Messages in this thread | | | Subject | Re: [patch 10/17] LTTng instrumentation - swap | From | Peter Zijlstra <> | Date | Wed, 16 Jul 2008 10:39:36 +0200 |
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On Tue, 2008-07-15 at 18:26 -0400, Mathieu Desnoyers wrote: > plain text document attachment (lttng-instrumentation-swap.patch) > Instrumentation of waits caused by swap activity. Also instrumentation > swapon/swapoff events to keep track of active swap partitions. > > 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 <mathieu.desnoyers@polymtl.ca> > CC: linux-mm@kvack.org > CC: Dave Hansen <haveblue@us.ibm.com> > CC: Masami Hiramatsu <mhiramat@redhat.com> > CC: 'Peter Zijlstra' <peterz@infradead.org> > CC: "Frank Ch. Eigler" <fche@redhat.com> > CC: 'Ingo Molnar' <mingo@elte.hu> > CC: 'Hideo AOKI' <haoki@redhat.com> > CC: Takashi Nishiie <t-nishiie@np.css.fujitsu.com> > CC: 'Steven Rostedt' <rostedt@goodmis.org> > CC: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro> > --- > include/trace/swap.h | 20 ++++++++++++++++++++ > mm/memory.c | 2 ++ > mm/page_io.c | 2 ++ > mm/swapfile.c | 4 ++++ > 4 files changed, 28 insertions(+) > > Index: linux-2.6-lttng/mm/memory.c > =================================================================== > --- linux-2.6-lttng.orig/mm/memory.c 2008-07-15 13:54:46.000000000 -0400 > +++ linux-2.6-lttng/mm/memory.c 2008-07-15 14:02:54.000000000 -0400 > @@ -51,6 +51,7 @@ > #include <linux/init.h> > #include <linux/writeback.h> > #include <linux/memcontrol.h> > +#include <trace/swap.h> > > #include <asm/pgalloc.h> > #include <asm/uaccess.h> > @@ -2213,6 +2214,7 @@ static int do_swap_page(struct mm_struct > /* Had to read the page from swap area: Major fault */ > ret = VM_FAULT_MAJOR; > count_vm_event(PGMAJFAULT); > + trace_swap_in(page, entry); > } > > if (mem_cgroup_charge(page, mm, GFP_KERNEL)) { > Index: linux-2.6-lttng/mm/page_io.c > =================================================================== > --- linux-2.6-lttng.orig/mm/page_io.c 2008-07-15 13:54:46.000000000 -0400 > +++ linux-2.6-lttng/mm/page_io.c 2008-07-15 14:02:54.000000000 -0400 > @@ -17,6 +17,7 @@ > #include <linux/bio.h> > #include <linux/swapops.h> > #include <linux/writeback.h> > +#include <trace/swap.h> > #include <asm/pgtable.h> > > static struct bio *get_swap_bio(gfp_t gfp_flags, pgoff_t index, > @@ -114,6 +115,7 @@ int swap_writepage(struct page *page, st > rw |= (1 << BIO_RW_SYNC); > count_vm_event(PSWPOUT); > set_page_writeback(page); > + trace_swap_out(page); > unlock_page(page); > submit_bio(rw, bio); > out: > Index: linux-2.6-lttng/mm/swapfile.c > =================================================================== > --- linux-2.6-lttng.orig/mm/swapfile.c 2008-07-15 13:54:46.000000000 -0400 > +++ linux-2.6-lttng/mm/swapfile.c 2008-07-15 14:02:54.000000000 -0400 > @@ -32,6 +32,7 @@ > #include <asm/pgtable.h> > #include <asm/tlbflush.h> > #include <linux/swapops.h> > +#include <trace/swap.h> > > DEFINE_SPINLOCK(swap_lock); > unsigned int nr_swapfiles; > @@ -1310,6 +1311,7 @@ asmlinkage long sys_swapoff(const char _ > swap_map = p->swap_map; > p->swap_map = NULL; > p->flags = 0; > + trace_swap_file_close(swap_file); > spin_unlock(&swap_lock); > mutex_unlock(&swapon_mutex); > vfree(swap_map); > @@ -1695,6 +1697,7 @@ asmlinkage long sys_swapon(const char __ > } else { > swap_info[prev].next = p - swap_info; > } > + trace_swap_file_open(swap_file, name); > spin_unlock(&swap_lock); > mutex_unlock(&swapon_mutex); > error = 0; > @@ -1796,6 +1799,7 @@ get_swap_info_struct(unsigned type) > { > return &swap_info[type]; > } > +EXPORT_SYMBOL_GPL(get_swap_info_struct);
I'm not too happy with this export.
> > /* > * swap_lock prevents swap_map being freed. Don't grab an extra > Index: linux-2.6-lttng/include/trace/swap.h > =================================================================== > --- /dev/null 1970-01-01 00:00:00.000000000 +0000 > +++ linux-2.6-lttng/include/trace/swap.h 2008-07-15 14:02:54.000000000 -0400 > @@ -0,0 +1,20 @@ > +#ifndef _TRACE_SWAP_H > +#define _TRACE_SWAP_H > + > +#include <linux/swap.h> > +#include <linux/tracepoint.h> > + > +DEFINE_TRACE(swap_in, > + TPPROTO(struct page *page, swp_entry_t entry), > + TPARGS(page, entry)); > +DEFINE_TRACE(swap_out, > + TPPROTO(struct page *page), > + TPARGS(page)); > +DEFINE_TRACE(swap_file_open, > + TPPROTO(struct file *file, char *filename), > + TPARGS(file, filename)); > +DEFINE_TRACE(swap_file_close, > + TPPROTO(struct file *file), > + TPARGS(file)); > + > +#endif >
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