| Message ID | 20240306020006.100449500@goodmis.org (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | tracing: Persistent traces across a reboot or crash | expand |
Hi Steven, kernel test robot noticed the following build warnings: [auto build test WARNING on next-20240305] [cannot apply to tip/x86/core akpm-mm/mm-everything linus/master v6.8-rc7 v6.8-rc6 v6.8-rc5 v6.8-rc7] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/Steven-Rostedt/ring-buffer-Allow-mapped-field-to-be-set-without-mapping/20240306-100047 base: next-20240305 patch link: https://lore.kernel.org/r/20240306020006.100449500%40goodmis.org patch subject: [PATCH 5/8] ring-buffer: Add ring_buffer_meta data config: sh-defconfig (https://download.01.org/0day-ci/archive/20240308/202403081831.EWSQPo2a-lkp@intel.com/config) compiler: sh4-linux-gcc (GCC) 13.2.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240308/202403081831.EWSQPo2a-lkp@intel.com/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp@intel.com> | Closes: https://lore.kernel.org/oe-kbuild-all/202403081831.EWSQPo2a-lkp@intel.com/ All warnings (new ones prefixed by >>): kernel/trace/ring_buffer.c: In function 'rb_set_commit_to_write': >> kernel/trace/ring_buffer.c:3224:45: warning: assignment to 'long unsigned int' from 'struct buffer_data_page *' makes integer from pointer without a cast [-Wint-conversion] 3224 | meta->commit_buffer = cpu_buffer->commit_page->page; | ^ vim +3224 kernel/trace/ring_buffer.c 3192 3193 static __always_inline void 3194 rb_set_commit_to_write(struct ring_buffer_per_cpu *cpu_buffer) 3195 { 3196 unsigned long max_count; 3197 3198 /* 3199 * We only race with interrupts and NMIs on this CPU. 3200 * If we own the commit event, then we can commit 3201 * all others that interrupted us, since the interruptions 3202 * are in stack format (they finish before they come 3203 * back to us). This allows us to do a simple loop to 3204 * assign the commit to the tail. 3205 */ 3206 again: 3207 max_count = cpu_buffer->nr_pages * 100; 3208 3209 while (cpu_buffer->commit_page != READ_ONCE(cpu_buffer->tail_page)) { 3210 if (RB_WARN_ON(cpu_buffer, !(--max_count))) 3211 return; 3212 if (RB_WARN_ON(cpu_buffer, 3213 rb_is_reader_page(cpu_buffer->tail_page))) 3214 return; 3215 /* 3216 * No need for a memory barrier here, as the update 3217 * of the tail_page did it for this page. 3218 */ 3219 local_set(&cpu_buffer->commit_page->page->commit, 3220 rb_page_write(cpu_buffer->commit_page)); 3221 rb_inc_page(&cpu_buffer->commit_page); 3222 if (cpu_buffer->ring_meta) { 3223 struct ring_buffer_meta *meta = cpu_buffer->ring_meta; > 3224 meta->commit_buffer = cpu_buffer->commit_page->page; 3225 } 3226 /* add barrier to keep gcc from optimizing too much */ 3227 barrier(); 3228 } 3229 while (rb_commit_index(cpu_buffer) != 3230 rb_page_write(cpu_buffer->commit_page)) { 3231 3232 /* Make sure the readers see the content of what is committed. */ 3233 smp_wmb(); 3234 local_set(&cpu_buffer->commit_page->page->commit, 3235 rb_page_write(cpu_buffer->commit_page)); 3236 RB_WARN_ON(cpu_buffer, 3237 local_read(&cpu_buffer->commit_page->page->commit) & 3238 ~RB_WRITE_MASK); 3239 barrier(); 3240 } 3241 3242 /* again, keep gcc from optimizing */ 3243 barrier(); 3244 3245 /* 3246 * If an interrupt came in just after the first while loop 3247 * and pushed the tail page forward, we will be left with 3248 * a dangling commit that will never go forward. 3249 */ 3250 if (unlikely(cpu_buffer->commit_page != READ_ONCE(cpu_buffer->tail_page))) 3251 goto again; 3252 } 3253
Hi Steven,
kernel test robot noticed the following build errors:
[auto build test ERROR on next-20240305]
[cannot apply to tip/x86/core akpm-mm/mm-everything linus/master v6.8-rc7 v6.8-rc6 v6.8-rc5 v6.8-rc7]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Steven-Rostedt/ring-buffer-Allow-mapped-field-to-be-set-without-mapping/20240306-100047
base: next-20240305
patch link: https://lore.kernel.org/r/20240306020006.100449500%40goodmis.org
patch subject: [PATCH 5/8] ring-buffer: Add ring_buffer_meta data
