhile for the frontend to attempt trim requests. > > + * If a backend does not recognise BLKIF_OP_TRIM, it should *not* > > + * create the "feature-trim" node! > > + */ > > +#define BLKIF_OP_TRIM 4 > > /* > > * Maximum scatter/gather segments per request. > > @@ -56,13 +67,23 @@ struct blkif_request { > > uint8_t nr_segments; /* number of > segments */ > > blkif_vdev_t handle; /* only for read/write > requests */ > > uint64_t id; /* private guest value, > echoed in resp */ > > - blkif_sector_t sector_number;/* start sector idx on > disk (r/w only) */ > > - struct blkif_request_segment { > > - grant_ref_t gref; /* reference > to I/O buffer frame */ > > - /* @first_sect: first sector in frame > to transfer (inclusive). */ > > - /* @last_sect: last sector in frame to > transfer (inclusive). */ > > - uint8_t first_sect, last_sect; > > - } seg[BLKIF_MAX_SEGMENTS_PER_REQUEST]; > > + > > + union { > > + struct blkif_request_rw { > > + blkif_sector_t > sector_number;/* start sector idx on disk (r/w only) */ > > + struct > blkif_request_segment { > > + > grant_ref_t gref; /* reference to I/O buffer frame */ > > + /* > @first_sect: first sector in frame to transfer (inclusive). */ > > + /* > @last_sect: last sector in frame to transfer (inclusive). */ > > + > uint8_t first_sect, last_sect; > > + } > seg[BLKIF_MAX_SEGMENTS_PER_REQUEST]; > > + } rw; > > + > > + struct blkif_request_trim { > > + blkif_sector_t sector_number; > > + uint64_t nr_sectors; > > + } trim; > > + }; > > }; > > struct blkif_response { > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@xxxxxxxxxxxxxxxxxxx > http://lists.xensource.com/xen-devel _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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