Date: Fri, 26 May 2017 12:13:27 +0000 (UTC) From: Andriy Gapon <avg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-vendor@freebsd.org Subject: svn commit: r318946 - vendor-sys/illumos/dist/common/zfs vendor-sys/illumos/dist/uts/common vendor-sys/illumos/dist/uts/common/fs/zfs vendor-sys/illumos/dist/uts/common/fs/zfs/sys vendor/illumos/di... Message-ID: <201705261213.v4QCDSsb097265@repo.freebsd.org>
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Author: avg Date: Fri May 26 12:13:27 2017 New Revision: 318946 URL: https://svnweb.freebsd.org/changeset/base/318946 Log: 8021 ARC buf data scatter-ization 8100 8021 seems to cause random BAD TRAP: type=d (#gp General protection) illumos/illumos-gate@770499e185d15678ccb0be57ebc626ad18d93383 https://github.com/illumos/illumos-gate/commit/770499e185d15678ccb0be57ebc626ad18d93383 https://www.illumos.org/issues/8021 The ARC buf data project (known simply as "ABD" since its genesis in the ZoL community) changes the way the ARC allocates `b_pdata` memory from using linear `void *` buffers to using scatter/gather lists of fixed-size 1KB chunks. This improves ZFS's performance by helping to defragment the address space occupied by the ARC, in particular for cases where compressed ARC is enabled. It could also ease future work to allocate pages directly from `segkpm` for minimal- overhead memory allocations, bypassing the `kmem` subsystem. This is essentially the same change as the one which recently landed in ZFS on Linux, although they made some platform-specific changes while adapting this work to their codebase: 1. Implemented the equivalent of the `segkpm` suggestion for future work mentioned above to bypass issues that they've had with the Linux kernel memory allocator. 2. Changed the internal representation of the ABD's scatter/gather list so it could be used to pass I/O directly into Linux block device drivers. (This feature is not available in the illumos block device interface yet.) https://www.illumos.org/issues/8100 My supermicro system is getting random BAD TRAP: type=d (#gp General protection) at about the stage where ZFS filesystems are mounted - usually console login prompt is already present but the services are still starting. After backing out 8021, the boot is completed and no panics do occur. Machine does dump, however savecore fails: savecore: bad magic number baddcafe I can get more data out with boot -k, if needed. # psrinfo -vp The physical processor has 4 cores and 8 virtual processors (0-7) The core has 2 virtual processors (0 4) The core has 2 virtual processors (1 5) The core has 2 virtual processors (2 6) The core has 2 virtual processors (3 7) x86 (GenuineIntel 306C3 family 6 model 60 step 3 clock 3500 MHz) Intel(r) Xeon(r) CPU E3-1246 v3 @ 3.50GHz # prtconf -m 32657 $ zpool status pool: rpool state: ONLINE scan: none requested config: NAME STATE READ WRITE CKSUM rpool ONLINE 0 0 0 raidz1-0 ONLINE 0 0 0 c3t0d0 ONLINE 0 0 0 c3t1d0 ONLINE 0 0 0 Reviewed by: Matthew Ahrens mahrens@delphix.com Reviewed by: George Wilson george.wilson@delphix.com Reviewed by: Paul Dagnelie pcd@delphix.com Reviewed by: John Kennedy john.kennedy@delphix.com Reviewed by: Prakash Surya prakash.surya@delphix.com Reviewed by: Prashanth Sreenivasa pks@delphix.com Reviewed by: Pavel Zakharov pavel.zakharov@delphix.com Reviewed by: Chris Williamson chris.williamson@delphix.com Approved by: Richard Lowe <richlowe@richlowe.net> Author: Dan Kimmel <dan.kimmel@delphix.com> Added: vendor-sys/illumos/dist/uts/common/fs/zfs/abd.c (contents, props changed) vendor-sys/illumos/dist/uts/common/fs/zfs/sys/abd.h (contents, props changed) Modified: vendor-sys/illumos/dist/common/zfs/zfs_fletcher.c vendor-sys/illumos/dist/common/zfs/zfs_fletcher.h vendor-sys/illumos/dist/uts/common/Makefile.files vendor-sys/illumos/dist/uts/common/fs/zfs/arc.c vendor-sys/illumos/dist/uts/common/fs/zfs/blkptr.c vendor-sys/illumos/dist/uts/common/fs/zfs/dbuf.c vendor-sys/illumos/dist/uts/common/fs/zfs/ddt.c vendor-sys/illumos/dist/uts/common/fs/zfs/dmu.c vendor-sys/illumos/dist/uts/common/fs/zfs/dmu_send.c vendor-sys/illumos/dist/uts/common/fs/zfs/dsl_scan.c vendor-sys/illumos/dist/uts/common/fs/zfs/edonr_zfs.c vendor-sys/illumos/dist/uts/common/fs/zfs/lz4.c vendor-sys/illumos/dist/uts/common/fs/zfs/sha256.c vendor-sys/illumos/dist/uts/common/fs/zfs/skein_zfs.c