Re: [PATCH v2 02/10] block: add helpers for accessing a bio_vec page
On Wed, May 6, 2015 at 1:05 PM, Dan Williams wrote: > In preparation for converting struct bio_vec to carry a __pfn_t instead > of struct page. > > This change is prompted by the desire to add in-kernel DMA support > (O_DIRECT, hierarchical storage, RDMA, etc) for persistent memory which > lacks struct page coverage. > > Alternatives: > > 1/ Provide struct page coverage for persistent memory in DRAM. The >expectation is that persistent memory capacities make this untenable >in the long term. > > 2/ Provide struct page coverage for persistent memory with persistent >memory. While persistent memory may have near DRAM performance >characteristics it may not have the same write-endurance of DRAM. >Given the update frequency of struct page objects it may not be >suitable for persistent memory. > > 3/ Dynamically allocate struct page. This appears to be on the order >of the complexity of converting code paths to use __pfn_t references >instead of struct page, and the amount of setup required to establish >a valid struct page reference is mostly wasted when the only usage in >the block stack is to perform a page_to_pfn() conversion for >dma-mapping. Instances of kmap() / kmap_atomic() usage appear to be >the only occasions in the block stack where struct page is >non-trivially used. A new kmap_atomic_pfn_t() is proposed to handle >those cases. > > Generated with the following semantic patch: > > // bv_page.cocci: convert usage of ->bv_page to use set/get helpers > // usage: make coccicheck COCCI=bv_page.cocci MODE=patch Now that it looks like this patchset can move forward, what do about this one? Run the Coccinelle script late in the merge window to catch all the new bv_page usages targeted for 4.2-rc1? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH v2 02/10] block: add helpers for accessing a bio_vec page
On Wed, May 6, 2015 at 1:05 PM, Dan Williams dan.j.willi...@intel.com wrote: In preparation for converting struct bio_vec to carry a __pfn_t instead of struct page. This change is prompted by the desire to add in-kernel DMA support (O_DIRECT, hierarchical storage, RDMA, etc) for persistent memory which lacks struct page coverage. Alternatives: 1/ Provide struct page coverage for persistent memory in DRAM. The expectation is that persistent memory capacities make this untenable in the long term. 2/ Provide struct page coverage for persistent memory with persistent memory. While persistent memory may have near DRAM performance characteristics it may not have the same write-endurance of DRAM. Given the update frequency of struct page objects it may not be suitable for persistent memory. 3/ Dynamically allocate struct page. This appears to be on the order of the complexity of converting code paths to use __pfn_t references instead of struct page, and the amount of setup required to establish a valid struct page reference is mostly wasted when the only usage in the block stack is to perform a page_to_pfn() conversion for dma-mapping. Instances of kmap() / kmap_atomic() usage appear to be the only occasions in the block stack where struct page is non-trivially used. A new kmap_atomic_pfn_t() is proposed to handle those cases. Generated with the following semantic patch: // bv_page.cocci: convert usage of -bv_page to use set/get helpers // usage: make coccicheck COCCI=bv_page.cocci MODE=patch Now that it looks like this patchset can move forward, what do about this one? Run the Coccinelle script late in the merge window to catch all the new bv_page usages targeted for 4.2-rc1? -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH v2 02/10] block: add helpers for accessing a bio_vec page
