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Rao's message of "Thu, 14 Aug 2025 19:18:20 +0530") References: <20250814134826.154003-1-bharata@amd.com> <20250814134826.154003-2-bharata@amd.com> Date: Fri, 15 Aug 2025 09:29:00 +0800 Message-ID: <87ectde5k3.fsf@DESKTOP-5N7EMDA> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii X-Stat-Signature: ritgkb9wcm3bfbtrfsebz36ug9fxprkc X-Rspam-User: X-Rspamd-Queue-Id: B51C9100007 X-Rspamd-Server: rspam05 X-HE-Tag: 1755221348-531306 X-HE-Meta: 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 QYozXGn+ BIkB5rbtwK6JWsPPBQWrSL6N9Tnyyw6B8gRG5Dc/OZR7WDATcjjByWGYAFyi7D4gsYlFK+RK3eNSrGpmf4VohC49XeZ5NY5JoulATSaNtIRPlYoSKZulGTrIwL58S2NPwQsHvXT1xuRec1J0xosN84cZGG5/TmX96VTFeHIxQbofKzdzLK1MlvOhj+d7zdkdcev32YSFeZWyPgq15Yx3gp082vPIqVz+obRm6eR4xOrmvx2zvKmaDxYle1AsRE2ix2DuOc+YoU6NuXOJqOy4/xBbrkDfNDXoocQDYagH72CgoUDa6DfdecT1DnKZ3aZ5pDUqlR4Qk+95r/ZiBykJ+ke+0CxGtlIJ6iDtQLfNUV9bWpDvcZL23kqxT+A== 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: Bharata B Rao writes: > We want isolation of misplaced folios to work in contexts > where VMA isn't available. In order to prepare for that > allow migrate_misplaced_folio_prepare() to be called with > a NULL VMA. > > Signed-off-by: Bharata B Rao > --- > mm/migrate.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/mm/migrate.c b/mm/migrate.c > index 425401b2d4e1..7e356c0b1b5a 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -2619,7 +2619,8 @@ static struct folio *alloc_misplaced_dst_folio(struct folio *src, > > /* > * Prepare for calling migrate_misplaced_folio() by isolating the folio if > - * permitted. Must be called with the PTL still held. > + * permitted. Must be called with the PTL still held if called with a non-NULL > + * vma. The locking rule is changed. IMO, it deserves more explanation in patch description. > */ > int migrate_misplaced_folio_prepare(struct folio *folio, > struct vm_area_struct *vma, int node) > @@ -2636,7 +2637,7 @@ int migrate_misplaced_folio_prepare(struct folio *folio, > * See folio_maybe_mapped_shared() on possible imprecision > * when we cannot easily detect if a folio is shared. > */ > - if ((vma->vm_flags & VM_EXEC) && folio_maybe_mapped_shared(folio)) > + if (vma && (vma->vm_flags & VM_EXEC) && folio_maybe_mapped_shared(folio)) > return -EACCES; > > /* --- Best Regards, Huang, Ying