vendor-sys/illumos/dist/uts/common/fs/zfs/spa.c vendor-sys/illumos/dist/uts/common/fs/zfs/sys/ddt.h vendor-sys/illumos/dist/uts/common/fs/zfs/sys/spa.h vendor-sys/illumos/dist/uts/common/fs/zfs/sys/vdev_impl.h vendor-sys/illumos/dist/uts/common/fs/zfs/sys/zio.h vendor-sys/illumos/dist/uts/common/fs/zfs/sys/zio_checksum.h vendor-sys/illumos/dist/uts/common/fs/zfs/sys/zio_compress.h vendor-sys/illumos/dist/uts/common/fs/zfs/vdev.c vendor-sys/illumos/dist/uts/common/fs/zfs/vdev_cache.c vendor-sys/illumos/dist/uts/common/fs/zfs/vdev_disk.c vendor-sys/illumos/dist/uts/common/fs/zfs/vdev_file.c vendor-sys/illumos/dist/uts/common/fs/zfs/vdev_label.c vendor-sys/illumos/dist/uts/common/fs/zfs/vdev_mirror.c vendor-sys/illumos/dist/uts/common/fs/zfs/vdev_queue.c vendor-sys/illumos/dist/uts/common/fs/zfs/vdev_raidz.c vendor-sys/illumos/dist/uts/common/fs/zfs/zil.c vendor-sys/illumos/dist/uts/common/fs/zfs/zio.c vendor-sys/illumos/dist/uts/common/fs/zfs/zio_checksum.c vendor-sys/illumos/dist/uts/common/fs/zfs/zio_compress.c Changes in other areas also in this revision: Modified: vendor/illumos/dist/cmd/zdb/zdb.c vendor/illumos/dist/cmd/zdb/zdb_il.c vendor/illumos/dist/cmd/ztest/ztest.c vendor/illumos/dist/lib/libzfs/common/libzfs_sendrecv.c Modified: vendor-sys/illumos/dist/common/zfs/zfs_fletcher.c ============================================================================== --- vendor-sys/illumos/dist/common/zfs/zfs_fletcher.c Fri May 26 12:08:38 2017 (r318945) +++ vendor-sys/illumos/dist/common/zfs/zfs_fletcher.c Fri May 26 12:13:27 2017 (r318946) @@ -24,6 +24,7 @@ */ /* * Copyright 2013 Saso Kiselkov. All rights reserved. + * Copyright (c) 2016 by Delphix. All rights reserved. */ /* @@ -133,17 +134,29 @@ #include <sys/byteorder.h> #include <sys/zio.h> #include <sys/spa.h> +#include <zfs_fletcher.h> -/*ARGSUSED*/ void -fletcher_2_native(const void *buf, uint64_t size, - const void *ctx_template, zio_cksum_t *zcp) +fletcher_init(zio_cksum_t *zcp) { + ZIO_SET_CHECKSUM(zcp, 0, 0, 0, 0); +} + +int +fletcher_2_incremental_native(void *buf, size_t size, void *data) +{ + zio_cksum_t *zcp = data; + const uint64_t *ip = buf; const uint64_t *ipend = ip + (size / sizeof (uint64_t)); uint64_t a0, b0, a1, b1; - for (a0 = b0 = a1 = b1 = 0; ip < ipend; ip += 2) { + a0 = zcp->zc_word[0]; + a1 = zcp->zc_word[1]; + b0 = zcp->zc_word[2]; + b1 = zcp->zc_word[3]; + + for (; ip < ipend; ip += 2) { a0 += ip[0]; a1 += ip[1]; b0 += a0; @@ -151,18 +164,33 @@ fletcher_2_native(const void *buf, uint6 } ZIO_SET_CHECKSUM(zcp, a0, a1, b0, b1); + return (0); } /*ARGSUSED*/ void -fletcher_2_byteswap(const void *buf, uint64_t size, +fletcher_2_native(const void *buf, size_t size, const void *ctx_template, zio_cksum_t *zcp) { + fletcher_init(zcp); + (void) fletcher_2_incremental_native((void *) buf, size, zcp); +} + +int +fletcher_2_incremental_byteswap(void *buf, size_t size, void *data) +{ + zio_cksum_t *zcp = data; + const uint64_t *ip = buf; const uint64_t *ipend = ip + (size / sizeof (uint64_t)); uint64_t a0, b0, a1, b1; - for (a0 = b0 = a1 = b1 = 0; ip < ipend; ip += 2) { + a0 = zcp->zc_word[0]; + a1 = zcp->zc_word[1]; + b0 = zcp->zc_word[2]; + b1 = zcp->zc_word[3]; + + for (; ip < ipend; ip += 2) { a0 += BSWAP_64(ip[0]); a1 += BSWAP_64(ip[1]); b0 += a0; @@ -170,50 +198,23 @@ fletcher_2_byteswap(const void *buf, uin } ZIO_SET_CHECKSUM(zcp, a0, a1, b0, b1); + return (0); } /*ARGSUSED*/ void -fletcher_4_native(const void *buf, uint64_t size, +fletcher_2_byteswap(const void *buf, size_t size, const void *ctx_template, zio_cksum_t *zcp) { - const uint32_t *ip = buf; - const uint32_t *ipend = ip + (size / sizeof (uint32_t)); - uint64_t a, b, c, d; - - for (a = b = c = d = 0; ip < ipend; ip++) { - a += ip[0]; - b += a; - c += b; - d += c; - } - - ZIO_SET_CHECKSUM(zcp, a, b, c, d); + fletcher_init(zcp); + (void) fletcher_2_incremental_byteswap((void *) buf, size, zcp); } -/*ARGSUSED*/ -void -fletcher_4_byteswap(const void *buf, uint64_t size, - const void *ctx_template, zio_cksum_t *zcp) +int +fletcher_4_incremental_native(void *buf, size_t size, void *data) { - const uint32_t *ip = buf; - const uint32_t *ipend = ip + (size / sizeof (uint32_t)); - uint64_t a, b, c, d; + zio_cksum_t *zcp = data; - for (a = b = c = d = 0; ip < ipend; ip++) { - a += BSWAP_32(ip[0]); - b += a; - c += b; - d += c; - } - - ZIO_SET_CHECKSUM(zcp, a, b, c, d); -} - -void -fletcher_4_incremental_native(const void *buf, uint64_t size, - zio_cksum_t *zcp) -{ const uint32_t *ip = buf; const uint32_t *ipend = ip + (size / sizeof (uint32_t)); uint64_t a, b, c, d; @@ -231,12 +232,23 @@ fletcher_4_incremental_native(const void } ZIO_SET_CHECKSUM(zcp, a, b, c, d); + return (0); } +/*ARGSUSED*/ void -fletcher_4_incremental_byteswap(const void *buf, uint64_t size, - zio_cksum_t *zcp) +fletcher_4_native(const void *buf, size_t size, + const void *ctx_template, zio_cksum_t *zcp) { + fletcher_init(zcp); + (void) fletcher_4_incremental_native((void *) buf, size, zcp); +} + +int +fletcher_4_incremental_byteswap(void *buf, size_t size, void *data) +{ + zio_cksum_t *zcp = data; + const uint32_t *ip = buf; const uint32_t *ipend = ip + (size / sizeof (uint32_t)); uint64_t a, b, c, d; @@ -254,4 +266,14 @@ fletcher_4_incremental_byteswap(const vo } ZIO_SET_CHECKSUM(zcp, a, b, c, d); + return (0); +} + +/*ARGSUSED*/ +void +fletcher_4_byteswap(const void *buf, size_t size, + const void *ctx_template, zio_cksum_t *zcp) +{ + fletcher_init(zcp); + (void) fletcher_4_incremental_byteswap((void *) buf, size, zcp); } Modified: vendor-sys/illumos/dist/common/zfs/zfs_fletcher.h ============================================================================== --- vendor-sys/illumos/dist/common/zfs/zfs_fletcher.h Fri May 26 12:08:38 2017 (r318945) +++ vendor-sys/illumos/dist/common/zfs/zfs_fletcher.h Fri May 26 12:13:27 2017 (r318946) @@ -24,6 +24,7 @@ */ /* * Copyright 2013 Saso Kiselkov. All rights reserved. + * Copyright (c) 2016 by Delphix. All rights reserved. */ #ifndef _ZFS_FLETCHER_H @@ -40,12 +41,15 @@ extern "C" { * fletcher checksum functions */ -void fletcher_2_native(const void *, uint64_t, const void *, zio_cksum_t *); -void fletcher_2_byteswap(const void *, uint64_t, const void *, zio_cksum_t *); -void fletcher_4_native(const void *, uint64_t, const void *, zio_cksum_t *); -void fletcher_4_byteswap(const void *, uint64_t, const void *, zio_cksum_t *); -void fletcher_4_incremental_native(const void *, uint64_t, zio_cksum_t *); -void fletcher_4_incremental_byteswap(const void *, uint64_t, zio_cksum_t *); +void fletcher_init(zio_cksum_t *); +void fletcher_2_native(const void *, size_t, const void *, zio_cksum_t *); +void fletcher_2_byteswap(const void *, size_t, const void *, zio_cksum_t *); +int fletcher_2_incremental_native(void *, size_t, void *); +int fletcher_2_incremental_byteswap(void *, size_t, void *); +void fletcher_4_native(const void *, size_t, const void *, zio_cksum_t *); +void fletcher_4_byteswap(const void *, size_t, const void *, zio_cksum_t *); +int fletcher_4_incremental_native(void *, size_t, void *); +int fletcher_4_incremental_byteswap(void *, size_t, void *); #ifdef __cplusplus } Modified: vendor-sys/illumos/dist/uts/common/Makefile.files ============================================================================== --- vendor-sys/illumos/dist/uts/common/Makefile.files Fri May 26 12:08:38 2017 (r318945) +++ vendor-sys/illumos/dist/uts/common/Makefile.files Fri May 26 12:13:27 2017 (r318946) @@ -1333,6 +1333,7 @@ NOTIFY_OBJS += md_notify.o TRANS_OBJS += mdtrans.o trans_ioctl.o trans_log.o ZFS_COMMON_OBJS += \ + abd.o \ arc.o \ blkptr.o \ bplist.o \ Added: vendor-sys/illumos/dist/uts/common/fs/zfs/abd.c ============================================================================== --- /dev/null 00:00:00 1970 (empty, because file is newly added) +++ vendor-sys/illumos/dist/uts/common/fs/zfs/abd.c Fri May 26 12:13:27 2017 (r318946) @@ -0,0 +1,940 @@ +/* + * This file and its contents are supplied under the terms of the + * Common Development and Distribution License ("CDDL"), version 1.0. + * You may only use this file in accordance with the terms of version + * 1.0 of the CDDL. + * + * A full copy of the text of the CDDL should have accompanied this + * source. A copy of the CDDL is also available via the Internet at + * http://www.illumos.org/license/CDDL. + */ + +/* + * Copyright (c) 2014 by Chunwei Chen. All rights reserved. + * Copyright (c) 2016 by Delphix. All rights reserved. + */ + +/* + * ARC buffer data (ABD). + * + * ABDs are an abstract data structure for the ARC which can use two + * different ways of storing the underlying data: + * + * (a) Linear buffer. In this case, all the data in the