In preparation for converting struct bio_vec to carry a __pfn_t instead of struct page. This change is prompted by the desire to add in-kernel DMA support (O_DIRECT, hierarchical storage, RDMA, etc) for persistent memory which lacks struct page coverage. Alternatives: 1/ Provide struct page coverage for persistent memory in DRAM. The expectation is that persistent memory capacities make this untenable in the long term. 2/ Provide struct page coverage for persistent memory with persistent memory. While persistent memory may have near DRAM performance characteristics it may not have the same write-endurance of DRAM. Given the update frequency of struct page objects it may not be suitable for persistent memory. 3/ Dynamically allocate struct page. This appears to be on the order of the complexity of converting code paths to use __pfn_t references instead of struct page, and the amount of setup required to establish a valid struct page reference is mostly wasted when the only usage in the block stack is to perform a page_to_pfn() conversion for dma-mapping. Instances of kmap() / kmap_atomic() usage appear to be the only occasions in the block stack where struct page is non-trivially used. A new kmap_atomic_pfn_t() is proposed to handle those cases. Generated with the following semantic patch: // bv_page.cocci: convert usage of ->bv_page to use set/get helpers // usage: make coccicheck COCCI=bv_page.cocci MODE=patch virtual patch virtual report virtual org @@ struct bio_vec bvec; expression E; type T; @@ - bvec.bv_page = (T)E + bvec_set_page(, E) @@ struct bio_vec *bvec; expression E; type T; @@ - bvec->bv_page = (T)E + bvec_set_page(bvec, E) @@ struct bio_vec bvec; type T; @@ - (T)bvec.bv_page + bvec_page() @@ struct bio_vec *bvec; type T; @@ - (T)bvec->bv_page + bvec_page(bvec) @@ struct bio *bio; expression E; expression F; type T; @@ - bio->bi_io_vec[F].bv_page = (T)E + bvec_set_page(>bi_io_vec[F], E) @@ struct bio *bio; expression E; type T; @@ - bio->bi_io_vec->bv_page = (T)E + bvec_set_page(bio->bi_io_vec, E) @@ struct cached_dev *dc; expression E; type T; @@ - dc->sb_bio.bi_io_vec->bv_page = (T)E + bvec_set_page(dc->sb_bio.bi_io_vec, E) @@ struct cache *ca; expression E; expression F; type T; @@ - ca->sb_bio.bi_io_vec[F].bv_page = (T)E + bvec_set_page(>sb_bio.bi_io_vec[F], E) @@ struct cache *ca; expression F; @@ - ca->sb_bio.bi_io_vec[F].bv_page + bvec_page(>sb_bio.bi_io_vec[F]) @@ struct cache *ca; expression E; expression F; type T; @@ - ca->sb_bio.bi_inline_vecs[F].bv_page = (T)E + bvec_set_page(>sb_bio.bi_inline_vecs[F], E) @@ struct cache *ca; expression F; @@ - ca->sb_bio.bi_inline_vecs[F].bv_page + bvec_page(>sb_bio.bi_inline_vecs[F]) @@ struct cache *ca; expression E; type T; @@ - ca->sb_bio.bi_io_vec->bv_page = (T)E + bvec_set_page(ca->sb_bio.bi_io_vec, E) @@ struct bio *bio; expression F; @@ - bio->bi_io_vec[F].bv_page + bvec_page(>bi_io_vec[F]) @@ struct bio bio; expression F; @@ - bio.bi_io_vec[F].bv_page + bvec_page(_io_vec[F]) @@ struct bio *bio; @@ - bio->bi_io_vec->bv_page + bvec_page(bio->bi_io_vec) @@ struct cached_dev *dc; @@ - dc->sb_bio.bi_io_vec->bv_page + bvec_page(>sb_bio->bi_io_vec) @@ struct bio bio; @@ - bio.bi_io_vec->bv_page + bvec_page(bio.bi_io_vec) @@ struct bio_integrity_payload *bip; expression E; type T; @@ - bip->bip_vec->bv_page = (T)E + bvec_set_page(bip->bip_vec, E) @@ struct bio_integrity_payload *bip; @@ - bip->bip_vec->bv_page + bvec_page(bip->bip_vec) @@ struct bio_integrity_payload bip; @@ - bip.bip_vec->bv_page + bvec_page(bip.bip_vec) Cc: Jens Axboe Cc: Matthew Wilcox Cc: Ross Zwisler Cc: Neil Brown Cc: Alasdair Kergon Cc: Mike Snitzer Cc: Chris Mason Cc: Boaz Harrosh Cc: Theodore Ts'o Cc: Jan Kara Cc: Julia Lawall Cc: Martin K. Petersen Signed-off-by: Dan Williams --- arch/powerpc/sysdev/axonram.c |2 + block/bio-integrity.c |8 ++-- block/bio.c | 40 +++--- block/blk-core.c|4 +- block/blk-integrity.c |3 +- block/blk-lib.c |2 + block/blk-merge.c |7 ++-- block/bounce.c | 24 ++--- drivers/block/aoe/aoecmd.c |8 ++-- drivers/block/brd.c |2 + drivers/block/drbd/drbd_bitmap.c|5 ++- drivers/block/drbd/drbd_main.c |6 ++- drivers/block/drbd/drbd_receiver.c |4 +- drivers/block/drbd/drbd_worker.c|3 +- drivers/block/floppy.c |6 ++- drivers/block/loop.c| 13 --- drivers/block/nbd.c |8 ++-- drivers/block/nvme-core.c |2 + drivers/block/pktcdvd.c | 11 +++---
[PATCH v2 02/10] block: add helpers for accessing a bio_vec page
