On Wed, 15 Jun 2022 09:12:52 +0200 Vincent Whitchurch <vincent.whitchurch@xxxxxxxx> wrote:
> Pss is the sum of the sizes of clean and dirty private pages, and the
> proportional sizes of clean and dirty shared pages:
>
> Private = Private_Dirty + Private_Clean
> Shared_Proportional = Shared_Dirty_Proportional + Shared_Clean_Proportional
> Pss = Private + Shared_Proportional
>
> The Shared*Proportional fields are not present in smaps, so it is not
> possible to determine how much of the Pss is from dirty pages and how
> much is from clean pages. This information can be useful for measuring
> memory usage for the purpose of optimisation, since clean pages can
> usually be discarded by the kernel immediately while dirty pages cannot.
>
> The smaps routines in the kernel already have access to this data, so
> add a Pss_Dirty to show it to userspace. Pss_Clean is not added since
> it can be calculated from Pss and Pss_Dirty.
>
> ...
>
> --- a/fs/proc/task_mmu.c
> +++ b/fs/proc/task_mmu.c
> @@ -406,6 +406,7 @@ struct mem_size_stats {
> u64 pss_anon;
> u64 pss_file;
> u64 pss_shmem;
> + u64 pss_dirty;
> u64 pss_locked;
> u64 swap_pss;
> };
> @@ -427,6 +428,7 @@ static void smaps_page_accumulate(struct mem_size_stats *mss,
> mss->pss_locked += pss;
>
> if (dirty || PageDirty(page)) {
> + mss->pss_dirty += pss;
> if (private)
> mss->private_dirty += size;
> else
> @@ -820,6 +822,7 @@ static void __show_smap(struct seq_file *m, const struct mem_size_stats *mss,
> SEQ_PUT_DEC(" kB\nPss_Shmem: ",
> mss->pss_shmem >> PSS_SHIFT);
> }
> + SEQ_PUT_DEC(" kB\nPss_Dirty: ", mss->pss_dirty >> PSS_SHIFT);
> SEQ_PUT_DEC(" kB\nShared_Clean: ", mss->shared_clean);
> SEQ_PUT_DEC(" kB\nShared_Dirty: ", mss->shared_dirty);
> SEQ_PUT_DEC(" kB\nPrivate_Clean: ", mss->private_clean);
Well it's certainly simple.
Can you please update Documentation/ABI/testing/procfs-smaps_rollup and
Documentation/filesystems/proc.rst, resend?