ABD is stored in one + * contiguous buffer in memory (from a zio_[data_]buf_* kmem cache). + * + * +-------------------+ + * | ABD (linear) | + * | abd_flags = ... | + * | abd_size = ... | +--------------------------------+ + * | abd_buf ------------->| raw buffer of size abd_size | + * +-------------------+ +--------------------------------+ + * no abd_chunks + * + * (b) Scattered buffer. In this case, the data in the ABD is split into + * equal-sized chunks (from the abd_chunk_cache kmem_cache), with pointers + * to the chunks recorded in an array at the end of the ABD structure. + * + * +-------------------+ + * | ABD (scattered) | + * | abd_flags = ... | + * | abd_size = ... | + * | abd_offset = 0 | +-----------+ + * | abd_chunks[0] ----------------------------->| chunk 0 | + * | abd_chunks[1] ---------------------+ +-----------+ + * | ... | | +-----------+ + * | abd_chunks[N-1] ---------+ +------->| chunk 1 | + * +-------------------+ | +-----------+ + * | ... + * | +-----------+ + * +----------------->| chunk N-1 | + * +-----------+ + * + * Using a large proportion of scattered ABDs decreases ARC fragmentation since + * when we are at the limit of allocatable space, using equal-size chunks will + * allow us to quickly reclaim enough space for a new large allocation (assuming + * it is also scattered). + * + * In addition to directly allocating a linear or scattered ABD, it is also + * possible to create an ABD by requesting the "sub-ABD" starting at an offset + * within an existing ABD. In linear buffers this is simple (set abd_buf of + * the new ABD to the starting point within the original raw buffer), but + * scattered ABDs are a little more complex. The new ABD makes a copy of the + * relevant abd_chunks pointers (but not the underlying data). However, to + * provide arbitrary rather than only chunk-aligned starting offsets, it also + * tracks an abd_offset field which represents the starting point of the data + * within the first chunk in abd_chunks. For both linear and scattered ABDs, + * creating an offset ABD marks the original ABD as the offset's parent, and the + * original ABD's abd_children refcount is incremented. This data allows us to + * ensure the root ABD isn't deleted before its children. + * + * Most consumers should never need to know what type of ABD they're using -- + * the ABD public API ensures that it's possible to transparently switch from + * using a linear ABD to a scattered one when doing so would be beneficial. + * + * If you need to use the data within an ABD directly, if you know it's linear + * (because you allocated it) you can use abd_to_buf() to access the underlying + * raw buffer. Otherwise, you should use one of the abd_borrow_buf* functions + * which will allocate a raw buffer if necessary. Use the abd_return_buf* + * functions to return any raw buffers that are no longer necessary when you're + * done using them. + * + * There are a variety of ABD APIs that implement basic buffer operations: + * compare, copy, read, write, and fill with zeroes. If you need a custom + * function which progressively accesses the whole ABD, use the abd_iterate_* + * functions. + */ + +#include <sys/abd.h> +#include <sys/param.h> +#include <sys/zio.h> +#include <sys/zfs_context.h> +#include <sys/zfs_znode.h> + +typedef struct abd_stats { + kstat_named_t abdstat_struct_size; + kstat_named_t abdstat_scatter_cnt; + kstat_named_t abdstat_scatter_data_size; + kstat_named_t abdstat_scatter_chunk_waste; + kstat_named_t abdstat_linear_cnt; + kstat_named_t abdstat_linear_data_size; +} abd_stats_t; + +static abd_stats_t abd_stats = { + /* Amount of memory occupied by all of the abd_t struct allocations */ + { "struct_size", KSTAT_DATA_UINT64 }, + /* + * The number of scatter ABDs which are currently allocated, excluding + * ABDs which don't own their data (for instance the ones which were + * allocated through abd_get_offset()). + */ + { "scatter_cnt", KSTAT_DATA_UINT64 }, + /* Amount of data stored in all scatter ABDs tracked by scatter_cnt */ + { "scatter_data_size", KSTAT_DATA_UINT64 }, + /* + * The amount of space wasted at the end of the last chunk across all + * scatter ABDs tracked by scatter_cnt. + */ + { "scatter_chunk_waste", KSTAT_DATA_UINT64 }, + /* + * The number of linear ABDs which are currently allocated, excluding + * ABDs which don't