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authorSuren Baghdasaryan <surenb@google.com>2023-06-30 14:19:52 -0700
committerAndrew Morton <akpm@linux-foundation.org>2023-08-24 16:20:16 -0700
commitb243dcbf2f13856e39e18df3a15a65f6fe33db85 (patch)
tree5bcb0ad2755dbb8a894258c24e10ded4685aca3b
parentd51b68469bc7804c34622f7f3d4889628d37cfd6 (diff)
swap: remove remnants of polling from read_swap_cache_async
Patch series "Per-VMA lock support for swap and userfaults", v7. When per-VMA locks were introduced in [1] several types of page faults would still fall back to mmap_lock to keep the patchset simple. Among them are swap and userfault pages. The main reason for skipping those cases was the fact that mmap_lock could be dropped while handling these faults and that required additional logic to be implemented. Implement the mechanism to allow per-VMA locks to be dropped for these cases. First, change handle_mm_fault to drop per-VMA locks when returning VM_FAULT_RETRY or VM_FAULT_COMPLETED to be consistent with the way mmap_lock is handled. Then change folio_lock_or_retry to accept vm_fault and return vm_fault_t which simplifies later patches. Finally allow swap and uffd page faults to be handled under per-VMA locks by dropping per-VMA and retrying, the same way it's done under mmap_lock. Naturally, once VMA lock is dropped that VMA should be assumed unstable and can't be used. This patch (of 6): Commit [1] introduced IO polling support duding swapin to reduce swap read latency for block devices that can be polled. However later commit [2] removed polling support. Therefore it seems safe to remove do_poll parameter in read_swap_cache_async and always call swap_readpage with synchronous=false waiting for IO completion in folio_lock_or_retry. [1] commit 23955622ff8d ("swap: add block io poll in swapin path") [2] commit 9650b453a3d4 ("block: ignore RWF_HIPRI hint for sync dio") Link: https://lkml.kernel.org/r/20230630211957.1341547-1-surenb@google.com Link: https://lkml.kernel.org/r/20230630211957.1341547-2-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Suggested-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Alistair Popple <apopple@nvidia.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hillf Danton <hdanton@sina.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Michel Lespinasse <michel@lespinasse.org> Cc: Minchan Kim <minchan@google.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Peter Xu <peterx@redhat.com> Cc: Punit Agrawal <punit.agrawal@bytedance.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r--mm/madvise.c4
-rw-r--r--mm/swap.h1
-rw-r--r--mm/swap_state.c12
3 files changed, 7 insertions, 10 deletions
diff --git a/mm/madvise.c b/mm/madvise.c
index b1f53a95e3a5..4dded5d27e7e 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -217,7 +217,7 @@ static int swapin_walk_pmd_entry(pmd_t *pmd, unsigned long start,
ptep = NULL;
page = read_swap_cache_async(entry, GFP_HIGHUSER_MOVABLE,
- vma, addr, false, &splug);
+ vma, addr, &splug);
if (page)
put_page(page);
}
@@ -262,7 +262,7 @@ static void shmem_swapin_range(struct vm_area_struct *vma,
rcu_read_unlock();
page = read_swap_cache_async(entry, mapping_gfp_mask(mapping),
- vma, addr, false, &splug);
+ vma, addr, &splug);
if (page)
put_page(page);
diff --git a/mm/swap.h b/mm/swap.h
index 7c033d793f15..8a3c7a0ace4f 100644
--- a/mm/swap.h
+++ b/mm/swap.h
@@ -46,7 +46,6 @@ struct folio *filemap_get_incore_folio(struct address_space *mapping,
struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
struct vm_area_struct *vma,
unsigned long addr,
- bool do_poll,
struct swap_iocb **plug);
struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
struct vm_area_struct *vma,
diff --git a/mm/swap_state.c b/mm/swap_state.c
index d157862ba0a6..01f15139b7d9 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -526,15 +526,14 @@ fail_put_swap:
*/
struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
struct vm_area_struct *vma,
- unsigned long addr, bool do_poll,
- struct swap_iocb **plug)
+ unsigned long addr, struct swap_iocb **plug)
{
bool page_was_allocated;
struct page *retpage = __read_swap_cache_async(entry, gfp_mask,
vma, addr, &page_was_allocated);
if (page_was_allocated)
- swap_readpage(retpage, do_poll, plug);
+ swap_readpage(retpage, false, plug);
return retpage;
}
@@ -629,7 +628,7 @@ struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask,
struct swap_info_struct *si = swp_swap_info(entry);
struct blk_plug plug;
struct swap_iocb *splug = NULL;
- bool do_poll = true, page_allocated;
+ bool page_allocated;
struct vm_area_struct *vma = vmf->vma;
unsigned long addr = vmf->address;
@@ -637,7 +636,6 @@ struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask,
if (!mask)
goto skip;
- do_poll = false;
/* Read a page_cluster sized and aligned cluster around offset. */
start_offset = offset & ~mask;
end_offset = offset | mask;
@@ -669,7 +667,7 @@ struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask,
lru_add_drain(); /* Push any new pages onto the LRU now */
skip:
/* The page was likely read above, so no need for plugging here */
- return read_swap_cache_async(entry, gfp_mask, vma, addr, do_poll, NULL);
+ return read_swap_cache_async(entry, gfp_mask, vma, addr, NULL);
}
int init_swap_address_space(unsigned int type, unsigned long nr_pages)
@@ -837,7 +835,7 @@ static struct page *swap_vma_readahead(swp_entry_t fentry, gfp_t gfp_mask,
skip:
/* The page was likely read above, so no need for plugging here */
return read_swap_cache_async(fentry, gfp_mask, vma, vmf->address,
- ra_info.win == 1, NULL);
+ NULL);
}
/**