config: s390-defconfig (https://download.01.org/0day-ci/archive/20240308/202403081843.QYKJKYk4-lkp@intel.com/config)
compiler: clang version 19.0.0git (https://github.com/llvm/llvm-project 503c55e17037436dcd45ac69dea8967e67e3f5e8)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240308/202403081843.QYKJKYk4-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202403081843.QYKJKYk4-lkp@intel.com/
All errors (new ones prefixed by >>):
In file included from kernel/trace/ring_buffer.c:8:
In file included from include/linux/trace_events.h:6:
In file included from include/linux/ring_buffer.h:5:
In file included from include/linux/mm.h:2208:
include/linux/vmstat.h:508:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
508 | return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
| ~~~~~~~~~~~~~~~~~~~~~ ^
509 | item];
| ~~~~
include/linux/vmstat.h:515:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
515 | return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
| ~~~~~~~~~~~~~~~~~~~~~ ^
516 | NR_VM_NUMA_EVENT_ITEMS +
| ~~~~~~~~~~~~~~~~~~~~~~
include/linux/vmstat.h:522:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
522 | return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
| ~~~~~~~~~~~ ^ ~~~
include/linux/vmstat.h:527:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
527 | return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
| ~~~~~~~~~~~~~~~~~~~~~ ^
528 | NR_VM_NUMA_EVENT_ITEMS +
| ~~~~~~~~~~~~~~~~~~~~~~
include/linux/vmstat.h:536:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
536 | return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
| ~~~~~~~~~~~~~~~~~~~~~ ^
537 | NR_VM_NUMA_EVENT_ITEMS +
| ~~~~~~~~~~~~~~~~~~~~~~
In file included from kernel/trace/ring_buffer.c:8:
In file included from include/linux/trace_events.h:10:
In file included from include/linux/perf_event.h:62:
In file included from include/linux/security.h:35:
include/linux/bpf.h:736:48: warning: bitwise operation between different enumeration types ('enum bpf_type_flag' and 'enum bpf_arg_type') [-Wenum-enum-conversion]
736 | ARG_PTR_TO_MAP_VALUE_OR_NULL = PTR_MAYBE_NULL | ARG_PTR_TO_MAP_VALUE,
| ~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~~~~~~~
include/linux/bpf.h:737:43: warning: bitwise operation between different enumeration types ('enum bpf_type_flag' and 'enum bpf_arg_type') [-Wenum-enum-conversion]
737 | ARG_PTR_TO_MEM_OR_NULL = PTR_MAYBE_NULL | ARG_PTR_TO_MEM,
| ~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~
include/linux/bpf.h:738:43: warning: bitwise operation between different enumeration types ('enum bpf_type_flag' and 'enum bpf_arg_type') [-Wenum-enum-conversion]
738 | ARG_PTR_TO_CTX_OR_NULL = PTR_MAYBE_NULL | ARG_PTR_TO_CTX,
| ~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~
include/linux/bpf.h:739:45: warning: bitwise operation between different enumeration types ('enum bpf_type_flag' and 'enum bpf_arg_type') [-Wenum-enum-conversion]
739 | ARG_PTR_TO_SOCKET_OR_NULL = PTR_MAYBE_NULL | ARG_PTR_TO_SOCKET,
| ~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~~~~
include/linux/bpf.h:740:44: warning: bitwise operation between different enumeration types ('enum bpf_type_flag' and 'enum bpf_arg_type') [-Wenum-enum-conversion]
740 | ARG_PTR_TO_STACK_OR_NULL = PTR_MAYBE_NULL | ARG_PTR_TO_STACK,
| ~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~~~
include/linux/bpf.h:741:45: warning: bitwise operation between different enumeration types ('enum bpf_type_flag' and 'enum bpf_arg_type') [-Wenum-enum-conversion]
741 | ARG_PTR_TO_BTF_ID_OR_NULL = PTR_MAYBE_NULL | ARG_PTR_TO_BTF_ID,
| ~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~~~~
include/linux/bpf.h:745:38: warning: bitwise operation between different enumeration types ('enum bpf_type_flag' and 'enum bpf_arg_type') [-Wenum-enum-conversion]
745 | ARG_PTR_TO_UNINIT_MEM = MEM_UNINIT | ARG_PTR_TO_MEM,
| ~~~~~~~~~~ ^ ~~~~~~~~~~~~~~
include/linux/bpf.h:747:45: warning: bitwise operation between different enumeration types ('enum bpf_type_flag' and 'enum bpf_arg_type') [-Wenum-enum-conversion]