own their data (for instance the ones which were + * allocated through abd_get_offset() and abd_get_from_buf()). If an + * ABD takes ownership of its buf then it will become tracked. + */ + { "linear_cnt", KSTAT_DATA_UINT64 }, + /* Amount of data stored in all linear ABDs tracked by linear_cnt */ + { "linear_data_size", KSTAT_DATA_UINT64 }, +}; + +#define ABDSTAT(stat) (abd_stats.stat.value.ui64) +#define ABDSTAT_INCR(stat, val) \ + atomic_add_64(&abd_stats.stat.value.ui64, (val)) +#define ABDSTAT_BUMP(stat) ABDSTAT_INCR(stat, 1) +#define ABDSTAT_BUMPDOWN(stat) ABDSTAT_INCR(stat, -1) + +/* + * It is possible to make all future ABDs be linear by setting this to B_FALSE. + * Otherwise, ABDs are allocated scattered by default unless the caller uses + * abd_alloc_linear(). + */ +boolean_t zfs_abd_scatter_enabled = B_TRUE; + +/* + * The size of the chunks ABD allocates. Because the sizes allocated from the + * kmem_cache can't change, this tunable can only be modified at boot. Changing + * it at runtime would cause ABD iteration to work incorrectly for ABDs which + * were allocated with the old size, so a safeguard has been put in place which + * will cause the machine to panic if you change it and try to access the data + * within a scattered ABD. + */ +size_t zfs_abd_chunk_size = 4096; + +#ifdef _KERNEL +extern vmem_t *zio_alloc_arena; +#endif + +kmem_cache_t *abd_chunk_cache; +static kstat_t *abd_ksp; + +static void * +abd_alloc_chunk() +{ + void *c = kmem_cache_alloc(abd_chunk_cache, KM_PUSHPAGE); + ASSERT3P(c, !=, NULL); + return (c); +} + +static void +abd_free_chunk(void *c) +{ + kmem_cache_free(abd_chunk_cache, c); +} + +void +abd_init(void) +{ + vmem_t *data_alloc_arena = NULL; + +#ifdef _KERNEL + data_alloc_arena = zio_alloc_arena; +#endif + + /* + * Since ABD chunks do not appear in crash dumps, we pass KMC_NOTOUCH + * so that no allocator metadata is stored with the buffers. + */ + abd_chunk_cache = kmem_cache_create("abd_chunk", zfs_abd_chunk_size, 0, + NULL, NULL, NULL, NULL, data_alloc_arena, KMC_NOTOUCH); + + abd_ksp = kstat_create("zfs", 0, "abdstats", "misc", KSTAT_TYPE_NAMED, + sizeof (abd_stats) / sizeof (kstat_named_t), KSTAT_FLAG_VIRTUAL); + if (abd_ksp != NULL) { + abd_ksp->ks_data = &abd_stats; + kstat_install(abd_ksp); + } +} + +void +abd_fini(void) +{ + if (abd_ksp != NULL) { + kstat_delete(abd_ksp); + abd_ksp = NULL; + } + + kmem_cache_destroy(abd_chunk_cache); + abd_chunk_cache = NULL; +} + +static inline size_t +abd_chunkcnt_for_bytes(size_t size) +{ + return (P2ROUNDUP(size, zfs_abd_chunk_size) / zfs_abd_chunk_size); +} + +static inline size_t +abd_scatter_chunkcnt(abd_t *abd) +{ + ASSERT(!abd_is_linear(abd)); + return (abd_chunkcnt_for_bytes( + abd->abd_u.abd_scatter.abd_offset + abd->abd_size)); +} + +static inline void +abd_verify(abd_t *abd) +{ + ASSERT3U(abd->abd_size, >, 0); + ASSERT3U(abd->abd_size, <=, SPA_MAXBLOCKSIZE); + ASSERT3U(abd->abd_flags, ==, abd->abd_flags & (ABD_FLAG_LINEAR | + ABD_FLAG_OWNER | ABD_FLAG_META)); + IMPLY(abd->abd_parent != NULL, !(abd->abd_flags & ABD_FLAG_OWNER)); + IMPLY(abd->abd_flags & ABD_FLAG_META, abd->abd_flags & ABD_FLAG_OWNER); + if (abd_is_linear(abd)) { + ASSERT3P(abd->abd_u.abd_linear.abd_buf, !=, NULL); + } else { + ASSERT3U(abd->abd_u.abd_scatter.abd_offset, <, + zfs_abd_chunk_size); + size_t n = abd_scatter_chunkcnt(abd); + for (int i = 0; i < n; i++) { + ASSERT3P( + abd->abd_u.abd_scatter.abd_chunks[i], !=, NULL); + } + } +} + +static inline abd_t * +abd_alloc_struct(size_t chunkcnt) +{ + size_t size = offsetof(abd_t, abd_u.abd_scatter.abd_chunks[chunkcnt]); + abd_t *abd = kmem_alloc(size, KM_PUSHPAGE); + ASSERT3P(abd, !=, NULL); + ABDSTAT_INCR(abdstat_struct_size, size); + + return (abd); +} + +static inline void +abd_free_struct(abd_t *abd) +{ + size_t chunkcnt = abd_is_linear(abd) ? 0 : abd_scatter_chunkcnt(abd); + int size = offsetof(abd_t, abd_u.abd_scatter.abd_chunks[chunkcnt]); + kmem_free(abd, size); + ABDSTAT_INCR(abdstat_struct_size, -size); +} + +/* + * Allocate an ABD, along with its own underlying data buffers. Use this if you + * don't care whether the ABD is linear or not. + */ +abd_t * +abd_alloc(size_t size, boolean_t is_metadata) +{ + if (!zfs_abd_scatter_enabled) + return (abd_alloc_linear(size, is_metadata)); + + VERIFY3U(size, <=, SPA_MAXBLOCKSIZE); + + size_t n = abd_chunkcnt_for_bytes(size); + abd_t *abd = abd_alloc_struct(n); + + abd->abd_flags = ABD_FLAG_OWNER; + if (is_metadata) { + abd->abd_flags |= ABD_FLAG_META; + } + abd->abd_size = size; + abd->abd_parent = NULL; + refcount_create(&abd->abd_children); + + abd->abd_u.abd_scatter.abd_offset = 0; + abd->abd_u.abd_scatter.abd_chunk_size = zfs_abd_chunk_size; + + for (int i = 0; i < n; i++) { + void *c = abd_alloc_chunk(); + ASSERT3P(c, !