Commit-ID: 3ea2f2b96f9e636f49eb10962e96db3e19cab157 Gitweb: http://git.kernel.org/tip/3ea2f2b96f9e636f49eb10962e96db3e19cab157 Author: Oleg Nesterov <o...@redhat.com> AuthorDate: Wed, 16 Oct 2013 22:10:04 +0200 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Tue, 29 Oct 2013 12:02:52 +0100
perf: Do not waste PAGE_SIZE bytes for ALIGN(8) in perf_event_mmap_event() perf_event_mmap_event() does kzalloc(PATH_MAX + sizeof(u64)) to ensure we can align the size later. However this means that we actually allocate PAGE_SIZE * 2 buffer, seems too much. Change this code to allocate PATH_MAX==PAGE_SIZE bytes, but tell d_path() to not use the last sizeof(u64) bytes. Note: it is not clear why do we need __GFP_ZERO, see the next patch. Signed-off-by: Oleg Nesterov <o...@redhat.com> Signed-off-by: Peter Zijlstra <pet...@infradead.org> Link: http://lkml.kernel.org/r/20131016201004.gc23...@redhat.com Signed-off-by: Ingo Molnar <mi...@kernel.org> --- kernel/events/core.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 3ea5605..b409e75 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -5113,17 +5113,18 @@ static void perf_event_mmap_event(struct perf_mmap_event *mmap_event) if (file) { struct inode *inode; dev_t dev; - /* - * d_path works from the end of the rb backwards, so we - * need to add enough zero bytes after the string to handle - * the 64bit alignment we do later. - */ - buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL); + + buf = kzalloc(PATH_MAX, GFP_KERNEL); if (!buf) { name = strncpy(tmp, "//enomem", sizeof(tmp)); goto got_name; } - name = d_path(&file->f_path, buf, PATH_MAX); + /* + * d_path() works from the end of the rb backwards, so we + * need to add enough zero bytes after the string to handle + * the 64bit alignment we do later. + */ + name = d_path(&file->f_path, buf, PATH_MAX - sizeof(u64)); if (IS_ERR(name)) { name = strncpy(tmp, "//toolong", sizeof(tmp)); goto got_name; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