747 | ARG_PTR_TO_FIXED_SIZE_MEM = MEM_FIXED_SIZE | ARG_PTR_TO_MEM,
| ~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~
include/linux/bpf.h:770:48: warning: bitwise operation between different enumeration types ('enum bpf_type_flag' and 'enum bpf_return_type') [-Wenum-enum-conversion]
770 | RET_PTR_TO_MAP_VALUE_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_MAP_VALUE,
| ~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~~~~~~~
include/linux/bpf.h:771:45: warning: bitwise operation between different enumeration types ('enum bpf_type_flag' and 'enum bpf_return_type') [-Wenum-enum-conversion]
771 | RET_PTR_TO_SOCKET_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_SOCKET,
| ~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~~~~
include/linux/bpf.h:772:47: warning: bitwise operation between different enumeration types ('enum bpf_type_flag' and 'enum bpf_return_type') [-Wenum-enum-conversion]
772 | RET_PTR_TO_TCP_SOCK_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_TCP_SOCK,
| ~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~~~~~~
include/linux/bpf.h:773:50: warning: bitwise operation between different enumeration types ('enum bpf_type_flag' and 'enum bpf_return_type') [-Wenum-enum-conversion]
773 | RET_PTR_TO_SOCK_COMMON_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_SOCK_COMMON,
| ~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~
include/linux/bpf.h:775:49: warning: bitwise operation between different enumeration types ('enum bpf_type_flag' and 'enum bpf_return_type') [-Wenum-enum-conversion]
775 | RET_PTR_TO_DYNPTR_MEM_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_MEM,
| ~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~
include/linux/bpf.h:776:45: warning: bitwise operation between different enumeration types ('enum bpf_type_flag' and 'enum bpf_return_type') [-Wenum-enum-conversion]
776 | RET_PTR_TO_BTF_ID_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_BTF_ID,
| ~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~~~~
include/linux/bpf.h:777:43: warning: bitwise operation between different enumeration types ('enum bpf_type_flag' and 'enum bpf_return_type') [-Wenum-enum-conversion]
777 | RET_PTR_TO_BTF_ID_TRUSTED = PTR_TRUSTED | RET_PTR_TO_BTF_ID,
| ~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~~~~
include/linux/bpf.h:888:44: warning: bitwise operation between different enumeration types ('enum bpf_type_flag' and 'enum bpf_reg_type') [-Wenum-enum-conversion]
888 | PTR_TO_MAP_VALUE_OR_NULL = PTR_MAYBE_NULL | PTR_TO_MAP_VALUE,
| ~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~~~
include/linux/bpf.h:889:42: warning: bitwise operation between different enumeration types ('enum bpf_type_flag' and 'enum bpf_reg_type') [-Wenum-enum-conversion]
889 | PTR_TO_SOCKET_OR_NULL = PTR_MAYBE_NULL | PTR_TO_SOCKET,
| ~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~
include/linux/bpf.h:890:46: warning: bitwise operation between different enumeration types ('enum bpf_type_flag' and 'enum bpf_reg_type') [-Wenum-enum-conversion]
890 | PTR_TO_SOCK_COMMON_OR_NULL = PTR_MAYBE_NULL | PTR_TO_SOCK_COMMON,
| ~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~~~~~
include/linux/bpf.h:891:44: warning: bitwise operation between different enumeration types ('enum bpf_type_flag' and 'enum bpf_reg_type') [-Wenum-enum-conversion]
891 | PTR_TO_TCP_SOCK_OR_NULL = PTR_MAYBE_NULL | PTR_TO_TCP_SOCK,
| ~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~~
include/linux/bpf.h:892:42: warning: bitwise operation between different enumeration types ('enum bpf_type_flag' and 'enum bpf_reg_type') [-Wenum-enum-conversion]
892 | PTR_TO_BTF_ID_OR_NULL = PTR_MAYBE_NULL | PTR_TO_BTF_ID,
| ~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~
>> kernel/trace/ring_buffer.c:3224:24: error: incompatible pointer to integer conversion assigning to 'unsigned long' from 'struct buffer_data_page *' [-Wint-conversion]
3224 | meta->commit_buffer = cpu_buffer->commit_page->page;
| ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
25 warnings and 1 error generated.
