The patch titled
Subject: mm: /proc/pid/smaps_rollup: convert to single value seq_file
has been added to the -mm tree. Its filename is
mm-proc-pid-smaps_rollup-convert-to-single-value-seq_file.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-proc-pid-smaps_rollup-convert-to-single-value-seq_file.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-proc-pid-smaps_rollup-convert-to-single-value-seq_file.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Vlastimil Babka <vbabka@xxxxxxx>
Subject: mm: /proc/pid/smaps_rollup: convert to single value seq_file
The /proc/pid/smaps_rollup file is currently implemented via the
m_start/m_next/m_stop seq_file iterators shared with the other maps files,
that iterate over vma's. However, the rollup file doesn't print anything
for each vma, only accumulate the stats.
There are some issues with the current code as reported in [1] - the
accumulated stats can get skewed if seq_file start()/stop() op is called
multiple times, if show() is called multiple times, and after seeks to
non-zero position.
Patch [1] fixed those within existing design, but I believe it is
fundamentally wrong to expose the vma iterators to the seq_file mechanism
when smaps_rollup shows logically a single set of values for the whole
address space.
This patch thus refactors the code to provide a single "value" at offset
0, with vma iteration to gather the stats done internally. This fixes the
situations where results are skewed, and simplifies the code, especially
in show_smap(), at the expense of somewhat less code reuse.
[1] https://marc.info/?l=linux-mm&m=151927723128134&w=2
Link: http://lkml.kernel.org/r/20180723111933.15443-5-vbabka@xxxxxxx
Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
Reported-by: Daniel Colascione <dancol@xxxxxxxxxx>
Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/task_mmu.c | 144 ++++++++++++++++++++++++++-----------------
1 file changed, 90 insertions(+), 54 deletions(-)
diff -puN fs/proc/task_mmu.c~mm-proc-pid-smaps_rollup-convert-to-single-value-seq_file fs/proc/task_mmu.c
--- a/fs/proc/task_mmu.c~mm-proc-pid-smaps_rollup-convert-to-single-value-seq_file
+++ a/fs/proc/task_mmu.c
@@ -404,7 +404,6 @@ const struct file_operations proc_pid_ma
#ifdef CONFIG_PROC_PAGE_MONITOR
struct mem_size_stats {
- bool first;
unsigned long resident;
unsigned long shared_clean;
unsigned long shared_dirty;
@@ -418,11 +417,12 @@ struct mem_size_stats {
unsigned long swap;
unsigned long shared_hugetlb;
unsigned long private_hugetlb;
- unsigned long first_vma_start;
+ unsigned long last_vma_end;
u64 pss;
u64 pss_locked;
u64 swap_pss;
bool check_shmem_swap;
+ bool finished;
};
static void smaps_account(struct mem_size_stats *mss, struct page *page,
@@ -775,58 +775,57 @@ static void __show_smap(struct seq_file
static int show_smap(struct seq_file *m, void *v)
{
- struct proc_maps_private *priv = m->private;
struct vm_area_struct *vma = v;
- struct mem_size_stats mss_stack;
- struct mem_size_stats *mss;
- int ret = 0;
- bool rollup_mode;
- bool last_vma;
-
- if (priv->rollup) {
- rollup_mode = true;
- mss = priv->rollup;
- if (mss->first) {
- mss->first_vma_start = vma->vm_start;
- mss->first = false;
+ struct mem_size_stats mss;
+
+ memset(&mss, 0, sizeof(mss));
+
+ smap_gather_stats(vma, &mss);
+
+ show_map_vma(m, vma);
+
+ SEQ_PUT_DEC("Size: ", vma->vm_end - vma->vm_start);
+ SEQ_PUT_DEC(" kB\nKernelPageSize: ", vma_kernel_pagesize(vma));
+ SEQ_PUT_DEC(" kB\nMMUPageSize: ", vma_mmu_pagesize(vma));
+ seq_puts(m, " kB\n");
+
+ __show_smap(m, &mss);
+
+ if (arch_pkeys_enabled())
+ seq_printf(m, "ProtectionKey: %8u\n", vma_pkey(vma));
+ show_smap_vma_flags(m, vma);
+
+ m_cache_vma(m, vma);
+
+ return 0;
+}
+
+static int show_smaps_rollup(struct seq_file *m, void *v)
+{
+ struct proc_maps_private *priv = m->private;
+ struct mem_size_stats *mss = priv->rollup;
+ struct vm_area_struct *vma;
+
+ /*
+ * We might be called multiple times when e.g. the seq buffer
+ * overflows. Gather the stats only once.
