From d088e6a48aa437b2bf706a5f6cc4967f0eceba64 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 3 Mar 2022 20:43:39 +0100 Subject: [PATCH] block: intoduce reqlist Split intersecting-requests functionality out of block-copy to be reused in copy-before-write filter. Note: while being here, fix tiny typo in MAINTAINERS. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Hanna Reitz Message-Id: <20220303194349.2304213-7-vsementsov@virtuozzo.com> Signed-off-by: Hanna Reitz --- MAINTAINERS | 4 +- block/block-copy.c | 116 +++++++++++++++--------------------------------- block/meson.build | 1 + block/reqlist.c | 76 +++++++++++++++++++++++++++++++ include/block/reqlist.h | 67 ++++++++++++++++++++++++++++ 5 files changed, 184 insertions(+), 80 deletions(-) create mode 100644 block/reqlist.c create mode 100644 include/block/reqlist.h diff --git a/MAINTAINERS b/MAINTAINERS index 68adaac373..101eb50619 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -2515,7 +2515,9 @@ F: block/stream.c F: block/mirror.c F: qapi/job.json F: block/block-copy.c -F: include/block/block-copy.c +F: include/block/block-copy.h +F: block/reqlist.c +F: include/block/reqlist.h F: block/copy-before-write.h F: block/copy-before-write.c F: include/block/aio_task.h diff --git a/block/block-copy.c b/block/block-copy.c index 0834e29b6e..ef948dccec 100644 --- a/block/block-copy.c +++ b/block/block-copy.c @@ -17,6 +17,7 @@ #include "trace.h" #include "qapi/error.h" #include "block/block-copy.h" +#include "block/reqlist.h" #include "sysemu/block-backend.h" #include "qemu/units.h" #include "qemu/coroutine.h" @@ -83,7 +84,6 @@ typedef struct BlockCopyTask { */ BlockCopyState *s; BlockCopyCallState *call_state; - int64_t offset; /* * @method can also be set again in the while loop of * block_copy_dirty_clusters(), but it is never accessed concurrently @@ -94,21 +94,17 @@ typedef struct BlockCopyTask { BlockCopyMethod method; /* - * Fields whose state changes throughout the execution - * Protected by lock in BlockCopyState. + * Generally, req is protected by lock in BlockCopyState, Still req.offset + * is only set on task creation, so may be read concurrently after creation. + * req.bytes is changed at most once, and need only protecting the case of + * parallel read while updating @bytes value in block_copy_task_shrink(). */ - CoQueue wait_queue; /* coroutines blocked on this task */ - /* - * Only protect the case of parallel read while updating @bytes - * value in block_copy_task_shrink(). - */ - int64_t bytes; - QLIST_ENTRY(BlockCopyTask) list; + BlockReq req; } BlockCopyTask; static int64_t task_end(BlockCopyTask *task) { - return task->offset + task->bytes; + return task->req.offset + task->req.bytes; } typedef struct BlockCopyState { @@ -136,7 +132,7 @@ typedef struct BlockCopyState { CoMutex lock; int64_t in_flight_bytes; BlockCopyMethod method; - QLIST_HEAD(, BlockCopyTask) tasks; /* All tasks from all block-copy calls */ + BlockReqList reqs; QLIST_HEAD(, BlockCopyCallState) calls; /* * skip_unallocated: @@ -161,42 +157,6 @@ typedef struct BlockCopyState { } BlockCopyState; /* Called with lock held */ -static BlockCopyTask *find_conflicting_task(BlockCopyState *s, - int64_t offset, int64_t bytes) -{ - BlockCopyTask *t; - - QLIST_FOREACH(t, &s->tasks, list) { - if (offset + bytes > t->offset && offset < t->offset + t->bytes) { - return t; - } - } - - return NULL; -} - -/* - * If there are no intersecting tasks