From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from toip6.srvr.bell.ca ([209.226.175.125]) by tomts40-srv.bellnexxia.net (InterMail vM.5.01.06.13 201-253-122-130-113-20050324) with ESMTP id <20080716144009.GANX1625.tomts40-srv.bellnexxia.net@toip6.srvr.bell.ca> for ; Wed, 16 Jul 2008 10:40:09 -0400 Date: Wed, 16 Jul 2008 10:40:08 -0400 From: Mathieu Desnoyers Subject: Re: [patch 10/17] LTTng instrumentation - swap Message-ID: <20080716144008.GG24546@Krystal> References: <20080715222604.331269462@polymtl.ca> <20080715222748.214360024@polymtl.ca> <1216197576.5232.27.camel@twins> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline In-Reply-To: <1216197576.5232.27.camel@twins> Sender: owner-linux-mm@kvack.org Return-Path: To: Peter Zijlstra Cc: akpm@linux-foundation.org, Ingo Molnar , linux-kernel@vger.kernel.org, Masami Hiramatsu , linux-mm@kvack.org, Dave Hansen , "Frank Ch. Eigler" , Hideo AOKI , Takashi Nishiie , Steven Rostedt , Eduard - Gabriel Munteanu List-ID: * Peter Zijlstra (peterz@infradead.org) wrote: > 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 > > CC: linux-mm@kvack.org > > CC: Dave Hansen > > 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 > > --- > > 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 > > #include > > #include > > +#include > > > > #include > > #include > > @@ -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 > > #include > > #include > > +#include > > #include > > > > 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 > > #include > > #include > > +#include > > > > 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. > Would it make more sense to turn get_swap_info_struct into a static inline in swap.h ? Mathieu > > > > /* > > * 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 > > +#include > > + > > +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 > > > -- Mathieu Desnoyers OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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