vim +3224 kernel/trace/ring_buffer.c
3192
3193 static __always_inline void
3194 rb_set_commit_to_write(struct ring_buffer_per_cpu *cpu_buffer)
3195 {
3196 unsigned long max_count;
3197
3198 /*
3199 * We only race with interrupts and NMIs on this CPU.
3200 * If we own the commit event, then we can commit
3201 * all others that interrupted us, since the interruptions
3202 * are in stack format (they finish before they come
3203 * back to us). This allows us to do a simple loop to
3204 * assign the commit to the tail.
3205 */
3206 again:
3207 max_count = cpu_buffer->nr_pages * 100;
3208
3209 while (cpu_buffer->commit_page != READ_ONCE(cpu_buffer->tail_page)) {
3210 if (RB_WARN_ON(cpu_buffer, !(--max_count)))
3211 return;
3212 if (RB_WARN_ON(cpu_buffer,
3213 rb_is_reader_page(cpu_buffer->tail_page)))
3214 return;
3215 /*
3216 * No need for a memory barrier here, as the update
3217 * of the tail_page did it for this page.
3218 */
3219 local_set(&cpu_buffer->commit_page->page->commit,
3220 rb_page_write(cpu_buffer->commit_page));
3221 rb_inc_page(&cpu_buffer->commit_page);
3222 if (cpu_buffer->ring_meta) {
3223 struct ring_buffer_meta *meta = cpu_buffer->ring_meta;
> 3224 meta->commit_buffer = cpu_buffer->commit_page->page;
3225 }
3226 /* add barrier to keep gcc from optimizing too much */
3227 barrier();
3228 }
3229 while (rb_commit_index(cpu_buffer) !=
3230 rb_page_write(cpu_buffer->commit_page)) {
3231
3232 /* Make sure the readers see the content of what is committed. */
3233 smp_wmb();
3234 local_set(&cpu_buffer->commit_page->page->commit,
3235 rb_page_write(cpu_buffer->commit_page));
3236 RB_WARN_ON(cpu_buffer,
3237 local_read(&cpu_buffer->commit_page->page->commit) &
3238 ~RB_WRITE_MASK);
3239 barrier();
3240 }
3241
3242 /* again, keep gcc from optimizing */
3243 barrier();
3244
3245 /*
3246 * If an interrupt came in just after the first while loop
3247 * and pushed the tail page forward, we will be left with
3248 * a dangling commit that will never go forward.
