linux-kernel - Re: [resend][PATCH 4/4] oom: don't ignore rss in nascent mm

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Message-ID: <20101129182332.GA21470@redhat.com>
Date:	Mon, 29 Nov 2010 19:23:32 +0100
From:	Oleg Nesterov <oleg@...hat.com>
To:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>,
	linux-mm <linux-mm@...ck.org>, pageexec@...email.hu,
	Solar Designer <solar@...nwall.com>,
	Eugene Teo <eteo@...hat.com>,
	Brad Spengler <spender@...ecurity.net>,
	Roland McGrath <roland@...hat.com>
Subject: Re: [resend][PATCH 4/4] oom: don't ignore rss in nascent mm

On 11/29, Oleg Nesterov wrote:
>
> I'll resend v2 today.

OK, please see below, just for your review.

I was going to sent it "officially" with the changelog/etc, but

> I am still not sure about compat_copy_strings()...

Yes, I think it needs the same checks. It should use get_arg_page()
or we need more copy-and-paste code, I think it should also check
fatal_signal_pending() like copy_strings() does.

I was going to export get_arg_page/acct_arg_size, but it is so
ugly. I'll try to find the way to unify copy_strings and
compat_copy_strings, not sure it is possible to do cleanly.

Probably this needs a separate patch in any case.

Oleg.

Changes:

	- move acct_arg_size() under CONFIG_MMU

	- add the "nop" version for NOMMMU

 include/linux/binfmts.h |    1 +
 fs/exec.c               |   32 ++++++++++++++++++++++++++++++--
 2 files changed, 31 insertions(+), 2 deletions(-)

--- K/include/linux/binfmts.h~acct_exec_mem	2010-08-19 11:35:00.000000000 +0200
+++ K/include/linux/binfmts.h	2010-11-29 17:29:35.000000000 +0100
@@ -29,6 +29,7 @@ struct linux_binprm{
 	char buf[BINPRM_BUF_SIZE];
 #ifdef CONFIG_MMU
 	struct vm_area_struct *vma;
+	unsigned long vma_pages;
 #else
 # define MAX_ARG_PAGES	32
 	struct page *page[MAX_ARG_PAGES];
--- K/fs/exec.c~acct_exec_mem	2010-11-25 15:16:56.000000000 +0100
+++ K/fs/exec.c	2010-11-29 17:51:43.000000000 +0100
@@ -164,6 +164,25 @@ out:
 
 #ifdef CONFIG_MMU
 
+static void acct_arg_size(struct linux_binprm *bprm, unsigned long pages)
+{
+	struct mm_struct *mm = current->mm;
+	long diff = (long)(pages - bprm->vma_pages);
+
+	if (!mm || !diff)
+		return;
+
+	bprm->vma_pages = pages;
+
+#ifdef SPLIT_RSS_COUNTING
+	add_mm_counter(mm, MM_ANONPAGES, diff);
+#else
+	spin_lock(&mm->page_table_lock);
+	add_mm_counter(mm, MM_ANONPAGES, diff);
+	spin_unlock(&mm->page_table_lock);
+#endif
+}
+
 static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
 		int write)
 {
@@ -186,6 +205,8 @@ static struct page *get_arg_page(struct 
 		unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start;
 		struct rlimit *rlim;
 
+		acct_arg_size(bprm, size / PAGE_SIZE);
+
 		/*
 		 * We've historically supported up to 32 pages (ARG_MAX)
 		 * of argument strings even with small stacks
@@ -276,6 +297,10 @@ static bool valid_arg_len(struct linux_b
 
 #else
 
+static inline void acct_arg_size(struct linux_binprm *bprm, unsigned long pages)
+{
+}
+
 static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
 		int write)
 {
@@ -1003,6 +1028,7 @@ int flush_old_exec(struct linux_binprm *
 	/*
 	 * Release all of the old mmap stuff
 	 */
+	acct_arg_size(bprm, 0);
 	retval = exec_mmap(bprm->mm);
 	if (retval)
 		goto out;
@@ -1426,8 +1452,10 @@ int do_execve(const char * filename,
 	return retval;
 
 out:
-	if (bprm->mm)
-		mmput (bprm->mm);
+	if (bprm->mm) {
+		acct_arg_size(bprm, 0);
+		mmput(bprm->mm);
+	}
 
 out_file:
 	if (bprm->file) {

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