X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=lib%2Fringbuffer%2Fring_buffer_frontend.c;h=6e4657093ee0328ebc170e45ee2b5254017bb085;hb=8e3b6653bf5bc3f64a6bc50d2fdce57ea5bbd4e8;hp=8257dcc63867410291d2dd7bf07ab176449edc3b;hpb=c11ab967decd550b28111b2767eda20e7e6be3fd;p=lttng-modules.git diff --git a/lib/ringbuffer/ring_buffer_frontend.c b/lib/ringbuffer/ring_buffer_frontend.c index 8257dcc6..6e465709 100644 --- a/lib/ringbuffer/ring_buffer_frontend.c +++ b/lib/ringbuffer/ring_buffer_frontend.c @@ -54,6 +54,7 @@ #include #include #include +#include #include #include @@ -64,6 +65,7 @@ #include #include #include +#include /* * Internal structure representing offsets to use at a sub-buffer switch. @@ -146,8 +148,8 @@ void lib_ring_buffer_free(struct lib_ring_buffer *buf) struct channel *chan = buf->backend.chan; lib_ring_buffer_print_errors(chan, buf, buf->backend.cpu); - kfree(buf->commit_hot); - kfree(buf->commit_cold); + lttng_kvfree(buf->commit_hot); + lttng_kvfree(buf->commit_cold); lib_ring_buffer_backend_free(&buf->backend); } @@ -244,7 +246,7 @@ int lib_ring_buffer_create(struct lib_ring_buffer *buf, return ret; buf->commit_hot = - kzalloc_node(ALIGN(sizeof(*buf->commit_hot) + lttng_kvzalloc_node(ALIGN(sizeof(*buf->commit_hot) * chan->backend.num_subbuf, 1 << INTERNODE_CACHE_SHIFT), GFP_KERNEL | __GFP_NOWARN, @@ -255,7 +257,7 @@ int lib_ring_buffer_create(struct lib_ring_buffer *buf, } buf->commit_cold = - kzalloc_node(ALIGN(sizeof(*buf->commit_cold) + lttng_kvzalloc_node(ALIGN(sizeof(*buf->commit_cold) * chan->backend.num_subbuf, 1 << INTERNODE_CACHE_SHIFT), GFP_KERNEL | __GFP_NOWARN, @@ -304,9 +306,9 @@ int lib_ring_buffer_create(struct lib_ring_buffer *buf, /* Error handling */ free_init: - kfree(buf->commit_cold); + lttng_kvfree(buf->commit_cold); free_commit: - kfree(buf->commit_hot); + lttng_kvfree(buf->commit_hot); free_chanbuf: lib_ring_buffer_backend_free(&buf->backend); return ret; @@ -1180,6 +1182,47 @@ void lib_ring_buffer_move_consumer(struct lib_ring_buffer *buf, } EXPORT_SYMBOL_GPL(lib_ring_buffer_move_consumer); +#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE +static void lib_ring_buffer_flush_read_subbuf_dcache( + const struct lib_ring_buffer_config *config, + struct channel *chan, + struct lib_ring_buffer *buf) +{ + struct lib_ring_buffer_backend_pages *pages; + unsigned long sb_bindex, id, i, nr_pages; + + if (config->output != RING_BUFFER_MMAP) + return; + + /* + * Architectures with caches aliased on virtual addresses may + * use different cache lines for the linear mapping vs + * user-space memory mapping. Given that the ring buffer is + * based on the kernel linear mapping, aligning it with the + * user-space mapping is not straightforward, and would require + * extra TLB entries. Therefore, simply flush the dcache for the + * entire sub-buffer before reading it. + */ + id = buf->backend.buf_rsb.id; + sb_bindex = subbuffer_id_get_index(config, id); + pages = buf->backend.array[sb_bindex]; + nr_pages = buf->backend.num_pages_per_subbuf; + for (i = 0; i < nr_pages; i++) { + struct lib_ring_buffer_backend_page *backend_page; + + backend_page = &pages->p[i]; + flush_dcache_page(pfn_to_page(backend_page->pfn)); + } +} +#else +static void lib_ring_buffer_flush_read_subbuf_dcache( + const struct lib_ring_buffer_config *config, + struct channel *chan, + struct lib_ring_buffer *buf) +{ +} +#endif + /** * lib_ring_buffer_get_subbuf - get exclusive access to subbuffer for reading * @buf: ring buffer @@ -1322,6 +1365,8 @@ retry: buf->get_subbuf_consumed = consumed; buf->get_subbuf = 1; + lib_ring_buffer_flush_read_subbuf_dcache(config, chan, buf); + return 0; nodata: @@ -1840,16 +1885,14 @@ static void _lib_ring_buffer_switch_remote(struct lib_ring_buffer *buf, } /* - * Taking lock on CPU hotplug to ensure two things: first, that the + * Disabling preemption ensures two things: first, that the * target cpu is not taken concurrently offline while we are within - * smp_call_function_single() (I don't trust that get_cpu() on the - * _local_ CPU actually inhibit CPU hotplug for the _remote_ CPU (to be - * confirmed)). Secondly, if it happens that the CPU is not online, our - * own call to lib_ring_buffer_switch_slow() needs to be protected from - * CPU hotplug handlers, which can also perform a remote subbuffer - * switch. + * smp_call_function_single(). Secondly, if it happens that the + * CPU is not online, our own call to lib_ring_buffer_switch_slow() + * needs to be protected from CPU hotplug handlers, which can + * also perform a remote subbuffer switch. */ - get_online_cpus(); + preempt_disable(); param.buf = buf; param.mode = mode; ret = smp_call_function_single(buf->backend.cpu, @@ -1858,15 +1901,23 @@ static void _lib_ring_buffer_switch_remote(struct lib_ring_buffer *buf, /* Remote CPU is offline, do it ourself. */ lib_ring_buffer_switch_slow(buf, mode); } - put_online_cpus(); + preempt_enable(); } +/* Switch sub-buffer if current sub-buffer is non-empty. */ void lib_ring_buffer_switch_remote(struct lib_ring_buffer *buf) { _lib_ring_buffer_switch_remote(buf, SWITCH_ACTIVE); } EXPORT_SYMBOL_GPL(lib_ring_buffer_switch_remote); +/* Switch sub-buffer even if current sub-buffer is empty. */ +void lib_ring_buffer_switch_remote_empty(struct lib_ring_buffer *buf) +{ + _lib_ring_buffer_switch_remote(buf, SWITCH_FLUSH); +} +EXPORT_SYMBOL_GPL(lib_ring_buffer_switch_remote_empty); + /* * Returns : * 0 if ok