return false. Otherwise, wait for the - * first found intersecting tasks to finish and return true. - * - * Called with lock held. May temporary release the lock. - * Return value of 0 proves that lock was NOT released. - */ -static bool coroutine_fn block_copy_wait_one(BlockCopyState *s, int64_t offset, - int64_t bytes) -{ - BlockCopyTask *task = find_conflicting_task(s, offset, bytes); - - if (!task) { - return false; - } - - qemu_co_queue_wait(&task->wait_queue, &s->lock); - - return true; -} - -/* Called with lock held */ static int64_t block_copy_chunk_size(BlockCopyState *s) { switch (s->method) { @@ -239,7 +199,7 @@ block_copy_task_create(BlockCopyState *s, BlockCopyCallState *call_state, bytes = QEMU_ALIGN_UP(bytes, s->cluster_size); /* region is dirty, so no existent tasks possible in it */ - assert(!find_conflicting_task(s, offset, bytes)); + assert(!reqlist_find_conflict(&s->reqs, offset, bytes)); bdrv_reset_dirty_bitmap(s->copy_bitmap, offset, bytes); s->in_flight_bytes += bytes; @@ -249,12 +209,9 @@ block_copy_task_create(BlockCopyState *s, BlockCopyCallState *call_state, .task.func = block_copy_task_entry, .s = s, .call_state = call_state, - .offset = offset, - .bytes = bytes, .method = s->method, }; - qemu_co_queue_init(&task->wait_queue); - QLIST_INSERT_HEAD(&s->tasks, task, list); + reqlist_init_req(&s->reqs, &task->req, offset, bytes); return task; } @@ -270,34 +227,34 @@ static void coroutine_fn block_copy_task_shrink(BlockCopyTask *task, int64_t new_bytes) { QEMU_LOCK_GUARD(&task->s->lock); - if (new_bytes == task->bytes) { + if (new_bytes == task->req.bytes) { return; } - assert(new_bytes > 0 && new_bytes < task->bytes); + assert(new_bytes > 0 && new_bytes < task->req.bytes); - task->s->in_flight_bytes -= task->bytes - new_bytes; + task->s->in_flight_bytes -= task->req.bytes - new_bytes; bdrv_set_dirty_bitmap(task->s->copy_bitmap, - task->offset + new_bytes, task->bytes - new_bytes); + task->req.offset + new_bytes, + task->req.bytes - new_bytes); - task->bytes = new_bytes; - qemu_co_queue_restart_all(&task->wait_queue); + reqlist_shrink_req(&task->req, new_bytes); } static void coroutine_fn block_copy_task_end(BlockCopyTask *task, int ret) { QEMU_LOCK_GUARD(&task->s->lock); - task->s->in_flight_bytes -= task->bytes; + task->s->in_flight_bytes -= task->req.bytes; if (ret < 0) { - bdrv_set_dirty_bitmap(task->s->copy_bitmap, task->offset, task->bytes); + bdrv_set_dirty_bitmap(task->s->copy_bitmap, task->req.offset, + task->req.bytes); } - QLIST_REMOVE(task, list); if (task->s->progress) { progress_set_remaining(task->s->progress, bdrv_get_dirty_count(task->s->copy_bitmap) + task->s->in_flight_bytes); } - qemu_co_queue_restart_all(&task->wait_queue); + reqlist_remove_req(&task->req); } void block_copy_state_free(BlockCopyState *s) @@ -450,7 +407,7 @@ BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target, ratelimit_init(&s->rate_limit); qemu_co_mutex_init(&s->lock); - QLIST_INIT(&s->tasks); + QLIST_INIT(&s->reqs); QLIST_INIT(&s->calls); return s; @@ -483,7 +440,7 @@ static coroutine_fn int block_copy_task_run(AioTaskPool *pool, aio_task_pool_wait_slot(pool); if (aio_task_pool_status(pool) < 0) { - co_put_to_shres(task->s->mem, task->bytes); + co_put_to_shres(task->s->mem, task->req.bytes); block_copy_task_end(task, -ECANCELED); g_free(task); return -ECANCELED; @@ -596,7 +553,8 @@ static coroutine_fn int block_copy_task_entry(AioTask *task) BlockCopyMethod