+ */
+ if (!mss->finished) {
+ for (vma = priv->mm->mmap; vma; vma = vma->vm_next) {
+ smap_gather_stats(vma, mss);
+ mss->last_vma_end = vma->vm_end;
}
- last_vma = !m_next_vma(priv, vma);
- } else {
- rollup_mode = false;
- memset(&mss_stack, 0, sizeof(mss_stack));
- mss = &mss_stack;
- }
-
- smap_gather_stats(vma, mss);
-
- if (!rollup_mode) {
- show_map_vma(m, vma);
- } else if (last_vma) {
- show_vma_header_prefix(
- m, mss->first_vma_start, vma->vm_end, 0, 0, 0, 0);
- seq_pad(m, ' ');
- seq_puts(m, "[rollup]\n");
- } else {
- ret = SEQ_SKIP;
- }
-
- if (!rollup_mode) {
- SEQ_PUT_DEC("Size: ", vma->vm_end - vma->vm_start);
- SEQ_PUT_DEC(" kB\nKernelPageSize: ", vma_kernel_pagesize(vma));
- SEQ_PUT_DEC(" kB\nMMUPageSize: ", vma_mmu_pagesize(vma));
- seq_puts(m, " kB\n");
- }
-
- if (!rollup_mode || last_vma)
- __show_smap(m, mss);
-
- if (!rollup_mode) {
- if (arch_pkeys_enabled())
- seq_printf(m, "ProtectionKey: %8u\n", vma_pkey(vma));
- show_smap_vma_flags(m, vma);
+ mss->finished = true;
}
- m_cache_vma(m, vma);
- return ret;
+
+ show_vma_header_prefix(m, priv->mm->mmap->vm_start,
+ mss->last_vma_end, 0, 0, 0, 0);
+ seq_pad(m, ' ');
+ seq_puts(m, "[rollup]\n");
+
+ __show_smap(m, mss);
+
+ return 0;
}
#undef SEQ_PUT_DEC
@@ -837,6 +836,44 @@ static const struct seq_operations proc_
.show = show_smap
};
+static void *smaps_rollup_start(struct seq_file *m, loff_t *ppos)
+{
+ struct proc_maps_private *priv = m->private;
+ struct mm_struct *mm;
+
+ if (*ppos != 0)
+ return NULL;
+
+ priv->task = get_proc_task(priv->inode);
+ if (!priv->task)
+ return ERR_PTR(-ESRCH);
+
+ mm = priv->mm;
+ if (!mm || !mmget_not_zero(mm))
+ return NULL;
+
+ memset(priv->rollup, 0, sizeof(*priv->rollup));
+
+ down_read(&mm->mmap_sem);
+ hold_task_mempolicy(priv);
+
+ return mm;
+}
+
+static void *smaps_rollup_next(struct seq_file *m, void *v, loff_t *pos)
+{
+ (*pos)++;
+ vma_stop(m->private);
+ return NULL;
+}
+
+static const struct seq_operations proc_pid_smaps_rollup_op = {
+ .start = smaps_rollup_start,
+ .next = smaps_rollup_next,
+ .stop = m_stop,
+ .show = show_smaps_rollup
+};
+
static int pid_smaps_open(struct inode *inode, struct file *file)
{
return do_maps_open(inode, file, &proc_pid_smaps_op);
@@ -846,18 +883,17 @@ static int pid_smaps_rollup_open(struct
{
struct seq_file *seq;
struct proc_maps_private *priv;
- int ret = do_maps_open(inode, file, &proc_pid_smaps_op);
+ int ret = do_maps_open(inode, file, &proc_pid_smaps_rollup_op);
if (ret < 0)
return ret;
seq = file->private_data;
priv = seq->private;
- priv->rollup = kzalloc(sizeof(*priv->rollup), GFP_KERNEL);
+ priv->rollup = kmalloc(sizeof(*priv->rollup), GFP_KERNEL);
if (!priv->rollup) {
proc_map_release(inode, file);
return -ENOMEM;
}
- priv->rollup->first = true;
return 0;
}
_
Patches currently in -mm which might be from vbabka@xxxxxxx are
mm-page_alloc-actually-ignore-mempolicies-for-high-priority-allocations.patch
mm-proc-pid-maps-remove-is_pid-and-related-wrappers.patch
mm-proc-pid-smaps-factor-out-mem-stats-gathering.patch
mm-proc-pid-smaps-factor-out-common-stats-printing.patch
mm-proc-pid-smaps_rollup-convert-to-single-value-seq_file.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