In preparation for converting struct bio_vec to carry a __pfn_t instead of struct page. This change is prompted by the desire to add in-kernel DMA support (O_DIRECT, hierarchical storage, RDMA, etc) for persistent memory which lacks struct page coverage. Alternatives: 1/ Provide struct page coverage for persistent memory in DRAM. The expectation is that persistent memory capacities make this untenable in the long term. 2/ Provide struct page coverage for persistent memory with persistent memory. While persistent memory may have near DRAM performance characteristics it may not have the same write-endurance of DRAM. Given the update frequency of struct page objects it may not be suitable for persistent memory. 3/ Dynamically allocate struct page. This appears to be on the order of the complexity of converting code paths to use __pfn_t references instead of struct page, and the amount of setup required to establish a valid struct page reference is mostly wasted when the only usage in the block stack is to perform a page_to_pfn() conversion for dma-mapping. Instances of kmap() / kmap_atomic() usage appear to be the only occasions in the block stack where struct page is non-trivially used. A new kmap_atomic_pfn_t() is proposed to handle those cases. Generated with the following semantic patch: // bv_page.cocci: convert usage of -bv_page to use set/get helpers // usage: make coccicheck COCCI=bv_page.cocci MODE=patch virtual patch virtual report virtual org @@ struct bio_vec bvec; expression E; type T; @@ - bvec.bv_page = (T)E + bvec_set_page(bvec, E) @@ struct bio_vec *bvec; expression E; type T; @@ - bvec-bv_page = (T)E + bvec_set_page(bvec, E) @@ struct bio_vec bvec; type T; @@ - (T)bvec.bv_page + bvec_page(bvec) @@ struct bio_vec *bvec; type T; @@ - (T)bvec-bv_page + bvec_page(bvec) @@ struct bio *bio; expression E; expression F; type T; @@ - bio-bi_io_vec[F].bv_page = (T)E + bvec_set_page(bio-bi_io_vec[F], E) @@ struct bio *bio; expression E; type T; @@ - bio-bi_io_vec-bv_page = (T)E + bvec_set_page(bio-bi_io_vec, E) @@ struct cached_dev *dc; expression E; type T; @@ - dc-sb_bio.bi_io_vec-bv_page = (T)E + bvec_set_page(dc-sb_bio.bi_io_vec, E) @@ struct cache *ca; expression E; expression F; type T; @@ - ca-sb_bio.bi_io_vec[F].bv_page = (T)E + bvec_set_page(ca-sb_bio.bi_io_vec[F], E) @@ struct cache *ca; expression F; @@ - ca-sb_bio.bi_io_vec[F].bv_page + bvec_page(ca-sb_bio.bi_io_vec[F]) @@ struct cache *ca; expression E; expression F; type T; @@ - ca-sb_bio.bi_inline_vecs[F].bv_page = (T)E + bvec_set_page(ca-sb_bio.bi_inline_vecs[F], E) @@ struct cache *ca; expression F; @@ - ca-sb_bio.bi_inline_vecs[F].bv_page + bvec_page(ca-sb_bio.bi_inline_vecs[F]) @@ struct cache *ca; expression E; type T; @@ - ca-sb_bio.bi_io_vec-bv_page = (T)E + bvec_set_page(ca-sb_bio.bi_io_vec, E) @@ struct bio *bio; expression F; @@ - bio-bi_io_vec[F].bv_page + bvec_page(bio-bi_io_vec[F]) @@ struct bio bio; expression F; @@ - bio.bi_io_vec[F].bv_page + bvec_page(bio.bi_io_vec[F]) @@ struct bio *bio; @@ - bio-bi_io_vec-bv_page + bvec_page(bio-bi_io_vec) @@ struct cached_dev *dc; @@ - dc-sb_bio.bi_io_vec-bv_page + bvec_page(dc-sb_bio-bi_io_vec) @@ struct bio bio; @@ - bio.bi_io_vec-bv_page + bvec_page(bio.bi_io_vec) @@ struct bio_integrity_payload *bip; expression E; type T; @@ - bip-bip_vec-bv_page = (T)E + bvec_set_page(bip-bip_vec, E) @@ struct bio_integrity_payload *bip; @@ - bip-bip_vec-bv_page + bvec_page(bip-bip_vec) @@ struct bio_integrity_payload bip; @@ - bip.bip_vec-bv_page + bvec_page(bip.bip_vec) Cc: Jens Axboe ax...@kernel.dk Cc: Matthew Wilcox wi...@linux.intel.com Cc: Ross Zwisler ross.zwis...@linux.intel.com Cc: Neil Brown ne...@suse.de Cc: Alasdair Kergon a...@redhat.com Cc: Mike Snitzer snit...@redhat.com Cc: Chris Mason c...@fb.com Cc: Boaz Harrosh b...@plexistor.com Cc: Theodore Ts'o ty...@mit.edu Cc: Jan Kara j...@suse.cz Cc: Julia Lawall julia.law...@lip6.fr Cc: Martin K. Petersen martin.peter...@oracle.com Signed-off-by: Dan Williams dan.j.willi...@intel.com --- arch/powerpc/sysdev/axonram.c |2 + block/bio-integrity.c |8 ++-- block/bio.c | 40 +++--- block/blk-core.c|4 +- block/blk-integrity.c |3 +- block/blk-lib.c |2 + block/blk-merge.c |7 ++-- block/bounce.c | 24 ++--- drivers/block/aoe/aoecmd.c |8 ++-- drivers/block/brd.c |2 + drivers/block/drbd/drbd_bitmap.c|5 ++- drivers/block/drbd/drbd_main.c |6 ++- drivers/block/drbd/drbd_receiver.c |4 +- drivers/block/drbd/drbd_worker.c|3 +- drivers/block/floppy.c |6 ++-
