Messages in this thread Patch in this message | | | Date | Tue, 14 Aug 2007 09:33:50 +0800 | From | Fengguang Wu <> | Subject | [PATCH] PSS(proportional set size) accounting in smaps |
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The "proportional set size" (PSS) of a process is the count of pages it has in memory, where each page is divided by the number of processes sharing it. So if a process has 1000 pages all to itself, and 1000 shared with one other process, its PSS will be 1500. - lwn.net: "ELC: How much memory are applications really using?"
The PSS proposed by Matt Mackall is a very nice metic for measuring an process's memory footprint. So collect and export it via /proc/<pid>/smaps.
Matt Mackall's pagemap/kpagemap and John Berthels's exmap can also do the job, providing pretty much details. But for PSS, let's do it in a simple way.
Cc: Matt Mackall <mpm@selenic.com> Cc: John Berthels <jjberthels@gmail.com> Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn> --- fs/proc/task_mmu.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-)
--- linux-2.6.23-rc2-mm2.orig/fs/proc/task_mmu.c +++ linux-2.6.23-rc2-mm2/fs/proc/task_mmu.c @@ -319,6 +319,7 @@ const struct file_operations proc_maps_o struct mem_size_stats { unsigned long resident; + u64 pss; /* proportional set size: my share of rss */ unsigned long shared_clean; unsigned long shared_dirty; unsigned long private_clean; @@ -341,6 +342,7 @@ static int smaps_pte_range(pmd_t *pmd, u pte_t *pte, ptent; spinlock_t *ptl; struct page *page; + int mapcount; pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); for (; addr != end; pte++, addr += PAGE_SIZE) { @@ -357,16 +359,19 @@ static int smaps_pte_range(pmd_t *pmd, u /* Accumulate the size in pages that have been accessed. */ if (pte_young(ptent) || PageReferenced(page)) mss->referenced += PAGE_SIZE; - if (page_mapcount(page) >= 2) { + mapcount = page_mapcount(page); + if (mapcount >= 2) { if (pte_dirty(ptent)) mss->shared_dirty += PAGE_SIZE; else mss->shared_clean += PAGE_SIZE; + mss->pss += (PAGE_SIZE << 12) / mapcount; } else { if (pte_dirty(ptent)) mss->private_dirty += PAGE_SIZE; else mss->private_clean += PAGE_SIZE; + mss->pss += (PAGE_SIZE << 12); } } pte_unmap_unlock(pte - 1, ptl); @@ -395,18 +400,20 @@ static int show_smap(struct seq_file *m, seq_printf(m, "Size: %8lu kB\n" "Rss: %8lu kB\n" + "Pss: %8lu kB\n" "Shared_Clean: %8lu kB\n" "Shared_Dirty: %8lu kB\n" "Private_Clean: %8lu kB\n" "Private_Dirty: %8lu kB\n" "Referenced: %8lu kB\n", (vma->vm_end - vma->vm_start) >> 10, - sarg.mss.resident >> 10, + sarg.mss.resident >> 10, + (unsigned long)(mss->pss >> 22), sarg.mss.shared_clean >> 10, sarg.mss.shared_dirty >> 10, sarg.mss.private_clean >> 10, sarg.mss.private_dirty >> 10, - sarg.mss.referenced >> 10); + sarg.mss.referenced >> 10); return ret; } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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