=, NULL); + abd->abd_u.abd_scatter.abd_chunks[i] = c; + } + + ABDSTAT_BUMP(abdstat_scatter_cnt); + ABDSTAT_INCR(abdstat_scatter_data_size, size); + ABDSTAT_INCR(abdstat_scatter_chunk_waste, + n * zfs_abd_chunk_size - size); + + return (abd); +} + +static void +abd_free_scatter(abd_t *abd) +{ + size_t n = abd_scatter_chunkcnt(abd); + for (int i = 0; i < n; i++) { + abd_free_chunk(abd->abd_u.abd_scatter.abd_chunks[i]); + } + + refcount_destroy(&abd->abd_children); + ABDSTAT_BUMPDOWN(abdstat_scatter_cnt); + ABDSTAT_INCR(abdstat_scatter_data_size, -(int)abd->abd_size); + ABDSTAT_INCR(abdstat_scatter_chunk_waste, + abd->abd_size - n * zfs_abd_chunk_size); + + abd_free_struct(abd); +} + +/* + * Allocate an ABD that must be linear, along with its own underlying data + * buffer. Only use this when it would be very annoying to write your ABD + * consumer with a scattered ABD. + */ +abd_t * +abd_alloc_linear(size_t size, boolean_t is_metadata) +{ + abd_t *abd = abd_alloc_struct(0); + + VERIFY3U(size, <=, SPA_MAXBLOCKSIZE); + + abd->abd_flags = ABD_FLAG_LINEAR | ABD_FLAG_OWNER; + if (is_metadata) { + abd->abd_flags |= ABD_FLAG_META; + } + abd->abd_size = size; + abd->abd_parent = NULL; + refcount_create(&abd->abd_children); + + if (is_metadata) { + abd->abd_u.abd_linear.abd_buf = zio_buf_alloc(size); + } else { + abd->abd_u.abd_linear.abd_buf = zio_data_buf_alloc(size); + } + + ABDSTAT_BUMP(abdstat_linear_cnt); + ABDSTAT_INCR(abdstat_linear_data_size, size); + + return (abd); +} + +static void +abd_free_linear(abd_t *abd) +{ + if (abd->abd_flags & ABD_FLAG_META) { + zio_buf_free(abd->abd_u.abd_linear.abd_buf, abd->abd_size); + } else { + zio_data_buf_free(abd->abd_u.abd_linear.abd_buf, abd->abd_size); + } + + refcount_destroy(&abd->abd_children); + ABDSTAT_BUMPDOWN(abdstat_linear_cnt); + ABDSTAT_INCR(abdstat_linear_data_size, -(int)abd->abd_size); + + abd_free_struct(abd); +} + +/* + * Free an ABD. Only use this on ABDs allocated with abd_alloc() or + * abd_alloc_linear(). + */ +void +abd_free(abd_t *abd) +{ + abd_verify(abd); + ASSERT3P(abd->abd_parent, ==, NULL); + ASSERT(abd->abd_flags & ABD_FLAG_OWNER); + if (abd_is_linear(abd)) + abd_free_linear(abd); + else + abd_free_scatter(abd); +} + +/* + * Allocate an ABD of the same format (same metadata flag, same scatterize + * setting) as another ABD. + */ +abd_t * +abd_alloc_sametype(abd_t *sabd, size_t size) +{ + boolean_t is_metadata = (sabd->abd_flags & ABD_FLAG_META) != 0; + if (abd_is_linear(sabd)) { + return (abd_alloc_linear(size, is_metadata)); + } else { + return (abd_alloc(size, is_metadata)); + } +} + +/* + * If we're going to use this ABD for doing I/O using the block layer, the + * consumer of the ABD data doesn't care if it's scattered or not, and we don't + * plan to store this ABD in memory for a long period of time, we should + * allocate the ABD type that requires the least data copying to do the I/O. + * + * Currently this is linear ABDs, however if ldi_strategy() can ever issue I/Os + * using a scatter/gather list we should switch to that and replace this call + * with vanilla abd_alloc(). + */ +abd_t * +abd_alloc_for_io(size_t size, boolean_t is_metadata) +{ + return (abd_alloc_linear(size, is_metadata)); +} + +/* + * Allocate a new ABD to point to offset off of sabd. It shares the underlying + * buffer data with sabd. Use abd_put() to free. sabd must not be freed while + * any derived ABDs exist. + */ +abd_t * +abd_get_offset(abd_t *sabd, size_t off) +{ + abd_t *abd; + + abd_verify(sabd); + ASSERT3U(off, <=, sabd->abd_size); + + if (abd_is_linear(sabd)) { + abd = abd_alloc_struct(0); + + /* + * Even if this buf is filesystem metadata, we only track that + * if we own the underlying data buffer, which is not true in + * this case. Therefore, we don't ever use ABD_FLAG_META here. + */ + abd->abd_flags = ABD_FLAG_LINEAR; + + abd->abd_u.abd_linear.abd_buf = + (char *)sabd->abd_u.abd_linear.abd_buf + off; + } else { + size_t new_offset = sabd->abd_u.abd_scatter.abd_offset + off; + size_t chunkcnt = abd_scatter_chunkcnt(sabd) - + (new_offset / zfs_abd_chunk_size); + + abd = abd_alloc_struct(chunkcnt); + + /* + * Even if this buf is filesystem metadata, we only track that + * if we own the underlying data buffer, which is not true in + * this case. Therefore, we don't ever use ABD_FLAG_META here. + */ + abd->abd_flags = 0; + + abd->abd_u.abd_scatter.abd_offset = + new_offset % zfs_abd_chunk_size; + abd->abd_u.abd_scatter.abd_chunk_size = zfs_abd_chunk_size; + + /* Copy the scatterlist starting at the correct offset */ + (void) memcpy(&abd->abd_u.abd_scatter.abd_chunks, + &sabd->abd_u.abd_scatter.abd_chunks[new_offset / + zfs_abd_chunk_size], + chunkcnt * sizeof (void *)); + } + + abd->abd_size = sabd->abd_size - off; + abd->abd_parent = sabd; + refcount_create(&abd->abd_children); + (void) refcount_add_many(&sabd->abd_children, abd->abd_size, abd); + + return (abd); +} + +/* + * Allocate a linear ABD structure for buf. You must free this with abd_put() + * since the resulting ABD doesn't own its own buffer. + */ +abd_t * +abd_get_from_buf(void *buf, size_t size) +{ + abd_t *abd = abd_alloc_struct(0); + + VERIFY3U(size, <=, SPA_MAXBLOCKSIZE); + + /* + * Even if this buf is filesystem metadata, we only track that if we + * own the underlying data buffer, which is not true in this case. + * Therefore, we don't ever use ABD_FLAG_META here. + */ + abd->abd_flags = ABD_FLAG_LINEAR; + abd->abd_size = size; + abd->abd_parent = NULL; + refcount_create(&abd->abd_children); + + abd->abd_u.abd_linear.abd_buf = buf; + + return (abd); +} + +/* + * Free an ABD allocated from abd_get_offset() or abd_get_from_buf(). Will not + * free the underlying scatterlist or buffer. + */ +void +abd_put(abd_t *abd) +{ + abd_verify(abd); + ASSERT(!(abd->abd_flags & ABD_FLAG_OWNER)); + + if (abd->abd_parent != NULL) { + (void) refcount_remove_many(&abd->abd_parent->abd_children, + abd->abd_size, abd); + } + + refcount_destroy(&abd->abd_children); + abd_free_struct(abd); +} + +/* + * Get the raw buffer associated with a linear ABD. + */ +void * +abd_to_buf(abd_t *abd) +{ + ASSERT(abd_is_linear(abd)); + abd_verify(abd); + return (abd->abd_u.abd_linear.abd_buf); +} + +/* + * Borrow a raw buffer from an ABD without copying the contents of the ABD + * into the buffer. If the ABD is scattered, this will allocate a raw buffer + * whose contents are undefined. To copy over the existing data in the ABD, use + * abd_borrow_buf_copy() instead. + */ +void * +abd_borrow_buf(abd_t *abd, size_t n) +{ + void *buf; + abd_verify(abd); + ASSERT3U(abd->abd_size, >=, n); + if (abd_is_linear(abd)) { + buf = abd_to_buf(abd); + } else { + buf = zio_buf_alloc(n); + } + (void) refcount_add_many(&abd->abd_children, n, buf); + + return (buf); +} + +void * +abd_borrow_buf_copy(abd_t *abd, size_t n) +{ + void *buf = abd_borrow_buf(abd, n); + if (!abd_is_linear(abd)) { + abd_copy_to_buf(buf, abd, n); + } + return (buf); +} + +/* + * Return a borrowed raw buffer to an ABD. If the ABD is scattered, this will + * not change the contents of the ABD and will ASSERT that you didn't modify + * the buffer since it was borrowed. If you want any changes you made to buf to + * be copied back to abd, use abd_return_buf_copy() instead. + */ +void +abd_return_buf(abd_t *abd, void *buf, size_t n) +{ + abd_verify(abd); + ASSERT3U(abd->abd_size, >=, n); + if (abd_is_linear(abd)) { + ASSERT3P(buf, ==, abd_to_buf(abd)); + } else { + ASSERT0(abd_cmp_buf(abd, buf, n)); + zio_buf_free(buf, n); + } + (void) refcount_remove_many(&abd->abd_children, n, buf); +} + +void +abd_return_buf_copy(abd_t *abd, void *buf, size_t n) +{ + if (!abd_is_linear(abd)) { + abd_copy_from_buf(abd, buf, n); + } + abd_return_buf(abd, buf, n); +} + +/* + * Give this ABD ownership of the buffer that it's storing. Can only be used on + * linear ABDs which were allocated via abd_get_from_buf(), or ones allocated + * with abd_alloc_linear() which subsequently released ownership of their buf + * with abd_release_ownership_of_buf(). + */ +void +abd_take_ownership_of_buf(abd_t *abd, boolean_t is_metadata) +{ + ASSERT(abd_is_linear(abd)); + ASSERT(!