From: Sergey Senozhatsky <senozhatsky@chromium.org>
To: Andrew Morton <akpm@linux-foundation.org>,
David Hildenbrand <david@redhat.com>,
Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
"Liam R. Howlett" <Liam.Howlett@oracle.com>,
Vlastimil Babka <vbabka@suse.cz>, Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>,
Suleiman Souhlal <suleiman@google.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Sergey Senozhatsky <senozhatsky@chromium.org>
Subject: Re: mm: swapin read-ahead and zram
Date: Fri, 15 Aug 2025 15:20:50 +0900 [thread overview]
Message-ID: <dr2ndbnav6ynrxjixfjjsbe4jr66a3niplzpxcbbt3ztjimwzh@l47amo3k5jt5> (raw)
In-Reply-To: <7ftwasufn2w3bgesfbp66vlchhpiuctxkhdxp24y5nzzgz2oip@pi4kdyqkl5ss>
On (25/08/15 14:51), Sergey Senozhatsky wrote:
[..]
> For instance, notice how entry 1615265 is read, decompressed, then
> presumably evicted from the memory, and read/decompressed again
> soon after, almost immediately. Also notice how that entry 1615265
> has already went through this cycle 189 times. It's not entirely
> clear why this happens.
>
> As far as I can tell, it seems that these extra zram reads are coming from
> the swapin read-ahead:
> handle_mm_fault
> do_swap_page
> swapin_readahead
> swap_read_folio
> submit_bio_wait
> submit_bio_noacct_nocheck
> __submit_bio
> zram_submit_bio
> zram_read_page
> zram_read_from_zspool
Sorry, I need to correct myself here, it seems that read-ahead win is 1
pretty much all the time in swap_vma_readahead(), so that's probably not
read-ahead after all.
prev parent reply other threads:[~2025-08-15 6:21 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-15 5:51 Sergey Senozhatsky
2025-08-15 6:20 ` Sergey Senozhatsky [this message]
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