Cool! Andrew picked up the patch I liked.
Andres, how about adding it to olpc-2.6 too? Along with the
latest Memphis patch, it would give use us invaluable stats
for those trying to reduce memory usage.
Original Message
Subject: + maps-pssproportional-set-size-accounting-in-smaps.patch added to -mm
tree
Date: Mon, 24 Sep 2007 13:32:10 -0700
From: [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
CC: [EMAIL PROTECTED], [EMAIL PROTECTED], [EMAIL PROTECTED],[EMAIL
PROTECTED], [EMAIL PROTECTED], [EMAIL PROTECTED],[EMAIL PROTECTED],
[EMAIL PROTECTED]
The patch titled
maps: PSS(proportional set size) accounting in smaps
has been added to the -mm tree. Its filename is
maps-pssproportional-set-size-accounting-in-smaps.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
--
Subject: maps: PSS(proportional set size) accounting in smaps
From: Fengguang Wu [EMAIL PROTECTED]
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. They are comprehensive tools. But for PSS, let's do it in the simple
way.
Cc: John Berthels [EMAIL PROTECTED]
Cc: Bernardo Innocenti [EMAIL PROTECTED]
Cc: Padraig Brady [EMAIL PROTECTED]
Cc: Denys Vlasenko [EMAIL PROTECTED]
Cc: Balbir Singh [EMAIL PROTECTED]
Acked-by: Matt Mackall [EMAIL PROTECTED]
Signed-off-by: Fengguang Wu [EMAIL PROTECTED]
Cc: Hugh Dickins [EMAIL PROTECTED]
Signed-off-by: Andrew Morton [EMAIL PROTECTED]
---
fs/proc/task_mmu.c | 29 -
1 files changed, 28 insertions(+), 1 deletion(-)
diff -puN fs/proc/task_mmu.c~maps-pssproportional-set-size-accounting-in-smaps
fs/proc/task_mmu.c
--- a/fs/proc/task_mmu.c~maps-pssproportional-set-size-accounting-in-smaps
+++ a/fs/proc/task_mmu.c
@@ -324,6 +324,27 @@ struct mem_size_stats
unsigned long private_clean;
unsigned long private_dirty;
unsigned long referenced;
+
+ /*
+* Proportional Set Size(PSS): my share of RSS.
+*
+* 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. - Matt Mackall, lwn.net
+*/
+ u64 pss;
+ /*
+* To keep (accumulated) division errors low, we adopt 64bit pss and
+* use some low bits for division errors. So (pss PSS_DIV_BITS)
+* would be the real byte count.
+*
+* A shift of 12 before division means(assuming 4K page size):
+* - 1M 3-user-pages add up to 8KB errors;
+* - supports mapcount up to 2^24, or 16M;
+* - supports PSS up to 2^52 bytes, or 4PB.
+*/
+#define PSS_DIV_BITS 12
};
struct smaps_arg
@@ -341,6 +362,7 @@ 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 +379,19 @@ 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 PSS_DIV_BITS) / mapcount;
} else {
if (pte_dirty(ptent))
mss-private_dirty += PAGE_SIZE;
else
mss-private_clean += PAGE_SIZE;
+ mss-pss += (PAGE_SIZE PSS_DIV_BITS);
}
}
pte_unmap_unlock(pte - 1, ptl);
@@ -395,6 +420,7 @@ static int show_smap(struct seq_file *m,
seq_printf(m,
Size: %8lu kB\n
Rss:%8lu kB\n
+