3249 */
3250 if (unlikely(cpu_buffer->commit_page != READ_ONCE(cpu_buffer->tail_page)))
3251 goto again;
3252 }
3253
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 367597dc766b..5a90ada49366 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -42,6 +42,11 @@ static void update_pages_handler(struct work_struct *work); struct ring_buffer_meta { + unsigned long head_buffer; + unsigned long commit_buffer; + __u32 subbuf_size; + __u32 nr_subbufs; + int buffers[]; }; /* @@ -497,6 +502,7 @@ struct ring_buffer_per_cpu { struct mutex mapping_lock; unsigned long *subbuf_ids; /* ID to subbuf addr */ struct trace_buffer_meta *meta_page; + struct ring_buffer_meta *ring_meta; /* ring buffer pages to update, > 0 to add, < 0 to remove */ long nr_pages_to_update; @@ -1206,6 +1212,11 @@ static void rb_head_page_activate(struct ring_buffer_per_cpu *cpu_buffer) * Set the previous list pointer to have the HEAD flag. */ rb_set_list_to_head(head->list.prev); + + if (cpu_buffer->ring_meta) { + struct ring_buffer_meta *meta = cpu_buffer->ring_meta; + meta->head_buffer = (unsigned long)head->page; + } } static void rb_list_head_clear(struct list_head *list) @@ -1453,50 +1464,124 @@ rb_range_align_subbuf(unsigned long addr, int subbuf_size, int nr_subbufs) } /* - * Return a specific sub-buffer for a given @cpu defined by @idx. + * Return the ring_buffer_meta for a given @cpu. */ -static void *rb_range_buffer(struct trace_buffer *buffer, int cpu, int nr_pages, int idx) +static void *rb_range_meta(struct trace_buffer *buffer, int nr_pages, int cpu) { - unsigned long ptr; int subbuf_size = buffer->subbuf_size + BUF_PAGE_HDR_SIZE; + unsigned long ptr = buffer->range_addr_start; + struct ring_buffer_meta *meta; int nr_subbufs; - /* Include the reader page */ - nr_subbufs = nr_pages + 1; + if (!ptr) + return NULL; + + /* When nr_pages passed in is zero, the first meta has already been initialized */ + if (!nr_pages) { + meta = (struct ring_buffer_meta *)ptr; + nr_subbufs = meta->nr_subbufs; + } else { + meta = NULL; + /* Include the reader page */ + nr_subbufs = nr_pages + 1; + } /* * The first chunk may not be subbuffer aligned, where as * the rest of the chunks are. */ - ptr = buffer->range_addr_start; - ptr = rb_range_align_subbuf(ptr, subbuf_size, nr_subbufs); if (cpu) { - unsigned long p; - - ptr += subbuf_size * nr_subbufs; - - /* Save the beginning of this CPU chunk */ - p = ptr; - ptr = rb_range_align_subbuf(ptr, subbuf_size, nr_subbufs); + ptr += subbuf_size * nr_subbufs; if (cpu > 1) { unsigned long size; + unsigned long p; + /* Save the beginning of this CPU chunk */ + p = ptr; + ptr = rb_range_align_subbuf(ptr, subbuf_size, nr_subbufs); ptr += subbuf_size * nr_subbufs; /* Now all chunks after this are the same size */ size = ptr - p; ptr += size * (cpu - 2); - - ptr = rb_range_align_subbuf(ptr, subbuf_size, nr_subbufs); } } - if (ptr + subbuf_size * nr_subbufs > buffer->range_addr_end) + return (void *)ptr; +} + +static void *rb_subbufs_from_meta(struct ring_buffer_meta *meta) +{ + int subbuf_size = meta->subbuf_size; + unsigned long ptr; + + ptr = (unsigned long)meta; + ptr = rb_range_align_subbuf(ptr, subbuf_size, meta->nr_subbufs); + + return (void *)ptr; +} + +/* + * Return a specific sub-buffer for a given @cpu defined by @idx. + */ +static void *rb_range_buffer(struct ring_buffer_per_cpu *cpu_buffer, int idx) +{ + struct ring_buffer_meta *meta; + unsigned long ptr; + int subbuf_size; + + meta = rb_range_meta(cpu_buffer->buffer, 0, cpu_buffer->cpu); + if (!meta) + return NULL; + + if (WARN_ON_ONCE(idx >= meta->nr_subbufs)) return NULL; + + subbuf_size = meta->subbuf_size; + + /* Map this buffer to the order that's in meta->buffers[] */ + idx = meta->buffers[idx]; + + ptr = (unsigned long)rb_subbufs_from_meta(meta); + + ptr += subbuf_size * idx; + if (ptr + subbuf_size > cpu_buffer->buffer->range_addr_end) + return NULL; + return (void *)ptr; } +static void rb_range_meta_init(struct trace_buffer *buffer, int nr_pages) +{ + struct ring_buffer_meta *meta; + void *subbuf; + int cpu; + + for (cpu = 0; cpu < nr_cpu_ids; cpu++) { + meta = rb_range_meta(buffer, nr_pages, cpu); + + meta->nr_subbufs = nr_pages + 1; + meta->subbuf_size = buffer->subbuf_size + BUF_PAGE_HDR_SIZE; + + subbuf = rb_subbufs_from_meta(meta); + + /* + * The buffers[] array holds the order of the sub-buffers + * that are after the meta data. The sub-buffers may + * be swapped out when read and inserted into a different + * location of the ring buffer. Although their addresses + * remain the same, the buffers[] array contains the + * index into the sub-buffers holding their actual order. + */ + for (int i = 0; i < meta->nr_subbufs; i++) { + meta->buffers[i] = i; + rb_init_page(subbuf); + subbuf += meta->subbuf_size; + } + } +} + static int __rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer, long nr_pages, struct list_head *pages) { @@ -1537,7 +1622,6 @@ static int __rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer, set_current_oom_origin(); for (i = 0; i < nr_pages; i++) { struct page *page; - int cpu = cpu_buffer->cpu; bpage = kzalloc_node(ALIGN(sizeof(*bpage), cache_line_size()), mflags, cpu_to_node(cpu_buffer->cpu)); @@ -1550,10 +1634,11 @@ static int __rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer, if (buffer->range_addr_start) { /* A range was given. Use that for the buffer page */ - bpage->page = rb_range_buffer(buffer, cpu, nr_pages, i + 1); + bpage->page = rb_range_buffer(cpu_buffer, i + 1); if (!bpage->page) goto free_pages; bpage->range = 1; + bpage->id = i + 1; } else { page = alloc_pages_node(cpu_to_node(cpu_buffer->cpu), mflags | __GFP_ZERO, @@ -1561,9 +1646,9 @@ static int __rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer, if (!page) goto free_pages; bpage->page = page_address(page); + rb_init_page(bpage->page); } bpage->order = cpu_buffer->buffer->subbuf_order; - rb_init_page(bpage->page); if (user_thread && fatal_signal_pending(current)) goto free_pages; @@ -1644,7 +1729,13 @@ rb_allocate_cpu_buffer(struct trace_buffer *buffer, long nr_pages, int cpu) cpu_buffer->reader_page = bpage; if (buffer->range_addr_start) { - bpage->page = rb_range_buffer(buffer, cpu, nr_pages, 0); + /* + * Range mapped buffers have the same restrictions as memory + * mapped ones do. + */ + cpu_buffer->mapped = 1; + cpu_buffer->ring_meta = rb_range_meta(buffer, nr_pages, cpu); + bpage->page = rb_range_buffer(cpu_buffer, 0); if (!bpage->page) goto fail_free_reader; bpage->range = 1; @@ -1654,8 +1745,8 @@ rb_allocate_cpu_buffer(struct trace_buffer *buffer, long nr_pages, int cpu) if (!page) goto fail_free_reader; bpage->page = page_address(page); + rb_init_page(bpage->page); } - rb_init_page(bpage->page); INIT_LIST_HEAD(&cpu_buffer->reader_page->list); INIT_LIST_HEAD(&cpu_buffer->new_pages); @@ -1669,6 +1760,10 @@ rb_allocate_cpu_buffer(struct trace_buffer *buffer, long nr_pages, int cpu) cpu_buffer->tail_page = cpu_buffer->commit_page = cpu_buffer->head_page; rb_head_page_activate(cpu_buffer); + if (cpu_buffer->ring_meta) { + struct