snowball/igloo-kernel.git/fs/buffer.c, branch u0

lttng-instrumentation/lttng-instrumentation-fs

2011-03-16T23:04:34+00:00

LTTng instrumentation - fs Core filesystem tracepoints. Tracepoints added : fs_buffer_wait_end fs_buffer_wait_start fs_close fs_exec fs_ioctl fs_llseek fs_lseek fs_open fs_poll fs_pread64 fs_pwrite64 fs_read fs_readv fs_select fs_write fs_writev Instrument the core FS events, extracting the information when it is available. e.g. the instrumentation of "reads" is inserted _after_ the read, when the information is ready. This would not be possible if the instrumentation would be placed elsewhere (at the beginning of the system call for instance). Those tracepoints are used by LTTng. About the performance impact of tracepoints (which is comparable to markers), even without immediate values optimizations, tests done by Hideo Aoki on ia64 show no regression. His test case was using hackbench on a kernel where scheduler instrumentation (about 5 events in code scheduler code) was added. See the "Tracepoints" patch header for performance result detail. Signed-off-by: Mathieu Desnoyers CC: Alexander Viro CC: Masami Hiramatsu CC: 'Peter Zijlstra' CC: "Frank Ch. Eigler" CC: 'Ingo Molnar' CC: 'Hideo AOKI' CC: Takashi Nishiie CC: 'Steven Rostedt' CC: Eduard - Gabriel Munteanu

fs: Use this_cpu_inc_return in buffer.c

2010-12-17T14:18:05+00:00

__this_cpu_inc can create a single instruction with the same effect as the _get_cpu_var(..)++ construct in buffer.c. Cc: Wu Fengguang Cc: Christoph Hellwig Acked-by: H. Peter Anvin Signed-off-by: Christoph Lameter Signed-off-by: Tejun Heo

fs: Use this_cpu_xx operations in buffer.c

2010-12-17T14:07:19+00:00

Optimize various per cpu area operations through these new percpu operations. These operations avoid address calculations through the use of segment prefixes and multiple memory references through RMW instructions etc. Reduces code size: Before: christoph@linux-2.6$ size fs/buffer.o text data bss dec hex filename 19169 80 28 19277 4b4d fs/buffer.o After: christoph@linux-2.6$ size fs/buffer.o text data bss dec hex filename 19138 80 28 19246 4b2e fs/buffer.o V3->V4: - Move the use of this_cpu_inc_return into a later patch so that this one can go in without percpu infrastructure changes. Cc: Wu Fengguang Cc: Christoph Hellwig Acked-by: H. Peter Anvin Signed-off-by: Christoph Lameter Signed-off-by: Tejun Heo

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6

2010-10-27T00:58:44+00:00

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (52 commits) split invalidate_inodes() fs: skip I_FREEING inodes in writeback_sb_inodes fs: fold invalidate_list into invalidate_inodes fs: do not drop inode_lock in dispose_list fs: inode split IO and LRU lists fs: switch bdev inode bdi's correctly fs: fix buffer invalidation in invalidate_list fsnotify: use dget_parent smbfs: use dget_parent exportfs: use dget_parent fs: use RCU read side protection in d_validate fs: clean up dentry lru modification fs: split __shrink_dcache_sb fs: improve DCACHE_REFERENCED usage fs: use percpu counter for nr_dentry and nr_dentry_unused fs: simplify __d_free fs: take dcache_lock inside __d_path fs: do not assign default i_ino in new_inode fs: introduce a per-cpu last_ino allocator new helper: ihold() ...

fs/buffer.c: remove duplicated assignment to b_private

2010-10-26T23:52:13+00:00

bh->b_private is initialized within init_buffer(), thus this assignment is redundant. Signed-off-by: Namhyung Kim Cc: Al Viro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

writeback: remove nonblocking/encountered_congestion references

2010-10-26T23:52:05+00:00

This removes more dead code that was somehow missed by commit 0d99519efef (writeback: remove unused nonblocking and congestion checks). There are no behavior change except for the removal of two entries from one of the ext4 tracing interface. The nonblocking checks in ->writepages are no longer used because the flusher now prefer to block on get_request_wait() than to skip inodes on IO congestion. The latter will lead to more seeky IO. The nonblocking checks in ->writepage are no longer used because it's redundant with the WB_SYNC_NONE check. We no long set ->nonblocking in VM page out and page migration, because a) it's effectively redundant with WB_SYNC_NONE in current code b) it's old semantic of "Don't get stuck on request queues" is mis-behavior: that would skip some dirty inodes on congestion and page out others, which is unfair in terms of LRU age. Inspired by Christoph Hellwig. Thanks! Signed-off-by: Wu Fengguang Cc: Theodore Ts'o Cc: David Howells Cc: Sage Weil Cc: Steve French Cc: Chris Mason Cc: Jens Axboe Cc: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

fs/buffer.c: call __block_write_begin() if we have page

2010-10-26T01:18:23+00:00

If we have the appropriate page already, call __block_write_begin() directly instead of releasing and regrabbing it inside of block_write_begin(). Signed-off-by: Namhyung Kim Signed-off-by: Al Viro

fs/buffer.c: remove duplicated assignment on b_private

2010-10-26T01:18:22+00:00

bh->b_private is initialized within init_buffer(), thus the assignment should be redundant. Remove it. Signed-off-by: Namhyung Kim Signed-off-by: Al Viro

fs: kill block_prepare_write

2010-10-26T01:18:20+00:00

__block_write_begin and block_prepare_write are identical except for slightly different calling conventions. Convert all callers to the __block_write_begin calling conventions and drop block_prepare_write. Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro

block: remove the BH_Eopnotsupp flag

2010-09-10T10:35:40+00:00

This flag was only set for barrier buffers, which we don't submit anymore. Signed-off-by: Christoph Hellwig Signed-off-by: Tejun Heo Signed-off-by: Jens Axboe