(abd->abd_flags & ABD_FLAG_OWNER)); + abd_verify(abd); + + abd->abd_flags |= ABD_FLAG_OWNER; + if (is_metadata) { + abd->abd_flags |= ABD_FLAG_META; + } + + ABDSTAT_BUMP(abdstat_linear_cnt); + ABDSTAT_INCR(abdstat_linear_data_size, abd->abd_size); +} + +void +abd_release_ownership_of_buf(abd_t *abd) +{ + ASSERT(abd_is_linear(abd)); + ASSERT(abd->abd_flags & ABD_FLAG_OWNER); + abd_verify(abd); + + abd->abd_flags &= ~ABD_FLAG_OWNER; + /* Disable this flag since we no longer own the data buffer */ + abd->abd_flags &= ~ABD_FLAG_META; + + ABDSTAT_BUMPDOWN(abdstat_linear_cnt); + ABDSTAT_INCR(abdstat_linear_data_size, -(int)abd->abd_size); +} + +struct abd_iter { + abd_t *iter_abd; /* ABD being iterated through */ + size_t iter_pos; /* position (relative to abd_offset) */ + void *iter_mapaddr; /* addr corresponding to iter_pos */ + size_t iter_mapsize; /* length of data valid at mapaddr */ +}; + +static inline size_t +abd_iter_scatter_chunk_offset(struct abd_iter *aiter) +{ + ASSERT(!abd_is_linear(aiter->iter_abd)); + return ((aiter->iter_abd->abd_u.abd_scatter.abd_offset + + aiter->iter_pos) % zfs_abd_chunk_size); +} + +static inline size_t +abd_iter_scatter_chunk_index(struct abd_iter *aiter) +{ + ASSERT(!abd_is_linear(aiter->iter_abd)); + return ((aiter->iter_abd->abd_u.abd_scatter.abd_offset + + aiter->iter_pos) / zfs_abd_chunk_size); +} + +/* + * Initialize the abd_iter. + */ +static void +abd_iter_init(struct abd_iter *aiter, abd_t *abd) +{ + abd_verify(abd); + aiter->iter_abd = abd; + aiter->iter_pos = 0; + aiter->iter_mapaddr = NULL; + aiter->iter_mapsize = 0; +} + +/* + * Advance the iterator by a certain amount. Cannot be called when a chunk is + * in use. This can be safely called when the aiter has already exhausted, in + * which case this does nothing. + */ +static void +abd_iter_advance(struct abd_iter *aiter, size_t amount) +{ + ASSERT3P(aiter->iter_mapaddr, ==, NULL); + ASSERT0(aiter->iter_mapsize); + + /* There's nothing left to advance to, so do nothing */ + if (aiter->iter_pos == aiter->iter_abd->abd_size) + return; + + aiter->iter_pos += amount; +} + +/* + * Map the current chunk into aiter. This can be safely called when the aiter + * has already exhausted, in which case this does nothing. + */ +static void +abd_iter_map(struct abd_iter *aiter) +{ + void *paddr; + size_t offset = 0; + + ASSERT3P(aiter->iter_mapaddr, ==, NULL); + ASSERT0(aiter->iter_mapsize); + + /* Panic if someone has changed zfs_abd_chunk_size */ + IMPLY(!abd_is_linear(aiter->iter_abd), zfs_abd_chunk_size == + aiter->iter_abd->abd_u.abd_scatter.abd_chunk_size); + + /* There's nothing left to iterate over, so do nothing */ + if (aiter->iter_pos == aiter->iter_abd->abd_size) + return; + + if (abd_is_linear(aiter->iter_abd)) { + offset = aiter->iter_pos; + aiter->iter_mapsize = aiter->iter_abd->abd_size - offset; + paddr = aiter->iter_abd->abd_u.abd_linear.abd_buf; + } else { + size_t index = abd_iter_scatter_chunk_index(aiter); + offset = abd_iter_scatter_chunk_offset(aiter); + aiter->iter_mapsize = zfs_abd_chunk_size - offset; + paddr = aiter->iter_abd->abd_u.abd_scatter.abd_chunks[index]; + } + aiter->iter_mapaddr = (char *)paddr + offset; +} + +/* + * Unmap the current chunk from aiter. This can be safely called when the aiter + * has already exhausted, in which case this does nothing. + */ +static void +abd_iter_unmap(struct abd_iter *aiter) +{ + /* There's nothing left to unmap, so do nothing */ + if (aiter->iter_pos == aiter->iter_abd->abd_size) + return; + + ASSERT3P(aiter->iter_mapaddr, !=, NULL); + ASSERT3U(aiter->iter_mapsize, >, 0); + + aiter->iter_mapaddr = NULL; + aiter->iter_mapsize = 0; +} + +int +abd_iterate_func(abd_t *abd, size_t off, size_t size, + abd_iter_func_t *func, void *private) +{ + int ret = 0; + struct abd_iter aiter; + + abd_verify(abd); + ASSERT3U(off + size, <=, abd->abd_size); + + abd_iter_init(&aiter, abd); + abd_iter_advance(&aiter, off); + + while (size > 0) { + abd_iter_map(&aiter); + + size_t len = MIN(aiter.iter_mapsize, size); + ASSERT3U(len, >, 0); + + ret = func(aiter.iter_mapaddr, len, private); + + abd_iter_unmap(&aiter); + + if (ret != 0) + break; + + size -= len; + abd_iter_advance(&aiter, len); + } + + return (ret); +} + +struct buf_arg { + void *arg_buf; +}; + +static int +abd_copy_to_buf_off_cb(void *buf, size_t size, void *private) +{ + struct buf_arg *ba_ptr = private; *** DIFF OUTPUT TRUNCATED AT 1000 LINES ***
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