From b40d4f84becd69275451baee7f0801c85eb58437 Mon Sep 17 00:00:00 2001 From: Nikanth Karthikesan Date: Wed, 27 Oct 2010 15:34:10 -0700 Subject: [PATCH] /proc/pid/smaps: export amount of anonymous memory in a mapping Export the number of anonymous pages in a mapping via smaps. Even the private pages in a mapping backed by a file, would be marked as anonymous, when they are modified. Export this information to user-space via smaps. Exporting this count will help gdb to make a better decision on which areas need to be dumped in its coredump; and should be useful to others studying the memory usage of a process. Signed-off-by: Nikanth Karthikesan Acked-by: Hugh Dickins Reviewed-by: KOSAKI Motohiro Cc: Matt Mackall Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/filesystems/proc.txt | 13 ++++++++++--- fs/proc/task_mmu.c | 6 ++++++ 2 files changed, 16 insertions(+), 3 deletions(-) diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt index a563b74c7aef..976de6e19dd8 100644 --- a/Documentation/filesystems/proc.txt +++ b/Documentation/filesystems/proc.txt @@ -370,6 +370,7 @@ Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 0 kB Referenced: 892 kB +Anonymous: 0 kB Swap: 0 kB KernelPageSize: 4 kB MMUPageSize: 4 kB @@ -378,9 +379,15 @@ The first of these lines shows the same information as is displayed for the mapping in /proc/PID/maps. The remaining lines show the size of the mapping (size), the amount of the mapping that is currently resident in RAM (RSS), the process' proportional share of this mapping (PSS), the number of clean and -dirty shared pages in the mapping, and the number of clean and dirty private -pages in the mapping. The "Referenced" indicates the amount of memory -currently marked as referenced or accessed. +dirty private pages in the mapping. Note that even a page which is part of a +MAP_SHARED mapping, but has only a single pte mapped, i.e. is currently used +by only one process, is accounted as private and not as shared. "Referenced" +indicates the amount of memory currently marked as referenced or accessed. +"Anonymous" shows the amount of memory that does not belong to any file. Even +a mapping associated with a file may contain anonymous pages: when MAP_PRIVATE +and a page is modified, the file page is replaced by a private anonymous copy. +"Swap" shows how much would-be-anonymous memory is also used, but out on +swap. This file is only present if the CONFIG_MMU kernel configuration option is enabled. diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 871e25ed0069..da6b01d70f01 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -327,6 +327,7 @@ struct mem_size_stats { unsigned long private_clean; unsigned long private_dirty; unsigned long referenced; + unsigned long anonymous; unsigned long swap; u64 pss; }; @@ -357,6 +358,9 @@ static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, if (!page) continue; + if (PageAnon(page)) + mss->anonymous += PAGE_SIZE; + mss->resident += PAGE_SIZE; /* Accumulate the size in pages that have been accessed. */ if (pte_young(ptent) || PageReferenced(page)) @@ -410,6 +414,7 @@ static int show_smap(struct seq_file *m, void *v) "Private_Clean: %8lu kB\n" "Private_Dirty: %8lu kB\n" "Referenced: %8lu kB\n" + "Anonymous: %8lu kB\n" "Swap: %8lu kB\n" "KernelPageSize: %8lu kB\n" "MMUPageSize: %8lu kB\n", @@ -421,6 +426,7 @@ static int show_smap(struct seq_file *m, void *v) mss.private_clean >> 10, mss.private_dirty >> 10, mss.referenced >> 10, + mss.anonymous >> 10, mss.swap >> 10, vma_kernel_pagesize(vma) >> 10, vma_mmu_pagesize(vma) >> 10); -- 2.20.1