Davidlohr Bueso 11163348a2 oprofile: reduce mmap_sem hold for mm->exe_file ... sync_buffer() needs the mmap_sem for two distinct operations, both only occurring upon user context switch handling: 1) Dealing with the exe_file. 2) Adding the dcookie data as we need to lookup the vma that backs it. This is done via add_sample() and add_data(). This patch isolates 1), for it will no longer need the mmap_sem for serialization. However, for now, make of the more standard get_mm_exe_file(), requiring only holding the mmap_sem to read the value, and relying on reference counting to make sure that the exe file won't dissappear underneath us while doing the get dcookie. As a consequence, for 2) we move the mmap_sem locking into where we really need it, in lookup_dcookie(). The benefits are twofold: reduce mmap_sem hold times, and cleaner code. [akpm@linux-foundation.org: export get_mm_exe_file for arch/x86/oprofile/oprofile.ko] Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Cc: Robert Richter <rric@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2015-04-17 09:04:11 -04:00
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buffer_sync.c	oprofile: reduce mmap_sem hold for mm->exe_file	2015-04-17 09:04:11 -04:00
buffer_sync.h
cpu_buffer.c
cpu_buffer.h
event_buffer.c
event_buffer.h
nmi_timer_int.c
oprof.c
oprof.h
oprofile_files.c
oprofile_perf.c
oprofile_stats.c
oprofile_stats.h
oprofilefs.c
timer_int.c