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fs/proc: cached = pagecache - shmem

PATCH In review Adrian Brzezinski 2 participants 2 messages Jul 24, 2013 – Aug 8, 2013

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Adrian Brzezinski

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#0 lore raw

PATCH 1/1 fs/proc: cached = pagecache - shmem

Cached value taken from /proc/meminfo counts also shmem pages. This can be very confusing when we encounter OOM problems.

Maybe the better solution would be, to not increment NR_FILE_PAGES, when we have NR_SHMEM page? Should I rewrote and resend this patch?

Signed-off-by Adrian Brzezinski <[email protected]>
---
 fs/proc/meminfo.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)
fs/proc/meminfo.c +6 -0
index 5aa847a..d00aef5 100644
@@ -40,7 +40,12 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
        allowed = ((totalram_pages - hugetlb_total_pages())
                * sysctl_overcommit_ratio / 100) + total_swap_pages;
 
+       /*
+        * NR_SHMEM pages can't be treated as a cache,
+        * but they are counted in NR_FILE_PAGES
+        */
        cached = global_page_state(NR_FILE_PAGES) -
+                       global_page_state(NR_SHMEM) -
                        total_swapcache_pages() - i.bufferram;
        if (cached < 0)
                cached = 0;

@@ -59,6 +64,7 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
                "Buffers:        %8lu kB\n"
                "Cached:         %8lu kB\n"
                "SwapCached:     %8lu kB\n"
+               "PageCache:      %8lu kB\n"
                "Active:         %8lu kB\n"
                "Inactive:       %8lu kB\n"
                "Active(anon):   %8lu kB\n"

@@ -111,6 +117,7 @@ static int meminfo_proc_show(struct seq_file *m,

void *v)

                K(i.bufferram),
                K(cached),
                K(total_swapcache_pages()),

+ K(global_page_state(NR_FILE_PAGES)),
K(pages[LRU_ACTIVE_ANON] + pages[LRU_ACTIVE_FILE]),
K(pages[LRU_INACTIVE_ANON] + pages[LRU_INACTIVE_FILE]), K(pages[LRU_ACTIVE_ANON]),
--
1.7.1

#1 lore raw
Quoted 7 lines · Adrian Brzezinski

Cached value taken from /proc/meminfo counts also shmem pages. This can be very confusing when we encounter OOM problems.

Maybe the better solution would be, to not increment NR_FILE_PAGES, when we have NR_SHMEM page? Should I rewrote and resend this patch?

I suggest to consider push this patch to mainline.

Quoted 46 lines
Signed-off-by Adrian Brzezinski <[email protected]>
---
 fs/proc/meminfo.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)
fs/proc/meminfo.c +7 -0
index 5aa847a..d00aef5 100644
@@ -40,7 +40,12 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
        allowed = ((totalram_pages - hugetlb_total_pages())
                * sysctl_overcommit_ratio / 100) + total_swap_pages;
 
+       /*
+        * NR_SHMEM pages can't be treated as a cache,
+        * but they are counted in NR_FILE_PAGES
+        */
        cached = global_page_state(NR_FILE_PAGES) -
+                       global_page_state(NR_SHMEM) -
                        total_swapcache_pages() - i.bufferram;
        if (cached < 0)
                cached = 0;

@@ -59,6 +64,7 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
                "Buffers:        %8lu kB\n"
                "Cached:         %8lu kB\n"
                "SwapCached:     %8lu kB\n"
+               "PageCache:      %8lu kB\n"
                "Active:         %8lu kB\n"
                "Inactive:       %8lu kB\n"
                "Active(anon):   %8lu kB\n"

@@ -111,6 +117,7 @@ static int meminfo_proc_show(struct seq_file *m,
 void *v)
                K(i.bufferram),
                K(cached),
                K(total_swapcache_pages()),
+               K(global_page_state(NR_FILE_PAGES)),
                K(pages[LRU_ACTIVE_ANON]   + pages[LRU_ACTIVE_FILE]),
                K(pages[LRU_INACTIVE_ANON] + pages[LRU_INACTIVE_FILE]),

                K(pages[LRU_ACTIVE_ANON]),

--
1.7.1
--
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