Messages in this thread Patch in this message | | | From | Jarmo Tiitto <> | Subject | [RFC PATCH 3/5] pgo: Wire up the new more generic code for modules | Date | Sat, 12 Jun 2021 06:24:24 +0300 |
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prf_open() now uses the inode->i_private to get the prf_object for the file. This can be either vmlinux.profraw or any module.profraw file.
The prf_vmlinux object is now added into prf_list and allocate_node() scans the list and reserves vnodes from corresponding prf_object(s).
Signed-off-by: Jarmo Tiitto <jarmo.tiitto@gmail.com> --- note: There is no module notifier code yet, so only vmlinux.profraw profile data is available with this commit.
Another thing is that pgo/reset will only reset vmlinux.profraw. Profile data reset for modules may be added later: maybe writing module's name into pgo/reset would reset only the specified module's profile data? Then writing "all" or zero would atomically reset everything.
I'm bit unsure about the new allocate_node() code since it is the first place I had to put rcu_read_lock() and the code is likely to change from this. --- kernel/pgo/fs.c | 30 ++++++++++++++++++++----- kernel/pgo/instrument.c | 49 +++++++++++++++++++++++++++-------------- kernel/pgo/pgo.h | 2 ++ 3 files changed, 60 insertions(+), 21 deletions(-)
diff --git a/kernel/pgo/fs.c b/kernel/pgo/fs.c index 7e269d69bcd7..84b36e61758b 100644 --- a/kernel/pgo/fs.c +++ b/kernel/pgo/fs.c @@ -32,8 +32,10 @@ static struct dentry *directory; struct prf_private_data { void *buffer; size_t size; + struct prf_object *core; }; +/* vmlinux's prf core */ static struct prf_object prf_vmlinux; /* @@ -281,7 +283,6 @@ static int prf_serialize(struct prf_object *po, struct prf_private_data *p, size prf_serialize_values(po, &buffer); return 0; - } /* open() implementation for PGO. Creates a copy of the profiling data set. */ @@ -292,13 +293,21 @@ static int prf_open(struct inode *inode, struct file *file) size_t buf_size; int err = -EINVAL; + if (WARN_ON(!inode->i_private)) { + /* bug: inode was not initialized by us */ + return err; + } + data = kzalloc(sizeof(*data), GFP_KERNEL); if (!data) return -ENOMEM; + /* Get prf_object of this inode */ + data->core = inode->i_private; + /* Get initial buffer size. */ flags = prf_lock(); - data->size = prf_buffer_size(&prf_vmlinux); + data->size = prf_buffer_size(data->core); prf_unlock(flags); do { @@ -318,12 +327,13 @@ static int prf_open(struct inode *inode, struct file *file) * data length in data->size. */ flags = prf_lock(); - err = prf_serialize(&prf_vmlinux, data, buf_size); + err = prf_serialize(data->core, data, buf_size); prf_unlock(flags); /* In unlikely case, try again. */ } while (err == -EAGAIN); if (err < 0) { + if (data) vfree(data->buffer); kfree(data); @@ -412,6 +422,8 @@ static const struct file_operations prf_reset_fops = { /* Create debugfs entries. */ static int __init pgo_init(void) { + unsigned long flags; + /* Init profiler vmlinux core entry */ memset(&prf_vmlinux, 0, sizeof(prf_vmlinux)); prf_vmlinux.data = __llvm_prf_data_start; @@ -430,19 +442,27 @@ static int __init pgo_init(void) prf_vmlinux.vnds_num = prf_get_count(__llvm_prf_vnds_start, __llvm_prf_vnds_end, sizeof(__llvm_prf_vnds_start[0])); + /* enable profiling */ + flags = prf_list_lock(); + list_add_tail_rcu(&prf_vmlinux.link, &prf_list); + prf_list_unlock(flags); directory = debugfs_create_dir("pgo", NULL); if (!directory) goto err_remove; - if (!debugfs_create_file("vmlinux.profraw", 0600, directory, NULL, - &prf_fops)) + prf_vmlinux.file = debugfs_create_file("vmlinux.profraw", + 0600, directory, &prf_vmlinux, &prf_fops); + if (!prf_vmlinux.file) goto err_remove; if (!debugfs_create_file("reset", 0200, directory, NULL, &prf_reset_fops)) goto err_remove; + /* show notice why the system slower: */ + pr_notice("Clang PGO instrumentation is active."); + return 0; err_remove: diff --git a/kernel/pgo/instrument.c b/kernel/pgo/instrument.c index 24fdeb79b674..e214c9d7a113 100644 --- a/kernel/pgo/instrument.c +++ b/kernel/pgo/instrument.c @@ -24,6 +24,7 @@ #include <linux/export.h> #include <linux/spinlock.h> #include <linux/types.h> +#include <linux/rculist.h> #include "pgo.h" /* @@ -56,22 +57,38 @@ void prf_unlock(unsigned long flags) static struct llvm_prf_value_node *allocate_node(struct llvm_prf_data *p, u32 index, u64 value) { - const int max_vnds = prf_get_count(__llvm_prf_vnds_start, - __llvm_prf_vnds_end, sizeof(struct llvm_prf_value_node)); - - /* - * Check that p is within vmlinux __llvm_prf_data section. - * If not, don't allocate since we can't handle modules yet. - */ - if (!memory_contains(__llvm_prf_data_start, - __llvm_prf_data_end, p, sizeof(*p))) - return NULL; - - if (WARN_ON_ONCE(current_node >= max_vnds)) - return NULL; /* Out of nodes */ - - /* reserve vnode for vmlinux */ - return &__llvm_prf_vnds_start[current_node++]; + struct llvm_prf_value_node *vnode = NULL; + struct prf_object *po; + struct llvm_prf_data *data_end; + int max_vnds; + + rcu_read_lock(); + + list_for_each_entry_rcu(po, &prf_list, link) { + /* get section limits */ + max_vnds = prf_vnds_count(po); + data_end = po->data + prf_data_count(po); + + /* + * Check that p is within: + * [po->data, po->data + prf_data_count(po)] section. + * If yes, allocate vnode from this prf_object. + */ + if (memory_contains(po->data, data_end, p, sizeof(*p))) { + + + if (WARN_ON_ONCE(po->current_node >= max_vnds)) + return NULL; /* Out of nodes */ + + /* reserve the vnode */ + vnode = &po->vnds[po->current_node++]; + goto out; + } + } + +out: + rcu_read_unlock(); + return vnode; } /* diff --git a/kernel/pgo/pgo.h b/kernel/pgo/pgo.h index 44d79e2861e1..59d0aa966fbe 100644 --- a/kernel/pgo/pgo.h +++ b/kernel/pgo/pgo.h @@ -19,6 +19,8 @@ #ifndef _PGO_H #define _PGO_H +#include <linux/rculist.h> + /* * Note: These internal LLVM definitions must match the compiler version. * See llvm/include/llvm/ProfileData/InstrProfData.inc in LLVM's source code. -- 2.32.0
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