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charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 5754F1C0015 X-Stat-Signature: gbhi791dn7jhhut4jgrstt7gxmeb4fbm X-Rspam-User: X-HE-Tag: 1764210147-143735 X-HE-Meta: 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 X6iDfXrf XVqESm4Xxx+0OnSjkDBfjx7Y+/ZuSznzMmMkgjDOR2HaDgosnUMyz/zlxUFwTTVHIaJVCH8MdnWJsHQqt0EcoHcMzNBWbEkd+9Hw6pgT0t0rbzIdVogzW6/4JNHF7P+JxFDLXRiWJTXihAAYm6jzWu10jR9ACTpPW0Q84RWd9POWJc8h1tDliBLnCnG+q626ulme10EEn0atvFoMwixookcyLVOaBbncFw8JvoQZQ6y0FC/MGP2SD3WaKBO7kR0hlLdtUVBXs8Polge1GvdpezXS34jecxAiPNoZfE8lELIjBdBqCh/Yxrc/prsLbxjKQN1MjSHoRI84Y+GA= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Nov 27, 2025 at 02:23:05AM +0800, Kairui Song wrote: > On Wed, Nov 26, 2025 at 12:31 AM Youngjun Park wrote: > > > > swap_sync_discard() has an issue where if the next device becomes full > > and is removed from the plist during iteration, the operation fails > > even when other swap devices with pending discard entries remain > > available. > > > > Fix by checking plist_node_empty(&next->list) and restarting iteration > > when the next node is removed during discard operations. > > > > Additionally, switch from swap_avail_lock/swap_avail_head to swap_lock/ > > swap_active_head. This means the iteration is only affected by swapoff > > operations rather than frequent availability changes, reducing > > exceptional condition checks and lock contention. > > > > Fixes: 686ea517f471 ("mm, swap: do not perform synchronous discard during allocation") > > Suggested-by: Kairui Song > > Signed-off-by: Youngjun Park > > --- > > mm/swapfile.c | 18 +++++++++++------- > > 1 file changed, 11 insertions(+), 7 deletions(-) > > > > diff --git a/mm/swapfile.c b/mm/swapfile.c > > index d12332423a06..998271aa09c3 100644 > > --- a/mm/swapfile.c > > +++ b/mm/swapfile.c > > @@ -1387,21 +1387,25 @@ static bool swap_sync_discard(void) > > bool ret = false; > > struct swap_info_struct *si, *next; > > > > - spin_lock(&swap_avail_lock); > > - plist_for_each_entry_safe(si, next, &swap_avail_head, avail_list) { > > - spin_unlock(&swap_avail_lock); > > + spin_lock(&swap_lock); > > +start_over: > > + plist_for_each_entry_safe(si, next, &swap_active_head, list) { > > + spin_unlock(&swap_lock); > > if (get_swap_device_info(si)) { > > if (si->flags & SWP_PAGE_DISCARD) > > ret = swap_do_scheduled_discard(si); > > put_swap_device(si); > > } > > if (ret) > > - return true; > > - spin_lock(&swap_avail_lock); > > + return ret; > > Nit: I'd prefer to avoid unnecessary changes like this, `return true` > is the same thing. No need to send an update for this though, a really > trivial issue. Okay, I will revert it to the original code. > > + > > + spin_lock(&swap_lock); > > + if (plist_node_empty(&next->list)) > > + goto start_over; > > } > > - spin_unlock(&swap_avail_lock); > > + spin_unlock(&swap_lock); > > > > - return false; > > + return ret; > > } > > > > /** > > -- > > 2.34.1 > > Thanks! > > Acked-by: Kairui Song > Thank you Youngjun Park