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| author | Dave Hansen <dave.hansen@linux.intel.com> | 2015-06-07 11:37:03 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-06-09 12:24:32 +0200 |
| commit | 2a1dcb1f796ad37028df37d96fc7c5b6b1705a43 (patch) | |
| tree | ef1afe258c5ccd08d723cabf7e78dbb50b48d7cc /arch/x86/mm/mpx.c | |
| parent | 97efebf1bc30a80122af3295ebdb726dbc040ca6 (diff) | |
| download | linux-2a1dcb1f796ad37028df37d96fc7c5b6b1705a43.tar.gz | |
x86/mpx: Trace the attempts to find bounds tables
There are two different events being traced here. They are doing similar things so share a trace "EVENT_CLASS" and are presented together. 1. Trace when MPX is zapping pages "mpx_unmap_zap": When MPX can not free an entire bounds table, it will instead try to zap unused parts of a bounds table to free the backing memory. This decreases RSS (resident set size) without decreasing the virtual space allocated for bounds tables. 2. Trace attempts to find bounds tables "mpx_unmap_search": This event traces any time we go looking to unmap a bounds table for a given virtual address range. This is useful to ensure that the kernel actually "tried" to free a bounds table versus times it succeeded in finding one. It might try and fail if it realized that a table was shared with an adjacent VMA which is not being unmapped. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Dave Hansen <dave@sr71.net> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20150607183703.B9D2468B@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/mm/mpx.c')
| -rw-r--r-- | arch/x86/mm/mpx.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/mm/mpx.c b/arch/x86/mm/mpx.c index 75e5d7043f65..55729ee9263e 100644 --- a/arch/x86/mm/mpx.c +++ b/arch/x86/mm/mpx.c @@ -668,6 +668,7 @@ static int zap_bt_entries(struct mm_struct *mm, len = min(vma->vm_end, end) - addr; zap_page_range(vma, addr, len, NULL); + trace_mpx_unmap_zap(addr, addr+len); vma = vma->vm_next; addr = vma->vm_start; @@ -840,6 +841,7 @@ static int mpx_unmap_tables(struct mm_struct *mm, long __user *bd_entry, *bde_start, *bde_end; unsigned long bt_addr; + trace_mpx_unmap_search(start, end); /* * "Edge" bounds tables are those which are being used by the region * (start -> end), but that may be shared with adjacent areas. If they |