From: Anatoly Burakov Date: Tue, 12 Jun 2018 09:46:16 +0000 (+0100) Subject: mem: provide thread-unsafe memseg list walk variant X-Git-Url: http://git.droids-corp.org/?a=commitdiff_plain;h=e26415428fe3f99c41f99e9c3b138a0eac3fb3d8;p=dpdk.git mem: provide thread-unsafe memseg list walk variant Sometimes, user code needs to walk memseg list while being inside a memory-related callback. Rather than making everyone copy around the same iteration code and depending on DPDK internals, provide an official way to do memseg_list_walk() inside callbacks. Also, remove existing reimplementation from memalloc code and use the new API instead. Signed-off-by: Anatoly Burakov --- diff --git a/lib/librte_eal/common/eal_common_memory.c b/lib/librte_eal/common/eal_common_memory.c index da45f31cf4..659cc08f64 100644 --- a/lib/librte_eal/common/eal_common_memory.c +++ b/lib/librte_eal/common/eal_common_memory.c @@ -513,14 +513,11 @@ rte_memseg_walk(rte_memseg_walk_t func, void *arg) } int __rte_experimental -rte_memseg_list_walk(rte_memseg_list_walk_t func, void *arg) +rte_memseg_list_walk_thread_unsafe(rte_memseg_list_walk_t func, void *arg) { struct rte_mem_config *mcfg = rte_eal_get_configuration()->mem_config; int i, ret = 0; - /* do not allow allocations/frees/init while we iterate */ - rte_rwlock_read_lock(&mcfg->memory_hotplug_lock); - for (i = 0; i < RTE_MAX_MEMSEG_LISTS; i++) { struct rte_memseg_list *msl = &mcfg->memsegs[i]; @@ -528,17 +525,23 @@ rte_memseg_list_walk(rte_memseg_list_walk_t func, void *arg) continue; ret = func(msl, arg); - if (ret < 0) { - ret = -1; - goto out; - } - if (ret > 0) { - ret = 1; - goto out; - } + if (ret) + return ret; } -out: + return 0; +} + +int __rte_experimental +rte_memseg_list_walk(rte_memseg_list_walk_t func, void *arg) +{ + struct rte_mem_config *mcfg = rte_eal_get_configuration()->mem_config; + int ret = 0; + + /* do not allow allocations/frees/init while we iterate */ + rte_rwlock_read_lock(&mcfg->memory_hotplug_lock); + ret = rte_memseg_list_walk_thread_unsafe(func, arg); rte_rwlock_read_unlock(&mcfg->memory_hotplug_lock); + return ret; } diff --git a/lib/librte_eal/common/include/rte_memory.h b/lib/librte_eal/common/include/rte_memory.h index c5a84c333b..c4b7f4cff1 100644 --- a/lib/librte_eal/common/include/rte_memory.h +++ b/lib/librte_eal/common/include/rte_memory.h @@ -299,6 +299,24 @@ rte_memseg_walk_thread_unsafe(rte_memseg_walk_t func, void *arg); int __rte_experimental rte_memseg_contig_walk_thread_unsafe(rte_memseg_contig_walk_t func, void *arg); +/** + * Walk each allocated memseg list without performing any locking. + * + * @note This function does not perform any locking, and is only safe to call + * from within memory-related callback functions. + * + * @param func + * Iterator function + * @param arg + * Argument passed to iterator + * @return + * 0 if walked over the entire list + * 1 if stopped by the user + * -1 if user function reported error + */ +int __rte_experimental +rte_memseg_list_walk_thread_unsafe(rte_memseg_list_walk_t func, void *arg); + /** * Dump the physical memory layout to a file. * diff --git a/lib/librte_eal/linuxapp/eal/eal_memalloc.c b/lib/librte_eal/linuxapp/eal/eal_memalloc.c index 36278d9ee7..69604f8236 100644 --- a/lib/librte_eal/linuxapp/eal/eal_memalloc.c +++ b/lib/librte_eal/linuxapp/eal/eal_memalloc.c @@ -172,32 +172,6 @@ get_file_size(int fd) return st.st_size; } -/* we cannot use rte_memseg_list_walk() here because we will be holding a - * write lock whenever we enter every function in this file, however copying - * the same iteration code everywhere is not ideal as well. so, use a lockless - * copy of memseg list walk here. - */ -static int -memseg_list_walk_thread_unsafe(rte_memseg_list_walk_t func, void *arg) -{ - struct rte_mem_config *mcfg = rte_eal_get_configuration()->mem_config; - int i, ret = 0; - - for (i = 0; i < RTE_MAX_MEMSEG_LISTS; i++) { - struct rte_memseg_list *msl = &mcfg->memsegs[i]; - - if (msl->base_va == NULL) - continue; - - ret = func(msl, arg); - if (ret < 0) - return -1; - if (ret > 0) - return 1; - } - return 0; -} - /* returns 1 on successful lock, 0 on unsuccessful lock, -1 on error */ static int lock(int fd, int type) { @@ -900,7 +874,8 @@ eal_memalloc_alloc_seg_bulk(struct rte_memseg **ms, int n_segs, size_t page_sz, wa.socket = socket; wa.segs_allocated = 0; - ret = memseg_list_walk_thread_unsafe(alloc_seg_walk, &wa); + /* memalloc is locked, so it's safe to use thread-unsafe version */ + ret = rte_memseg_list_walk_thread_unsafe(alloc_seg_walk, &wa); if (ret == 0) { RTE_LOG(ERR, EAL, "%s(): couldn't find suitable memseg_list\n", __func__); @@ -965,7 +940,10 @@ eal_memalloc_free_seg_bulk(struct rte_memseg **ms, int n_segs) wa.ms = cur; wa.hi = hi; - walk_res = memseg_list_walk_thread_unsafe(free_seg_walk, &wa); + /* memalloc is locked, so it's safe to use thread-unsafe version + */ + walk_res = rte_memseg_list_walk_thread_unsafe(free_seg_walk, + &wa); if (walk_res == 1) continue; if (walk_res == 0) @@ -1252,7 +1230,8 @@ eal_memalloc_sync_with_primary(void) if (rte_eal_process_type() == RTE_PROC_PRIMARY) return 0; - if (memseg_list_walk_thread_unsafe(sync_walk, NULL)) + /* memalloc is locked, so it's safe to call thread-unsafe version */ + if (rte_memseg_list_walk_thread_unsafe(sync_walk, NULL)) return -1; return 0; } diff --git a/lib/librte_eal/rte_eal_version.map b/lib/librte_eal/rte_eal_version.map index c5d1513803..1ace2dfc50 100644 --- a/lib/librte_eal/rte_eal_version.map +++ b/lib/librte_eal/rte_eal_version.map @@ -294,6 +294,7 @@ EXPERIMENTAL { rte_memseg_contig_walk; rte_memseg_contig_walk_thread_unsafe; rte_memseg_list_walk; + rte_memseg_list_walk_thread_unsafe; rte_memseg_walk; rte_memseg_walk_thread_unsafe; rte_mp_action_register;