ring_buffer_meta *meta = cpu_buffer->ring_meta; + meta->commit_buffer = meta->head_buffer; + } return cpu_buffer; @@ -1780,6 +1875,8 @@ static struct trace_buffer *alloc_buffer(unsigned long size, unsigned flags, nr_pages--; buffer->range_addr_start = start; buffer->range_addr_end = end; + + rb_range_meta_init(buffer, nr_pages); } else { /* need at least two pages */ @@ -2464,6 +2561,52 @@ static void rb_inc_iter(struct ring_buffer_iter *iter) iter->next_event = 0; } +/* Return the index into the sub-buffers for a given sub-buffer */ +static int rb_meta_subbuf_idx(struct ring_buffer_meta *meta, void *subbuf) +{ + void *subbuf_array; + + subbuf_array = (void *)meta + sizeof(int) * meta->nr_subbufs; + subbuf_array = (void *)ALIGN((unsigned long)subbuf_array, meta->subbuf_size); + return (subbuf - subbuf_array) / meta->subbuf_size; +} + +static void rb_update_meta_head(struct ring_buffer_per_cpu *cpu_buffer, + struct buffer_page *next_page) +{ + struct ring_buffer_meta *meta = cpu_buffer->ring_meta; + unsigned long old_head = (unsigned long)next_page->page; + unsigned long new_head; + + rb_inc_page(&next_page); + new_head = (unsigned long)next_page->page; + + /* + * Only move it forward once, if something else came in and + * moved it forward, then we don't want to touch it. + */ + (void)cmpxchg(&meta->head_buffer, old_head, new_head); +} + +static void rb_update_meta_reader(struct ring_buffer_per_cpu *cpu_buffer, + struct buffer_page *reader) +{ + struct ring_buffer_meta *meta = cpu_buffer->ring_meta; + void *old_reader = cpu_buffer->reader_page->page; + void *new_reader = reader->page; + int id; + + id = reader->id; + cpu_buffer->reader_page->id = id; + reader->id = 0; + + meta->buffers[0] = rb_meta_subbuf_idx(meta, new_reader); + meta->buffers[id] = rb_meta_subbuf_idx(meta, old_reader); + + /* The head pointer is the one after the reader */ + rb_update_meta_head(cpu_buffer, reader); +} + /* * rb_handle_head_page - writer hit the head page * @@ -2513,6 +2656,8 @@ rb_handle_head_page(struct ring_buffer_per_cpu *cpu_buffer, local_sub(rb_page_commit(next_page), &cpu_buffer->entries_bytes); local_inc(&cpu_buffer->pages_lost); + if (cpu_buffer->ring_meta) + rb_update_meta_head(cpu_buffer, next_page); /* * The entries will be zeroed out when we move the * tail page. @@ -3074,6 +3219,10 @@ rb_set_commit_to_write(struct ring_buffer_per_cpu *cpu_buffer) local_set(&cpu_buffer->commit_page->page->commit, rb_page_write(cpu_buffer->commit_page)); rb_inc_page(&cpu_buffer->commit_page); + if (cpu_buffer->ring_meta) { + struct ring_buffer_meta *meta = cpu_buffer->ring_meta; + meta->commit_buffer = cpu_buffer->commit_page->page; + } /* add barrier to keep gcc from optimizing too much */ barrier(); } @@ -4691,6 +4840,9 @@ rb_get_reader_page(struct ring_buffer_per_cpu *cpu_buffer) if (!ret) goto spin; + if (cpu_buffer->ring_meta) + rb_update_meta_reader(cpu_buffer, reader); + /* * Yay! We succeeded in replacing the page. * @@ -5381,11 +5533,16 @@ rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer) cpu_buffer->lost_events = 0; cpu_buffer->last_overrun = 0; - if (cpu_buffer->mapped) - rb_update_meta_page(cpu_buffer); - rb_head_page_activate(cpu_buffer); cpu_buffer->pages_removed = 0; + + if (cpu_buffer->mapped) { + rb_update_meta_page(cpu_buffer); + if (cpu_buffer->ring_meta) { + struct ring_buffer_meta *meta = cpu_buffer->ring_meta; + meta->commit_buffer = meta->head_buffer; + } + } } /* Must have disabled the cpu buffer then done a synchronize_rcu */