method = t->method; int ret; - ret = block_copy_do_copy(s, t->offset, t->bytes, &method, &error_is_read); + ret = block_copy_do_copy(s, t->req.offset, t->req.bytes, &method, + &error_is_read); WITH_QEMU_LOCK_GUARD(&s->lock) { if (s->method == t->method) { @@ -609,10 +567,10 @@ static coroutine_fn int block_copy_task_entry(AioTask *task) t->call_state->error_is_read = error_is_read; } } else if (s->progress) { - progress_work_done(s->progress, t->bytes); + progress_work_done(s->progress, t->req.bytes); } } - co_put_to_shres(s->mem, t->bytes); + co_put_to_shres(s->mem, t->req.bytes); block_copy_task_end(t, ret); return ret; @@ -771,22 +729,22 @@ block_copy_dirty_clusters(BlockCopyCallState *call_state) trace_block_copy_skip_range(s, offset, bytes); break; } - if (task->offset > offset) { - trace_block_copy_skip_range(s, offset, task->offset - offset); + if (task->req.offset > offset) { + trace_block_copy_skip_range(s, offset, task->req.offset - offset); } found_dirty = true; - ret = block_copy_block_status(s, task->offset, task->bytes, + ret = block_copy_block_status(s, task->req.offset, task->req.bytes, &status_bytes); assert(ret >= 0); /* never fail */ - if (status_bytes < task->bytes) { + if (status_bytes < task->req.bytes) { block_copy_task_shrink(task, status_bytes); } if (qatomic_read(&s->skip_unallocated) && !(ret & BDRV_BLOCK_ALLOCATED)) { block_copy_task_end(task, 0); - trace_block_copy_skip_range(s, task->offset, task->bytes); + trace_block_copy_skip_range(s, task->req.offset, task->req.bytes); offset = task_end(task); bytes = end - offset; g_free(task); @@ -807,11 +765,11 @@ block_copy_dirty_clusters(BlockCopyCallState *call_state) } } - ratelimit_calculate_delay(&s->rate_limit, task->bytes); + ratelimit_calculate_delay(&s->rate_limit, task->req.bytes); - trace_block_copy_process(s, task->offset); + trace_block_copy_process(s, task->req.offset); - co_get_from_shres(s->mem, task->bytes); + co_get_from_shres(s->mem, task->req.bytes); offset = task_end(task); bytes = end - offset; @@ -879,8 +837,8 @@ static int coroutine_fn block_copy_common(BlockCopyCallState *call_state) * Check that there is no task we still need to * wait to complete */ - ret = block_copy_wait_one(s, call_state->offset, - call_state->bytes); + ret = reqlist_wait_one(&s->reqs, call_state->offset, + call_state->bytes, &s->lock); if (ret == 0) { /* * No pending tasks, but check again the bitmap in this @@ -888,7 +846,7 @@ static int coroutine_fn block_copy_common(BlockCopyCallState *call_state) * between this and the critical section in * block_copy_dirty_clusters(). * - * block_copy_wait_one return value 0 also means that it + * reqlist_wait_one return value 0 also means that it * didn't release the lock. So, we are still in the same * critical section, not interrupted by any concurrent * access to state. diff --git a/block/meson.build b/block/meson.build index e42bcb58d5..553b8eddbc 100644 --- a/block/meson.build +++ b/block/meson.build @@ -32,6 +32,7 @@ block_ss.add(files( 'qcow2.c', 'quorum.c', 'raw-format.c', + 'reqlist.c', 'snapshot.c', 'throttle-groups.c', 'throttle.c', diff --git a/block/reqlist.c b/block/reqlist.c new file mode 100644 index 0000000000..5e320ba649 --- /dev/null +++ b/block/reqlist.c @@ -0,0 +1,76 @@ +/* + * reqlist API + * + * Copyright (C) 2013 Proxmox Server Solutions + * Copyright (c) 2021 Virtuozzo International GmbH. + * + * Authors: + * Dietmar Maurer (dietmar@proxmox.com) + * Vladimir Sementsov-Ogievskiy + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ + +#include "qemu/osdep.h" + +#include "block/reqlist.h" + +void reqlist_init_req(BlockReqList *reqs, BlockReq *req, int64_t offset, + int64_t bytes) +{ + assert(!reqlist_find_conflict(reqs, offset, bytes)); + + *req = (BlockReq) { + .offset = offset, + .bytes = bytes, + }; + qemu_co_queue_init(&req->wait_queue); + QLIST_INSERT_HEAD(reqs, req, list); +} + +BlockReq *reqlist_find_conflict(BlockReqList *reqs, int64_t offset, + int64_t bytes) +{ + BlockReq *r; + + QLIST_FOREACH(r, reqs, list) { + if (offset + bytes > r->offset && offset < r->offset + r->bytes) { + return r; + } + } + + return NULL; +} + +bool coroutine_fn reqlist_wait_one(BlockReqList *reqs, int64_t offset, + int64_t bytes, CoMutex *lock) +{ + BlockReq *r = reqlist_find_conflict(reqs, offset, bytes); + + if (!r) { + return false; + } + + qemu_co_queue_wait(&r->wait_queue, lock); + + return true; +} + +void coroutine_fn reqlist_shrink_req(BlockReq *req, int64_t new_bytes) +{ + if (new_bytes == req->bytes) { + return; + } + + assert(new_bytes > 0 && new_bytes < req->bytes); + + req->bytes = new_bytes; + qemu_co_queue_restart_all(&req->wait_queue); +} + +void coroutine_fn reqlist_remove_req(BlockReq *req) +{ + QLIST_REMOVE(req, list); + qemu_co_queue_restart_all(&req->wait_queue); +} diff --git a/include/block/reqlist.h b/include/block/reqlist.h new file mode 100644 index 0000000000..0fa1eef259 --- /dev/null +++ b/include/block/reqlist.h @@ -0,0 +1,67 @@ +/* + * reqlist API + * + * Copyright (C) 2013 Proxmox Server Solutions + * Copyright (c) 2021 Virtuozzo International GmbH. + * + * Authors: + * Dietmar Maurer (dietmar@proxmox.com) + * Vladimir Sementsov-Ogievskiy + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ + +#ifndef REQLIST_H +#define REQLIST_H + +#include "qemu/coroutine.h" + +/* + * The API is not thread-safe and shouldn't be. The struct is public to be part + * of other structures and protected by third-party locks, see + * block/block-copy.c for example. + */ + +typedef struct BlockReq { + int64_t offset; + int64_t bytes; + + CoQueue wait_queue; /* coroutines blocked on this req */ + QLIST_ENTRY(BlockReq) list; +} BlockReq; + +typedef QLIST_HEAD(, BlockReq) BlockReqList; + +/* + * Initialize new request and add it to the list. Caller must be sure that + * there are no conflicting requests in the list. + */ +void reqlist_init_req(BlockReqList *reqs, BlockReq *req, int64_t offset, + int64_t bytes); +/* Search for request in the list intersecting with @offset/@bytes area. */ +BlockReq *reqlist_find_conflict(BlockReqList *reqs, int64_t offset, + int64_t bytes); + +/* + * If there are no intersecting requests return false. Otherwise, wait for the + * first found intersecting request to finish and return true. + * + * @lock is passed to qemu_co_queue_wait() + * False return value proves that lock was released at no point. + */ +bool coroutine_fn reqlist_wait_one(BlockReqList *reqs, int64_t offset, + int64_t bytes, CoMutex *lock); + +/* + * Shrink request and wake all waiting coroutines (maybe some of them are not + * intersecting with shrunk request). + */ +void coroutine_fn reqlist_shrink_req(BlockReq *req, int64_t new_bytes); + +/* + * Remove request and wake all waiting coroutines. Do not release any memory. + */ +void coroutine_fn reqlist_remove_req(BlockReq *req); + +#endif /* REQLIST_H */ -- 2.11.0